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2K views 27 replies 10 participants last post by  peteski 
#1 ·
:cool2:

On 8/15/05 we picked up a 95 De Ville Concours in CA and drove it to PA. It ran fine until we hit Nebraska and then a misfire started. New wires haven't fixed it and new coils didn't fix it.

I am in PA now and talked with one of my mechanics yesterday. He ran a TSB on the 95 De Ville Concours and almost 300 TSB's appeared. Stopped at the one discussing wires/plugs/carbon tracking and misfires. The TSB says to use spark plug AC-929 (ribless insulator). It also mentions wires (GM part of course). The TSB states, "The new AC 929 spark plug and boot design significantly reduces carbon tracking and reduces engine misfire." Reduces? How about eliminates???? The TSB also states, "The boots contain FHC grease as a lubricant. If silicone type lubricants are added to FHC coated boots, carbon tracking of spark plugs may occur." Well isn't that just ducky. Many of the wires you buy already have a small amount of silicone rubbed applied to the boots.


I guess I now see why the PO spent 0ver $900 at the dealer for wires and coils. UNREAL! Minor tune up items costing $900.

IMHO the wiring loom on this car is made for carbon tracking and or arcing. The wires to the rear plugs are longer than needed and create a 90 degree bend, the wires going to the front tubes lay on top the manifold tubes and are held down on the metal tubes by the plastic cover.

For the past 15 years I've driven Jags and never need to pay for dealer only items like plugs or wires. The after market parts from my parts guy in Idaho work very well, the local parts stores also work for my Jag parts.

$900 for wires and coils. Give me a physical break! The engineers went way out of their way on this car to cement dealer only maintenance. I'm not thrilled with the maintenance part of the car.


It is a nice car to ride in, has a lot of power but I'm not sure I want to own a car that I can't even do a plug/wire job without dealer assistance. :hmm:
 
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#2 ·
You CAN do it without dealer assistance. While the OEM plug wires are not cheap, they are a LOT cheaper at http://www.gmpartsdirect.com or http://www.rockauto.com. as well as any other parts you may need.

BTW, there was a fuel rail recall on the '95-'97's. If your fuel rail is black nylon, it wasn't done. If it is stainless steel, it was. A misfire after the recall is a common problem due to moving the old wire around. I had the problem myself. Also, the wires run pretty close to the blower motor. Don't let them rest against it. They will take out the blower, another common problem. The blower motor has since been redisigned.
 
#4 ·
jsjag said:
:cool2:

On 8/15/05 we picked up a 95 De Ville Concours in CA and drove it to PA. It ran fine until we hit Nebraska and then a misfire started.
I've heard that Nebraska is the Bermuda Triangle of DeVilles.

I find $900 for a tuneup hard to swallow too. I'd be interested in a breakdown of parts and labor.

I recommend Magnecor wires. Check out their site and learn everything you ever wanted to know about spark plug wires. You can order them directly from Magnecor or get them significantly cheaper from a distributor like UltraRev. They cost as much as discounted factory sets and have a lifetime warranty. Google on "magnecor distributor" and you can find other distributors.
 
#6 ·
EcSTSatic said:
I've heard that Nebraska is the Bermuda Triangle of DeVilles.

I find $900 for a tuneup hard to swallow too. I'd be interested in a breakdown of parts and labor.

I recommend Magnecor wires. Check out their site and learn everything you ever wanted to know about spark plug wires. You can order them directly from Magnecor or get them significantly cheaper from a distributor like UltraRev. They cost as much as discounted factory sets and have a lifetime warranty. Google on "magnecor distributor" and you can find other distributors.
The Magnecore wires probably work well on a SBC, but they were never tested on a Northstar and the engines and engine compartments are very, very different. The Delco wires were designed to work well with the Northstar and its engine compartment. The Magnecores were not. It might be difficult or impossible to route the Magnecores properly, especially under the appearance cover, since they are larger in diameter than the factory wires. If I was racing the Northstar, I might consider the Magnecores, but for daily driving and where reliability counts, I think I'd stick with the Delcos. Just my opinion. I'm not saying the Magnecores are bad, just that they might not work as well as the Delcos in this particular application. If you have a Honda Civic, the Magnecore sticker on your rear window will give you another 35 H.P. :cool2:
 
#7 ·
Ranger said:
You CAN do it without dealer assistance. While the OEM plug wires are not cheap, they are a LOT cheaper at http://www.gmpartsdirect.com or http://www.rockauto.com. as well as any other parts you may need.

BTW, there was a fuel rail recall on the '95-'97's. If your fuel rail is black nylon, it wasn't done. If it is stainless steel, it was. A misfire after the recall is a common problem due to moving the old wire around. I had the problem myself. Also, the wires run pretty close to the blower motor. Don't let them rest against it. They will take out the blower, another common problem. The blower motor has since been redisigned.
Thanks for the info! I did notice that the one wire was touching the blower motor and that one wire had a flat rub mark on it. Running a wiring loom without wires touching is impossible. I can't figure out why some of the plug wires have so much extra wire to them that you must make almost a 180 degree turn.

Autolite has some that they call their professional series for around $90 and from what I read, they are very good wires. If they don't work for me my parts store will give me a credit toward the $138 for the AC Delco wires (must be special ordered).
 
#8 ·
Eldyfig said:
How much of that $900 was for labor?
Here is the break down from the GMC dealer, date 4/13/2001:

Spark plugs $ 80.96
Wire kit $189.90
Coil ASM $237.28

Total Parts $508.14
The remaining $917.79 invoice was tax and labor.

All the above work was done @40,000 miles ago.

On 2/20/2003 the poor PO was also talked into getting a new engine. Apparently there was (what PO was later told by another mechanic) a valve sound that could have been fixed. Instead the PO spent $8,42.49 on getting another engine installed.

So in about 4 years the guy spent almost $10,000 on maintenance. Ouch! A parts guy told me today, wait until you try to change a starter. I asked why? He said it is located under the intake manifold. Was that loaction picked for the ease of the production line or for the consumer?

I've been a Jag owner for a long time and the De Ville will be my wife's car. On the Jag forum it is commonly accepted that we stay far away from the dealers.
 
#9 ·
mcowden said:
The Magnecore wires probably work well on a SBC, but they were never tested on a Northstar and the engines and engine compartments are very, very different. The Delco wires were designed to work well with the Northstar and its engine compartment. The Magnecores were not. It might be difficult or impossible to route the Magnecores properly, especially under the appearance cover, since they are larger in diameter than the factory wires. If I was racing the Northstar, I might consider the Magnecores, but for daily driving and where reliability counts, I think I'd stick with the Delcos. Just my opinion. I'm not saying the Magnecores are bad, just that they might not work as well as the Delcos in this particular application. If you have a Honda Civic, the Magnecore sticker on your rear window will give you another 35 H.P. :cool2:
The Magnecore's come in 7mm (like current OEM size) 8mm or for the racing types 8.5. On my XJ6 I have 8mm (7mm was OEM). I had to buy new loom holders that would accept 8mm but other than that I love them. Plus the dark blue wires are very nice looking.

I don't know about the Mag's for one reason, if in a last ditch attempt I must go to a dealer I dont want them to use the, "wires aren't OEM AC Delco" for a reason of misfire. I could see them putting on new wires / coils / ICM and everything else under the sun just to stop the misfire. Then how could I prove if it was or wasn't the wires. So if I go with OEM AC-delco wires the dealer can't use the wires as a reason.
 
#10 ·
I have never used and don't believe I ever will use a dealer to get work done to any of my vehicles (unless it is a cosmetic item on our new truck). Only mechanic I have ever used is my transmission man. And he has is own business and does costum rod work among some regular daily driver cars. He has done a TH400 and the 4T80 for me and I have nothing but compliments for him. Point being, I can get most work done myself for alot cheaper and I have the peace of mind knowing exactly what has been done to the vehicles.

The north* starter isn't neccessarily too hard to get at. It is in a off beat spot. It isn't much to get the intake out of the way. It is a dry well under the intake, so you won't be troubled with sealing a valley pan.

Like Ranger said, the parts can be bought for alot cheaper than the dealer sells them.
 
#11 ·
EcSTSatic said:
I've heard that Nebraska is the Bermuda Triangle of DeVilles.

I find $900 for a tuneup hard to swallow too. I'd be interested in a breakdown of parts and labor.

I recommend Magnecor wires. Check out their site and learn everything you ever wanted to know about spark plug wires. You can order them directly from Magnecor or get them significantly cheaper from a distributor like UltraRev. They cost as much as discounted factory sets and have a lifetime warranty. Google on "magnecor distributor" and you can find other distributors.
At least I didn't get sucked into the Nebraska Triangle!!!

Thanks for the UltraRev site. I just bought some 8mm Magnecors that, with shipping, came to $125. The car is supposed to have the Platinum spark plugs and I doubt if the plugs are the problem. I am guessing that the wires were hitting the metal fan housing, starting arcing / tracking until they were cooked. My fingers are crossed.

There is one thing that I am not famaliar with and that is the code check using the climate control buttons. I get a reading of no codes for all the other codes but when it reaches PCM it reads PCM? What's with the question mark?
 
#13 ·
davesdeville said:
That's to allow you to go deep into the enchanted world of settings and info outputs the PCM has to offer. This enchanted world has many dangerous things not to be tampered with by the untrained (or at least those without a factory service manual.)
But I like entering dangerous and enchanted worlds. Seriously though, my Haynes manual says that after all the checks I should get a number 7 to show it is finished. Haynes has been known to be wrong.
 
#14 ·
As mentioned the starter is not as big of a deal as it would seem. It does stay clean and dry where it is and you won't be on your back getting dirt in your eyes.

Haynes is relatively useless for all but the most basic stuff. If you are going to do your own maintanence, do yourself a favor and get a factory service manual by Helm inc. You can probably score one on ebay, but even at full price from Helm they are worth their weight in gold. I just pulled the air bag on my daughters '99 SLS to get at one of the steering wheel switches and I never would have been able to figure it out without the manual. Got it for $45 on Ebay. Heed Daves advice. I would not venture past "PCM?" without a REAL manual.
 
#16 ·
Ranger said:
As mentioned the starter is not as big of a deal as it would seem. It does stay clean and dry where it is and you won't be on your back getting dirt in your eyes.

Haynes is relatively useless for all but the most basic stuff. If you are going to do your own maintanence, do yourself a favor and get a factory service manual by Helm inc. You can probably score one on ebay, but even at full price from Helm they are worth their weight in gold. I just pulled the air bag on my daughters '99 SLS to get at one of the steering wheel switches and I never would have been able to figure it out without the manual. Got it for $45 on Ebay. Heed Daves advice. I would not venture past "PCM?" without a REAL manual.
Yea, I know Haynes is basic but it was a start. My wife kept expecting to find useful maintenance information in the little book that comes with the car. I kept telling her she won't find much if anything about misfire in that little book. She started getting mad at me soooooo I just let her keep looking.

Forty five dollars sounds like a good price. I remember paying $125 for a service manual for a SIII Jag I had owned. My current XJ6 has a service manual on CD I can buy for very low dollars.

With temptation in check I will heed Dave's warning and not venture past PCM. Before the warning I did try to see what PDM was about but it would not go past "PCM?". I'll do a search on E-Bay and try to snag a service manual.
 
#17 ·
jsjag said:
my Haynes manual says that after all the checks I should get a number 7 to show it is finished. Haynes has been known to be wrong.
Your Haynes is correct about the "7". However, that is the OBD I for 4.x engines, excluding the north*.

Here are two pages from my manual explaining PCM Data and Overrides. You can go into PCM Data and get some useful info.



 
#18 ·
Eldyfig said:
Your Haynes is correct about the "7". However, that is the OBD I for 4.x engines, excluding the north*.

Here are two pages from my manual explaining PCM Data and Overrides. You can go into PCM Data and get some useful info.

http://img375.imageshack.us/my.php?image=pcmoutputoverride2hf.png

http://img375.imageshack.us/my.php?image=pcmdatainput6pq.png
Excluding the N*? Is the N* and OBDII system?

Looking at the AllData page for wire routing, I see much shorter wires for the rear plugs. It makse sense to have shorter plug wires for the rear and sure makes a better wiring loom. For some reason my current set of wires the rear are much longer than needed and a set I bought (that kept arching and now going for better set) also had longer wires than needed for the rear plugs. AllData shows a nice wiring clip that keep all the rear wires in a nice tidy position.

What I currently see with the AC OEM set is a mess of wires, turning and bending directly by the fan motor housing. I hope that my set of Mag wires I just ordered come with shorter wires for the rear plugs. I am guessing they won't and will be cut to the AC Delco OEM length.
 
#19 ·
North*s up to 95 are OBD I. The 96 to current are OBD II.

When the PCM ends testing with a 7...that is for other OBD I Cadillacs with the 4.x engines, not the 4.6 North*.

About your wires, I really can't say much on that subject except this. I honestly have not had a problem with wires being too long. If I ever had an arcing wire, it was because the insulation was compromised. I try my best to keep the wires from laying on each other with separators and keep all bends rounded.
 
#20 ·
Eldyfig said:
North*s up to 95 are OBD I. The 96 to current are OBD II.

About your wires, I really can't say much on that subject except this. I honestly have not had a problem with wires being too long. If I ever had an arcing wire, it was because the insulation was compromised. I try my best to keep the wires from laying on each other with separators and keep all bends rounded.
Actually, all cars 1995 and older are OBD-I, including the Northstars. Everything 1996 or newer is OBD-II.

The longer wires are fine. Route them sensibly and you will have no problems. Don't let them get pinched and avoid extreme bends and kinks. Keep them away from other wiring. Use the looms and cable ties if you need to, or wrap them in the plastic conduit stuff if you want. Lots of people have used them successfully, so it's not a problem that they're longer than necessary.
 
#21 ·
my Haynes manual says that after all the checks I should get a number 7 to show it is finished.
Case in point...a 90 Deville I recently worked on for a buddy ended its OBD I testing with a 7. The OBD I for 95 and older North*s is different of course because much more is being monitored and it ends testing with "PCM?" Same holds true for OBD II for 96 and newer North*s.
 
#22 ·
mcowden said:
Actually, all cars 1995 and older are OBD-I, including the Northstars. Everything 1996 or newer is OBD-II.

The longer wires are fine. Route them sensibly and you will have no problems. Don't let them get pinched and avoid extreme bends and kinks. Keep them away from other wiring. Use the looms and cable ties if you need to, or wrap them in the plastic conduit stuff if you want. Lots of people have used them successfully, so it's not a problem that they're longer than necessary.
I just thought maybe the N* had a leg up over the other 1995's. In my State having ODBII means more emission tests must be done to a car. If it is an OBDI car, all that must be done is gas cap testing and a look to see if Cat convertors are on the car, air pumps, etc. So if our 1995 N* was ODBII we could not, at the current time, get an emissions sticker and maybe not re-titled in our State. But if we coughed up $450 we would get a pass on the emission test. Go figure?
 
#23 ·
On the starter...they are the easiest thing to change in the world. Much cleaner and lighter than a SBC, a helluva lot nicer to do than a BB chrysler, and it only takes about a half hour...four long bolts and your're there. Super super easy.
 
#24 ·
mcowden said:
Actually, all cars 1995 and older are OBD-I, including the Northstars. Everything 1996 or newer is OBD-II.

The longer wires are fine. Route them sensibly and you will have no problems. Don't let them get pinched and avoid extreme bends and kinks. Keep them away from other wiring. Use the looms and cable ties if you need to, or wrap them in the plastic conduit stuff if you want. Lots of people have used them successfully, so it's not a problem that they're longer than necessary.
Thanks to you all for ideas and places to get parts.
Yesterday my Magnecore 8mm plug cables arrived. UltraRev had the best price but it did take 8 days to get to me. That's about 4 days longer than my Jag parts guy that is out in the western States but what the hey, they were a good price.

So far I replaced the 4 coils, air filter, plugs and now the cables. I bought more cable separators and also some of the black electrical loom stuff to put around the cables where they may touch / rub.

The car is now running very well and I think better than when we picked it up several weeks ago.

Here is what I do not understand. Four years ago (40,000 miles) the PO spent $917 at the dealer for new coils and cables. The OEM plug cables were dead in 4 years. Why is that? Is the N* high energy ign. a plug cable eater? :)

The total cost for parts was $300 and that includes my 8mm Magnecores. Because this car engine is new to me I am sure I over did it on the new parts. Probably the new Magnecore's would have fixed the problem. Because the old cables had been arcing for a lot of miles I was assuming that the coils were working even harder to compensate and I didn't want to guess if any coil had small cracks (they all were within OHM spec) nor did I want to replace coils in a year. I didn't need 8 plugs, 2 plugs would have been ok. From the misfire one plug was very fouled and another was almost as bad. The plugs had 40,000 on them. Here's is what I thought about the spark plugs.....all the plug cables were off, the coil tower was off, everything was laying wide open, I was in the engine and what the heck, replace all of them and I'm good to go for a long time.

For the past what is it now, 9 years or more (I've lost track) of owning different Jaguars what I have decided is, when you are in there (the engine area) and you have parts removed, replace other parts that are i the open area that may be prone to failure and may soon need to be replaced.

I still don't understand the need for such long plug cables for the rear bank # 1, 3, 5, 7? To me it would be a much, much less cluttered wiring loom if those four were shorter plug cables.

For the first time since picking up the car in CA, my wife drove the car to work this morning. I think she will be very, very happy with it.


:cool2:
 
#26 ·
jsjag said:
Here's is what I thought about the spark plugs.....all the plug cables were off, the coil tower was off, everything was laying wide open, I was in the engine and what the heck, replace all of them and I'm good to go for a long time.

...when you are in there (the engine area) and you have parts removed, replace other parts that are i the open area that may be prone to failure and may soon need to be replaced.
That is my philosophy.
 
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