Quick question about coils

seekonkholen1

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Before anybody says "Use the Search Function" this is not really a standard question. Yesterday my car was running fine. Today as I am driving to work my car starts sputtering quite a bit. I immediately knew it was going to be a coil that had gone bad. Now, the CEL has not come on but I put the scanner on it and it gave me 4 codes. p0353, p0356, p0357, and p0358.

Does that sound right that 4 would go all in one shot, or is it possible that one is truly bad and causing the others to react? It just seems odd that from one day to the next bang 4 gone. I guess anything is possible, but just curious.
 
Before anybody says "Use the Search Function" this is not really a standard question. Yesterday my car was running fine. Today as I am driving to work my car starts sputtering quite a bit. I immediately knew it was going to be a coil that had gone bad. Now, the CEL has not come on but I put the scanner on it and it gave me 4 codes. p0353, p0356, p0357, and p0358.

Does that sound right that 4 would go all in one shot, or is it possible that one is truly bad and causing the others to react? It just seems odd that from one day to the next bang 4 gone. I guess anything is possible, but just curious.

I had all of mine go bad in about two months time. At one time, I had three go bad, so I think four could be a possibility. Mine was all of a sudden. Stealership said it happens all of the time.
 
Ok.... so this is really strange! I went outside on my lunch break and started the car. It was still shuddering a bit, but I noticed that if I acclerated it would run a little better.... so like all good back yard mechanics... if a little helps, a little more can't hurt. Well I revved the snot out of it in bursts and it continued to get better and better. So now here we are it is running like a champ again and the there are no codes showing.

So here is the question, is it possible that because of the weather we recently had (rediculously high humidity) that a plug or two were fouled and by revving it it burned off the gunk or maybe the pcm is on the fritz?

I am perplexed.
 
Ok.... so this is really strange! I went outside on my lunch break and started the car. It was still shuddering a bit, but I noticed that if I acclerated it would run a little better.... so like all good back yard mechanics... if a little helps, a little more can't hurt. Well I revved the snot out of it in bursts and it continued to get better and better. So now here we are it is running like a champ again and the there are no codes showing.

So here is the question, is it possible that because of the weather we recently had (rediculously high humidity) that a plug or two were fouled and by revving it it burned off the gunk or maybe the pcm is on the fritz?

I am perplexed.

Maybe moisture in the fuel.
 
Ok so some codes are back, but not all of them, and it is skipping again. It seems to be idling really well, so it is just under load. I have a P0308 pending and a P0351 pending and a soldid P0351. Here is my question, does it sound like the #8 and #1 are bad and the other codes that I had was the computer trying to figure out what the hell was going on. One thing I did notice is that when it starts skipping really bad there is no a/c. Sounds pretty strange to me.
 
Oh and it threw a P0316 which is misfire during 1st 1000 rpm.

I'm sure it will help to know it is a 3.9L V8 gen II.

One last question, how are the cylinders #'d on this car? Does it start #1 at the passanger side fire wall and work it's way around the front then back to the drivers side firewall ending at #8

P-D
1-8
2-7
3-6
4-5
 
It could be an electrical noise issue. It might be that one of the coils (maybe not even 1 or 8) is creating so much RF that the PCM is getting confused.

It is at all possible that water could have made it into the PCM? That would probably drive it crazy too.


The PCM will disable the AC compressor if it can't hold minimum idle or is too unstable. It's just reducing loading so that it is less likely that the engine will stall.
 
Oh and it threw a P0316 which is misfire during 1st 1000 rpm.

I'm sure it will help to know it is a 3.9L V8 gen II.

One last question, how are the cylinders #'d on this car? Does it start #1 at the passanger side fire wall and work it's way around the front then back to the drivers side firewall ending at #8

P-D
1-8
2-7
3-6
4-5

Firewall
Passenger Driver
4 8
3 7
2 6
1 5
Radiator
 
Joe,

Thank you very much for helping me out with this. As far as I know the PCM was not exposed to any water. In fact everything looks very dry. So here is what I have found so far. I pulled the cover off that covers the coils (while I am waiting for the coils to come in the mail) to check if there is any oil in there and sure enough there is. I mopped it up with some paper towels for the hell of it (since I will be ordering VC gasket tonite). The two codes I keep getting consistantly are P0308 and P0351 I decided to switch the coil located at Cyl 1 with the one on Cyl 3 hoping to see the fault change locations (P0353). However, What I am finding is that the P0351 is still being reported as a fault. I am now wondering if there is a break in the wire going to the #1 cyl coil. Is it just 12V that is going to the coil?

Thanks,

Once I get this sorted out, we need to talk but in the PM ;)
 
If it is coils going bad, they will get worse quick, 3 weeks. I had a little miss that turned into an, almost, non-running car. This is on a car with less than 50k miles on it. ALSO, believe it or not, I did NOT get as much as one CEL or code the whole time. I replaced all COPs and plugs and now purrs like a kitten. I always suggest ALL COPs at the same time.
 
If it is coils going bad, they will get worse quick, 3 weeks. I had a little miss that turned into an, almost, non-running car. This is on a car with less than 50k miles on it. ALSO, believe it or not, I did NOT get as much as one CEL or code the whole time. I replaced all COPs and plugs and now purrs like a kitten. I always suggest ALL COPs at the same time.

Thanks for the input. Yeah at this point there is no question that I have some coils that are either fried or close to it. My concern is the P0351 code. The code indicates a circuit failure. Which I tested by switching another coil into it's place only to still have that same code. I am starting to question the wiring or the PCM.
 
.... However, What I am finding is that the P0351 is still being reported as a fault. I am now wondering if there is a break in the wire going to the #1 cyl coil. Is it just 12V that is going to the coil?

Thanks,

Once I get this sorted out, we need to talk but in the PM ;)

There is a constant +12V feed (as long as the key is on) and a pulsed ground supplied by the PCM.

The +12V feed comes from a green /w blue band wire that comes from fuse F1.12 in the under hood fuse box. It is hot when the key is in the run or start position. At junction S131 it splits out to coils 1 to 4. It becomes a green /w yellow band wire when it gets to coil #1.
The pulsed ground to coil 1 is a brown (no band) wire that runs to pin 58 of PCM connector C175e.

If you are curious, the firing order is 1-3-7-2-6-5-4-8 according to the wiring diagrams.
 
So just a quick update. Fired the car up this morning, cleared the codes and while the engine temp was cold it ran like a champ! No skipping/misfires etc. After it got to running temp the skipping started and the P0351 is pending again. The odd thing is that I have placed a coil from another cyl in that location, so it has to be something other than the coil. Is it possible to be something like a camshaft position sensor?
 
I would loosen the PCM from its connector and remove it, then replace it and see if anything changes. A reseat of the connection seems to be in order.
 
I am not opposed to trying that. I just need to know where the PCM is located? Is it under the cabin air filter?
 
I am not opposed to trying that. I just need to know where the PCM is located? Is it under the cabin air filter?

More or less. Here it is.
http://deneau.info/ls/s6x~us~en~file=s6x3e006.htm~gen~ref.htm


I don't see anyway that any position sensor would trip an electrical code for a coil.

Reseating the PCM connector is a very good idea. Be sure to disconnect the battery before and while doing this.
Also look really closely at the harness connector to coil 1. Check the contacts for dirt or damage, check the shell to make sure it snaps in all the way, and check for breaks where the wires exit.
 
OK just swapped COP8 with COP5 and cleared the codes. I am hoping that since#8 is the only one that threw a legit P0308 code that it was setting off the P0351. I'll be driving home in a few hours. I guess we will see how that goes.
 
OK just swapped COP8 with COP5 and cleared the codes. I am hoping that since#8 is the only one that threw a legit P0308 code that it was setting off the P0351. I'll be driving home in a few hours. I guess we will see how that goes.

I had this same problem many and many of times, it sucks I know, but every-time for me on cop8 that has oil in there as well it throws off a odd code for some reason.

ok example: car would tell me 4 was bad when it was really 8, but I saw 8 a while back before I started changing coils so I replaced 8 and 4 hasn't miss fired since.

ok my thoughts on why from my experience,

Coils 5-8 have oil, and I haven't fixed it and I now leave the covers off for 2 years as a test and have not gone through as many coils. My take is moister, oil is getting hot and then cold, under covers it creates condensation, well if you leave covers off the oil can evap and it wont drain and smell running down the engine.

That has been working for me though as I don't plan on having this car much longer "2002 ls v8" 84,000 miles

Another test you can do that has worked for me to make sure it isnt tricking me, is while the car is on take off the wire going to that cob and see if idle get worse or not.

you said internet on the cobs? good luck! huge mistake I made, cheap is NOT good, go to napa they have a cheaper one and a more expensive one that is new, get that one it is coated better.

Now you will also notice that you can drive the car for at least 1/2 hour then start hitting hills and the car starts misfiring then you wake up and car is running good all of a sudden, well that tells you huge amounts of oil is going from cylinder 5-8 as it gets warm it moves easier. then the boot is now so swollen it is arcing on the side casing misfire to other coils also.

Also, get oil cover fixed, the reason this happens is because, the engine had more power than the cover design. but there is a fix for it I believe.

There are also wires under the Big black round cover green wire likes to rub on a bolt, make sure that is not grounding out. its the upper right cover i believe for the shocks or struts or whatever.

Check fuses EVERYWHERE especially in the trunk there is a few computer fuses back there and they blow easy and on both panels in the front driver and front side passenger, look carefully you may have to pull every fuse out.

Sorry if messy I just in a hurry good luck.

Hope some of this helps, also note: weather changes from winter to summer and summer to winter is when most happens, I replaced this spring 4 in one week, don't bother the swapping them around just replace them as they go, you will get so good at it you can drive around with a spare one and replace it in under 4 min. my record i think is about 3 min. Only because I don't bother potting the covers back on, I figure whats the point.

One Last advice, The v8 ls they do not like to IDLE, don't warm the car up for long times in the morning or let it sit running. That is when you blow coils allot.
 

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