im looking for some help with this problem. my check engine light is flashing. it doesnt stays on it just start flashing. no codes or anything else. some one told me it could be a ground issue??? any one with experience about this??

my car is a 2001 z if that helps.

any help or advice would be good.

thank you guys,

 

that indicates that a cylinder is misfiring. Pull codes, and check the plugs and wires.

 

LUCKY is correct. Pull the DTCs IMMEDIATELY or as the problem happens.. You can read the DTCs without turning the engine OFF. The P-0300 codes clear them selves each time you turn the ignition off. So,,,unless you read the DTCs when the issue happen, you will loose your data.

Just pull up the DTCs (do not be a distracted driver) while the engine continues to run. If your not familiar with the process,,,here ya go:

READING YOUR Engine Diagnostic Trouble Codes (DTC)

This procedure should be carried out any time you experience a problem with your C5. Most inexpensive store bought aftermarket code readers will ONLY read power train DTC’s. Reading the DTC’s with the C5 built in code reader will allow you to read ALL the modules in the vehicle.

The Diagnostic Display Mode is entered with the following procedure:
1) Turn on the ignition but don't start the engine.
2) Press the RESET button to turn off any warning messages. (i.e. door open, trunk open ect)
3) Press and hold the OPTIONS button
4) While holding OPTIONS, press FUEL button four times within a 10 -second period.

Initially, the on-board diagnostics go into an Automatic Mode which will cycle through each module and shows diagnostic codes in a pre-set sequence: PCM - TCS - RTD - BCM - IPC - RADIO - HVAC - LDCM - RDCM - SCM - RFA. All codes will be displayed for each module. ( i.e. PCM = 4 codes) If none are present in a given module, you will see No More Codes on the display.

There are two types of diagnostic codes, Current and History designated with a letter suffix, “C” or “H”. A current code indicates a malfunction is present in the module displaying data. A history code indicates a problem existed sometime in the last 40 or 50 ignition cycles. When not accompanied by a current code of the same number, it's potential evidence of a previous problem, now resolved, that was not removed by clearing the codes. More likely it's an indication of an intermittent malfunction.

Intermittent codes are the most challenging of the diagnostics. An intermittent code may have happened once, may have happened more than once but is inconsistent or may be happening on a regular basis but not at the time the codes are displayed. History codes can also be caused by a current malfunction in a system that is not operating at the time codes are displayed. An example is the rear window defogger which doesn't operate until the Body Control Module detects engine rpm. For history codes set by a module 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 system has displayed all modules, it goes into the manual mode which allows selection of each module using combinations of Driver Information Center buttons. Manual mode can also be entered during the automatic sequence by pressing any button except E/M. Once the display shows Manual Diagnostics, select a module by pressing the OPTIONS button to go forward or the TRIP button to go back. Once a module is selected, a code is displayed, and if more than one are present; press GAGES to go forward or FUEL to go back.
To exit the diagnostic mode at any time, press E/M. If you want to erase codes in a given module, press RESET To reset the codes once in manual mode, press and hold RESET until it displays NO CODES Press OPTIONS to go to the next module. Repeat the steps until you have reset the codes in all the computer modules.
NOTE!! Only reset the codes IF you want to - it is NOT necessary to do this. Clearing a code does not repair a problem. You are simply erasing the evidence of it in the module's memory. If you clear the code/s, and extinguish the Check Engine Light, your emissions status ready will NOT allow you to pass an emissions test until you have completed the required driving cycles. There are a few body module DTC’s that if set will prevent the module from operating properly. Once the DTC is cleared, the module will return to full function. This is not true for power train DTCs.

If you have never read and cleared your codes, there will probably be a lot of old history DTCs. It is recommended that you clear your codes and see if any come back during a driving cycle. Those are the ones that you need to concentrate on diagnosing.

Once you have the codes, the next question is: What to do with the information?
First, consult the factory service manual. Any serious C5 Do-It-Yourself owner should invest in the Corvette Service Manual of the appropriate model year. The Service Manual is really a requirement if you want to understand and work on your C5.

These are some very good C5 Diagnostic Trouble Code (DTC) explanation web sites!!! They also explain how to read the DTCs

Here are some very good sites that explain what DTC mean:

http://www.gearchatter.com/viewtopic11755.php

http://www.obd-codes.com/trouble_cod...d-ii-codes.php

Make sure to include the H or C suffix when you post your DTCs!!

 

Guys,

I'm not getting any codes indicating a missfire or p0300 code! I did it with the car running while the light was flasing. When I reset the code (with no codes showing) it does goes away for a couple or seconds so I believe the code is there but I just cant see it probably bcs of the tune?? Is it possible that the tuner block the code? Any other way to find out which cylinder is the one?

Thank you guys!

 

You need to have a talk with your tuner... asap.

Tuners sometimes tune out a code (like a MAP sensor for a huge cam that just wont stop tripping the code, etc) but having a misfire code disabled shouldn't be in the game plan.

Check the plugs and wires, they are cheap and can fail (especially wires)

If you were in the Atlanta area I could help out since I have hptuners (I've got an '01 Zo6 as well too)

 

Thank you Joshua, I'll check the wires and plugs. Can it be a coil?

I have changed the plugs twice already so I don't think it's a plug but I'll check anyways. I have ngk tr6 gapped at 30

 

Try to read the codes when it happens, you should see a P030x where X is the cylinder when it happens.

 

It's extremely rare for a coil to fail.

My money is on the plug wires since the boots can eaily become detached internally as you're pulling them off the plugs/coils. The wire may just barely be hanging on internally and causing that misfire.

If you have a computer or other issue that would cause a misfire surely you would have codes.

If you've changed you plug wires recently, especailly several times over their life it's common for one to be damaged.

$60 GM performance wires (red in color) are just as good as MSD or anything else. Get some and let us know.

I'm betting $50 that you'll be fixed.

 

hopefully it's just a bad wire !!! I'll get new wires today and let u guys know!!

Thanks a lot!

 

What mods are done to the car?

If it's cammed and only doing this at idle, it is possible just the lope rhythm is causing it.
If you are not seeing the P0300 code (you have to check for it while the light is flashing), the tuner probably did set it to not report (a hack move), but doing so does nothing to prevent the flashing CE light.

If it is genuinely misfiring, than checking the usual ignition components is the next step, followed by valvetrain inspection ( a broken valvespring can cause this too). Connected to a scan tool can also further isolate the misfire to a specific cylinder, which can greatly aid in troubleshooting.

But regardless of cause, I would talk with, or get it to your tuner, and especially make sure P0300 remains a functional code if it is in fact disabled. There are better methods of eliminating the flashing CE light at idle, IF it is cam lope that's triggering it.

 

Ok guys the misfire comes from cylinder 4 and 7. I swap the coils and cables and still misfire on cylinder 4 and 7 so doesn't look lik a wire problem. I'll do a compression test to verify that but I don't think it's that bcs I did it a while back and it was 170 / 175 on each cylinder! MoDs on the car are:

383 forged internal
212/218 258/263 114lsa
darts pro1 heads

I already checked the injectors and they are better than new, now my car is on 11.03 air fuel ratio ( the tuner sucks). Not sure if that can be causing the problem?? I spoke with the tuner and he's going to enable the code.

Thanks, I'll post the next result

 

How did you check the injectors? Swap one with a cylinder not misfiring and see what happens.

 

With the machine to test and flush them!

 

I just noticed that the light starts flashing when u keep the RPM
around 2000 . It doesnt happen on idle or over 25/27 rpm. At the moment u go over 2500 rpm the light goes away immediately and if u go down it starts again

It's driving me crazyyyy :/

 

i already put new msd 8.5 cables and new spark plugs (NGK TR6 gapped at .30). compression test = 165-170 on each cylinder. injectors are good. i put the computer back to stock and the only code is p0300. and when i cruise around 1800 - 2000 rpm the light starts flashing.

any suggestion on what to do next?

thanks.

 

ttt

 

Try stock Iridium plugs with stock gap.

 

good info......thanks guys

 

have you found your problem... i do have almost the same problem.. but in my case... the engine light start flashing when i floor it and then the car start to miss at 4500rpm and then the light start flashing...

can wire and plug make me loose power at those rpm.. power is good till 4500rpm and then rpm go up slower from there...

any help appreciated..i will start with getting the plug and wire change tomorrow

thanks