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?

big vacuum leak or leak between the AFM and the turbo. pressure check the intake system, cap off the turbo inlet and blow into a vacuum hose and check for leaks.

yeah sure, let me find where I put them! https://www.nopistons.com/forums/pub...#>/biggrin.png Theres a box of all the seals and such somewhere in the garage, hopefully they are all there. I had no intentions of reusing them so there may be some small stuff like corner seals missing... but you can have whatever is there.



also did you figure out if you can use the S4 power steering pump? mine works and is sitting in the garage waiting for someone to give me a few bucks for it... but I'm not sure if it's compatible with your S5.

S4 power steering is different.

S4 power steering is different. [/quote]

bummer.

My power steering works now... I think. It moves freely now. I haven't put a belt on it yet. We'll see...



I'll take out the TID and double check that. Maybe there is more than just that little crack.

if you just unplugged the omp it won't let you push the car at all. Since the s5 cars have an electric omp, it can tell if you took it off.

you can try connecting the OMP just to satisfy the ECU to see if it makes the car go, maybe some kind of limp mode. If it works you can probably

rig some resistor setup using the connector from the OMP (chop it off) and trick the ECU into thinking it's there that way.

yeah the ecu has a cow if you dont have the metering pump. yet another s5 shortfall. you cant hook it up with a resistor because the ecu looks for a resistance range, per load vs rpm. so if you put a resistor in you can get it to work in a 1500-2000rpm band. its best to tie the pump out of the way.



mike

Oh great!!!!! I'l try that right away. Man I hope that's it.





Thanks!!!!

Hey, it works! I just plugged in the metering oil pump tied it down with some wire and it worked. I was in a good mood so I filled her up with some 100 octane to get that nice smell. Kind of expensive but hell nothing smells better than racing fuel, ehh?



Thanks for all your input. It was much appreciated. rotary>piston, you're my hero!



Time to cruise.

vrewm