Please Help with these lean codes p1128 p1130

[f4m0u5]

It's a 2001.5 6 speed s4. Just installed new f21s , inlets, 550 injectors, fuel pump, and 85mm maf. Along with a solo motorsports tune. All done 2k miles ago.

Car was runing fine on this exact tune with fuel trims +/-4% on all 4 blocks in vagcom com. And at wastegate pressure, a/f was in the 10s.

Now my car is having issues with going lean at part the tittle and wot. My part throttle trims are.both at +20% now! And when under wot at wastegate pressure my a/f went from 10s to 12s.

One thing I noticed is my g/s from maf in the logs from before when car ran perfect to now is a round 30 g/s less on new logs.
Wich would indicate air sneaking past the maf.



Things done/ checked:

-New known working maf
-One front o2 sensor is only 3 months old.
-Fuel pressure is at 55 at idle . And when I clamp return line shoots up past 100psi.
- boost leak test up to 20psi no problems or leaks. (Had a few small inlet leaks that I thought for sure was problem and they didn't fix anything)
-fuel pump/ injectors have only 2k miles.



Any thing on motor stay under vacum under boost and could suck in air still ? Something that wouldn't show on a boost leak Test

[james 408]

is it the same injectors/maf that they were tuned for? kinda reads like those were swapped before it was tuned... but I know even small changes to the MAF flow can have an impact...

obviously 02 sensors are prime candidates... maybe a sticking throttle body?

don't really know without wild dart throwing, hopefully someone better at this stuff than I am can help

[f4m0u5]

It's remote tuned, it's the the 3rd revision for my exact car and mods. Was runing this before the problem happend, in logs it shows the throttle body working fine and under wot it leans out still. So it has to be getting some air past the maf (wich logs show less air flow coming through maf at same boost levels.

But under boost testing comditions nothings leaking. So it has to be something.that is still in vacum with the car in boost. If it where a boost leak car would run rich under wot not lean. It has to be something allowing extra air in

[NOTORIOUS VR]

how does it run with the MAF unplugged

[S4tech2]

Sounds like a crank case leak to me. Like the spider hoses are broken. That would be the first thing I would check.

[f4m0u5]

how does it run with the MAF unplugged

Cleared codes and trims then Unplugged maf, after a 5 mile drive my ltft were at -1% both banks at idle and +9,+10 for part throttle trims. (No more then 3 or 4 psi of boost) after 25 more miles to work today trims are the same.watching my short term trims I realized on Highway in 6th gear around 3000 rpms holding 3 psi my sort term trims go to +5% still. And when cruising in vac they stay in the +/-2% range

Sounds like a crank case leak to me. Like the spider hoses are broken. That would be the first thing I would check.

It's funny u mention that cause.thays wat u was starting to think about knowing it's the only thing that stays in vac always and that isn't tested during the boost leak test.

It's a 2001.5 so it had the newer style spider hose. Looking at it looks good. But I'm not sure if it will be visible knowing idle is fine and part throttle(where there's alot more suction going 9n ) is when the problem starts.

How do you normally test it?

[Calif_Kid]

As far as a possible leak, did you look at the black plastic check valve that is on top fairly near the coolant recovery tank and is say 2-3" long? I think it has 4 hoses going to it. I had that valve break, and I think that I had a lean code from it. - Jim

[f4m0u5]

I'll double check it, would it show up in a boost leak test?

It has to be an external leak in something that stays in vac and doesn't get boost to it.

Also tried a 3rd maf sensor. Still no change

[S4tech2]

Normally just see if they're broken. I use a nitrogen smoke machine at work that fills the intake system with smoke and reveals leaks at like 5 psi.

[f4m0u5]

OK thank you I will check it out and try to smoke test.my vacume and pcv system

I double checked fuel pressure under load. At 14psi wastegate pressure my fuel pressures holds a steady 73 psi.

100% not fueling so I am definitely getting too much air somehow

[jpurre]

As far as a possible leak, did you look at the black plastic check valve that is on top fairly near the coolant recovery tank and is say 2-3" long? I think it has 4 hoses going to it. I had that valve break, and I think that I had a lean code from it. - Jim

I've has that stupid valve fail twice. Worth checking.

[f4m0u5]

Took out that stupid check valve near n249 and coolant tank. Damn thing broke a leg. Blocking the piece I broke taking it off showed it was a a good valve otherwise. So waisted my.time.and has to spend 40 on a new one haha

Since there was multiple things coming off of that valve I totally bypassed it and ran the line from intake manifold to the barb near n249 that leads to discuss.

Car still runs lean so I know it's nothing to do with the Vac lines associated with that multi line Chek valve.



Looks like my only options going to be my pcv system?

[S4tech2]

That's what it sounds like to me. Look for areas where oil residue is visible, that is a big sign of a leak. Do you need any help in explanation of exactly what to look at for the pcv system?

[f4m0u5]

Well there's not much to it, it connects to y pipe with the pancake valve, then goes to each valve cover, all meeting up at the spider assembly, then from there a check valve between that and intake manifold right?



Took another look at it today( still attached to car) there is a little oil residue around where the pancake valve connects to the tube.going to spider maybe that's it?

[S4tech2]

I doubt it, with trims in the 20s it would be rather obvious

[f4m0u5]

Gets around 18s for most part. I'm stumped. Idk what else it can be. Still going too smoke test when I have a chance.

N e other ideas

[S4tech2]

I had a turbo seal cause me am off idle lean issue but it was noticeable with smoke. Other than that I have no clue. Where are you located? I see you've been to solo in atl

[f4m0u5]

OK cool I'll keep looing, I'm not smoking or anything so not sure it it would be turbo seal. (Hope not they have 3k miles on then)

And never been there physically, josh was remote tuning my car.

And I'm from ma.

[S4tech2]

I got ya. It may not hurt to go to your local stealership and ask for pressure test with smoke. May be worth the $100-$200 they should charge. That way some one with specialized equipment and confirm a leak or non leak.

[f4m0u5]

So ended up going back to my cousins garage to use the smoke machine. 0 leaks through out system when capped off at y pipe between there and maf.


That got me thinking the only thing that's not tested now is the maf housing/ silicone adapter to y pipe. Smoke tested now with that on and capped where cone filter goes.

WHAT DO YOU KNOW! It was leaking where the maf connects to the housing without any pressure (the smoke machine doesn't generate any pressure really under 1psi)

Pulled it and added a thicker o ring and problems solved

[S4tech2]

Sweet! Nice work!

[f4m0u5]

Thanks alot!