View Full Version : New MAF conflicting with injectors

05-11-2006, 07:16 PM
I recently had my car taken to the shop because it broke down on me about 200 miles away from home. The mechanics(?) at the shop replaced the MAF sensor. They told me now that the car runs fine when driving it but when it sits at idle it doesn't idle right. They told me that the new MAF is not tuned right to the aftermarket injectors and therefore the fuel/air mixture is off. For some reason this doesn't sound right. Any help would be appreciated. -Austin

05-11-2006, 07:34 PM
If you had a stock MAF sensor on there and they replaced it with an aftermarket stock style sensor, chances are the new sensor is reading too low. Do a search and you will find numerous topics about how the stock replacements are very often miscalibrated to begin with out of the box. Do you have a scantool? At idle, the MAF should be reading ~ 4-7. Chances are it is reading too low. You may be a good canidate for the LS1 and translater MAF upgrade:


Not exactly cheap, but you might end up spending more swapping out MAF sensors just to get one that reads right. Plus they flow more, supposedly have better throttle response, etc. Just keep in mind that you will also need the translator with the MAF sensor. It is a plug and play setup.

Nice to meet you Austin,


05-11-2006, 08:07 PM
Would installing new, stock injectors be cheaper or even fix the problem? Sorry I'ma newbie to the mechanics of cars.

Harry Mash
05-11-2006, 09:59 PM
You first need some kind of scan tool to see whats going on with the sensors and actuators on the car --- otherwise your throwing parts at the problem and shooting in the dark. for example, do you have the correct comrputer prom for the size of the injectors?--- are the idle air valve and throttle position sensor set correctly?

05-11-2006, 10:32 PM
1. What parts are in the car? i.e. Which injectors, which MAF, which fuel pump, etc. Brands and P/N's if possible.

2. What are the readings from the IAC, TPS, and MAF at idle?

3. Who is the shop? A 'repair shop' or a 'shop that knows TRs'? Anyone we would know? Do they have a scan tool? Do they know how to use it? Are the mechanics/technicians out of diapers yet?

4. Do you have a scan tool?

Sounds like a possible MAF issue or IAC needing reset. There are instructions for the latter on this site.

05-12-2006, 09:31 AM
Scott's list is a good one ...

A comment about your shop ... they are full of it. :rant:

The MAF doesn't "have to be matched" ... it's a device that measures the air that goes into the engine. It knows nothing about injectors or anything else on the car ... if it's calibrated correctly, then it'll work.

Scantool data will help narrow the problem down (and I'm guessing it's a remanned MAF that isn't reading right).

05-12-2006, 02:09 PM
Thanks for all the help guys. I'm think I'm going to get a scantool and go from there. I figure I need one anyways so I'm gunna get one and see if I can narrow down the problem. If I have anymore issues I'll let you guys know. Thanks again -Austin

05-12-2006, 03:06 PM
BTW does anyone know where I can find instructions on how to reset the IAC?

05-12-2006, 03:27 PM
w/out scantool: