Lean under boost!! - Page 2

TouringBubble · Oct 28, 2008, 02:01 PM

the resolution in those logs isn't great so it's difficult to say. You swing a bit rich and then WAY lean between samples. The O2 reading looks almost like you're running super rich and freaking out the sensor ... it's basically flatlining on the lean side after maxing out the rich side (.98 then .02). The WB at that point is basically showing free air or barely any fuel at all.

the big issue I see first is that your load values are a bit off. You're only showing ~80% load when you should be around 110%. EDIT :: Looked at the wrong load vale ... your still only around 90% which is low.

This may be a long shot, but pull the plugs and see what they say. I almost think you're running overly rich ... not lean.

Complink · Oct 28, 2008, 06:33 PM

ok so i reflashed my ecu to stock form just to see what would happen and it was alot better but still leaning out. so i made it richer from 4k up that helped some. but my fuel trims are probably going crazy. my cel came on so it prob maxed out the middle fuel trim in the negatives, but the way it is now it actually pulls under boost so im gonna leave it like this for now until i figure out something. it hits about 13-13.5 afr at 4k rpm then drops to 12.7-13 after 4.5k.

ive also noticed that on my logs when the AFRmap column would say 188, doesn't that translate to 10.0 on the Fuel map(128/188*14.7)? if so then something weird is happening because my fuel maps were maxed to 7.4 not 10.0. Does this mean that 10.0 would be the lowest you can go until it stops having an effect on our ecu's fueling?

sykou · Nov 8, 2008, 12:42 AM

Just came across this thread... Im having the same problem. I got my values maxed at 7.4 also but i still got about 11.8 AFRs when in boost too... Only difference in my setup is Im running an EVO fpr with no FMU. Curious, what psi are you hitting when you see your afrs so lean?

Complink · Nov 9, 2008, 09:14 PM

Quote:

Originally Posted by sykou

Just came across this thread... Im having the same problem. I got my values maxed at 7.4 also but i still got about 11.8 AFRs when in boost too... Only difference in my setup is Im running an EVO fpr with no FMU. Curious, what psi are you hitting when you see your afrs so lean?

well when i had stock injectors and fmu, by 7 psi it was at around 12.5afr. then with injectors and no fmu it was like it wasn't getting any fuel under boost. i didn't want to hook up the fmu with the 440cc's cuz of the potentially high fuel pressures so i hooked a mbc inline to the fmu and now it hits 6.5-7 psi at nearly perfect afr of 11.5. but i think that its either my fuel pressure or my maf. for some reason the maf airflow in my logs maxes at like 900 hertz, when i think it should be more than that. oh and my injector scaling is stock too so i don't know whats going on. i am beginning to think that once you get to 10 on the fuel maps, it won't go any lower even if you put in 7.4

sykou · Nov 10, 2008, 12:51 AM

maybe try putting in a box of tens in the higher end and see what happens. Ill try that too next weekend. Im also running the stock injector latency and the stock injector scaling but i still have that problem. I was using WRX 440s with a FMU but it got worse when I took out the FMU. I checked my plugs and all were good, not overly rich or lean. I even have my fuel pump hotwired but i still see around 11.5ish under 10psi. We need to hear from someone who has boosted higher than 7-10 cuz it seems that even though we are a bit lean it is still safe for the boost level. Im gonna try using some larger injectors just to see if thats the problem but i highly doubt it. The wrx 440s should be well beyond enough fuel for us even if we boost upwards of 15 psi...I just purchased a FPR from another member so Ill see if that solves the problem too....

Complink · Nov 10, 2008, 01:48 PM

have you been able to check your fuel pressure?

sykou · Nov 21, 2008, 12:13 AM

not yet sorry. this weekend I will be putting in some larger injectors so I will give you a heads up on the results. I have a FPR kit coming in also just waiting for it to arrive. If the injectors do not solve the problem then i will definately be fuel pressure problems. But i will change them out and let you now whats up. BTW what do you have your injector scaling set at?

4g94T · Nov 28, 2008, 10:38 AM

i have a leaning problem also, except mine starts off at 11.2 AFR and tapers to 12.2 AFR @ 10 psi.

i tried with FMU and no FMU, same thing. I am running RC 370cc and a walbro

last night i scaled my injectors 20% lower than 370cc and played with my 14v injector latency to get it to idle right. i'll be doing some pulls shortly

sykou · Nov 29, 2008, 02:12 AM

hmmm^ interesting 370cc injectors and about the same lean condition as me. but i have 440cc injectors.... I got mines scaled at 210 and i am still lean.... havent messed with the latencies tho.. Which way did you go to adjust? increment up or increment down?

4g94T · Nov 29, 2008, 11:00 AM

stock injector scaling seems to work best for me for some reason.

As for the latency, you increase to add fuel on idle.
Because I noticed when I scaled my injectors but didn't touch the latency it was so lean at idle it wouldn't stay running.

So increment about .100ms at a time until you can idle

Complink · Nov 30, 2008, 12:47 AM

question about latency

sykou · Nov 30, 2008, 12:39 PM

K heres an update. Put in an AMS FPR kit and noticed something weird. The instructions say to adjust fuel pressure at idle with the vacuum line off till 40-45 psi. Then reconnect vacuum line. So while I was setting the idle fuel press I noticed that the RPMs were going up as I increased fuel pressure. And also the fuel press before with no adjustment was way below 30psi so I turned it up quite a bit. Havent done any WOT pulls yet but i will be doing some later today hopefully. I will try adjusting the biss screw and play with the latencies to see what I can do.

4g94T · Nov 30, 2008, 01:20 PM

Quote:

Originally Posted by sykou

K heres an update. Put in an AMS FPR kit and noticed something weird. The instructions say to adjust fuel pressure at idle with the vacuum line off till 40-45 psi. Then reconnect vacuum line. So while I was setting the idle fuel press I noticed that the RPMs were going up as I increased fuel pressure. And also the fuel press before with no adjustment was way below 30psi so I turned it up quite a bit. Havent done any WOT pulls yet but i will be doing some later today hopefully. I will try adjusting the biss screw and play with the latencies to see what I can do.

nice keep us updated.
where did you get the AMS FPR kit?

dont mess with the biss screw, you can adjust idle through ecuflash

what i also noticed is that after a flash, my AFR are off

but after driving for a couple of miles... they go back to where they belong

sykou · Dec 1, 2008, 04:05 AM

Got the kit from another user on here, its made for an evo but i made it all fit.
So over the weekend i tried the following..
- Put all 10s in the cells(NO CHANGE-STILL LEAN)
- Turned fuel pressure up(STILL LEAN)
there is another idea that i had when i was doing this. I have gotten positive results from adjusting the "MAF Size". The stock setting is 29g/s and i upped it to 31g/s. It makes the ECU think there is more air coming in and in turn makes the car run richer. But heres the downside to doing this... By adjusting the MAF size, you in turn change both the idle and WOT fuel trims accordingly. So I either got a rich WOT afr with a rich idle or a lean WOT afr with a lean idle. So you think it would be possible to set the MAF size larger say maybe 33g/s or so. Then adjust for the rich idle by increasing injector scaling. Oh and I got a decent idle using 31g/s for the MAF size and 240cc for the injector scaling, got me about 10.8 afr at WOT.
It seems like everything I do doesnt help to richen up the mixture... I also noticed that my ECU doesnt read any load past 100 during any wot pull. The most I see is 96%.

Oh and as far as adjusting the latencies goes, decreasing it causes the idle to become leaner, and increasing causes it to become richer. But does this also affect the WOT afrs in the same way at the same time? Im about to just swap my injectors out for larger ones already cuz this just seems impossible to tune out...

4g94T · Dec 1, 2008, 10:37 AM

I also get about 98% max load.

It's not our fuel pressure or injectors. It's a setting we're not getting right.

With my 370cc I get about 40-50% injector duty cycle at WOT.
Now if I can find a way to get them to put out more fuel I'll be set