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Lean condition?

Would a clogged fuel pump sock cause a lean condition at WOT? My logger is showing ft trims in the 81% range for LT/HT goes up to the 90% range when I turn the blower on heat/ac. LT goes back to 81.2% (too much fuel idk fp@37psi base?) 96% for MT. Car has 880cc fic injectors, Keydiver ecu (for my setup), aeromotive afpr (-6 holds pressure fine), Walbro 255 rewired (verified 12v at the fuel pump already) aem wideband (11.4-11.5 at WOT) new fuel filter and a brand new optima red top 880cc tested under load, also still puts out 14v+ under load according to my logger . Problem is after doing a compression test/check 2 cylinders are down a bit.The car doesn't smoke anymore under boost or idle(fixed small boost leak). So as far as I can tell except for the walbro sock which I cant get to because the damn fuel tank studs are rusted and I don't want to break them. All the fuel related components seem to be ok. For some reason I cant get my fuel trims stabilized either and after looking at my spark plugs it seems that I'm running a bit lean. O2 trims look normal under low to partial throttle swings all the way up to.85v under WOT the O2 voltage rarely goes pass .78v-.80v and 5-14 counts of knock if I'm in it.I tried turning up the fp but it wont go any richer and it was running a little hot until I changed the tstat. Btw my tailpipe is sooty black. Any ideas???? Sorry for the long post but I am at my wits and it doesn't add up. Rich at the tailpipe,lean at the spark plugs,logger all over the place I'm lost please help. Sorry for the long post...
 

Do you have your fuel pressure set to what your chip wants?

How old is your O2 sensor? Is it a four-wire or three-wire?
 

jepherz

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Quoting Blown1:
Would a clogged fuel pump sock cause a lean condition at WOT?


Yes, it very well could. Your "rich at tailpipe, lean at plugs" comment makes no sense. Maybe the soot in the tail pipe is from prior to the problem? Or vice-versa with the plugs?
 

Quoting Darksyne:
Do you have your fuel pressure set to what your chip wants?

How old is your O2 sensor? Is it a four-wire or three-wire?



Yes I had the fp set at 37psi base pressure which is what the chip was programmed for
O2 sensor is only a few months old wire count I would have to check and get back why?
 
Last edited by a moderator:

Quoting jepherz:
Quoting Blown1:
Would a clogged fuel pump sock cause a lean condition at WOT?


Yes, it very well could. Your "rich at tailpipe, lean at plugs" comment makes no sense. Maybe the soot in the tail pipe is from prior to the problem? Or vice-versa with the plugs?



I don't think its from a prior issue I wash my car religiously even inside the tailpipe i just think my tune was bad..
What I was trying to say is that visually (black sooty tail pipe) and electronically (fuel trims in the 81% range)I would presume the car to be running quite rich. However on my logger at WOT I am only seeing mid 11's for O2 voltage(not too rich). In addition when I removed the spark plugs the outer edges are black and sooty indicating a rich condition. However the insulator area is white (I'm assuming lean condition)? So I cant understand how it is rich and lean at the same time?

Update: good news turned the fp up a bit and the car is running a little better way less knock fuel trims are still whacked
bad news also did a leak down test after finding 2 cylinders were down on compression and it looks like I need a rebuild. I am still
amazed at how the car still runs strong even with 2 cylinders running low compression so for now I'm babying her until she gets a new heart
 
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