HELP! Running lean?
HELP! Running lean? I searched a lot but couldn't find anythig. Hope this is the right place to post this.
Anyway, I just got my throttle body ported and reinstalled it on Saturday. On the way to dinner that night, I could notice a big difference in acceleration and everything ran great. On the way home, it had trouble starting and when I pulled out in 1st gear, it almost stalled because there was just no power there. Now it still has trouble starting, taking off in 1st gear, bucking when getting on the gas, overall loss of power, and occasional popping when it bucks. Now the SES light is on. My friend (a mechanic) drove it and said the popping was from running lean. We read the codes (PO131, PO151, PO174, PO171) and he thinks there is a vacuum leak or too much air getting into the system somehow. Also, we unplugged the MAF and it ran slightly better, but still pretty bad. Any suggestions on where to look for a leak or what else might be the problem? Thanks in advance.
Anyway, I just got my throttle body ported and reinstalled it on Saturday. On the way to dinner that night, I could notice a big difference in acceleration and everything ran great. On the way home, it had trouble starting and when I pulled out in 1st gear, it almost stalled because there was just no power there. Now it still has trouble starting, taking off in 1st gear, bucking when getting on the gas, overall loss of power, and occasional popping when it bucks. Now the SES light is on. My friend (a mechanic) drove it and said the popping was from running lean. We read the codes (PO131, PO151, PO174, PO171) and he thinks there is a vacuum leak or too much air getting into the system somehow. Also, we unplugged the MAF and it ran slightly better, but still pretty bad. Any suggestions on where to look for a leak or what else might be the problem? Thanks in advance.
who did the porting? they could have F-ed up and there is extra air getting around the blade.
i just found a vacum leak on the passenger side of the engine, just behind the TB, attaching to a port on the bottom of the intake manifold. i beleive its the PVC tube. the short rubber connector was deteriorated and had a hole.
try that
did a quick pic to show it
i just found a vacum leak on the passenger side of the engine, just behind the TB, attaching to a port on the bottom of the intake manifold. i beleive its the PVC tube. the short rubber connector was deteriorated and had a hole.
try that
did a quick pic to show it
Last edited by teke184; Oct 22, 2008 at 09:33 AM.
That's about like posting "What's my gas gauge read right now?" 
Your answer lies under your car's hood, not here.
Two things to check:
1.) Vacuum leaks often have an audible hiss when the engine's running, go take a listen.
2.) Vac leaks will make the engine idle higher than spec if they're big enough...is yours idling higher than normal at operating temp?
Or if you have access to a scanner, check your Idle Air Control value and see if it's maxed out. The PCM will be closing the IAC trying to bring the idle down to spec if there's a big vacuum leak.
Your answer lies under your car's hood, not here.
Two things to check:
1.) Vacuum leaks often have an audible hiss when the engine's running, go take a listen.
2.) Vac leaks will make the engine idle higher than spec if they're big enough...is yours idling higher than normal at operating temp?
Or if you have access to a scanner, check your Idle Air Control value and see if it's maxed out. The PCM will be closing the IAC trying to bring the idle down to spec if there's a big vacuum leak.
Two things to check:
1.) Vacuum leaks often have an audible hiss when the engine's running, go take a listen.
2.) Vac leaks will make the engine idle higher than spec if they're big enough...is yours idling higher than normal at operating temp?
Or if you have access to a scanner, check your Idle Air Control value and see if it's maxed out. The PCM will be closing the IAC trying to bring the idle down to spec if there's a big vacuum leak.
1.) Vacuum leaks often have an audible hiss when the engine's running, go take a listen.
2.) Vac leaks will make the engine idle higher than spec if they're big enough...is yours idling higher than normal at operating temp?
Or if you have access to a scanner, check your Idle Air Control value and see if it's maxed out. The PCM will be closing the IAC trying to bring the idle down to spec if there's a big vacuum leak.
Still Need Help I think I am going to see if my friend will let me borrow his MAF and/or TB just to see if that fixes the problem since those are the only things that were really touched during the removal/ reinstall process. Unless anyone else has more input...
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Update I hooked up the scan tool and at idle the short term fuel trims are between 10 and 14, at little high is what my friend says. So we sprayed all around the intake system with carb/choke cleaner and they didn't change. When we unplug the MAF, the STFTs go down to 6 to 8. Does this mean the MAF is bad? I don't mind replacing it as long as that is the problem, but I don't want to start throwing parts at it.
All help is appreciated!
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then its not your maf, i drove for over a year with a bad maf (well i thought it really was just then 10a engine fuse) didnt know it was bad till i went to get the car tuned and my maf was dead in the water... you def have a vaccum leak with thoose codes and what your describing
I know it's kind of a vague question, but where are key spots to look for a vacuum leak considering all I did was get the tb ported? I've sprayed all around it with carb cleaner and the STFTs didn't change and idle didn't change. I figure it has to be a pretty big leak to have these symptoms, but I'm just not finding it.
