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17K views 63 replies 16 participants last post by  cadchris 
#1 ·
I have a 1992 Seville with a 4.9. When I start the car it fires right up and goes to 2,500rpm and stays there. There are no codes.


After reading through some threads, I assumed it was the ISC motor, so I replaced it and adjusted it according to factory shop manual instructions. It's still the same.

The ISC motor seems to be hold the throttle just off the min idle air screw. How can it idle so fast with the throttle plates nearly closed? Do I have a monster vacuum leak? or is something else the problem?

Thanks in advance.
 
#35 ·
I read all these posts and I have something else to add. I have a 96 Deville with occasional idle problems. Half the time that this occurs, the air conditioning compressor goes off line and no cool air of course. I pull off the road, turn everything off. Sometimes this is all it needs. I feel like the car is running Windows XP with bugs or something. I run a diagnostic and get no codes. That is why the ISC motor thing caught my attention.

Any explanation why the AC compressor goes off at the same time the idle goes high? I have seen 3500 RPM with the transmission in neutral or park. ON the freeway, it is like the cruise control is set to 75 or 80 MPH.

I look forward to hearing any ideas.

Thanks!
 
#37 ·
...don't know the 4.5, however, you can probably follow the manual process to have the ISC's plunger retract. That is,

1. Start engine and get under the hood.

2. With 1 hand, open the throttle slightly to 2k engine rpm or higher. The ISC plunger should begin to retract.

3. Once the ISC is fully retracted, use your 2nd and 3rd hand to disconnect the ISC at its pigtail/connector.

The following may work to do the relearn:
1. Find the idle screw and turn out to reduce engine speed to 425rpm or less (yep, the engine will stumble and putter and just about die).

2. Disconnect the battery for some time to clear the computer memory. If I recall correctly, 30 seconds is sufficient....better yet, leave it disconnected for 5 minutes.

3. Reconnect the battery and ISC. Start the engine. Run engine in Park for 2 minutes, then in drive (w/ foot on brake) for 2 minutes.
This procedure is taken from memory and may or may not be accurate.
 
#38 ·
High or erractic idle on my 4.9

I realize this is an old thread, but I just read the entire thread and copied 6 pages of stuff from all you Cadillac experts and will keep these notes handy just in case.

My 93 Seville 4.9 sometimes (not all the time) idles pretty high (never as high as 2,500 though!) but it comes back down after a few minutes. I park my car in a dry, relatively warm garage (has a furnace vent going into it but of course that's worthless with gaps in the overhead door!). It never gets below about 45-50 degrees in my garage, so it's not like my sensors are "thinking" it's an icey morning.

Sometimes when I start it, it goes up pretty high, like close to 2,000 but slowly goes down, yet sometimes is stays above 1,000 and feels like I'm getting ready to do a big power brake smoke show in a RWD hot rod. I attempt to "kick it down" (just a habit from my carb engine days) to no avail. But eventually it will go down.

Another thing my car does (but only when it decides it wants to, NOT all the time) is when I start it, it will start and die, start and die, start and die... until I give it a little gas pedal and start it then it sounds like it's missing for a minute (like old cars when they were flooded) and eventually clears out and runs fine. Once in awhile, after it does this, it will start fine but the RPM's go up and down drastically like 500 to 1500 and back and forth a few times like it wants to die. I'm sure there's a name for this, but I'll just call it stumbling or erratic idle.

Since the higher RPM idle only lasts a matter of minutes, I'm not too concerned about it yet. But the up & down idle and sometimes starting and instantly dying is driving me crazy!!!
:hmm:
I keep thinking it's related to the TPS but not sure, since Cadillacs seem to have like several thousand sensors and plugs and wires and harnesses and like 150 fuses under the hood! (Slight exaggeration).

Any suggestions would be greatly appreciated. This is my first Cadillac and I've only had it 2 weeks so I'm still learning things.

BTW, I do have a DMM if there are any tests I can do with it.
 
#41 ·
Re: High or erractic idle on my 4.9

Another thing my car does (but only when it decides it wants to, NOT all the time) is when I start it, it will start and die, start and die, start and die... until I give it a little gas pedal and start it then it sounds like it's missing for a minute (like old cars when they were flooded) and eventually clears out and runs fine. Once in awhile, after it does this, it will start fine but the RPM's go up and down drastically like 500 to 1500 and back and forth a few times like it wants to die. I'm sure there's a name for this, but I'll just call it stumbling or erratic idle.
.
This right here is a classic by-the-book leaking fuel pressure regulator symptom. When the car is shut down, the residual fuel pressure is bled off into the intake manifold through the leaking diaphragm, causing hard flooded starts.

This could also be whats causing the random fast idle. The computer has learned the idle with the hard starting problem. As the engine initially chugs, like you say it does, the pcm calls for more throttle to bump the idle up. When it clears out the idle ends up being too high and it has to dial it back.
 
#40 ·
Thanks. :thumbsup:

I hope I didn't confuse anyone will all the things my car is doing or not doing. It's really only 2 things. I just wanted to be as specific as possible to help others offer their advice or opinion.

Oh, BTW, I copied that procedure last week! I just haven't used it because the only thing showing on my dash is "Low Refrigerant Level, A/C Pump Disabled". But I can pull the codes in the morning and post back. No problem.

So, it will show a bunch of codes even though the Check Engine light never comes on or the OBD isn't saying anything is wrong? Dang! Guess I better check!

And I was thinking TPS. But since it only does it "when it wants to" and is not a regular thing, I haven't pulled the codes.

I'll let ya know! Thanks again! :worship:
 
#45 ·
SWEET! I'll take one! BUT... it might be a week or so. I'm short on coinage right now but I'm about to get a HUGE check from my parents' estate. When I get it, I'll order one of those! I figured they were like a hundred bucks or more. Didn't realize they were that cheap!

Thanks so much!
 
#47 ·
Hey, I love this car! There's really not much wrong with it. An off and on idle speed issue that lasts a couple minutes is the least of my worries. This car is gorgeous, and even the local dealer's service adviser was impressed. He said it was obvious someone took super good care of this car. And hey, I only paid $2000 for the nicest car I've ever owned. It only has a few very minor issues that the FSM would help me with, and I really want a wiring diagram. The check isn't THAT big, just big enough to get new tires and wheels, all new stereo system, and struts.

I know you were probably joking. But hey, this isn't such a bad car...
 
#48 ·
Hey, I love this car!
That'll change...:poke:

There's really not much wrong with it.
Give it time...:sneaky:

Yes, they are beautiful cars, but some come with a laundry list of "minor things wrong" that can sometimes make you question the day you were born and why it came to be. One thing will be constant, we'll be here to help you the best we can....:thumbsup:
 
#52 ·
I do plan to purchase an FSM as soon as I can. But as for other stuff, I already got the wheels and tires and installed the alarm but have put the stereo stuff on hold for now. You're right, and FSM is important! Thanks.

Here is my baby with the new tires & wheels (shots taken at Sears after I went to have a new battery installed)...


 
#53 · (Edited)
Glad someone awoke this old thread as I saved the old links "awadecki" posted a month earlier in 2007 as I need to explore this too. He has written the best info and thorough instructions on TPS and ISC adjustments and is a valuable member here on the forum:
http://www.cadillacforums.com/forums/ht4100-4-1-4-5-4/106184-tps-question.html#post1071803

http://www.cadillacforums.com/forums/ht4100-4-1-4-5-4/106966-intermittent-isc-tps-problem-still.html


Beatiful car "Hariball", Funny shyt above "Seok" as your in knee deep shyt with that door problem you have on your last post in the link below.........still thinking about it today:

http://www.cadillacforums.com/forum...15060-newbie-needs-help-79-eldorado-no-2.html

Hopefully some others can help and have some ideas or maybe you should post up a new thread on how to get a 79 Eldo Pass. Door open when ALL releases won't work on an unlocked door.

chris
 
#54 ·
LOL! that I am Chris! hahaha. You put up some good info for me on my thread too! good ideas, most of them I hope to live without!
... why couldnt McGyver be my next door neighbor.

the weather is crap right now (NW) so it leaves me with a day or two every couple weeks to get down on the 79 thats NOT in a garage :hmm:

And YES, that Seville up top is nice looking! great find, and that 4.9 will treat you well. Its getting so hard to find a nice taken care of "popular American" ride that hasnt been mechanically treated like ass and covered up with $5000 of cosmetics.

great choice on the wheel pckg BTW! are those 18? looks classy
 
#55 ·
Thanks! Yeah, it took a few weeks of deciding on the wheels. As for the tires, I chose the Cooper CS4 tires after reading what other Seville owners in this forum liked and found a great majority loved the CS4's. So far I love them too. No, those are 17x7.5 wheels. I thought about going with 18's but didn't want too low of a profile tire since we have so many pot holes around my town. The tires are 225/55-17's. Went up one size and this was the closest to an exact match in a plus 1 size. I just keep thinking there sure seems to be a lot of extra room in the wheel wells on this car. Heck, I'll bet 20's would have worked out nice! It seems to sit up too high. And yes, the car is gorgeous. It's been very well taken care of. Even the local Cadillac dealer guys were impressed. The interior is as clean as the outside. Not a rip or tear or scratch inside, it's never been wrecked, no bondo, no dings, nothing.
 
#56 · (Edited)
Hairball, the gap should be the same if you went "Plus 1", is it still? What was size the orig. wheel/tire combo?

Off the subject; here's an idea to close the gap:

I checked both Eibach and Tokico for lowering springs and NOTHING! Maybe another mfg. makes a 1" lowering perf. spring. Of course, you would need matched lowering struts for the spring. Your car has the electronic struts right, and do they still work?

But the professional builders use air bag suspensions:

I'd love to do an airbag suspension on my cars like what Chip Foose and other high end builders use on their "Resto Rods" that they build on the show "Overhaulin" or when they build show cars for the SEMA show. I get so jelouse on how any new car handles and is so smooth compared to my Cads, and these air bag kits seem to be the best upgrade and way to lower, firm up, and give an ultra smooth ride. These are not the ghetto type airbag hydralic lowrider stuff. They actually lower the car a few inches and the better kits like Air Ride Technologies make the car handle extrememly well and extremely smooth.

Here's the universal A.R.T. Shockwave page:
http://www.ridetech.com/store/streetrod/

I saw an article in HotRod Mag? 5+ yrs ago, when they converted a late model Camaro and they couldn't believe how it handled on the track and showed Still Photos of body roll before and after the Shockwave Airbag Kit. They remarked that the car drove unbelieabley smooth (like a Caddy) too......

Here's their media page: http://www.ridetech.com/info/category/in-the-media/page/2/

This company makes a kit but I think its very universal and not a direct bolt on:
http://www.airbagit.com/product-p/fbs-cad-31-kit3.htm

The way that company advertises their kits; it seems to be a 1 size fits all, but I don't know. The AirRideTech. is supposed to be the best. Maybe some day I'm going to convert both my cads. when I get the long list of bugs worked out. Unfortunatly, the bugs are happening faster than I can work them out!
:bricks:
chris
 
#57 ·
There was a gap there before these tires, but now the car is a half inch higher from an inch taller tire. It originally came with 225/60-16's and now has 225/55-17's but I didn't think it would raise the car enough to notice. Yep, the electronic suspension still works but all the struts are shot! I need to replace them as soon as I can decide how much I want to spend. I certainly can't afford $4000 from the dealer! I was thinking about Gabriel Ultras but I would lose my electronic suspension. But I'd be happy to not feel like I'm in a boat! Can't decide. No matter how much I pay, if I get aftermarket I'll lose the electronic part. I'm tempted to check into used from a wrecking yard. If I can find a car that has had the struts replaced with OEM, I'd buy them.

(Looks like this thread got a bit off topic. Sorry, O.P.)
 
#58 · (Edited)
It looks very close Google Tire Size Caluculator or go here and see that the diameter difference is only about 1/8" taller on this calc:
http://www.discounttiredirect.com/direct/brochure/info/tmpInfoTireMath.jsp

Try some other calcs on the web.

You won't find electronic strut any longer. Long been discontinued along with the 2nd generation manual Delco "Reac-tecs" that I heard from Allante Source were great and gave a nice firm ride and lasted. The new Delco Struts appear to maybe be Monroe SensaTracks but I've heard they don't last very long. I just bought a set for my 91 Eldo as I went on the Junkyard excursion looking for them.

I was also told by either Allante Source or NorthStarPerformance , that even if you find new or used OEM Electronic Struts; they'll probably be locked up from sitting and he and one dealer he knew of a few years back went through a couple of new sets and had to cycle the electronic valveing all night to free them up. He stopped me looking for these things either new or used and everyone I ohm tested in the yard never ohmed out correctly.

Also, NorthdstarPerformance often posts on the forum, I can't remember his screen name but he's the mfg of a better block inserts for the Northstar Motors:
He has put together a deal with Delphi to re-make the discontinued Magnetic Struts for later model Cads. He told me, that he is working on sourcing the old CCR Cad. Struts some day in the future.
http://www.northstarperformance.com/suspension.php

Also, I came accross this thread on the Cad Forum about dissableing the CCR/SDD suspension indicator message: I thought everyone had to use the Relay method from what I've read to deactivate the message and it appears it can be deactivated according to this TSB. I have mine deactivated by jumping the two wires on the Control Module. This is performed to get into the Suspensions Diagnostic Mode to read the flashing lights on the module but also deactivates the message! I never heard anyone say anything about using that message so at least I don't see the message until I get some new struts.

http://www.cadillacforum. com/forum/showthread.php?t=3160

I had to separate the link as it wouldn't paste because its a different forum.

Hope this helps, and your right! This thread did get off the topic!

chris
 
#59 ·
Electronic not available? That's odd, since there are people in the forum still selling them. But I'm not stupid enough (or rich enough) to pay $1000 each for any strut, even if it was gold plated with diamonds on it!

Looks like I'll buy the Gabriel Ultras tomorrow. $88/pair for fronts and $86/pair for rears at Auto Zone, or even cheaper online. I'll lose that famous Cadillac ride and lose my working electronically controlled suspension, but oh well. I don't plan on going on any road race courses anytime soon.

In my 40+ years around cars I've never heard of struts or shocks that freeze up from sitting, but then the electronic ones are probably a bit different than normal struts/shocks.

I also thought I might look for some in a wrecking yard, but then it will be too hard to tell if they're worn out too so I'd be taking a huge chance buying used. Maybe I can find someone parting out a 93 Seville who replaced their struts recently.
 
#60 ·
Where have you seen those struts located on the forum. I've never browsed the "for sale" ads? I may just ask them to test cycle them to see if they'll pass and guarentee them.

If you still want the best ride overall, then the Monroe SensaTracs that have a speed sesnsative valveing is probably the better strut out there but I've been told they all wear out as compared to the old Delco React-tecs. Maybe those are on this forum somewhere for sale and I was told have much better sporty ride that the Allante guys like and last a long time.

Also try Rockauto.com

chris
 
#62 · (Edited)
Hi HAIRBALL,

Do you have the posts where they mentioned the elect. struts? I'm interested what dealer is sitting on those struts?

I was looking up your application on Rockauto and comparing it to the Monroe site. Very Bizzarre listings on both Rocks site and Monroes site.

This shyt's going to get complicated and if you bought the Gabriels, fine but I'm doing a write up on this anyway because the listings are so screwed up and confusing between Rock and Monroe........................ This should be moved to another thread so other's can see the suspension updates for their Sevilles and not get spooked by the bad info on the parts sites or at their local parts stores who may have recieved the wrong info from Monroe or some other company that lists the parts in some universal database that the parts stores use. It's all goofed up if someone is looking for Monroe SensaTrac Struts an anyone considering it should call Monroe for the part#'s as I'm only trying to rationalize the application using 2 sites.

1st, on the Rock site: under the shock absorber tab, I see the Delco Elect rear struts for $1128 pc. WOW but that maybe for the pair since Air Struts are always packaged by the pairs, and Monroe #40046 $124. That also should be for 2 struts on the Monroe's and should be the better SensTrac line. Rock's site must have the everything mixed up.
http://www.rockauto.com/catalog/x,carcode,1027752,parttype,7556

Now if you go to Rocks site under Struts, http://www.rockauto.com/catalog/x,carcode,1027752,parttype,7584
I only see Gabriels for the front but no rear application which is very strange, and also see the wrong applications for the Monroe's. Someone had to mess up that listing for 93 Sevilles and hopefully its not messed up in ALL vendor databases from bad info from Monroe. I see where its states "AK49 Kit" requiered to install the Monroe #71796. That isn't even your strut or shock so the listing is wrong and you should not need that Adapter. I also see the Delco front struts on that page# 580101 for $960 but the photo doesn't show its the electronic. I still can't believe Delco made these things but now that I think about it, I was told they did and only for a short time.

Now if you go by the Monroe site, http://www.monroe.com/catalog/ecatalog.asp there's some weird things they did there but if you use the part#'s from there and plug them into the Rock Site, you'll get the correct parts and prices.

When you get to the Monroe site, and you put in your modle year, you'll see 2 options:
"All - Exc.Electronic Adjustable Suspension"

On that page I only see rear adj. air struts which really should be a part# for the pair but you'd have to ask Monroe or some other vendor. The rear's should be Part# 40046 and you don't need the AK29 Adpt. Kit since you should already have air struts in the rear.


Now if you hit your back page on that site above and click on the other option:
Electronic Adjustable Suspension -- For Converting Front Electronic Adjustable Struts to Conventional Struts

You'll see the full conversion Kit # 90008 which they give you struts, mounts, bearing's EVERYTHING and they just packaged it in a complete kit which is a smart because you really should consider replacing the mount/bearing plate anyway since it's all going to be appart. Rock has it priced for $240 but the struts should be available from Monroe by single part# and I would call them for the part# if you would go that route. Very strange they would MAKE you buy the whole kit eventhough its a smart thing to do when replacing struts on a car with high mileage.

Now for the rear on that page they list coil-over's for the rear which I would NEVER use. They are the #90009.

If anyone goes this route, they should call Monroe and ask for the single strut #'s for the front if they don't want to buy the mounts/bearings, ect.ect. in the packaged kit. I'm wondering if Monroe is ONLY packageing this complete assembly because maybe old plate/bearings would fail and damage their struts or there were too many warranty returns when the fault was a failed strutmount/bearing. It very well could be an updated design for a factory flaw.

Thats my take on it!

Hope it helps someone!
 
#63 ·
I don't remember which posts I seen it in. It was when I did a search in the forum for Struts and was reading posts about which ones other members used. Everyone said their local dealers sells the electronic ones and the guy from Rippy Cadillac mentioned he can get us all a set for $2500 instead of $4000. Otherwise, I don't recall which posts mentioned it.

I know what you mean about the Monroes. That's partly why I decided to run with the Gabriel Ultras. They're a decent price and I'll lose the feeling that I'm out in a charter boat. Sure, I'll lose the electronically adjusted control in the corners, but I don't plan on doing any high speeds on country back roads (I save those for my bike). So the Gabriels seem like a better choice due to their low cost. Those other brands everyone mentions, StrutMasters and Arnotts, are two expensive. SunCore is a decent price, but still $300-600 per pair! I'm just not ready to spend that much, so I'm still looking at options.

There's a little info here but not much: http://www.cadillacforums.com/forum...rum/196949-93-seville-strut-replacements.html

That's quite the write up you did. Apparently I'm not the only one who does his research! Maybe you can ask the Mods to move this discussion to a thread that people will read. They might not find this information since the thread title mentions high idle and nothing about struts.

Good investigation work!

Shawn
 
#64 · (Edited)
According to a recent conversation with Allante Source, he said he hasn't had luck with any aftermarket struts lasting more than 20-30k which is why he's still trying to locate the discontinued Delco React-Tecs that were the replacements for the discontinued O.E. Electronic Struts. I'll ask him about Gabriels for the hell of it. I e-mailed A/C Delco but never heard back about the Reac Tecs and old part numbers as I would try to locate them. He said these struts lasted and gave very sporty handleing for the Allante's. I'm trying to find them and return my SensaTracs that I haven't installed. But if not, I bought the Monroes at my local parts wholsaler same price as Rock, no sales Tax, no shipping, and sent in the Monroe Shocktober Rebate, buy 3 get one free.

I wouldn't think the SensaTracs would give a floating feeling as I use them on my Brougham and they were firmer than O.E.; the internal valveing bleeds off to smooth out the bumps/potholes ect. which I want. Maybe the Gabriels have better multi-valving but my problem is I run Vogue Tires which have a stiffer side wall. I also have complete Moog front end parts that need to be put on my Brougham and Eldo. to try to restore the ride. Always consider Mooge if you need to replace any suspension components but they're expensive for the higher quality.

Either Allante Source or Northstarperformance told me that Suncore, Arnott & Strutmasters were using Monroe's either their regular line or SensaTracs.... of course, they could even be the Gabriels. It even looks like A/C Delco's current struts are SensaTracs from the description or maybe the Gabriel Ultras. Too bad Bilstein or Koni don't make replacements for our cars.

I see from the Gabriel site that my 91 Eldo and your 93 Seville use the exact same part#'s. You should really consider replacing all mounts too especially the fronts since its dissassembled. Moog is expensive so I'm sure the Gabriel mounts are less expensive hopefully the quality is there.

You will get the Computer Command Ride Warning Message when you disconect the struts. I've heard about so many ways to bypass it like the resistor kits, relays, ect. Here's how I did mine which was supposed to be temporary but I've been running it that way for 4 yrs...............Inorder to pull the susupension codes from the module, you need to jump 2 wires on the module to get the light on the module to flash to read suspension codes. When this is done, it turns off the CCR Message on the dash display. I've been running like this for a few years so I don't keep seeing the message! I don't know why its never mentioned to just do that to turn off the message and leave the module in diagnostics mode and let it flash to its hearts content in the trunk!

Have you ever come accross anyone else who mention this method as a permanant fix on this forum as I've really never searched this forum for suspension problems?

But as I stated in a previous post, I came accross a thread on a different Cad Forum about dissableing the CCR/SDD suspension indicator message: I thought everyone had to use the Relay method from what I've read to deactivate the message and it appears it can be deactivated according to that TSB posted in the thread I posted above but you need to copy/paste that link and make it into a complete URL and close the space between the "." and "com" since this site will not allow the the posting of a link from the other Cad Forum with a similar address.

Here it is the "Suspension Message Deactivation TSB" again which looks pretty unique and I wonder if it can be undone if the electronic struts would ever get re-made by NorthstarPerformance:
http://www.cadillacforum. com/forum/showthread.php?t=3160

If you have any links to the other suspension forums, poste them here and I'll see if these postes can be moved or just copy and paste them somehow manually.
 
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