So I just finished my build and had a start map put on the car. I have a Full Blown Duel Pump installed with 2150 FIC and an HKS fuel regulator (doesn't have pressure gauge on the regulator). Once I got my map, I was told that the idle and cruising AFRs should be from 14-15. I ran into a few fuel problems before I could get the car started.

I drilled the siphon as I was told to do because I'm running both pumps all the time. I start the car and at idle it's very lean (16-17), and at cruising it's extremely rich (10-11). My tuner adjusted the injector cycle and everything and we were able to get the idle close to the desired AFR. However, at cruising, I still get very rich AFR readings.

Can someone enlighten me what could be the problem?

Thank you.

 

Anyone?

 

This would be better in the engine management/ tuning forum. Do you have a data log? Also, you should have a fuel pressure gauge so you can set it correctly if not already done so.

What are you running for your ECU? Haltech, AEM, MoTec, stock? Running SD or MAF?

 

My tuner already sent me 3 different maps to see where the problem is and we agreed that its mechanical problem. Im running an SD setup stock ECU.

I do have a fuel pressure gauge which reads in kPA. With both fuel pumps on I'm getting around 300 kPA of fuel pressure.

 

So, no matter what tune you have, you have the same afr's when driving and idling?

If that's the case, have you done a boost leak check? Also I ran into a similar issue last summer. It was a clogged sock on the fuel filter causing weird afr's.

Also, post all your mods, what fuel you are running and any other info on your car.

 

I cant really do a boost leak check, I dont have the necessary equipment (unless you could tell me a simple way to do one without any special tools).

The car has skunk2 intake manifold + skunk2 68mm throttle. Hks fuel regulator and hks fuel regulator. 2150cc injectors. Ets intercooler kit. Full blown dual pump. Running on 93 gas.

I just gave the car a slight acceleration (maybe 75% throttle and nothing above 5 psi). The AFRs would remain reasonable around 12-13. I don't know what more info to give. The fuel pressure would rise to 350 kPA at 75% throttle.

I dont know what more info to give.

 

You can make a simple boost leak tester by getting a couple things at a local hardware store. http://www.rslibertyclub.org/forums/...t-leak-testers

The only tool you need is a drill and basic hand tools.

The link is a picture of what you would need. You can get a valve stem from a local tire place. Drill a hole in the PVC pipe to put the valve stem in. You need a silicone coupler and 2 clamps.

Once you pressurize it, use soapy water on all the vacuum lines and hoses and look for bubbles.

Im not sure what mechanical problem could cause rich afrs only mid throttle cruising and not anywhere else when driving. It has to be a fuel delivery related. feed line, return, restriction, or tune.