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Evo x lean issue

5K views 16 replies 6 participants last post by  Evox@2014 
#1 ·
Hey guys I need some help with my 11 evo x.

I got the car a while back with some mods already on it and I noticed right away it was running lean on e85 at wot, 13 afrs.

I took it right away to a very reputable evo shop/tuner. Got it retuned on both e85 and 91, as soon as I got it back it ran great all the way home which is about 2 hrs home. I get home and did a pull near my neighborhood and it was lean again! I checked fpr hose, relay, any boost leak, exhaust leak, cleaned maf.
Called the shop the next day and brought it back to them and they said my fuel pump is going out. Had them put a brand new walbro 450 in it and they retuned it again. Ran good all the way home and of course lean again! Called again and I brought it back and he checked the fuel pump again, he even put another brand new fuel pump in! Checked my fuel pressure, did a boost leak test and everything checks out fine!! They put it back on the dyno to see if possibly my wideband was maybe reading wrong and wideband was fine. Eventually they tuned it slightly richer and this time it was all good.

Fast forward about a year I had them do a turbo swap, MHI 18k, full race manifold, new downpipe, synapse dv, in-line fuel filter and retune of course. Back to the same thing. Ran good on the way home, perfect afrs, smooth pulls. I get home and do a pull again and boom lean. High 12s at wot, next day I decided to check again and this time it’s low 13s afr. So I called and brought it back and they checked plugs, did a compression test and all is good. So they tuned me slightly richer and it ran good all the way home again.

I know this isn’t right, it shouldn’t have to be tuned richer so I do a bunch of digging on the forums to find something & every post seems to lead to a dead end.

as soon as I’m getting into boost about 20-25% throttle I hit a lean spot for a split second, afrs go from 14.7 to 16 and then goes right back to high 11s for wot on e85. Everynow and then about 50% of the time as I’m in the high 11s for wot the car kind of hesitates & stutters and afrs bounce from high 11s to high 12s.

i don’t know what else to do at this point. I’ve gotten an p0134 code a few times in the past before the turbo upgrade. Could it possibly be my o2 sensor, maf sensor? I don’t have any access to log anything and honestly im not even sure how to, haven’t ventured that way yet lol. Any help is appreciated, sorry for the long post, I just wanted to get everything out there.

mods (2011 evo X 80k miles)
Id1000 Injectors (Forgot to mention in the post but yes Injectors have been cleaned & flow tested)
Walbro 450
Map inline fuel filter
MHI 18k turbo
Ets intake
Ets intercooler
Ets upper & lower intercooler piping
Cobb 3 port boost solenoid
Shorty downpipe
Cat less testpipe
Top speed catback
Full race manifold
Synapse dv
 
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#4 ·
First thing I did was change the fuel pump relay because I’ve read the horror stories on those lol. The car is running fine at the moment because I had my tuner richen my map slightly but obviously something is up and the car isn’t running how it should be. Check out my reply to the other comment.
 
#3 ·
You have pretty low miles, I'd be surprised if it ended up being anything major. System too lean just sounds like it isn't getting enough gas. If it isn't coming on right away, it couldn't be anything that's at a complete failure point. Maybe a worn out fuel pump or semi clogged injector. Could be a goofy or dirty sensor too. Start by having someone look at it and see what they think.




Kodi nox
Yeah I don’t think it’s anything major because the cars running fine at the moment. Just had the tuner richen the map up slightly to accommodate. I don’t understand because after I got tuned the 1st time it ran so good on the way home, which is a 2 hour drive. When I got home it was lean. We thought fuel pump at first as well so I swapped it out for a brand new walbro 450 & still no luck. I got my injectors cleaned as well & nothing. I’m honestly leaning towards goofy or dirty sensor. My tuner & I have tried almost everything except that.
 
#7 ·
I actually just changed my wideband sensor about 2 months ago lol and there actually was a decently sized exhaust leak right before my wideband sensor. So I fixed it & checked my entire exhaust setup & there’s no leak, I mean at least I can’t find one. That’s why I’m so stumped on this whole situation because I’ve tried doing almost everything to narrow it down. The only thing I haven’t done that may or may not help is replacing my MAF sensor or my upstream/front o2 sensor.

I really appreciate you trying to help me out!!
 
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