Edwardo

I just moved from GIAC's regular K04 programming to the PC-16 file. Apparently that requires de-chipping the ECU and moving to a flashloader system. Anyway, I decided to go with the Genesis 315cc injectors over the Bosch 310cc units because of their better spray pattern. I went to the dyno to tweak the FPR and ended up seeing horrible AFR curves (and obviously low power). Recommended fuel pressure is 3bar (44.1 psi) with the 310s, I ended up having to drop down to 34 psi to keep the AFR from dropping well below 10:1 around 4k RPM (it comes back up to 12 closer to redline). Meanwhile the ECU likes to throw a lean code after 2 or 3 trips of driving around casually. So it's running nice and rich under load, yet thinks it's lean during casual driving. Not only that, I'm getting pretty low boost. Is anyone else running this software/injector combo? I'm pretty sure the closest GIAC dealer that can actually tune this SW is AWE which sucks because I'm in Boston. Are these injectors really completely different? Do I really have to dump GIAC and go to REVO or someone else so I can actually get it tuned?

I attached a plot of boost and AFR for my last three runs which were the best of the day.

600whpA4

Have you checked your fuel trim readings on block 032 to see which one is causing the lean code? The PC16 tune does tend to run rich in the mid range, so if you lean that out you might end up lean at idle/part throttle.

Recommended fuel pressure is 3bar but that is for 310cc injecors and even then it still runs on the rich side. Most people end up lowering the fuel pressure to 2.6-2.8 bar(37.7-40.6psi) but thats on 310's, this is why you had to drop it down to 34psi for the 315's.


Have you checked to see if you have any boost leaks, this could be causing the lean issue during normal driving.

Edwardo

I guess it should have hit me earlier to check for a boost/vacuum leak. I have done testing in the past and it seemed to hold pressure just fine from the hose from the airbox all the way to the hose to the throttlebody. Boost hasn't gone above 18-19psi since I replaced my wastegate actuator after I killed one when the diaphram gave out. During that time it was obviously overboosting if I wasn't gentle with the throttle so that may have caused this issue.

I decided to go over all the vacuum lines with a propane torch and I'm 99% sure that I've found the leak. It's right at the check valve that goes between the brake booster and the intake manifold. Doing the pressure check from the turbo to the TB obviously wouldn't have indicated this because that line isn't pressurized at all. I'm going to replace the rubber elbow, the check valve and the hard plastic line that goes to the brake booster and hopefully that will solve the problem.

600whpA4

If you would have done a pressure test with the TB hose still on you would have noticed the leak since the IM also gets pressure during testing.

It is very common for those parts back there to crack.

Edwardo

I was following the writeup on here. You're right though.

Can any of you Etka folk help me out with part numbers for the rubber elbow, check valve, and hard vacuum line to the brake booster? Vagcat is not particularly helpful.