Data Log
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From: Hell was full so they sent me to NJ
Re: Data Log
I already downloaded the log yesterday, took a quick look at it. I see where DTC 33 sets immediately on startup. Had you cleared the code before startup?
The criteria for DTC 33 on a 94 is "Less than 3% throttle angle, MAP greater than 80kPa, MAP greater than 90 kPa with A/C on, RPM greater than 500 RPM, and DTCs 21 and 22 not set. All conditions met for 1 second."
First, your MAP sensor appears to be working. At key on, before the engine cranks, the PCM reads the barometric pressure from the MAP sensor. Your log indicates 99.65 kPa, which is reasonable value at or near sea level. When the engine starts, the MAP reading is higher than expected (60 to 70 kPa, vs a typical value of 35 kPa). But I have to assume that is the result of the boost from the S/C. I will warn you right up front... I am not a tuner and I do not know what the tuner may have done to your program to accommodate the S/C. And I do not know if you are even supposed to get boost at idle/low RPM.
Do you have a boost gauge? If so, what does it read at idle? 70 kPa would appear to indicate about 4 to 5 PSI boost.
That possibly is the issue of DTC 33. Has it had the SES light on and DTC 33 from the day you got it? The conditions to set DTC 33 were not met when the code set. MAP was 65.70 kPa and throttle position was 5%. That tells me someone may have altered the tune. Do you know how the tuner set it up to add the extra fuel for boost? Does is have an FMU, boost referenced fuel pressure regulator, or a 2-bar MAP sensor?
As far as the comment about the code is set by both high voltage and low vacuum, not exactly correct. The only thing the PCM can "see" from the MAP sensor is the voltage. The PCM has a table of voltage vs. kPA and just assumes from the table that if the voltage is high enough, vacuum is low at 80 kPA.
Next, what do you mean by "running like crap"? Not a technical term I'm familiar with
. Does it start OK? Does is run OK for the first 4 minutes (time it took your PCM to go into closed loop)? Does it get worse after 4 minutes? Is it running rough, misfiring, backfiring, wandering idle, stumbles on opening the throttle, etc.? Need that kind of detail.
I will continue to look at the log, but the more info you can provide in response to the questions, the better chance we have of finding the problem.
PS - Welcome to CamaroZ28.com!
The criteria for DTC 33 on a 94 is "Less than 3% throttle angle, MAP greater than 80kPa, MAP greater than 90 kPa with A/C on, RPM greater than 500 RPM, and DTCs 21 and 22 not set. All conditions met for 1 second."
First, your MAP sensor appears to be working. At key on, before the engine cranks, the PCM reads the barometric pressure from the MAP sensor. Your log indicates 99.65 kPa, which is reasonable value at or near sea level. When the engine starts, the MAP reading is higher than expected (60 to 70 kPa, vs a typical value of 35 kPa). But I have to assume that is the result of the boost from the S/C. I will warn you right up front... I am not a tuner and I do not know what the tuner may have done to your program to accommodate the S/C. And I do not know if you are even supposed to get boost at idle/low RPM.
Do you have a boost gauge? If so, what does it read at idle? 70 kPa would appear to indicate about 4 to 5 PSI boost.
That possibly is the issue of DTC 33. Has it had the SES light on and DTC 33 from the day you got it? The conditions to set DTC 33 were not met when the code set. MAP was 65.70 kPa and throttle position was 5%. That tells me someone may have altered the tune. Do you know how the tuner set it up to add the extra fuel for boost? Does is have an FMU, boost referenced fuel pressure regulator, or a 2-bar MAP sensor?
As far as the comment about the code is set by both high voltage and low vacuum, not exactly correct. The only thing the PCM can "see" from the MAP sensor is the voltage. The PCM has a table of voltage vs. kPA and just assumes from the table that if the voltage is high enough, vacuum is low at 80 kPA.
Next, what do you mean by "running like crap"? Not a technical term I'm familiar with
. Does it start OK? Does is run OK for the first 4 minutes (time it took your PCM to go into closed loop)? Does it get worse after 4 minutes? Is it running rough, misfiring, backfiring, wandering idle, stumbles on opening the throttle, etc.? Need that kind of detail.I will continue to look at the log, but the more info you can provide in response to the questions, the better chance we have of finding the problem.
PS - Welcome to CamaroZ28.com!
Last edited by Injuneer; Apr 7, 2017 at 11:09 AM.
Thread Starter
Registered User
Joined: Apr 2017
Posts: 12
Re: Data Log
Yes the code was cleared before startup. When I start the car I actually have to pump the gas pedal to get it to fire up and then rev it for about 10 secs for it to stay at idle and not die. The couple of times that I have been able to drive it, upon warm up it will stall when coming to a stop. At idle boost gauge reads 10lbs on vacuum side. I know it's been tuned for my setup but don't know the specifics. Original owner ran NOS but don't know specifics on it either. It does have a NOS fuel pump and has 40lbs of pressure.
Thread Starter
Registered User
Joined: Apr 2017
Posts: 12
Re: Data Log
Has far as a fmu or a boost reference fuel pressure regulator I'm not sure. How would I know or where would I look if I have that? It has a 1 bar map sensor. Once I get it idleing it seems to be fine untill I put it in gear, then it stumbles and dies. No backfiring, it's not missing and a/c is not hooked up at the moment.