Leaning out under wot

[a1320eclipse]

Ok, its a 90 tsi. k&n, turbo xs boost controller set at 15psi, rewired fuel pump, and about 1800 miles on rebuilt bottom end. so i got my a\f gauge put in today and under wot, it leans all the way out at about 3500 and above. and i get detonation. so to avoid detonation, i pulled timing out of the cam angle sensor, no detonation. is it common for these to lean out under boost at high rpm, or should it stay running rich the whole pull? im new to tuning turbo cars. im planning on picking up a s-afcII very soon, so can i just deal with this till then. btw, the car ran a 13.28@102 with open downpipe. its very fast and gets good gas mileage, like 28 on the freeway.

 

[GVR4592]

It's normal for a car running 15 psi on the stock fuel pump. You should get a datalogger before you get the safc.

 

[a1320eclipse]

Ya im getting the safc for doin a throw out bearing in a 91 tsi, so in a way its kinda free. but as long as theres nothing abnormal goin on with it ill feel alot better. but ya, it is the stock pump. and also, just sitting there under idle, the a\f gauge doesnt sweep back and forth like it does in my crx, but under normal driving it does.

 

[majik2k5]

If it's leaning way out, that's not good at all. And no, it's not normal for it to lean out under boost in any way with a rewired fuel pump at 15psi. My runs slightly rich throughout the whole pull on a completely stock fuel pump at 18psi. Check your fuel lines and filter and make sure the lines are kinked and the filter isn't clogged. Picking up some Lucas Fuel System treatment wouldn't hurt either.

 

[a1320eclipse]

Ya ive tried everything. checked for boost leaks, replaced the fuel filter, checked my wiring on the fuel pump re-wire. im lost. what about the vacuum line to the fpr, where is that supposed to come from, just a vacuum port on the manifold, cause its run through one of those emissions divices on the firewall. on my crx the vacuum for the fpr pulls straight from the intake mani.

 

[a1320eclipse]

nevermind on the fpr, i checked the chiltons and its supposed to run through the fuel pressure solenoid. i would think that as much as its leaning out i would be getting detonation at 15 psi, but im not.

 

[majik2k5]

Are you sure you hooked your A/F Ration gauge up? The gauges themself are not precise, and not good to tune with. But they are somewhat acurate. When one of my fuel lines was kinked it showed the car leaning out on the A/F gauge.

 

[a1320eclipse]

ya its hooked up right. it works really well at normal driving conditions. just out of curiousity, where was your fuel line kinked at, i did a quick once over and saw no problems.

 

[majik2k5]

I swapped the throttle body on my car for a better one with good sensors, and the fuel line from the fuel filter to the fuel rail was kinked up by the throttle body coolant line causing me to lean out under WOT.