Hi guys just wanted to share with you my code 33 experience. Finally got rid of it!!...I bought the autoprom from Craig Motes last week and increased the value of the MAF threshold to about 75 gm/sec and pow!! code 33 gone...had this intermittenly and was driving me nuts for the longest time, had to turn the engine off and resart the enigine to get rid of it for a while until the next morning the same problem would occur!!! FINALLY gone, cooked, adios..

Craig Moates is the man!!!...and the service was awesome...emailed him a few times to ask him questions and he responded right away..now thats service!!

thanks Craig for all you help

 

Yes, that error code will drive one crazy. Once the engine is modified the SD setups have the same issue. Code 33, MAP high (and in your case MAF high). Increasing the diag threshold does the trick.

Did you find that the engine ran smoother when the code was present? Sometimes they do, which is interesting.

RBob.

 

Hi RBob, the engine actually ran like crap when the code would appear .....I set the threshold to 75 gm/sec..Is this value ok??...I know a few people set them to 55..Just wanted to play it on the safe side

 

As for setting it to 75 vs 55 gms/sec, would need to datalog the area/time that the malfunction test is run. Then make a decision based on what values are normal. Or lower it until the code comes back and bump the threshold from there.

Since the real interest is to avoid false 33's, I'd do what you did and just bump it to a reasonable value.

So it ran bad with the code set. . . hmm, that means that the cal values to create the airflow term from RPM & TPS is way off. This is something that can be left as is, or the values can be changed for a better fit. My preference has been to tweak the code 33/34 present tables enough so that it runs OK. That way it will run well enough if the MAF does go out.

RBob.

 

You would have to keep your foot on the gas to keep the RPM in the 650 range it would bounce below 650..one time I didnt keep my foot off the gas at a stop light to see what would happen and the car stalled out.....So bumping the gm/sec wont harm the engine in the long run right??.....hopefully at 75 it will still detect a real error code or will it??..I am using the $32B for my 88 tpi..I copied my original chip bin and tweaked the value of the gm/sec..left all other parameters stock..It is running great so far but have heard alot of people using $6E.....adjusted my minimum airflow way back before burning chips to 650rpm and the tps to .54 and the idle is great now...before adjustment the idle was bouncing and would have to keep my foot on the gas....bought a new AIC then did the above adjustments afterwards and like i said now the idle is awesome..it was just he dam code 33 popping up after the adjustments...wondering if the minimum idle air was out of wack with the tps causing the code??....either way burned my own chip and pow!! code gone..finally!!

 

You can pretty much go ahead and just disable the max airflow check altogether. To properly check the MAF, you could need to run speed density type calculations to get a valid airflow value to compare the MAF flow to. The max and min checks are of little use in my experience due to how dynamic the airflow can be. Early on, I ran the $6E MAF code with my first MAF setup, and I just disabled the high airflow check. The only thing I left in was a low airflow check so that if something went wrong with the MAF and it dropped the signal, the car would still start and set a code.

 

Even with the high airflow test disabled, if the MAF were to fail in that manner you would know it immediately. The engine would be flooded with fuel, then foul the plugs and die. IOW, I wouldn't completely disable it. It is useful and does work when needed.

RBob.

 

Thanks guys for your help....interesting stuff