Engine misses, stumbles, coughs - undriveable

MichBC3

Member
Sounds as if you have diagnosed most elements. But as you well know these cars will make you gray headed quickly. If Scott can can't find a solution on the read out. I would consider having it tolled up to Don Cruz Performance in Tampa. ? Good Luck.
Thanks for suggesting Don Cruz. However if Eric at TurboTweak and I can't figure this out, I will have it flat bedded to Cal Hartline in Melbourne (about 100 miles north of me). That's the last resort. I hate to give up though!
 

Pittguy

New Member
Check the maf sensor plug wiring. Ecu pins for condition.corrosion.etc. caspers tool setting doesnt always hold true for every car
 

ScottHeidinger

Active Member
Looks like your MAF is reading too high. If I remember correctly there is another car in your garage that may have a good MAF sensor. I would swap the MAF from the white car and test it. I assume they both have the stock MAF sensors. Please verify the sensor is not installed backwards as that may also cause issues. I know you said you swapped it out before but maybe the plugs were fouled before? If you’re using a stock sensor I would swap to a translator and a newer sensor LT1 or LS1 style. HTH

Scott


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GNRick

Retired member
I had an O2 sensor fail at the dragstrip. Couldn't go past 30 mph like you. I would dump that Bosche O2 and put in an AC Delco.
 

MichBC3

Member
Ok guys. Thanks for all the help. Time to put this thread to bed. Yes, it turned out to be a bad MAF - as per the high reading (16) which according to Eric is about twice as high as it should have been at idle. The high MAF value was making the ECM throw twice as much fuel into the engine - making it run super rich. As a test, Eric said to make a log with no MAF (the computer would assign a base value). That leaned it out a lot. Instead of seeing 7 to 1 A/F in the Powerlogger, it was about 15 to 1. Because my TTA has an ACCEL Gen 7+ running it, I had a spare MAF that I forgot about. I just installed it and the A/F numbers are now about right. Not perfect, but at least I have the car running off of dead rich which is something that I can work with. I will install a new set of plugs and re-check for any possible vacuum leaks. But chances are that it just needs fresh plugs.

When I was trying to troubleshoot this problem in the previous engine, I borrowed a friend's MAF and saw no difference in the way the car was running. But by the time I tried that, the spark plugs were most likely badly fouled out. It's also possible that my friend's spare was no good. Back then I knew nothing about typical values for MAFs at idle. I didn't have enough experience with MAFs. I am used to the speed density system in the TTA.
 

MichBC3

Member
Looks like your MAF is reading too high. If I remember correctly there is another car in your garage that may have a good MAF sensor. I would swap the MAF from the white car and test it. I assume they both have the stock MAF sensors. Please verify the sensor is not installed backwards as that may also cause issues. I know you said you swapped it out before but maybe the plugs were fouled before? If you’re using a stock sensor I would swap to a translator and a newer sensor LT1 or LS1 style. HTH

Scott


Sent from my iPhone using Tapatalk
Missed it before, but just saw this Scott. I will go offline with you on email. Catch you there.
 
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