FAQ: Mass Air Flow (MAF) Sensor Issues?

After i got the cam installed I put on the 3.3" pulley because the belt wouldn't fit around the 3.5". I don't have the headers on yet either.

Just got an aeroforce scanner and I was getting around 7* of knock at about 80% throttle. I was getting between 1-3* in low throttle.

I used some electronic cleaner today on the MAF sensor. Went for a few runs after I did it and I'm not getting any knock under light throttle anymore. I'm only getting between 2-3* at around the 80% throttle now.

Its the same temperature as it was earlier. I did the other scans about an hour before it.

Does that make any sense to you guys?

It also did a surging thing before when I was stopped or just started it. It didn't do it all the time but it usually did it at least once each drive. I didn't get that either.

Possible, imo. Did you fill up with gas before the 2nd scan? Just to be sure, do another scan in a day or two. If the results are consistent, I'd say it was the MAF. Have you tuned for the cam yet?

AA wrote:

Possible, imo. Did you fill up with gas before the 2nd scan? Just to be sure, do another scan in a day or two. If the results are consistent, I'd say it was the MAF. Have you tuned for the cam yet?

I have the same gas as the scans before it. I filled up a couple days ago.

I was cleaning the MAF because I read it was supposed to help with the surging.

I haven't tuned for the cam yet. I'm getting the headers put in next week and then Derek is going to tune the car when he gets back from vacation.


All the scans I've done until after I cleaned the MAF had bad KR issues. I'll do some more tonight and tomorrow and I'll see how they are.

on my LS1M i normally see at least 260ish Horepower, now i see 222 ......... basically my MAF doesn't exist....... my car idle's sorta funny....... my teacher said that if i unplug my MAF that my PCM will use the TPS........... i ordered a new connector for my MAF since that is my issue........ ALSO i will be buyin MAF cleaner........


so BASICALLY..... is it normal to lose power with my MAF being lame?

yes, with the MAF gone your pcm will go into limp mode. try a good cleaning before you replace it.

98riviera98 wrote:

on my LS1M i normally see at least 260ish Horepower, now i see 222 ......... basically my MAF doesn't exist....... my car idle's sorta funny....... my teacher said that if i unplug my MAF that my PCM will use the TPS........... i ordered a new connector for my MAF since that is my issue........ ALSO i will be buyin MAF cleaner........


so BASICALLY..... is it normal to lose power with my MAF being lame?

Do the wires have to be cut/spliced to replace the MAF connector?

Bert

ibmoses wrote:

Do the wires have to be cut/spliced to replace the MAF connector?

Bert

YES THEY DO!!!!!!

Are you sure that it isn't the maf that is bad? I would try to clean it first and then see if it needs replacing. Also, the horsepower numbers aren't that accurate on the LS1m. It is a cool little feature though.

Considering that I've seen gains and losses of 10 WHP on the dyno just form tweaking the MAFF table, I can believe a substantial loss could occur if your MAF sensor wasn't communicating at all with the PCM. Even more so with mods than in a stock car.

You should NOT go WOT without the MAF unless you have extensively tuned your VE table.

If you unplug the MAF does it run any differently than when it's plugged in?

deekster_caddy wrote:

You should NOT go WOT without the MAF unless you have extensively tuned your VE table.

If you unplug the MAF does it run any differently than when it's plugged in?

Bingo YOU WIN!

i have my MAF unplugged so my PCM doesnt commit suicide.......... it runs rougher with the MAF plugged in unplugged it still scares me to drive...


nope my VE table isnt tuned.

Righto.. when you are missing the maf sensor your car doesn't hit GM's version of limp mode. That's actually something different. The PCM reverts to the VE table to base the airflow off the expectations from other sensors and values.

A tuned VE table is a great thing. Really changes the way the motor runs with and without the sensor being unplugged. .

BillBoost37 wrote:

Righto.. when you are missing the maf sensor your car doesn't hit GM's version of limp mode. That's actually something different. The PCM reverts to the VE table to base the airflow off the expectations from other sensors and values.

A tuned VE table is a great thing. Really changes the way the motor runs with and without the sensor being unplugged. .

i will be talking with my tuner

SES light was coming on in my car and mechanic said the code was for the mass airflow sensor. I'm picking up a replaecement tomorrow but will it hurt the car at all to drive it if it goes out completely between now and when the new one gets put on?

It will still run, but you should not go WOT. Your PCM reverts to other sensors to run your engine.

Have you tried cleaning your MAF?

Haven't tried cleaning the MAF. No WOT either, just driving back and forth to work...

Ya, definately try cleaning it first, because they are not cheap

54_nailhead wrote:

SES light was coming on in my car and mechanic said the code was for the mass airflow sensor. I'm picking up a replaecement tomorrow but will it hurt the car at all to drive it if it goes out completely between now and when the new one gets put on?

it must be a minnesota thing......... i replaced my wire going from my MAF connector to the PCM....... it worked

54_nailhead wrote:

Haven't tried cleaning the MAF. No WOT either, just driving back and forth to work...

going WOT is cleaning the MAF.

I know new ones aren't cheap, picked up a used one and it's fine now.

Glad to hear the repl sensor solved the problem. If you saved the old sensor, you should try cleaning it with CRC sensor/electronics spray cleaner, and swapping it back to test. Could have been just dirty, worth checking it out.

I thouht about that but the mechanic kept it. I'll probably get some of that and keep on hand just in case since the one that's in there now is used.

Hopefully he didnt just clean yours and lie about changing it. There are alot of mechanics that do those kinds of things to people sadly

I was right there when he changed it. Actually I picked up the used one for him and took it to his shop, the place that had it was on my way home from work.

oh thats good, but why didnt you just try cleaning it first, did you get a really good deal on it?