car running lean...
10-12-2007, 03:53 AM
#1
car running lean...
i've checked everything that i could think of... why is my car running lean?
first i get a 02 sensor code, got a new one, code went away but my WB02 still shows super lean during any kind of acceleration, but when cruising, it goes to stoich mixture....
what can cause the car to run lean?
can you guys start listing everything possible so i can check one by one? thanx. this is driving me crazy......
Peter
first i get a 02 sensor code, got a new one, code went away but my WB02 still shows super lean during any kind of acceleration, but when cruising, it goes to stoich mixture....
what can cause the car to run lean?
can you guys start listing everything possible so i can check one by one? thanx. this is driving me crazy......
Peter
10-13-2007, 05:40 PM
#4
Supporting Maxima.org Member
iTrader: (29)
Join Date: Oct 2005
Location: Middleboro/Carver, Ma
Posts: 4,572
Vacuum Leak, Bad Maf, Fuel Delivery Problem (check pressure AND volume), incredibly horrible exhaust leak, to name a few, maf gets my vote, but that's pure speculation. I think the FSM lists several more. What are your long term fuel trims looking like?
10-13-2007, 06:52 PM
#6
haha nah. decided not to, so i just got a 3.5 swap...
well... my fuel pressure looks ok.
-no exhaust leak for sure.
-im guessing maybe maf, but car still seems to be quick for what it is, but a little slower than usual.
-maybe a vac. leak but i dont know what's the best way to check for that.
Divewjason, my car seems to hesitate a little bit, but not that much.
im speculating a lean mixture since my wb02 says it is, but for some reason, i have a feeling that my wb might be broken, but not too sure.
-if running lean, wouldn't my exhaust smell like as$?
well... my fuel pressure looks ok.
-no exhaust leak for sure.
-im guessing maybe maf, but car still seems to be quick for what it is, but a little slower than usual.
-maybe a vac. leak but i dont know what's the best way to check for that.
Divewjason, my car seems to hesitate a little bit, but not that much.
im speculating a lean mixture since my wb02 says it is, but for some reason, i have a feeling that my wb might be broken, but not too sure.
-if running lean, wouldn't my exhaust smell like as$?
10-13-2007, 07:01 PM
#7
Supporting Maxima.org Member
iTrader: (29)
Join Date: Oct 2005
Location: Middleboro/Carver, Ma
Posts: 4,572
That's why I was wondering what your long-term fuel trims were, to rule out the WB possibly being off, most of the time the 5th gen guys have there maf's go "bad" they either get lean codes or have long-term fuel trims that are close to tripping the lean code. What o2 sensor code did you have? and I'm geussing that you are running stock fuel-pressure specs right? Also, you can take a look at your plugs to see if you are indeed running lean, plugs can tell a lot.
10-14-2007, 05:44 PM
#8
yeah, i should check out my plugs....
well my fuel pressure is running in spec. i believe my 02 code was a 0403 or something like that. rear bank lean.... but now i no longer have that code.
if the MAF goes out, doesn't the car start to bog like crazy?
well my fuel pressure is running in spec. i believe my 02 code was a 0403 or something like that. rear bank lean.... but now i no longer have that code.
if the MAF goes out, doesn't the car start to bog like crazy?
10-14-2007, 07:59 PM
#10
I tap on them during idle . Check out my thread it may help a lil
both banks were running extremely lean. But only the rear after fixing vacuum leaks. Dont drive that car you can fry your valves, melt your cat and blow a head gasket down the road. FYI running lean can over heat your engine and exhaust and dont count on your coolant temp gauge because it will not reflect the combustion chamber/head temps. Trust me on this one I dont want anyone to have to pull the engine back out.Like I did
Good luck.http://forums.maxima.org/showthread.php?t=539556
10-14-2007, 09:44 PM
#11
Senior Member
Join Date: Aug 2007
Location: FL
Posts: 704
haha nah. decided not to, so i just got a 3.5 swap...
well... my fuel pressure looks ok.
-no exhaust leak for sure.
-im guessing maybe maf, but car still seems to be quick for what it is, but a little slower than usual.
-maybe a vac. leak but i dont know what's the best way to check for that.
Divewjason, my car seems to hesitate a little bit, but not that much.
im speculating a lean mixture since my wb02 says it is, but for some reason, i have a feeling that my wb might be broken, but not too sure.
-if running lean, wouldn't my exhaust smell like as$?
well... my fuel pressure looks ok.
-no exhaust leak for sure.
-im guessing maybe maf, but car still seems to be quick for what it is, but a little slower than usual.
-maybe a vac. leak but i dont know what's the best way to check for that.
Divewjason, my car seems to hesitate a little bit, but not that much.
im speculating a lean mixture since my wb02 says it is, but for some reason, i have a feeling that my wb might be broken, but not too sure.
-if running lean, wouldn't my exhaust smell like as$?
http://www.aa1car.com/library/vacleak.htm
Good luck. If you find out that it isn't a vacuum leak it MAY be a fuel injector, but you are looking at a pricey repair if you have to go through with that. Good luck man. Keep us updated.
10-14-2007, 10:52 PM
#13
well im guessing i can rule out the maf since there's no bogging here....
weird thing is, is that when im in gear, and when i let off my throtle to come to a stop, shouldn't my wideband read lean? well.... it doesn't, it reads 15.2 or something and when i step on the gas, it shows lean.... chance my WB02 might be broken? what do you guys think?
thanx for the link on finding the leak, i will look into that right now.
anymore help appreciated. thanx guys.
weird thing is, is that when im in gear, and when i let off my throtle to come to a stop, shouldn't my wideband read lean? well.... it doesn't, it reads 15.2 or something and when i step on the gas, it shows lean.... chance my WB02 might be broken? what do you guys think?
thanx for the link on finding the leak, i will look into that right now.
anymore help appreciated. thanx guys.
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