rdavidsrx7

Hey all,
Car had been doing fine till 2 days ago. 14.7-15 under vacuum with a slope down to 12afr by 13 psi of boost. Now I see afrs around 15 when i am in boost with it ocasionally going to 16! Needless to say I have not pushed the car because I know these are bad numbers to see under boost. I have only tested this at lower rpm's in 4th and 5th gear never topping 4k rpms.
My thoughts are that either 1 or both of my secondaries isn't working right, or that my ignition is falling on its face and making it appear lean.

Little extra back ground is that I just relocated the relay box that attaches near where the hood release is. The only thing that I think should effect anything there is the relay for the fuel pump right, but if that got shorted out wouldn't I not even be able to start the car?

TIA
Bob

MrDizzy

just speculating but to me it feels like its not the fuelpump, but something with secondary injectors, as you got fuel but running lean on boost.

Dont know enuff about ignition on FD yet to speculate in that area

XSTransAm

what are your injector duty cycles when it leans out... Def do not go wot with that kind of afr. check you fuel pressure.

if your ignition were breaking up you would be overly rich not lean.

rdavidsrx7

Pretty sure ignition problem would make it appear lean right, as it would see alot of oxygen in the exhaust due to it not being consumed in combustion, and yes I am leaning toward a secondary injector problem. As for duty cycles....will it get lower if the secondaries do not kick in or will the commander read the duty cycle that the PFC is trying create?


EDIT: note that i say "appear lean", i know it would actually be richer than the engine is using but the wideband would see a lean condition.

twokrx7

iTrader: (1)

I bet it's your fuel pump. The box you mentioned has the relay that switches your pump from low to high voltage. The ECU switches to high voltage under high load, without this your pump will not support boost conditions.

Ignition problem would make it appear rich!

Fix your fuel pump relay now before driving it again.

rdavidsrx7

ah ha
I thought I had heard something about that in the past, that was why I thought I would mention it. I will have to drive home from work in a couple of hours but believe me I will keep it off boost all together, the local traffic will love me! That will be the first thing to check since that is the only thing that I have done to the car in the past couple days.

Thanks

Bob