SR 20 leaning out

[Haso240sx]

So i put a new turbo on my s14 sr20det of a rb26 everything works fine i am running a sfac aem wide band and the car is leaning out after 5 thousand rpms i adjusted the fuel on the sfac still nothing its in the 14 on the wideband after 5 thousand rpms so i checked the fuel pump fine injectors fine i have isis fuel pressure regulator set on 41 could it be it or the maf the car pops hard...

[240_SeX]

How much boost?

[PyR0NiAk]

I'm going to go with the obvious thing first. Something's loose and you have a post-maf leak. If you're running anything over 12 pounds of boost, it's possible you're going past your injectors' efficiency range.

[Haso240sx]

Well im only running like 9 pounds but it will only do it if the throttle is all the way open...But im go over everything and see if there is something loose any suggestions....

[PyR0NiAk]

Loose or torn coupler is the most likely.. Build yourself a boost leak tester or buy one from z1motorsports.net If I remember right, they're like $20-$30 shipped.

[Haso240sx]

I went over the intercooler hot and cold pipes evrithing is fine il do a boost check today and see if i have a boost leak thanks guys...

[PyR0NiAk]

np. Hope it works out for you..

[240_SeX]

A boost leak would make it rich under boost (losing metered air). It would be lean at idle or under a vacuum (sucking in unmetered air).

What do you have for a fuel pump, sounds like you're maxing out your fuel system. The pop is probably fuel cut.

[PyR0NiAk]

Not entirely true. It'll go rich at first, but once the ECU realizes it's running too rich, it'll pull fuel.. I just went through this exact issue with my S13 SR.

[240_SeX]

A mass air system is pretty simple, if there is a leak post MAF it will suck in air under vacuum that doesn't get counted by the MAF. And under boost you will push out the counted air.

So in a vacuum situation (negative pressure) the motor will take in uncounted air, causing there to be air in the intake manifold that the ECU doesn't know is there so it has not matched that air with fuel, causing a lean situation. On the other hand, under boost (positive pressure) you will lose air that HAS been counted and matched with fuel, causing a rich condition due to the amount of air the intake manifold that the ECU HAS counted and thinks is there, so it has matched that air with fuel.

[PyR0NiAk]

You're leaving out another sensor.. There's more than just the MAF involved to tell the ecu what's going on..

[240_SeX]

Very true, however the A/F sensor does not have nearly the infulence on the ECU as the MAF does. Think of it this way, have you ever seen a car with a bad A/F run poorly? How about a car with a bad MAF? it's quite the difference.

The A/F changes what's called short and long term fuel trims.

The MAF determines how much air is entering the intake manifold, and depending on the programming determines how much fuel to match it with. This is all done before the A/F even has a clue on whats happening. Yes the A/f has some say in how much fuel is added however it is mainly determined by the MAF.

[PyR0NiAk]

After it runs rich for a while, it will reduce fuel. My SR was doing it to me BAD... (Going off my aem wideband from being so lean type bad..)

[240_SeX]

That's the long/short term fuel trim change.

[PyR0NiAk]

I'll agree with that..

[240_SeX]

Fuel trim changes will not cause fuel cut (as decribed). a change in long or short trem fuel trim will not change the fuel map enough to cause a very lean or rich condition either. I'm not ruling out the boost leak test, as i think its a great place to start with any problem, just stating it's not likely that there is a post maf leak if there is a lean condition under boost.

Plus if there is a post MAF leak it will idle like poop.

[PyR0NiAk]

Plus if there is a post MAF leak it will idle like poop.

This part is true, although I still disagree with the extremely lean under boost, because, as I said before, my s13 sr was doing it..

[Haso240sx]

Well id will idle funky sometimes for the fuel i have a walboro 255 fuel pump isis fuel pressure reg did a boost test it was fine so im back at square one im just stuck.....

[PyR0NiAk]

What happens when you remove the SAFC?

[Haso240sx]

Hmmm havent tried that yet do you think the sfac could be causing it to act like that but the car was fine and strong with the old turbo ...

[PyR0NiAk]

It's possible... Personally, I hate SAFCs. I think that if a person is having an issue, they should get a tune... I'm not a fan of FMUs either, but several of the KA-T guys run them with no issues, so that is ALL personal opinion. My friend, Roman, had issues with his SAFC on his KA-T. He had to constantly reset it and then he finally did something that seemed to fix it, but I have no idea what he did. Besides, you could unhook it, and find that it's still doing the same thing, and then once you fix the problem, decide to put it back on. Worse case scenario is it's NOT the problem, but then you have one less thing that could be your problem causer. Keep us updated..

[Haso240sx]

Will do i dont like them neither but with my budget standalone is wish lol i have a z32 maf so im change my mafs tom and see what it does...

[PyR0NiAk]

You realize MAFs aren't just plug and play, right? You need to tune for them..

[Haso240sx]

Oh yea the setting for that maf are 2 in 6 out i think correct me if im wrong what other setting do i have to change...

[PyR0NiAk]

Not entirely sure... I've never messed with tuning. It's one of the few things I'm quick to pay someone else to do for me. My car currently has a rom tune, but this winter is getting switched to 1000cc injectors and an aem ems.. The tuning will be done by National Speed Inc. in Wilmington, NC.

[Haso240sx]

Wow what turbo you running and built motor im guessing il have this guy help me he tunes most of the cars up here in knoxville i hope that fixes it i just dont wana blow up my motor...

[PyR0NiAk]

On the left, look at "Car". If you click the website link, it'll take you to my thread..

[Haso240sx]

So figured out the problems it was the maf and fuel pressure reg did the z32 maf did the tune car ran good for like a day and this morning i tried to go to work and it want rev past 2500 im thinking the ecu is in limp mode any other advice i mean the car ran rly good and strong than the morning after its doing this...Thanks in advance ...

[PyR0NiAk]

2500 is definitely limp mode. See if you can pull any codes.. Most common reason for this is an inability to read the maf. (bad connection or bad maf)

[Haso240sx]

Im trie to pull the codes i hope its not a bad maf connections should be good but il go over them again but you def think its limp mode ......