Gm Mas Make Car Feel Like A Boost Leak!

[turbotsi92]

I recently installed the GM MAFT setup. I went to take my car for a 3rd gear pull, and when I put it to the floor it started stuttering very bad, and I thought I had a bad boost leak, I haven't built my boost leak detector yet, so i just thought I would unhook the sensor, and hook back up my stock MAS. I did that and my car ran fine again, so I was just wondering if there is anything that could be causing this. I watched my logger while trying to pull in 3rd, and I had no knock, and the 02 was right around .89. I don't understand it. Any help would be greatly appreciated. Also, all of the settings on the translator are 0.

 

[DrDSMGSX]

My first guess would be the computer is seing too much air. Read the manual it specifies what the base setting should be for 550s. Even with the base set you still will need to play with it to get all the settings right. I am still adjusting mine trying to get it in the sweet spot but as it is right now I can feel improvement from stock sensor.

 

[sweet97]

You need to have the base knob on "C" to start and then watch the trims to get them around 100%. If the trims are low set the base to the left(counterclockwise) , turn clockwise if the trims are over 100%. Do this until you get them around 100%. Set the idle knob for a good idle. Mid knob is for the time you are rolling into boost, maybe the first 5PSI and WOT is for, well WOT!! Sounds like you were rich no matter what the logger says unless you have a leak after the maf. Mark

 

[turbotsi92]

I have an SAFCII, and I am tuning with that. I already have the fuel turned down for the 550ccs, but if it is seeing alot more air it might be a little lean, but I even tried putting the entire stock intake system (sensor and all) back in, but not hooking it up, just keeping the GM MAS hooked up so there should not have been any more air coming in than before because the stock mas was restricting it.

 

[sweet97]

I would still set the base on "C" and be sure all the 4 dip switches are off and go from there. I love the MAFT! Works great and I have gotten a 12.03 with the MAFT as the only tuning device. mark

 

[rowlex]

hooked up so there should not have been any more air coming in than before because the stock mas was restricting it.

It's not a restriction issue, it's the fact that the GM MAFT is not calibrated correctly for our cars, sure it's in the ballpark but it really isnt very close at all.

here is what you need to do:

Hook up your stock MAS, go for a drive (ofcoarse do a few pulls) log you airflow
unplug the stock MAS, plug in the maft, go for the same drive log airflow

you will notice the airflow numbers being a lot different you need to make them the same, I assume you would need to change the dial things in the MAFT --I have no experience with this(maft box settings changes) as I do all my tuning with DSMLink. Anyway this will calibrate your maft to a state much closer to your stock MAS.