I posted this on another topic but haven't gotten an answer on it so I thought I might as well post it on it's own topic. The problem is that at about 25% throttle the fuel just cuts off. I can see it on the A/F ratio gauge it just all of a sudden goes to full lean. This has something to do with the load on the engine. I can give it more throttle in idle (not much more). It seems like something electrical. It only cuts the fuel when the throttle is higher than the cetain amount other wise it'll go back to normal. I'm afraid that maybe it'll detonate somehow with the fuel cut. I want to punch it with out any hesistation after it's been broken in. Any ideas?



Thanks

fuel filter!

It just suddenly cuts off not proggresively like something is clogged. I'll check it out tomorrow anyways though.

do your secondary injectors work ?

I'm not sure. I had them cleaned and tested during the rebuild. They're good up to 288 hp. Could it be that the injectors are hooked up wrong (left connector pluged to right injector)?

have you checked the vacuum source for the FPR? If it's connected to a nipple before the throttle body, it will see low/no vacuum at idle/low load, which will make the fuel pressure high at idle/low load. Then once you open up the throttle, the vacuum increases before the throttle plates, and if the FPR is getting it's vacuum from before, the fuel pressure will _drop_ as the vacuum it's getting increases.



it's the inverse of what you want it to do when it's connected to the wrong nipple. Unless you've gone through them and monitored which nipples are getting high vacuum at idle and made sure to connect the boost sensor/FPR to one of those, that would be my first suspect.



when it's connected after the throttle body (like it's supposed to), the vacuum should be high at idle/low load and the fuel pressure low, then as the throttle opens the vacuum decreases and the FPR raises the fuel pressure.



just think what it will be like if the fuel pressure drops when your secondary injectors want to come on.

check the ecu for codes



mike

I just checked the codes.



Here's what I got:



Split air solenoid valve

Solenoid valve (relief)

Solenoid valve (switch)

Port air solenoid valve

Solenoid valve (BAC)

And the rest is for the oil metering pump crap that i took out.



I unplugged those three solenoid valves on the rats nest. Nothing is hooked up on that. Are those the solenonid valve that the ECU is telling me is messed up? I'm gonna check the FPR vacuum lines maybe that's it.



Hopefully we'll get to the bottom of this.



Thanks guys!

Matt was getting most of those engine codes before.

OK, the FPR wasn't getting vacuum from the right place. Gave it the vacuum it should get but I still have the same problem. The S-AFC doesn't show any pressure. It's always at -760 mmHg The gauge in the dash doesn't show anything either. I just measured 15 in Hg vacuum 5 minutes ago so there is vacuum.



Back to the drawing board.



Hey pengaru. Can I stop by sometime to pick up the old seals?