On my 94 Z28 i noticed yesterday it running rich on me after I got through with installing a new opti. I have pacesetter long tubes (no egr headers), egr block off plates, k and n cai, and suspension done on the car. Now my service engine soon light is on and it's from the egr block off i did and it has a code 48 for mass air flow sensor, I've tested the maf sensor and have yet to find a reason to replace it car runs outstanding as is (on the scan tool the maf is pulling in 99.99% i know this is way to high). My question is will a tuen get rid of the running rich condition or should I actually start by replacing the mass air flow sensor before spending the money on a tune? Thanks for all your help.

 

Clean the MAF

 

also check your connections and wires, clean those if they need it

 

I've checked the wires and ground for the mass air flow it was on before the opti replacement. Is there any certain type of cleaner or just the mass air flow cleaner you can pick up in local parts stores like advance or something like that

 

Electrical cleaner or MAF.... be very carful of the sensor wires

 

Seems like a bit of a contradiction. What you you mean by "the MAF is pulling in 99.99%"? 99.99% of what.... the MAF reads in GPS or #/min????

 

grams/minute. Ok I'll try the electrical cleaner tonight

 

Sounds strange but check sensor in water pump mine ran rich when it went. Made car think it was always cold. Caused hard starts when hot too.

 

Exactly WHEN is your MAF reading 99.99 grams/minute?

As noted, the MAF signal is interpreted by the PCM as either GRAMS/SECOND (metric units) or POUNDS/MINUTE (English units). It is not calibrated in "grams/minute", and should only read 99.99 when you are running the enigne at about 1/2 of its power capacity.

I really don't think you are even looking at the MAF output.

 

I read it wrong was grams/second and i was reading maf. Went to use electrical cleaner and the resistor inside was broke and oil soaked. So i replaced it and it ran better no more ses light on or anything. But after getting this problem fixed my transsion went out and lost all the gears in it.I'm just not having any luck this month on this car