Fuel System leaning out.

jabartram · 12-19-2011, 01:14 AM

I have an issue, a little back ground info. as most of you know i auto cross the shit out of my Alero, well the races have been cancelled for the past 4 months and the car has been sitting for the last 7 months. i didn't drive it at all for 3 months except in and out of the garage and it had very little gas in the tank. i have recently started driving it again at least on the weekends and to work sometimes just to keep the cobwebs out. auto cross should be running again in January, but now i have severe lean-out, fuel pressure is running 45psi at idle 55 at throttle, i bumped up the fuel pressure the 50 psi at idle, 60 at throttle, replaced the fuel filter, i have increased the injector output twice and im still having the same issue, it acts as if it is running of gas, it has literally no power and im getting lean codes. so im at a loss, i don't think its the fuel pump its one of the high pressure pumps from milzy, any other ideas?

a.graham52 · 12-19-2011, 07:16 AM

leaking intake? vaccume leaks?

G.I.Ceo · 12-19-2011, 09:10 AM

^^ I have the exact same problem so I am very curious on what you find out. The only thing I could think of myself was possibly a bad injector but I get no codes for one being bad.

jabartram · 12-19-2011, 01:39 PM

Quote:

Originally Posted by G.I.Ceo

^^ I have the exact same problem so I am very curious on what you find out. The only thing I could think of myself was possibly a bad injector but I get no codes for one being bad.

how/when did this problem start for you?

G.I.Ceo · 12-19-2011, 03:49 PM

^At first I thought it was my tune. When I changed my tune in my car and deleted my EGR it started showing up. It would come and go every once in a while and now I cant get rid of it. I went back and used different tunes to see if maybe that was causing it but it didn't take care of it. I also did a few relearns and that didn't work. I would have to say it probably started about 4 months ago or so.

a.graham52 · 12-19-2011, 04:15 PM

GIC. are you sure its not because you deleted the egr? grantad we are comparing apples to oranges but my 85 sierra had wicked issues when i removed the egr.

G.I.Ceo · 12-19-2011, 04:30 PM

^ It might be but I removed all the codes pertaining to the EGR. After I deleted the EGR it was like 3 or 4 months after I deleted it the code up. I really started noticing it when I was tweaking the tune and messing with the spark tables. But after the lean code showed up I went back to the original tune and still had the code. I'm still thinking its a injector being either stuck open or possibly stuck closed.

unchained01 · 12-19-2011, 04:35 PM

i would check both 02 sensor sensors that where your codes may be coming from also . They wont throw codes unless they are not getting power Is this happening when cold or hot? PE mode ? What the temp outside ? JAb you added fuel but the ECM is still pulling fuel from your tune so it maybe the 02 or ECT settings I am not ruling out a injector but more and more ethanol is being used in fuel (upto 20%) and its going to affect your tune too Just my .02 Good luck guys keep us posted !!

jabartram · 12-31-2011, 12:47 PM

I decided to unplug the Maf sensor and let the pcm default to speed density, power seem to comeback a little but im still having lean out issues, i may have some maf issues also so im gonna look for an ls1 maf. i ordered a fuel injector cleaning kit, the type that uses air pressure and a chemical canister to pressure clean the injectors, if that doesnt help, im dropping in a new pump. i may attemp to go external with a pump. but i still have to pull the tank again to remove the walbro i have now. has anybody attempted to cut the floor to access the pump from inside the car?

a.graham52 · 12-31-2011, 04:25 PM

honestly iv never seen a fuel pump cause lean codes. there either working or not working.

jabartram · 01-09-2012, 11:33 PM

An update, i purchased an air pressurized fuel injector cleaning kit, ran cleaner through the system twice and had the same issue. so i looked into my calibration file, compared it to a stock calibration found that the maf table and ve table have not been altered,( i thought i increased my maf output frequency, but i was wrong ) so i added 25% to my maf table across the board and 15% to my ve table across the board and then smoothed the ve table. programmed the updated calibration reset the fuel trims and ran her, so far so good, i will need to run her some more, but no more lean out at this time.

a.graham52 · 01-10-2012, 06:38 AM

i understand ur programing things but whats the ve tabel?

jabartram · 01-10-2012, 07:17 AM

Quote:

Originally Posted by a.graham52

i understand ur programing things but whats the ve tabel?

volumetric efficiency

G.I.Ceo · 01-10-2012, 08:53 AM

You know I have tried resetting the fuel trim too and I couldn't get mine to straighten out either.

Let me know if you get it fixed because I am really close to ordering a new Racetronix fuel pump but I need it for my turbo build anyways.

I'm still leaning to a faulty injector but I don't get any kind of injector code.