As of late, I've had an interesting problem with fueling, or atleast I think it's related. Alright, I changed my headgaskets from copper back to graphite... everything seemed fine with it install went fine, got everything back together. So I take the car out and I notice when I roll into it, it starts to lean out. I triple check the tune and everything is exactly like it was before... the injectors are all tightly plugged in, fuel pressure is optimal. No vacuum leaks, Map sensor is fine, car is throwing no unusual codes. I've got the rails off now, got the injectors soaking in gas trying to find something else wrong. I'm stumped and starting to get frusterated. The wideband is not wrong, I can feel the car responding differently. I took it to the track before I realised it was an issue, made a half pass rolling into it noticed it was leaning out and got several small lean pops/stutter. I'm not sure if the fuel pump is going out or what. I'd really appreciate some advise.

 

Maybe your ECU just needs some time to re adjust after your battery has been unplugged for a while.

 

it's been like this for 3 days and multiple dynotune reflashes.

 

Does it actually lean out or does the car feel like it does? Seems pretty weird if everything else seems normal.

 

car leans out, and if I keep in it, it starts to detonate. I lift before it ever gets bad but I can feel the car doing what the AFR is telling me. I'm wondering if the pump is having trouble keeping up with the fuel usage into boost. The car stays where it needs to be at partial throttle ~14.7 idle looks good. It never attempts to richen up into boost. It always did before. It just stays stoich and slowly leans.

 

Wouln't your fuel pressure gauge show if your pump is having problems? And why whould it start now if it hasn't done it before?

 

hah... fuel pressure stays solid. I'm stumped, I'm going to try and get a hold of my tuner tomorrow, send him my configuration see if anything got changed somehow. It's difficult eliminating like 500 things.

 

well if the head gasket was blown when you tuned it the first time that could affect your A/F I believe

 

How do you tune? What is your fuel setup?

 

60lb mototrons weldon big external... sumped tank, billet rails. It's a pretty big fuel setup. HP tuners, I wonder if my MAP/MAF/or TPS is bad... maybe it's not going into PE mode.

 

Why not play with the tune and see if you can fix that tip-in lean spot?

 

Is it possible that an injector o-ring was rolled from a dry install and thus was able to suck in air? Seen this recently. If nothing else, log it with HPT at your tuners, and look at the LTFTs to determine if its one bank or both, as well look at misfire history to determine which cylinders...good luck, I know how frustrating this can be.

Charlie

 

so if air was getting by an injector it would cause it to detonate? that would make a lot of sense, especially since I just reinstalled the fuel system! awesome idea!

 

Just a thought from the ***** of history. My buddy forgot to lube the orings and rolled a couple, didnt leak fuel, but there was air getting in.

 

Hey man, if that turns out to not be it.. give me a PM and I'll tell you what to log for me and you can email me the logs so I can look at them.

 

will do bud, thanks!

 

Did the thickness of the gaskets change at all???

Rick

 

No, the gaskets are the same. and the problem doesnt seem like it would be compression related anyway. Or atleast it'd have to changed a tremendous amount to effect the car like it is.