Knock & Fuel Cut w/ AFC, need help.

[ChvyKc]

Note: This all started happening after I installed new plugs and wires. I had the AFC on there for two days before swapping plugs and wires and it ran fine. It has NGK BPR7's (gap is at .028) and Bosch wires in it now. The car is running the stock 14B @ 19lb's. I took it to the track last weekend and it ran a 13.7 with no problems, but on the way back from the track (an hour trip) it started bucking. The knock count actually started to go up on the way down there, but didn't start bucking until the trip back.

Installed 550's, 255HP and AFC II a week and a half ago. Now, I am having a problem with the car wanting to buck like it is hiting fuel cut and it will buck at half throttle as well. The knock count will start out at zero when I first start the car up but then it will start to go up. Knock count has gotten as high as 20. O2 sensor voltage will drop right as it bucks, just like it's hitting fuel cut. I talked to the people that I bought the fuel stuff from (extreme psi) and they said that it was probably running to rich. I have tried leaning it out by taking it down from the original setting that I had it on by 5% total.

Low throttle settings on the AFC are as follows:

1000 +5
1600 +5
2200 +3
2800 +2
3400 +0
4000 -1
4600 -2
5200 -3
5800 -3
6400 -3
7000 -3

I am extremely confused about what is going on. I don't know if it could be the plug wires doing that because I know that bosch stuff is by far not the best. That was just the best that I could afford at the time. I also thought that I could be overflowing the stock MAS, but I have never heard of that causing a car to hit fuel cut. Any help will be appreciated, I am stumped as of now. If I left anything out that will help you please let me know. I need to get this solved soon, I put my front mount piping on hold until I can get this solved.

David

 

[CanadianTSi]

well considering the 550's are about 18% bigger then 450's and your only at -3 I would say your quite rich.

 

[ChvyKc]

Alright, that's what I thought. I am going to go way below what I am set at right now and see what it does. Any other suggestions would be great.

David

 

[ken inn]

you will never TUNE that sucker without an adjustable fuel pressure regulator. you will get it to run, but you will never tune it. too much fuel can cause knock just like too little. and, with 550's AND a non regulated 255 fp, that thing is way rich. you need at least, and afpr, and a logger.

 

[rob_rousseau]

change the plug wires

 

[ChvyKc]

Yeah, I think that I am going to go pick up some NGK wires for it from Mitsubishi tomorrow after work. It's got to be a misfire making it do that. The check engine light will come for a little bit then it will go right off, so I think that the ECU is reading a misfire on one of the cylinders and then it goes away so the code goes away.

Guess I better pick up a FPR when I get some extra cash as well.

David