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Discussion Starter #1
2002 Z06. Bought with 30k+ miles. PGMFI light coming on in the first week. Turns out to be plug wires. Ran fine for 2 weeks. Check light coming back on and now it barely runs. Will not get out of the subdivision. Due to running rough and smoke out of the exhaust. What is going on. Anyone seen these symptoms yet? I cannot believe the car is crapping out this early on in life. I will need to test compression and leak down but It feels like bad electrical/ignition. Anyone have experience with this? Smoke?
 

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Check your spark plugs next. You know that your wires are new. Start by checking the least expensive stuff. Move up from there.

Also, check what codes are thrown.

Good luck and keep us posted.

Alex
 

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it depends what kinda of smoke? as bad as its running you could have a few cylinders not firing, besides electrical ect it could be a coil pack, or maybe bad cylinder by broken internals, do you know the history of the vehicle?
 

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Since it is continually getting worse, it sounds like the computer is trying to adjust to something. Try checking the rear O2 sensors. The previous owner might have pulled off headers and reinstalled the original exhaust manifolds, accidentally installing the sensors on the wrong sides. If that is the case, the computer is making lean/rich adjustments to the wrong sides making the problem worse.
 

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The IPC display, the 20-character, vacuum florescent screen above the steering column that says "Corvette by Chevrolet" every time you turn on the key is a powerful device.
DIY Service Techs are going to be most interested in the LPG’s ability to show diagnostic trouble codes (DTC) for all the modules that transmit them..

The "diagnostic display" mode is entered with the following Procedure: Page 8-500

Turn on the ignition but don't start the engine.
Press the "reset" button to turn off any warning messages
Press and hold "options" and
While holding "options", press "fuel" four times within a 10-Second period.
Initially, the on-board diagnostics go into the "automatic" mode, which shows each module's DTCs in a pre-set sequence: (Page No. are for the GM Service Manual)

10 PCNI Powertrain Control Module page 6-357 - 6-361
28 TCS Traction Control system ABS on page 5-86
?? RTD Real Time damping page 3-136
40 BCM Body Control Module page 8-405 LTD Page 8-727
60 [PC instrument Pane! Cluster page 8-508
80 radio page 8-213
99 FIVAC Heater Vent-Air Conditioning page 1-118
A0 LDCM Left Door Control module page 8-904 to 8-951
Al RDCM Right Door Control Module page 8-904 to 8-951
AC SCM Seat Control module page 8-1064-8-1082
B0 RFA Remote Function Actuation page 8-676
For each module, all DTCs will be displayed. If none are present in a module, you will see "no more codes" on the ICP display. There are two kinds of DTCs, "Current" and "History," designated with a letter suffix, "C" or "H". A current code indicates that the malfunction is present in the system whose module is displaying data. A history code indicates a problem existed in that module sometime in the last 40 or 50 ignition cycles. When not accompanied by a current code of the same number, it is possible it's evidence of a previous problem. Now solved, that was not removed by clearing codes. More likely is that a history code indicates an intermittent malfunction.

"Intermittent" are the most challenging DTCs. An intermittent may have happened only once, may have happened more than once but is inconsistent in its appearance or may be happening on a regular basis but not at the time the IPC is displaying codes. History codes can also be caused by a current malfunction in a system that is not Operating at the time DTCs are displayed. An example is the rear window defogger, which doesn't operate until the BCM detects engine rpm. For history codes set by a system that does not operate with the key on and engine off, a special diagnostic tool called a "scan tester is necessary to properly diagnose the malfunction.

Once the IPC has displayed all 11 modules, the system goes into the manual mode, which allows selection of each module, using combinations of DIC buttons. The manual mode can also be entered at any time during the automatic sequence by pressing any button except "E/M". Once the IPC displays "manual diagnostics", you may select a particular module by pressing the options button to go forward or the "trip" button to go back. Once a system is selected and a DTC is displayed, if more than one are present; press "gages" To move forward or "fuel" to go back. To exit the diagnostic mode at any time, press E/M". If you want to erase or "clear" codes, press "reset". Clearing a code does not repair a problem. You are simply erasing the evidence of it in the module's memory.
 

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Erasing DTC Codes -- 1 of 1

You can acess all of the cars trouble codes from the dic and erase them! I know it works on my 99 and up but, I am not so sure on the earlier C5's. Here is what you do: Press and hold options and then press Fuel 4 times while still holding the options button you must do this quickly. A message will appear saying "Diagonstics" then it will automatically read off the codes. Like....02-PCM(No codes)....03-BCM(No Codes)...ect. if there is a code it will look something like this 02-PCM (1052H) NOTICE THE H at the end of the code, That represents a code that has happened in HISTORY. If there is a C after the code it is CURRENT. To clear the codes let it automatically cycle through the codes then it will come to (MANUAL DIAGNOSTICS) this is where you can clear codes. Use the options button to scroll forward and the TRIP to scroll backward find the code(s) to be erased like 02-PCM (2Codes). To erase this, press and hold the reset button until it says "NO CODES" There you have done it!!!. To exit the Diagonstic menu press the METRIC BUTTON!!!
 

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I can remember all that. :lol:
 

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Discussion Starter #8
Thanks for all the replys....

It L GO, that post rules!!!!! I did not know any of that stuff. I was wondering if this was posible on the Corvettes, now I know. I found some more symptoms that are quite intriguing to me. I do not own this beast of a car, but at times (like during full throttle acceleration) I wish I had one of my own. I have had these cars out on track at VIR and they are Phenoms all over the track. That being said.....

The rest of the symptoms:
1. Raw liquid fuel coming out of the Driv (Left) exhaust, stinking very bad! Fuel smoke from the exhaust choking me to death! Engine light on!
2. Changed the spark plug wires with some that I had from a buddy from a normal C5. Car began to run better with no miss. Then it developed it again. Cleaned the Denso plugs, it helped again. Drove it and it did not miss a beat. I could tell that it did not have all the 405 ponies in order though.
3. Turned it back over to the owner. He said that the next day it was doing it again. Nasty smoke. I told him to get the car out and drive the fule out of it. He would not do it so I went over and checked it out again. # 7 cylinder was not making any difference when the spark plug wire was disconnected. Fuel dripping out the back again. Disconnected the injector, reconnected and then I took it out for a drive. Smoke lasted about a mile and then it ran good.
Drove it for 15 minutes and cleared it out good! :thumb: Owner was with me so he had a fun drive.
4. Told him to drive the car for a while until the gas tanks were empty and put an additive into the tank that I believe in very much (Seafoam) and fill it up with Amoco 93 octane. He did so at my direction and the engine light actually went out on its own and then came back on after getting on a road where partial throttle is the normal. But the owner says that it is running very good.

I have ordered Magnacore wires for the car and I picked up some NGK iridiums and intend on getting those in the car tomorrow. This should help some as I know that it has with other C5s that I have helped with. I know that it could be a injector stuck open, but I have faith in the cleaner that it will deal with that somewhat. If the raw fuel drip continues, I will send the injectors to Marren Motorsports and have them balanced.

One question - - Does the Z06 have an external (from tank) fuel filter and where is it? I really need a manual. Where do you get one? (That was three questions, but one might answer the first two with the last).
 

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Not knowing the codes makes this a guess------ BAD INJECTOR
 

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hondaman said:
One question - - Does the Z06 have an external (from tank) fuel filter and where is it? I really need a manual. Where do you get one? (That was three questions, but one might answer the first two with the last).
The 01 I have, and I believe the 02s and 03s have a filter external to the tank. From under the car it is located on the left side of the trans, bolted to a frame rail.

The 04 cars (I believe) have the filter in the tank, as they had the C6 fuel system. Be warned tho, that the filter isn't a $15 deal, I paid about $50 for mine. They have the pressure regulator built into them, so they're spendy.

For the manual, I got mine through Helm (the publisher) for $125 or so. There may be cheaper sources, but I'm not sure where. I'd much rather have it on cd, but whatever.
 

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Discussion Starter #12
I'll Check it out.....

As soon as I get the chance, I will let you know what I find. I went to go pick up a scantool from Pepboys since they have it on sale and they were closed 20 minutes before I got there (45 minute drive to get to the place!). I should have known they would close on Memorial Day soon, but when I called the guy did not tell me that they were closing early. Jerk!

Anyways, this car is having many problems and I hope to ID them all an let all of you know.

Again, thanks for the input and I will try to get him to buy the manual.
 

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Discussion Starter #13
OK, new update.....

I left for vacation for a while and sorry for the delay.

I changed the Spark Plugs and wires and checked all the coils. Anyone know the proper resistance on the 4 posts of the connector of the coil packs? I tested all 8 coils for each position on the coil pack and only two were slightly different in the resistance from one contact point to the other.

Irregardless of that, the spark pulg and wires did the trick, mostly. I still think that the fuel injectors are clogging open and that is what is causing the light to come on for the first time in almost a month. It is running rough again and has the PGMFI light on. I will scantool it tonight and see what is going on, but apparently this car has more problems than just the ignition. But for the last 3 weeks it has been running like a top!

Sounds like its off to Marren with the injectors and a new, High $ fuel filter and we should be ready to go. We'll see!
 

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Discussion Starter #15
Update from yesterday....

I scanned the computer on the '01 and it said that it had an open injector circuit. It listed it twice too!! I guess that I have one or more injectors dying. This means total failure of the injector, not only for fuel reasons or clogged injectors, but a full dead circuit in one or more of the injectors. It could come back to the issue of the wiring harness being chaffed, but does anyone know where this "standard" chaffing occurs exactly. Someone mentioned firewall, but where?

Anyone ever seen this before?
Good place for purchasing injectors other than dealership?
Good time for an upgrade?
 
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