Car is running rich after installing 42lb inectors - PLEASE HELP!

[92stanglx]

My car is running very rich after I swapped in 42lb injectors. I had 24's and a pro-m maf in it before and it ran fine. In addition to the injectors I installed an SCT Big Air Mass air meter (along with a custom chip). If I pull all of my plugs they are pitch black. The car idles ok but when I put it in gear and give it gas it kind of sputters and will die.

So far this is what I have done to trouble shoot the problem:

- Pulled all of my plugs and cleaned them
- Tested the voltage in the MAF connector power wire and maf sig wire
- Swapped out MAF's
- Swapped out chips
- Had the tuner turn off the O2 sensors.
- Set the fuel pressure to 46lbs (vac off)
- Adjusted TPS

The car is running so rich that I can't even drive it. My combo is as follows:

92 Mustang lx
331 (9:1 compression)
TFS heads
TFS stage 1 cam
255lpr intake pump
BBK inline pump
vortech S-trim (3.33 blower pulley)
MSD 6A
SCT Big Air maf
A9L computer w/ custom SCT chip
GT-40 intake w/ 65mm tbody

Any suggestions on how to trouble shoot this one? I am very frustrated and don't know what to do next

[speedytang]

First thing lower your fuel pressure back down to stock setting.
Why shut off the 02's?
Now was this tuning on a Dyno for the chip because I see the chip in being your problem. If you could borrow a real Fox meter for 42lb injectors and remove that chip I am sure it will run correctly. It is in the MAF and the Chip trying to trick everything into working and with No O2s the Primary ECIV Map can't correct out of the table and the Chip is trying to take control. Also what is your timing at because if the Chip is taking out to much since it usually does(Bad), since it has no way to sense boost so they kill the car by taking out timing.

[92stanglx]

First thing lower your fuel pressure back down to stock setting.
Why shut off the 02's?
Now was this tuning on a Dyno for the chip because I see the chip in being your problem. If you could borrow a real Fox meter for 42lb injectors and remove that chip I am sure it will run correctly. It is in the MAF and the Chip trying to trick everything into working and with No O2s the Primary ECIV Map can't correct out of the table and the Chip is trying to take control. Also what is your timing at because if the Chip is taking out to much since it usually does(Bad), since it has no way to sense boost so they kill the car by taking out timing.

I just tried playing with my fuel pressure and it didn't seem to make much of a difference. The car has not been to the dyno yet. I had my tuner burn me a baseline so that I could run with the 42's and drive it down to him (50 miles away).

I actually have two chips. One with the O2's on and one with them off. Both with similar results. The only reason the tuner turned off the O2's is because he said they were probably fouled out. He said that I didn't need them with a custom chip.

Unfortunately I changed the wiring to accomidate the new SCT meter so it is kinda difficult to swap in a pro-m.

Timing is set to 10 degrees

What would be the best way to tell if it is in the chip? Would I need a data logger for this?

I guess my biggest problem is I don't know how to trouble shoot this one

[Alex]

I had problems when switching to 42 pounders, however my car would run great under boost, but would not idle. I'm sure a tuner can fix your issue - this is why i bought a PMS so I could back down the fuel. BTW your fuel pressure should be at 38-40lbs vac off.

[92stanglx]

Ok, so I re-wired my MAF harness and plugged in the pro-m w/o the chip. The car runs fine!!!! Plugs show I am not running rich. I took the car to the tuner and then we swapped in the SCT meter w/ a chip. The car ran better than before but still kinda sh*ty and rich. The tuner was able to dial it in and now it runs *great* with the SCT maf.

More to come...