bad gas mileage with LT1 swap!!....no MAF sensor on 94' - Third Generation F-Body Message Boards

mateo · 11-02-2005, 09:07 PM

The engine in this is a 94' LT1 from a Z28.....the car constantly smells like fuel...so im assuming its running rich....gas milege (odo doesnt work right not) seems to be VERY crappy.....the gears are stock form a 90 trans am 700r4 but i did notice that there is NOO MAF sensor....I know 94's had it and 93's did not. The car drives great but the mileage sucks, so does the missing MAF cause this on a 94' engine??? Id really like to fix this, what are my options....the wiring harness doesnt seem to have the maf connections in it so could I add them...or can I put an LT1 scanner or something to change some peramiter

sorry for being a newbie but any helpful info would be much appriciated.

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Klortho · 11-02-2005, 11:00 PM

LT1's run rich from the factory, if you are positive it's a '94 it should have a MAF plug, unless someone give you a '93 harness to go with it. Here's what the MAF plug looks like. And with no MAF you will be in limp home mode which will cause it to drink the gas.

mateo · 11-02-2005, 11:04 PM

from doing research im seeing that there is no "limp home mode" but rather it reverts to the speed density way of determining air/fuel data

now...if in fact my engine is a 94' with a 93' wiring harness....can I reprogram the computer to better situate the speed density to gain better fuel mileage?? Or install MAF?

TexasLT1 · 11-03-2005, 12:10 AM

no you can't reprogram it. get the correct harness, or dig around in yours to find the wires, and a MAF.

grover85 · 11-03-2005, 01:01 AM

You can reprogram it I think. I know my shop was doing that with late modle lt1's and ls1's

Klortho · 11-03-2005, 07:52 AM

The '93 program is different than the '94-95 models because it is a different PCM. '93 you still had to burn chips for and the PROM is a different size than the '94-95 models.

I call it limp home mode because the car is throwing a code for no MAF and really relies on both the MAF and MAP to determine air/fuel mixture and can end up dumping more fuel into the engine than needed.

With my MAF unplugged, the car ran ok, but didn't have the pickup that it did with the MAF. Like TexasLT1 said, find the plug, it should be around where the coil is, and if it isn't there....you'll probably end up buying another harness that is for the '94-95 model engines.