lean spike going WOT

[Ryze]

Okay, obviously I'm not completely familiar with HPT since I am asking these basic questions. But I am having an issue with a lean spike right when I go WOT,

You can see this right around 1300-1350 timestamps on the log I will attach.
the spike lasts a good 300rpms or more from what I can tell. Is there any way to fix this problem, I tried adding fuel in the maf, but that leaves a huge spike which doesn't seem right to me?

04 Saturn ION Redline, 3.1" pulley, Intake, Water Meth injection, H/E

Attachment 11770
Attachment 11771

[jimbos'ss]

http://www.hptuners.com/forum/showthread.php?t=17535
request the beta , once you get it go to: engine>airflow>dynamic airflow>
and lower your rpms till this no longer happens. once completed do a maf retune. what it is doing is giving the maf control of fueling earlier. should fix your issue.

[fast98]

jimbo thats not the problem with this one. your enrichment rate for PE is set very low try moving it up to .500

[jimbos'ss]

jimbo thats not the problem with this one. your enrichment rate for PE is set very low try moving it up to .500

wow good catch, i didn't even see that, i usually keep mine at around 1.0

[Ryze]

okay thanks guys, now I've had another problem for some time and i've just worked around it, but now its just really annoying maybe someone here can help

Last night I was tuning, just put a 2.9 pulley on getting fuel figured out. Got it nailed after an hour or so. Ran great yadda yadda yadda.. AFR right at 11.5-11.6

Now this morning it was the same, but i drove alot today ~100 miles. The ONLY difference from last night/this morning and now that I'm having this problem is my gas level has gone down past 1/2 tank

Now that its that low, my car is running about 13.2-13.4:1 AFR..I didn't touch the tune at all today.

I've been having this problem for a long time actually, since I put the stage 2 flash on my car this winter, gas gets low car spikes lean under WOT.. I assumed it was my fuel pump going out since the car has almost 90k on it. I replaced the pump with a Walbro 255, -6 Return line, Aeromotive FPR. I was hoping this would solve the problem. But no dice, still does it

The only other thing I can think of is its in the ECM somewhere controlling the fuel pump?

[my_bd]

do you have a log showing the lean under wot condition?
and is it the same tune you posted up above?

[Ryze]

same tune, no logs, just going by my UEGO gauge when under WOT.. people on cobaltss, said reset fuel trims and set PE really rich (about 11:1AFR) and give it 2 weeks and it should learn itself?

the car has been doing it since i put stage 2 on the car, gas gets low, AFR spikes very very high, fill gas up and it goes back to normal. I assumed it was a failing fuel pump, so I did a return line set-up, with a walbro 255, aeromotive fpr, and -6 line all the way back, but nope it still does it, just not as lean now

[my_bd]

gee, I dunno, I wouldn't really want to wait 2 weeks crossing my fingers hoping it 'fixes' itself.

see if you can catch it in a log file.
and try to add some of the evap system monitoring pids n bits.
include fuel trim cell so you will know if/when evap is active, %evap valve opened, things like that, etc.

[Ryze]

i believe the issue lays in the pickup/bucket in the tank..i'm taking the tank out on wednesday

[my_bd]

let us know how it goes!

[Ryze]

well I pulled the tank again today, nothing looked out of the ordinary. Both sediment filters were decently clean. I took off the return one completely because my return line does not connect in the stock location any more, so there was no point to have it.

I think the issue lays in the bucket, there is a tiny hole at the bottom about 3/8" in diameter where the fuel is fed into the bucket. I do not believe that this little hole could flow enough fuel once the level got lower (not enough pressure to get fuel into the bucket)

My fix, which seemed to work great, was drill a few dozen holes in the bucket so there is more area for fuel to plow to the pump, I did do a lil driving tonight and with almost a 1/4 tank of gas WOT afr's are where they are at with a full tank. I think I fixed my problem