MAFT issue, car runs as if its vented incorrectly

[rabi42]

First off, the car is vented correctly. Car runs great except for a small phantom knock issue that comes and goes. However, its dies or almost dies if I let off the gas after reving it or coming to a stop light. I've read all kinds of posts on MAFT's but most are about settings and how to hook it up and such. I don't have an SAFC, but should that matter if the car is pulling good and not misfiring or anything? Thanks for any info.

 

[jott5555]

could be an isc or idle control issue..

 

[spoolup]

Also be sure ot pressure test your setup. ALOT of times after people install IC piping they have a leak somewhere. You would be surprised how many times I see it. And the Maft is just a piggy back to the factory ECU, which uses differnt maps based off of airflow, throttle ect. So when you say it does pulls good and does not missfire, you could have a problem with your low or mid fuel trim which could easily be masked with the WOT table, and can actually cause your phatom knock issue. Do you have some sort of logger? If not, I would HIGHLY recommend atleast borrowing someones to log your car (I loan mine ot fellow local DSMers intrade for dinner at some fast food joint) and follow this guide:
http://www.dsmtuners.com/forums/showthread.php?t=58403

The MAFT provided injector setting tables are just approximates and vary even more when in a blowthru setup. I know mine was off few ticks. So just "setting and forgetting" is not applicable.

 

[exile]

I'm assuming the MAF-T is setup for 450cc injectors correct? You reset the ECU after you made those changes? You've allowed 30-40 minutes of driving to let the ECU remap itself?

I noticed my car (untuned and uncalibrated for the MAF-T) ran slightly better than my friends car (untuned and uncalibrated for the MAF-T) and he had a turbo back exhaust system.

I suggest like what was suggested above, run a log *some how*. If it's possible do a boost leak test also. You may have created a leak in the process of adding these new pipes and what not. (We did, twice.. from the sidemount)

If your car worked fine before you put it on, and all you put on was the MAF-T, you can bet your money the problem lies with the MAF-T. So I doubt it's your ICS (enless you broke it during install).

 

[rabi42]

Thanks for the info guys. I have a logger and have logged it a few times. I'll have to get one and post it. I've reset the ECU, tried different injector settings (450 to 500), and allowed plenty of time for the ECU to recalibrate itself. I just noticed the other day that the couplings holding the GM MAS seem to have slipped a bit and were disrupting the airflow through the MAS. I moved everything back so that it's nice and smooth, and it seems to have solved the problem. I'll give it a few days and see what happens. Thanks again.