You see the sig,

I've been having a problem fouling plugs. I've been thru about 10 plug changes in about a year. They last about a month or two then the car starts missing on the bottom end. Back in April I put on a new opti and water pump. I had an MSD on the car and it ran fine. I desided not to run the MSD on the new opti.

I had Ed Wright program the PCM, the deal is he axed me what size Throtle body and I told him a 58mm. Well I said that with intentions of buying one soon after and I didn't. I still have the stock 46mm on the car.

Is this my problem?? I thought the Pcm would adjust for this?? Should I change plugs with a new TB?

help me with your thoughts!!

thanks
sean

 

that is definately a start he programmed your fuel curve to allow for the extra air coming in from the 58mm compared to the 46mm the MSD would help a little with the added spark that it introduces to the system
hope that helps

 

That's exactly what I was thinking! Too bad it only hit me about a week ago

thanks!

anyone else have something to add?

sw

 

What fuel curve? Or cars run in closed loop on the street.

You need to log some data while driving and make sure the BLMs aren't going below 108. If they are then you got a problem with your fule pressure regulator, or O2 sensors, or possibly the fuel injector constant was programmed a little off.

The MSD isn't going to solve it. Maybe your coil is getting old and weak. Mine was 5 years old when I replaced it with a fresh one and it made a big difference.

 

well, I thought our cars ran closed loop until the o2s warmed up. Then ran open loop??

 

That's backwards. Open loop means no feedback from the O2s. Closed loop means the fuel is constantly being adjusted according to the O2 readings. This can be observed by logging the BLMs. They bottom out at 108. 128 is normal, and 160 is the highest. If yours bottom out then you're running so rich that the computer can no longer compensate and you'll foul plugs and blow black tailpipes.