: 97 N* Shaky idle



N*Caddy
11-05-06, 01:55 AM
Hi guys,
It seems that I got the same idle problem like CaddyNewbie, about 50% or more of the time the idle is rough. I would describe the problem as RPM “drops” with a 3-5 sec. frequencies, sometime (very rarely) continuos drops (the car shakes pretty badly especially if is in gear). The engine doesn’t stall, the drops are just a few tens of RPM. Once I touch the gas pedal is like floating on a cloud. Also, some time I got hesitations on highway speeds when accelerating moderately (gas only premium).
About 20000 Km ago I changed the spark plugs (wiring looks fine) and recently I got the TB cleaned, no codes. I went with the car to my mechanic and guess what: that day the idle was perfect (this Murphy…) so no wonder his conclusion: “there is nothing wrong with the car”.
Oil consumption, less than a quarter every 5000 Km, recently I got low on coolant (no leak detected :confused: ), I appreciate that the amount and color of the smoke is normal. I also got that grinding-whistling sound at low speeds when the steering wheel is turned all the way (witch I believe is normal). Everything is perfect except that idle thing.
Aa…, the car is a 97 STS with 128000 Km (~80.000 Miles).

History (since I got-it):
- Air Filter and spark plugs changed (Bosch Platinum +4) at about 106.000 Km;
- Fuel pump changed at about 108.000 Km (brand new OEM);
- Brake pads changed at about 112.000 Km,
- Front right wheel speed sensor changed (at 121.000 Km);
- Never drove more than 5000 Km with the same oil (Valvoline).

Returning to the idle problem, it was always there (coming and going). After changing the spark plugs I had a good idle for a few weeks. As an overall image the idle seems to be somehow better than before changing the spark plugs. Absolutely no difference detected after cleaning the TB (except no more that sticky pedal).

Anyway I guess not to many Toyota and Honda drivers get thumbs up to a traffic light when exactly the same car is stopped on the other line...

chazglenn3
11-05-06, 08:22 AM
The generally agreed upon issue with spark plugs around here is that these cars are far more likely to run correctly with genuine AC-Delco double platinum spark plugs. A few have gotten their cars to run okay on Bosch plugs, but the majority that have tried other brands came back to OEM. Also, even thought the wires "look fine", they may need to be changed, also AC-Delco recommended.

RDHambrice
11-05-06, 09:12 AM
Hello N*Caddy
I had similar problem awhile back. Replacement of plugs AND plug wires solved the problem for me. I also noticed my fuel rails were loose so I tightened those. Runs GREAT now.
Good luck,
RDH

dp102288
11-05-06, 11:38 AM
I second staying with OEM. On this forum, no one had recommended Bosch or any other brand.

N*Caddy
11-05-06, 04:08 PM
A, yeah, good point with those fuel rails, when I bought the car (about one year ago) I did notice that for a mysterious reason the previous owner cut the bracket welded between the fuel lines (right were they go under the beauty cover). But since there is no apparent looseness I did nothing about it.
This is the only “funny” stuff discovered on the car so far.
As for the ignition (hoping that the problem is electrical), I think would start with the wiring.

Ranger
11-05-06, 04:17 PM
My $0.02 is the same as everyone elses. A/C Delco plugs & wires.

1999STSCresskill
12-20-06, 04:48 PM
I am experiencing a very similar situation. I had a rough idle very soon after buying my 1999 STS. I changed the plugs AND wires (oem) and my problem was solved.... for a few weeks. Now the rough idle is back and a bit worse. A friend of mine that used to own a repair shop took a quick look the other day. He said it sounded like one of the spark plugs was damaged and arcing, causing the rough idle. He cautiously suggested that I since I'm not a Pro (like him) I may have cracked one when I was putting them in. Even though there's NO WAY :suspense: I could have cracked a plug I'll check them out anyway this weekend. If one's cracked I'll tell him it was defective when I bought it!

I'll let you know if it solved my problem.

dp102288
12-20-06, 10:25 PM
^^ Yeah do keep us posted. I am hoping to do plugs & wires in the spring.

N*Caddy
12-23-06, 10:40 PM
Update referring my shaky idle…
Yesterday I just had my car to the shop to change the water pump (yeah, she finally gave up on me at 131000 Km).
When they started the engine to check if everything is ok after the water pumps replacement they discovered that my car was shooting fuel (literally).
It turned out to be a small hose mounted on the fuel lines witch was replaced by the previous owner. Apparently the hose was not fuel use rated and in time got socked with gas like a sponge. Well … I did notice a thin sent of gas while driving (especially lately) but according to my mechanic that smell was coming from the fuel tank. Now I know probably why the fuel rails bracket was cut in the first place.
I was very happy to finally find something wrong on the fuel delivery system, possible cause of all those idle shakes (especially considering the misfires on highway accelerations were more frequent lately). Guess what, looks like the problem is not solved yet because in the 100-km or so driven, since I got the car repaired, I felt the shakes once while waiting on a traffic light. Is true, the car is performing like in her best days before the repair but still. Is true I didn’t have the misfires yet (hope to stay that way) but in just a 100 km is hard to tell.
The good news with the water pump is that I was just planing to do a coolant flush, which would have been money well spent…

Before changing the spark plug wire set I will try to unplug each wire to se if I can determine the bad wire (that in case is just one), but unfortunately I don’t have the place and somehow the time to do that. I tried once the front ones and it seems like piston no 2 was not doing much difference with the plug off (I mean not as much as the other three).

Anyway I will keep you updated…

dp102288
12-24-06, 10:11 AM
^^ Wow at the fuel line!! I would have been scared and pissed off at the same time!

clarkz71
12-24-06, 11:01 AM
they discovered that my car was shooting fuel (literally).
It turned out to be a small hose mounted on the fuel lines witch was replaced by the previous owner. Apparently the hose was not fuel use rated and in time got socked with gas like a sponge. Well … I did notice a thin sent of gas while driving (especially lately) but according to my mechanic that smell was coming from the fuel tank. Now I know probably why the fuel rails bracket was cut in the first place.
I was very happy to finally find something wrong on the fuel delivery system, …

Call your local Caddy dealer. That fuel rail was recalled. They will replace it with a stainless steel one for FREE. The recall was for 95-97 Cadillacs.

N*Caddy
12-25-06, 12:47 AM
I just came for a hundred km trip and guess what, shakes are there, misfires are there, maybe not as frequent as before and a little more discrete but still… the good news: no more gas smell.
As for the fuel lines recall on the 96-97 (the way I knew, looks like 95 is to), I assumed that the previous owner got it to GM (I mean is a pretty well known problem). I will have to check with my local dealer if my car had it done ore not because if is free who doesn’t like the price! (Not to mention the safety factor involved).
Anyway thanks’ for the advice clarkz71 is not something to relax about…

Ranger
12-25-06, 04:37 PM
No need to check with the dealer. Just remove the silver beauty cover and have a look at the fuel rails. If they are black plastic, they are OEM. If they are stainless steel, they are the recall replacment rails.

clarkz71
12-25-06, 05:23 PM
He said the original owner replaced a small hose on the rail. He couldn't do that on a stainless rail. Checking with the dealer is just to see if he can get a free rail. I don't know if he can in Canada.

Ranger
12-25-06, 05:27 PM
OH Canada! I think we went through this before and it was only a U.S. recall. I forgot about the fix. Yeah, if that was in place, I am pretty sure it is stil OEM.

clarkz71
12-25-06, 05:28 PM
OK, so I guess he needs to buy a fuel rail.

clarkz71
12-25-06, 05:38 PM
Part # for that fuel rail is 12499784. You can order it online or go to any GM dealer.

N*Caddy
12-27-06, 05:16 AM
Well, up to the point where they go under the beauty cover is all metal, under I can not tell. The trouble hose was about 4’’ long probably under the beauty cover (I guess at the end of the metal part of the rails). Got to open one of these days to check…
Maybe if it rings a bell, the shop where I fixed the problem told me that GM does not sell this part of the fuel circuit separately and one option is to buy a $200 adapter kit (witch according to them is not worthing). They used an air-conditioning pressure duct (quite stiff) to solve the problem (apparently they use this thing all the time for this kind of repairs).
The bill states (among the others):
”Check for gas leaks remove top cover and replace two lines at injector rail”
1 Fuel pressure hose (from witch they cut the two smaller pieces)
4 Fuel line pressure clamps
As for the random idle drops and misfires (witches now are less noticeable) the hose was not the cause (at least the primal cause). The fuel pressure was never abnormal as the car ALWAYS started on the first key and NEVER stalled (except fort that day, one year ago, when my fuel pump died). When misfires occur is enough to press/release the gas pedal a little and all gone. Definitely the idle thing and misfires are related. On idle looks like every a few revolutions, not all the time, a piston (or two) fails to fire (either no spark or no gas). I can not tell if is the same (probably the spark plugs color could light up this problem). If is/are the same piston(s) all the time the fuel pressure is eliminated from the equation. Misfires are occurring only on a certain engine regime (when accelerating moderately at around 2000 RPM in the fourth speed and again: not always). By “moderate” I understand in such a way that the tranny will not downshift. And another thing, very rarely the idle shakes are noticeable when the car is in neutral (as the engine encounters less resistance) and this adds difficulty to the troubleshooting process.
So many things could be wrong:
- Ignition coils;
- Spark plug wires;
- Spark plugs;
- Injectors;
And so many others than I can not see right now.
Don’t ask about codes because I got NONE (current or history).
This behavior is very strange…I am puzzled.
Probably I will start with some injector cleaning agent (and I don’t believe in fixings coming from a container) then the spark plug wire set (and this is where I have high expectations) if not…I just don’t know…

clarkz71
12-27-06, 06:04 AM
The replacement fuel rail retails for about $200, that might be what they are talking about (adapter?). You can get it online for half that, $90-$100. The beauty cover is easy to remove, 4 1/2 nuts. Can you take a picture? If not, I can take a pic of mine, and you can see if you have the updated fuel rail. I don't think you do, and I don't know that a/c hose will hold up to gasoline.

clarkz71
12-27-06, 06:16 AM
Here's what it should look like, remove your cover and compare.


http://i86.photobucket.com/albums/k120/clarkz71/SSfuelrail.jpg

clarkz71
12-27-06, 06:44 AM
Here's a pic of the defective plastic rail. If you have this one, replace it with the part# I gave you. Don't take a chance with fire for a $100 part.




http://i86.photobucket.com/albums/k120/clarkz71/plasticfuelrail.jpg

dp102288
12-27-06, 03:41 PM
:yeah: & good pics. :thumbsup:

Before the fuel rail was replaced on my Eldo, the car did smell like gasoline. Since it was done, no smell or problems. Come to think of it, the car was driving a little rough before the rail was changed...:hmm:

N*Caddy
12-27-06, 05:51 PM
Oh yeah, that’s the one (second picture), I did removed the beauty cover about one year ago (just out of curiosity) and yeah I remember is plastic alright, I don’t have the nice metal rail all around (pretty neat setup, looks safer to)…
Now I am really curious to se what was replaced and how the heck I did not notice the VERY PINK hose in the first place…
Thanks’ guys

P.S. A thing is sure, so far no more gas smell (in almost 400-km following the repair)

Ranger
12-27-06, 06:06 PM
Judging from your misfire discription 2 posts back, my money is on plugs & wires. Same symptoms I had on my '97. Do a search for "Stutter, engine or trans". It's somewhat lengthy but I think you'll find a lot of similarities.

1999STSCresskill
01-02-07, 01:41 PM
I am experiencing a very similar situation. I had a rough idle very soon after buying my 1999 STS. I changed the plugs AND wires (oem) and my problem was solved.... for a few weeks. Now the rough idle is back and a bit worse. A friend of mine that used to own a repair shop took a quick look the other day. He said it sounded like one of the spark plugs was damaged and arcing, causing the rough idle. He cautiously suggested that I since I'm not a Pro (like him) I may have cracked one when I was putting them in. Even though there's NO WAY :suspense: I could have cracked a plug I'll check them out anyway this weekend. If one's cracked I'll tell him it was defective when I bought it!

I'll let you know if it solved my problem.

I jumped in on this thread about 2 weeks ago with a similar idle problem. I had changed the plugs about 4 months ago so I had ruled out the possibility that the spark plugs were my problem. It turns out that either I damaged a plug when installing (although I don't think that's likely) or one of the plugs was defective. I was reading an earlier thread this morning on this forum about defective AC-Delco plugs so evidently it happens some times. Luckily my damaged plug was easy to get to and replace. I drove the car quite a while today and haven't had the idle issue resurface.

Hopefully your issue is as simple (and relatively inexpensive) too.

BCRICH
01-04-07, 12:07 PM
I'm keeping an eye on this thread. I just bought me a 96STS a week ago. 270 miles later you guessed it Rough idle. I'm gonna do the TB and plugs&wires a.s.a.p. I really hope it works. I'll let everyone know.

BCRICH
01-06-07, 07:15 PM
I'm keeping an eye on this thread. I just bought me a 96STS a week ago. 270 miles later you guessed it Rough idle. I'm gonna do the TB and plugs&wires a.s.a.p. I really hope it works. I'll let everyone know.
I changed the plugs & wires and cleaned the TB an it runs great again:D

hardrockcamaro@mac.c
01-10-07, 04:56 PM
Here's a pic of the defective plastic rail. If you have this one, replace it with the part# I gave you. Don't take a chance with fire for a $100 part.




http://i86.photobucket.com/albums/k120/clarkz71/plasticfuelrail.jpg

Holy cr*p!!!

That's the same fuel rail as is on my 2000 (!) STS (the little black tubes between each injector?).

Mine is a European RHD model.
Surely Caddy didn't send dangerous parts out on the euro models when they knew years before that they were faulty?!?!

clarkz71
01-10-07, 05:00 PM
Holy cr*p!!!

That's the same fuel rail as is on my 2000 (!) STS (the little black tubes between each injector?).

Mine is a European RHD model.
Surely Caddy didn't send dangerous parts out on the euro models when they knew years before that they were faulty?!?!

No, GM claims the 98 & up rails used a "different" plastic material that doesn't have a cracking problem.

hardrockcamaro@mac.c
01-10-07, 05:41 PM
Thanks!

Phew!!!

I was just burying my head wondering where to buy the steel one, how to persuade somoene to ship it to the UK (at huge expense) where to find the money for the import taxes on it and all to risk installing it myself...

Cheers for the reassurance!!!

I'm happy again!

N*Caddy
01-12-07, 12:55 PM
Well guys I finally found some time to go to the GM dealer. After some 10-15 minutes spent waiting for a guy to finish the phone conversation, then go in the back and return only to pick up another phone call then look for some papers, finally asked me what I want. “Fuel lines recall, I don’t think so, let me check…no there is no recall, anything else?”
So you were right, in Canada apparently things are different.

clarkz71
01-12-07, 12:57 PM
So, looks like you need someone in the US to send you a stainless rail.:hmm:

N*Caddy
03-18-07, 01:27 AM
Just changed the spark plugs and wiring (everything ACDELCO). The spark plugs were looking fine (no cracked insulation, yes some carbon deposits but I have seen worst). The spark plug wire set looks like being original (if is the one with cylinder numbers printed on). Strange is that the new cables (bought from rockauto.com) don’t have the numbers (also some small length variations). Anyway with this occasion I discovered another plastic fuel line cracked (the one between cylinder 1 and 3). I had hard time to see the cracks, the gas smell was pretty noticeable in the last week, some fuel leaks when idling, and the most obvious proof was the gas dripping from the rail after removing the beauty cover. The cracks are plenty and minute and they develop along the rail. You can only see the cracks if you slightly bend the rail. Now is clear I GOT to replace the darm plastic things with the stainless steel rail (right now I have 3 hoses and that’s a Mickey Mouse solution).
Question for those who replaced the rails: The stainless steel kit from rockauto.com (ACDELCO Part # 12499784 ) is ALL I need, do I need to buy some additional parts or not? My concern is the connection between the rail and the injectors. Aaa … and one more thing, how do you remove the plastic things on top of the injectors, do I need a special tool or something? I’ve notice that they appear to be fixed in place by a metal tab. I tried to remove the tab but after some attempts I aborted (I was afraid to crack the top plastic part).
As for the tune up, in the 50 km or so driven after, I had no more shaky idle (maybe a slight roughness witch I believe is due to the hoses elasticity, you know, the Mickey Mouse solution) but other than that is a 98% improvement. Also the misfires (more and more frequent lately) are gone (so far). But then again, one year ago when I replaced first time the spark plugs, I had two weeks or so of perfect idle and gradually the problems came back. My question is … will I finally close this thread after I replace the fuel line?

mysts98
03-18-07, 02:09 AM
yeah i had the same problem , and i had to by a new egr vavle , ran perfect after i installed it

CadiJeff
03-18-07, 02:48 AM
and then there is always a flakey coil pack to check for

Ranger
03-18-07, 10:59 AM
N*caddy,
The fuel rail was recalled by GM for the '95 - '97 Northstars. Go to a dealer and get it replaced for free. SOON!

9BlackN*Black6
03-18-07, 11:07 AM
Here dude! For a mere $76 you can eliminate your problems! :thumbsup:
http://cgi.ebay.com/ebaymotors/Cadillac-Seville-Deville-Eldorado-intake-96-97-98-99_W0QQitemZ200089899165QQcategoryZ38634QQrdZ1QQcm dZViewItem

N*Caddy
03-18-07, 11:48 AM
Ranger,

I tried that, don’t forget the car is made for Canada, and apparently in Canada exactly the same plastic fuel lines don’t crack (must be something with this air). If you read the previous postings you will get the full picture (frustration) with the dealer. By the way, for free no, but for a $500 bargain I should jump right into it (sorry I am just sarcastic, been there done that).
Anyway, thanks man, this might be useful information for somebody in the states.

9BlackN*Black6, you just made my day
Thanks’

Ranger
03-18-07, 03:54 PM
Ah, I didn't notice the Canada thing. In that case, I'd be all over post #37.

N*Caddy
03-18-07, 09:52 PM
By the way this are the old spark plugs (mint condition for 20k miles)

9BlackN*Black6
03-19-07, 02:51 AM
Your welcome N*Caddy. I just got my Fuel Rail Recall done saturday. Car seems a little more peppy after recall.

If I remember correctly Im pretty sure you need to get injector O-rings and Fuel pressure regulator orings when you put new rail on.

O yea one thing I did notice, If you wanted to clean your EGR valve out, do it before you change the rail. I was lazy and didnt clean mine out and now I cant due to the mounting of the new rail.

Did a few WOT runs on the highway this weekend and it seemed to help out my idle, i was idling at around 700-800rpm and now im at a steady 550 rpm. I probably blew some carbon out of the EGR or something. BTW plugs look good. Replace wires at 100k mile but if it isnt missing then dont bother the wires yet.

Nick_C
03-20-07, 06:39 PM
Maybe I am learning a bit about cars, my 92 El, was doing it just a bit, and first thing I thought is it needs a Tune up, new plugs, Damn, have to put it off another week though...

N*Caddy
04-14-07, 08:56 PM
Update…
Today I just changed my fuel line from nylon to metal. Thanks RDHambrice, dp102288, Ranger, Klarkz71 and 9BlackN*Black, for the advice and for the ebay tip.
The whole process took me about 3 hour. The most difficult part was to disconnect the fuel line from the main lines (looks like you need a special tool for those clips, I managed to disconnect them eventually using a plain ordinary knife, but I wouldn’t recommended).
The metal fuel line fit like a glove the only problem was, as you will se in the pictures, the new line has a bent end while the old one is straight. This is why, unfortunately, I bent the nylon incoming main line (in two places). So right now I kind of need to cut the bent portion and reattach it to the metal end connector (anyway is too long for the new setting, this is why got bent in the first place). Anybody knows how (looks pretty tight, does it work with heat or how?). Another thing is due to the fact that the fuel line brackets are held by the same lugs that hold the beauty cover; I had a hard time to put the cover back (the lugs are slightly shifted). As for the EGR valve, I regret that I opened, was clean as a whistle.
So, after 40 miles with the new fuel line and 1000 miles with the new plugs and wiring I can safely say that the car RUNS GREAT. The RPM needle is rock solid at around 600 RPM, no more shakes no more misfires and no more gas smell (except from the fuel tank filler neck, I have to fix that sometime).
Next is the auxiliary input project for the HU. I got to find the time for it cause we are living the MP3/Ipod era.
Here are the pictures from the fuel line replacement project (sorry for the dirt, we just finished the winter here, but that engine will be clean again in a few weeks).

P.S. Now I know why the bracket holding together the old fuel lines was cut - they changed the return hose (under the TB).

coppertop
04-15-07, 08:30 PM
Ranger,

I tried that, don’t forget the car is made for Canada, and apparently in Canada exactly the same plastic fuel lines don’t crack (must be something with this air). If you read the previous postings you will get the full picture (frustration) with the dealer. By the way, for free no, but for a $500 bargain I should jump right into it (sorry I am just sarcastic, been there done that).
Anyway, thanks man, this might be useful information for somebody in the states.

9BlackN*Black6, you just made my day
Thanks’
N*caddy it is not a recall here but is on a special bullliten that gm dealers have. I'll post the Bulliten # for you. Call Gm canada and complain about it. I was informed to take it to a caddy dealer and have it checked. Just dont bother to go to City Cadillac if they tell you to bring it do a dealer. I was fighting with Jim Wildman (service manager) over the rail. I inspected my rails as per recall or special bulliten and they failed. couldn't read writing at all. All sevice department did was wipe them down with silicon spary to make the rails look black again. I told him Making the rails look pretty doesnt fix the problem but he refused to fix the rails. To make a long story short, its now about 8 months later and the rail is leaking and oh yeah shacky idle. Going to have fun with GM Canada now.

N*Caddy
01-29-09, 07:26 PM
I am reviving something from the past…

So I was having problems with my shaky idle, turned out to the spark plugs. Ok so after that I kind of still feel a slight shake here and there, in an average car that will be perfectly normal but not for a Cadillac.
Ok so the other day I just unplugged the vacuum line that goes to the vacuum tank. Drove the car with the open vacuum (free to air) until today and what do you know…NO SHAKES AT ALL :cloud9:. I mean shouldn’t be the other way? :hmm::hmm::hmm::hmm::bonkers:
Obviously now the line is plugged back and here and there I can fell a small shake.

N*Caddy
11-01-09, 08:25 PM
Since is a day after Halloween I thought is the perfect time to bring this dead thread from down under…
So the other day I went to met a fellow Cadillac owner (’96 STS and ’97 ETC) and he was looking to my car just out of curiosity (you know the same way dogs sniffing their behind). And when I popped the hod up he had two remarks: “Wow I have never seen such a clean engine” and “man this engine is so quite almost like idling low”.
Well I didn’t pay much attention (we were discussing about the recent exhaust job I did) so I missed the “idle low” remark. Until today when driving home all of a sudden it cam to me…HEY! My car always had a slight shake when idling (I mean nothing that anybody but me will notice) that I could never figure out in 4 years. This usually happens after 3-5 seconds after stopping at a traffic light and now I realize is only whit the engine at normal temperature. Could it be that the idle is too low?
So I was just stopped at the traffic light and I watched the tach…in the first 3-4 seconds it was still going slowly down from 700 RPM or so. When it finally cam to a “resting” position I noticed the slight shake starting (again don’t imagine a rough idle or such just a very, very slight shake here and there). And what do you know the engine does idle little low than the normal 650 RPM. Is more like a 625 RPMs.
Between 0 and 1000 RPM there are 4 segments (250 RPM each). My idle stays DEAD on half way between 500 and 750 RPM lines (i.e. 625 RPM). I just slightly touched the gas pedal (just a tiny bit) and the needle climbed to 640-650 (is just an impression over where it was) and what do you know…is smooth like ... a Cadillac. Absolutely perfectly dead smooth, really you can not tell the engine is on (even if you are in a silent garage) that is the butter zone.
So it took me 4 years to finally realize the obvious…it idles just a tad to low. In these 4 years I change the fuel line, the FPR, the EGR the PCV, spark plugs, cleaned throttle body, inspected every singe vacuum junction… I was just about to buy a new set of injectors; the price was pretty good for a brand new set of AC Delco injectors but still unnecessary. Well an IAC is little under $50 and I was planing to change mine any way since the surface is not shiny any more (just esthetics reasons), I should be able to adjust the one I have but now I got another reason to get a new one.

Ranger
11-01-09, 10:02 PM
When was the last time you cleaned the TB? I think the recommendation is every 30K, but I do mine every spring.

N*Caddy
11-02-09, 08:29 PM
Last year (so about 20K-25K ago) no difference then (I do-it every year in fall).

creeker
11-02-09, 10:48 PM
OH Canada! I think we went through this before and it was only a U.S. recall. I forgot about the fix. Yeah, if that was in place, I am pretty sure it is stil OEM.

When I bought my 97 sts about 2 years ago
I got in touch with G.M. canada, and it was like it was news to them,
when I asked about s.s. fuel rail replacement, yadda, yadda, they have no record of any problem with fuel rails.

Skiller.
03-15-10, 09:13 PM
N*Caddy, did you solve the problem with an IAC?? I have the same exact issue with my car. There are no signs of any misfire during acceleration or at cruising speed, but at idle, it's slightly rough. I do need a new EGR valve because it's throwing a P0404 code, even after cleaning it. Could it also be an EGR?

jsiddall
03-16-10, 07:22 PM
I dunno. Mine has always had a slight shake at idle. Being a high performance engine my guess is the cams are a bit aggressive and that's just the way it is. I can hardly imagine a problem like that being caused by IAC. I have replaced the EGR also and never noticed a change.

Maybe the better question is whether anyone has a non-VVT N* that doesn't shake at idle around 650 RPM? I guess the issue with all this is how sensitive each person is to the shake. At least on mine it is pretty subtle.

Ranger
03-16-10, 08:59 PM
No shake from mine.

Submariner409
03-17-10, 09:54 AM
My VIN9 Northstar is rock steady at 650, warm, in D.

ponyboyt
03-18-10, 02:11 PM
yep mine used to be smooth as hell in gear at a stop. If its shaking its a problem. Mine stutters just a tiny bit, like a subtle but lumpy cam. It should NOT be shaking at all, just smooth.

jsiddall
03-18-10, 07:33 PM
yep mine used to be smooth as hell in gear at a stop. If its shaking its a problem. Mine stutters just a tiny bit, like a subtle but lumpy cam. It should NOT be shaking at all, just smooth.

I hope this isn't just a terminology problem.

So if by shaking you mean something you can see shaking, then no, definitely not. This is something that if you are paying attention you can feel -- you could definitely call it a "tiny stutter". It is also very random, not constant. Next time I drive the STS I'll take note of the RPM when it is happening.

ponyboyt
03-19-10, 08:36 AM
naw not visibly. You really shouldnt be able to feel it unless you are high. It should run very smooth, but then again if you are like me you cant expect much from 340,000 km's....

N*Caddy
03-19-10, 09:13 PM
Since I am stuck here in Mexico with work for 2 months I had the "opportunity" to ride in lots of non Cadillac cars and now that I am thinking, boy my idle (and car in general) is SO much better. Definitely the slight shakes I get when the car is idling are insignificant (comparing the other cars) but since this is a Cadillac we are talking about I would like it to be just as smooth as when is not in gear (if is not in gear you literally can't tell the engine is running), the same happens if I gently press the gas pedal to raise the RPM by ~50 or so (about the amount it drops when is in gear).
Since my last post I cleaned the TB and no change, there is a very, very slight barely noticeable miss/shake (one every 1 to 3 seconds) when the car is idling in gear with warm engine (cold is smooth as the idle is little higher). So don’t imagine some teeth braking shakes is just something that I notice (because I pay attention) a passenger will not notice this.
But the most important thing is this is something that bugs me; in the next 20K I am due for a tune up so expectations, expectations…

Skiller.
03-19-10, 10:21 PM
That's the same thing I told myself the other day. My car idles better than my father's '07 Silverado. We just expect things to be perfect because it's a Cadillac. I'm pretty sure that my idle is now perfect after replacing a sticky EGR valve, cleaning the throttle body, and replacing the air filter. I'm sure the WOTs I performed the past few days didn't hurt either.

N*Caddy
10-01-11, 11:11 PM
Today I replaced the ~90K, 5 year old sparkplugs.
I had to 3 surprises:
1. Canadian discount price for AcDelco sparkplug is about double the price from rockauto.com so that's how you end up paying just shy of $100 for a set.
2. When I removed the old sparkplugs, started right (rear) bank and the plugs were normal looking for 90K, except for the gap witch was about 3 times more than it should. But when I got to the left (front) bank well, is looks like is running lean, the gap was enlarged just like the others but whereas the left bank plugs had perfect center electrode and slightly worn ground electrode, the left bank plugs had almost no center electrode and perfect ground electrode:
http://img821.imageshack.us/img821/7561/imag0182g.jpg
Notice how bad the electrode was worn down on the right bank plugs.
http://img405.imageshack.us/img405/4859/imag0179dt.jpg
Notice how consistent are all plugs from the same bank.
I mean if it was one or two I can blame it on injectors but why all are the same on each bank? What could cause this (cams)?
3. Man is so smooth now, I can't imagine how I didn't notice it, it was not missing (yet) but I can tell the engine is smoother, quieter and is more alive, and I am talking about that car runs better after the car wash.
Then I could not help myself and on an empty street (industrial area) I floored the car from ~10MPH until ~50MPH and that's when I noticed my RPM went all the way up to 6800RPM, I mean in about 3 seconds went from ~1200 to 78000!!!!!! All I had in my mind was ponyboyt '01 STS with the valve coming out trough the block so instantly released the gas. The question is WHY it does that, how come the PCM allows the engine to rev almost to 7000. I am not sure how much more was about to go since it stopped because I instantly released the gas not because it went into the limiter.

Submariner409
10-02-11, 09:51 AM
Are/were your spark plug cables connected exactly like this - ??

The GM waste spark ignition system ICM reverses coil polarity as it fires each coils' power plug - positive spark - center electrode TO ground. (This might be a tip wear factor, but I doubt it.........) Mixture-wise, all the plugs are identical.

The over-rev is a mystery - that transmission should be commanded to upshift at just about 6300 rpm, WOT.

N*Caddy
10-02-11, 10:15 AM
Yeah the wires are correct, no doubt about it, just I don't get it, why all from the front (left) bank have no more central electrode while the others are fine. Also the front ones show clearly a sign of running lean (white grayish), comparing with the rear (right) bank where are a slightly darker gray (look carefully at the pictures, in reality the difference is more visible than in the pictures). Again in the same bank all the plugs are identical (which is great) but not between banks. I shine a light trough the sparkplug ports and saw the top of the pistons and look identical (kind of dirty-black) on both banks. The waste spark thing is on all 8 spark plugs not just on the front bank so that's not it (that's how they get away using only 4 coils).
Overreving, ponyboyt has an engine with a valve coming out trough the block, same scenario reved to 7000 and bam! Almost had a panic attack when I saw that needle in there, is like when you drop your priceless vase in the very moment before hitting the floor, then it bounces on the floor but it doesn’t break (the huh is fine! moment).

Ranger
10-02-11, 01:19 PM
Overreving, ponyboyt has an engine with a valve coming out trough the block, same scenario reved to 7000 and bam!
:hmm: Why don't I remember this?

Not sure why the over rev. Does the PCM shut it down if you try to rev it over 4K (I think that's where the rev limiter is set) in neutral?

N*Caddy
10-02-11, 03:53 PM
Nope, no rev limiter in neutral either, it ONLY cuts my gas at top speed, not REV related.
I believe the 4K neutral limiter was introduced ~'99.
Now I seriously consider a '99 "Z" rated Eldorado PCM, if I can only find one and somebody to program the VIN and whatever is required to match my car.

Ranger
10-02-11, 10:42 PM
I thought the rev limiter was there from the get go, but not positive.

Sure sounds PCM related.

ponyboyt
10-07-11, 11:18 AM
I thought i mentioned to you i could get those plugs for about $6.80 each!

Thinking back, when mine over-reved it was going through 2nd gear on its way to 2-3 shift. I think i hit a patch of snow in the side of the road and it spiked, then it just suddenly sounded like a hose spraying (was the piston hitting the valve and shattering). The oil light came on and i instantly shut the key off (i have good reflexes). When we stopped and looked, didnt see any oil, cranked the engine and knew it was cooked. Shook very badly just cranking. Saw chunks of metal on the bottom of the windshield..... almost cried and called a tow truck.

Oh and, that was my 98 with a nearly brand new engine.

As for the rough idle, my white 99 is doind it again, same as it did in the spring when it was cold and wet. It smooths out when it warms up (also dries up). I definitly have a missfire still. Im sure its wires.

There is a TSB on plug wires, something about swapping 2 wires to eliminate noise and possibly missfire. (pre-2000 only).

Oh and, N* we just picked up a 98 Eldo, California car, but it is not an ETC :( Still very nice :)

N*Caddy
10-08-11, 08:25 AM
Oh and, N* we just picked up a 98 Eldo, California car, but it is not an ETC :( Still very nice :)

How's the INFO button panel above the HU??????
It should have the YES/NO/RESET yellow writing.
If mint I WANT IT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I can give you back (other than the cash) 2 of these, one with the yellow writing (but not so great looking) and the one originally came with my car (absolutely MINT) and obviously all free.
I wish I could drop by this weekend but I am heading in the opposite direction to help a friend to rebuild his rear calipers (I am picking up the gasket kit in 1h).

As for the idle, now is smooth, it is still not like I can’t tell the engine is running, I feel just a little vibration but really nothing anybody else will notice, is just me because I pay attention. My fuel consumption now is UP 1 MPG (21.2MPG in just 1 week since installed). Good stuff.

ponyboyt
10-09-11, 01:46 PM
Thats a lot of dust

:lildevil:

http://i194.photobucket.com/albums/z143/ponyboyt/eldo_buttons.jpg

http://i194.photobucket.com/albums/z143/ponyboyt/98_eldo.jpg

N*Caddy
10-09-11, 04:07 PM
Is kind of OK I have to really look beyond the dust. What ever you do, do not scratch it.
I also may want the PZM of this car (in can exchange with mine). I need it for some extra feature mine doesn’t support. And get this, I will never use the feature (beep at door lock) but I like to have it available. That is really crazy :bonkers::histeric:
AND since is a '98 if it has the Km IPC I also want to exchange my dials with the ones in this one.
I guess you see only $$$ flying around...what can I say...I have the bug and I pay for it (within reason). :)

ponyboyt
10-09-11, 11:22 PM
This car is getting engine swapped, already have one out for it. Anything that comes off needs to be replaced immediatly.

N*Caddy
10-10-11, 09:03 PM
Next weekend I may be in North Carolina, I have to see exactly when is the trip scheduled. How long you will have the car for?
I will put back all the parts I remove (I'm doing a swap basically) but I need to be in Canada to do so.

ponyboyt
10-11-11, 04:27 PM
:hmm: Why don't I remember this?

http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/216929-rip-my-98-engine-goes-boom.html

N* the car will be sitting for a bit. I have a few engines to swap before that one, then it goes up with a for sale sign, who knows how long that will take. Lots of work ahead of me before we start on that car.

As for that blown engine, the valve is bent. We found peices of piston near the bottom of the windshield, and the lower piston ring under the intake. There is a hole in the valley in the block. Piston is nowhere to be found. One of these days ill yank it, im hoping the heads are salvageable. That bent valve has me nervous. Will the seat be ok? Or at least the cams? Those cams were near brand new.

N*Caddy
10-16-11, 07:11 PM
Today I replaced the ICM and all the coils.
It definitely runs the best ever but I am still aware I have an engine idling, is just like I saw in other Cadillacs but I want it to idle like butter, it does so while in park (there is no noise, no shake) but once in gear I can still feel ever so slightly here and there a small shimmy (once every 4-6 seconds). I have to pay attention to notice it but is NOT as smooth as I would like.

N*Caddy
10-20-11, 10:43 PM
Almost 1 week on the new ICM & coils and although is much improved is not perfect. This morning I was really pushing it on my way to work and as I exit the HWY and stopped at the traffic light I could feel a vibration at idle (not as bad as before but still noticeable). It does it for years and something tells me is not ignition (at least not sparkplugs, ICM or coils relate).
What else could it be?
My car has no codes, never had (well it had but were always addressed). 1:5 years ago it passed emissions with flying colors something like all values were 10% or less of the limit).