Help diagnosing hesitation at WOT
12-12-2011, 11:38 PM
#21
Melting Slicks
Has to be in the tune, get some logs from your tuner and post them up here. I would guess your tuner tuned the PE table and didnt smooth it properly and right at that point is where he started tuning so you have a drastic change in fueling right there. A spike either rich or lean in the PE table and you will feel it.
12-12-2011, 11:40 PM
#22
Melting Slicks
Ahh yep like I said above, your PE table is not smoothed properly causing the issue I bet. Ask him to interpolate between the two blocks where the said problem is and I bet it goes away.
12-12-2011, 11:48 PM
#23
Melting Slicks
Just for your reference here is what the PE table looks like, you can see how the numbers smoothly change. If you just hit the car with fuel it will stumble a little bit.
12-13-2011, 12:16 AM
#24
Le Mans Master
Thread Starter
Thank you very much for the help! Ill let you know how it goes
12-13-2011, 01:30 AM
#25
Safety Car
[QUOTE=95BlueBomber;1579457365]Just for your reference here is what the PE table looks like, you can see how the numbers smoothly change. If you just hit the car with fuel it will stumble a little bit.
I mentioned that in post #7. I was on the right track?
I'll keep reading.
Ron
I mentioned that in post #7. I was on the right track?
I'll keep reading.
Ron
12-13-2011, 07:45 AM
#26
Le Mans Master
Thread Starter
[QUOTE=RonSSNova;1579457775]
08-15-2013, 10:53 AM
#27
Drifting
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Im curious I have a similar issue and im raising the dead on this thread. What was the end result?The issue I have is anything past half throttle it feels like I hit a brick wall with the hesitation.
09-08-2013, 12:42 PM
#28
Burning Brakes
I noticed this is an old thread but I Also am having these issues... I even had a tuner Check it out... Tuner said that might be my BCM since I have a 98 also he said he couldn't tune my car cause of a bad BCM..... but my car doesn't throw ANY codes? I think tuner just didn't have the right tools to tune a 98... Idk frankly I'm tired of the run around hopefully a much more educated tuner can chime in....
09-08-2013, 05:09 PM
#29
Tech Contributor
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CI 6,7,8,9,11 Vet
St. Jude Donor '08
I noticed this is an old thread but I Also am having these issues... I even had a tuner Check it out... Tuner said that might be my BCM since I have a 98 also he said he couldn't tune my car cause of a bad BCM..... but my car doesn't throw ANY codes? I think tuner just didn't have the right tools to tune a 98... Idk frankly I'm tired of the run around hopefully a much more educated tuner can chime in....
In fact,,, If you have EFI Live, you don't even need a license to tune a 97 or 98.
Find a more competent tuner!
09-09-2013, 12:48 AM
#30
Burning Brakes
I would start your own thread and maybe reference this one.. The BCM has NOTHING to do with tuning. You only tune the PCM.. You cant tune the BCM but you can access it with a GM Tech2.
In fact,,, If you have EFI Live, you don't even need a license to tune a 97 or 98.
Find a more competent tuner!
In fact,,, If you have EFI Live, you don't even need a license to tune a 97 or 98.
Find a more competent tuner!
I made a typo I meant PCM ...supposedly my 98 PCM is "none responsive and won't go in to rich mode"?? As I was told by tuner... He suggests that I upgrade to a 99-up at least PCM so he can tune it properly... Funny thing is .. All the broken PCM I read about.. Car would be throwing codes left and right .. Mine doesn't throw any codes (knock on wood) so I smell something fishy there.. Def need to find a more competent tuner... Can someone chime in and make some sense for me regards to what I was told? Thanks
09-09-2013, 06:10 PM
#31
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Location: Anthony TX
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St. Jude Donor '08
Hmmmmm,,, Yes the 97-98 Pcm is not as responsive as the 99+ PCM but,, what HP. Mod level are you at>
The stock PCM should easily handle simple bolt on mods and standard tuning. When you hammer the throttlem does the respond properly?
Rich Mode?? Maybe he said Power Enrichment (PE) Mode.
How are you reading the DTCs?? Are you using the built in code reader?
READING YOUR Engine Diagnostic Codes (DTCs)
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 etc…)
3) Press and hold OPTIONS
4) While holding OPTIONS, press FUEL four times within a 10-second period.
Initially, on-board diagnostics go into an Automatic Mode which 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. ( 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 kinds 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.
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.
Here is very good site of DTC definitions:
http://www.gearchatter.com
Make sure to include the H or C suffix!!
The stock PCM should easily handle simple bolt on mods and standard tuning. When you hammer the throttlem does the respond properly?
Rich Mode?? Maybe he said Power Enrichment (PE) Mode.
How are you reading the DTCs?? Are you using the built in code reader?
READING YOUR Engine Diagnostic Codes (DTCs)
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 etc…)
3) Press and hold OPTIONS
4) While holding OPTIONS, press FUEL four times within a 10-second period.
Initially, on-board diagnostics go into an Automatic Mode which 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. ( 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 kinds 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.
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.
Here is very good site of DTC definitions:
http://www.gearchatter.com
Make sure to include the H or C suffix!!
09-09-2013, 07:00 PM
#32
Burning Brakes
Bill.. I think it is the PE he was talking about? But as for mod level goes I have done h/c/I changed all injectors and plugs and all the necessary supporting mods... When my car was on the dyno he said it wasn't going on to PE mode? That's why didn't proceed with the dyno tune.. I'm a newb in all of this I'm really just trying to make sense of things. My car doesn't throw any codes I do check the dtc often and I have no codes showing anything so I'm confused as why he would say that... I just want to know of it's my car there's something wrong with or just an incompetent tuner
Hmmmmm,,, Yes the 97-98 Pcm is not as responsive as the 99+ PCM but,, what HP. Mod level are you at>
The stock PCM should easily handle simple bolt on mods and standard tuning. When you hammer the throttlem does the respond properly?
Rich Mode?? Maybe he said Power Enrichment (PE) Mode.
How are you reading the DTCs?? Are you using the built in code reader?
READING YOUR Engine Diagnostic Codes (DTCs)
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 etc…)
3) Press and hold OPTIONS
4) While holding OPTIONS, press FUEL four times within a 10-second period.
Initially, on-board diagnostics go into an Automatic Mode which 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. ( 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 kinds 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.
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.
Here is very good site of DTC definitions:
http://www.gearchatter.com
Make sure to include the H or C suffix!!
The stock PCM should easily handle simple bolt on mods and standard tuning. When you hammer the throttlem does the respond properly?
Rich Mode?? Maybe he said Power Enrichment (PE) Mode.
How are you reading the DTCs?? Are you using the built in code reader?
READING YOUR Engine Diagnostic Codes (DTCs)
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 etc…)
3) Press and hold OPTIONS
4) While holding OPTIONS, press FUEL four times within a 10-second period.
Initially, on-board diagnostics go into an Automatic Mode which 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. ( 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 kinds 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.
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.
Here is very good site of DTC definitions:
http://www.gearchatter.com
Make sure to include the H or C suffix!!
10-22-2013, 01:02 AM
#33
Burning Brakes
Just wanted to make an update regards this issue.. Got the car street tuned and I guess the cars a/f ratio was all messed up.. It wasn't giving enough fuel under load or wot so tuner had to work some magic and have it put out more fuel... 2 weeks of driving after street tune.. no more hesitation! Car gets dynod end of nov hopefully all goes well and I never have to run in to this problem again
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