Help - running rough, new plugs, wires, cap and rotor

[99Yuk]

I don't know enough about this stuff to do it myself dropped my baby off at the stealership this morning for diagnostics, wish me luck!

---------- Post added at 10:03 AM ---------- Previous post was at 09:29 AM ----------


Check this out sunlitcomet and 99Yuk:
http://store.mp3car.com/Car_Computer_Systems_s/25.htm

Good Luck!
Let us know what happened!

 

[SunlitComet]

to much hardware and cost and I could live without a touch screen. I found this for my unused laptop:

http://www.gpscity.com/ram-mount-chevrolet-gmc-laptop-vehicle-mount-ram-vb-103-sw1.html

More space left over in the truck for other ideas I have.

My crystal smily predicts good times coming to your truck soon.

 

[gulleyman]

My crystal smily predicts good times coming to your truck soon.

Hope your right.

 

[gulleyman]

Okay, so I called the dealership yesterday to see if they had figured out what the problem was. The guy tells me it's the plugs and the cap...
I asked if he had read my email and shared it with the tech (I emailed him all of the things that have been done up to this point). He said that he had not read it. I told him I would send it again, he said he would call me tomorrow (today) if he did not see it.
I went back to the dealership today to check on their progress. He says he still has not read the email and that the tech has confirmed that the cap and the plugs were bad and that they had to start there.
He said that there were a couple of plug wires crossed and that Autolite plugs would not work in my truck, because the heat range was not right. Said that the cap was firing in two places at the same time because it shorted when the wires were crossed and it was firing back into the cap.
They wanted to charge me $80 for the diagnostic and another $440 to change the cap, rotor and plugs.
I asked if they even tested the cap and plugs to see if they were bad because they had just been replaced...twice. I asked if he even shared this information with the tech, he said he did and had to stick by his recommendation.
I told him I would pick the truck up and give him his $80 in half an hour...
I'm pretty pissed, I think the dealer is just throwing the same parts at it that I already have instead of really diagnosing the problem.
What do you guys think, are they yank'n my chain or should I get another cap, rotor and some GM plugs and try it again? Damn sure not gonna pay them $440 to do it and tell me that wasn't the problem

 

[SunlitComet]

Based on dealership parts prices and labor rate to do it seems high but there labor rate might be higher than others. Ussually when repairs are done any diag. fees are put toward that final cost. I would have demanded that with a no charge if wrong clause if possible.

Crossfire damage can happen and those autolites are not a good idea either. I love the Honeywell Corp. but the fact is some vehicles are picky. I used a bosch cap on a nissan stanza with dual plugs per cylinder and nothing but major misfires when in overdrive. Went away with oem.

I would trust the dealers diagnosis. That is the immediate problem although there might be more. It seems like they want to take an unbias view and that is the way to start.They have more experience and training and see this stuff on these vehicle more than anyone else I am sure.

My opinion is get acdelco cap, rotor and the platinum plugs using part numbers specified by dealer where ever cheapest inspect your wires closely and electrically for any damage and try againand double check your firing order. Included here http://www.sunlitcomet.com/images/automotive/93025186.gif if you want a second reference although I think the cap is marked. Disconnect your battery the while doing the work to ensure code erasure if you don't have a scanner yet. Maybe even read you plugs and cap and post what you find.

If the problem is not solved and you have to go back, what you would have paid them to do it the first time would have paid for both first and second diag. visits and your parts. Still save money.

If it is solved you still saved.

I do not however know how the p1345 code is going to be affected. IMO it is that possible distributor alignment that is causing the problem but not the other way around unless the crossfiring in the cap is electrically interfering with the cam sensor. I could be wrong.

 

[gulleyman]

Well, I got the truck back and it's in the backyard again
Thanks for you help Sunlitcomet, hopefully it was a combination of the injection system taking a dump and the Autolite plugs
I'm gonna try swapping them again and hope the problem is gone. I talked to Autozone, they might give me a refund on the plugs, cap and rotor since I bought two sets and both went bad in under 100mi. Maybe I can recoup a little bit of my money.
If this doesn't work I guess I'll be talking to another mechanic or just replacing the engine, obviously I will exceed the cost of a reman'd engine at the dealership in no time at all

 

[gulleyman]

So I replaced the cap, rotor and plugs for the third time, this time I used the ACDelco Iridium Plugs like the dealer suggested. All of the plugs I pulled from the truck looked terrible again. It still runs the same.
I got an email from Justin of Black Bear Tunning, I had emailed him a while back when I was going to replace the ECM to see if that was the problem, was going to replace it with a performance tuned ECM.
Justin asked if anyone had mentioned the o2 Sensors (the front ones) because it sounded like a fuel delivery problem. This is something that I haven't heard yet or thought of myself. The mechanic said that it was dumping a lot of fuel before and after the fuel injection system upgrade to MFI. Any thoughts on that guys?

 

[SunlitComet]

Unless something was disabled in your pcm codes would have been thrown for a malfunctioning oxygen sensor, front or rear-side to side, or for something they see out of the ordinary such as left or right bank to rich or lean. How convinced are you about the quality of that performance tune? Have you gotten rid off the sensor code yet.

 

[gulleyman]

...How convinced are you about the quality of that performance tune? Have you gotten rid off the sensor code yet.

I don't actually have a performance tune yet, I just bought an ECM at a junkyard for $50 and swapped it out to see if the problem would go away but it didn't. Still getting the same codes as before.
Looking back it seems like this all started with the truck running real rich every once in a while, then gradually it started to miss a little and the check engine light started to come on intermittently, then a few months later it would just stay on, so I had O'Reily scan it for codes and they told me I'd need a tune up soon, then a few months after that the CEL started blinking and it was running really rough. That's when I replaced the cap, rotor, plugs and wires...now we've replaced those three times,
Pulled the distributor and checked it
Re-adjusted the timing
R&R Injector spider w/ new improved MFI
R&R crank and cam sensors
Checked all the wires to and from the ECM with an ohmmeter
R&R ECM
Checked compression,
Checked the sweep (for TPS failure)

I've thought about replacing the motor thinking the only thing left was a warped head but that wouldn't fix the issue with it running rich and fouling plugs would it? Seems like I'd just have a new motor with the same problem. The only things that haven't been replaced in the ignition system is the distributor and coil, I think?

Justin suggested o2 Sensors, what else could possibly be left? Seriously, I'm at a loss here

 

[95TwinTT]

Seems to me you are treating symptoms here. The same parts are replaced over and over with the same results.

There are other failures that can contribute to running too rich. The comment about being intermittent at first is an important clue.

I would be looking towards things like the MAF (Mass Air Flow) sensor and the MAP (Manifold Air Pressure) sensor. Even the IAT (Intake Air Temp) sensor. Seems like you go into a failure that causes all 8 plugs to come out black. Oxygen sensors are a possibility, but they would seem to want to fail one at a time rather than all four at once.

If you have a lot of miles, could be wiring degradation, possible broken wire. Know it’s a pain to do, but checking wiring between these above mentioned sensors and the ECM, while moving the wires as much as possible might be a cheap test.

And then there is the distant long shot of run-a-way, fuel pressure. The ECM has no way of knowing what the fuel pressure is.

So before you order up a replacement engine, might want to do a little testing on these sensors.