DR1665
Well-known member
464/1000 has been running like ass lately. I don't know if it's got anything to do with the accident last week, but she caught a Jetta with the rear clip and I'm not ruling out the impact might have knocked something loose/off. Looking for a little input regarding my theories if you wouldn't mind. I've done some searching, but still not entirely sure.
Symptoms:
Part throttle hesitation under acceleration. Typically around 2500-3500rpm. Tach climbs, boost gauge climbs (steady, no twitching), speed climbs, and pulls like a raped ape on Opposite Day. Noticeable loss of power under loads at part throttle.
Usual suspects:
Boost leak - I don't have a tester. I've never needed one. Did a thorough once-over of the plumbing last night. Stock IC and "piping" is secure. One of the two lines to the EGR had come off, but replacing it didn't mitigate symptoms. The only other questionable vac location I could find is the little BCS-looking solenoid on the front of the airbox. This was a California car until I opened up the ECU last summer. No CEL at this time. If I recall, I'm pulling down closer to 20in vac at idle.
Dirty MAF - Before the trip to SoCal this past weekend, I swapped out the dirty K&N for a clean one. I am generally very light with the oil, but the MAF got a good cleaning anyway.
Running rich - On the way to SoCal Friday night, I added a can of Seafoam to the tank, as it has probably been a while. Added to low tank, filled up on top.
Fuel filter - I wonder if getting rear-ended at 50 might have knocked some shiz loose inside the gas tank, which is now trying to make its way through the system. Don't know how long the current filter has been installed, but I dunno...
Fuel pump - Sometimes they overheat. Sometimes they just get old. Sometimes they suck up so much loose shiz in the gas tank that the pre-filter gets clogged and they can't flow enough. It's barely getting into the low 90s here in Phoenix and this pump did just fine last summer at 120* with the AC on in traffic. I doubt it's suddenly started bitching about its job. Although, shiz in the tank...?
EDIT:
Also, replaced the plugs prior to the trip. NGK BPR6ES looked good, despite being installed in January 2008, 17k+ on them. Nobody local had the right plugs, so I tried NGK BPR6EYs, which are their V-Power jobbers. I lost 4mpg on the way to SoCal. Sourced the right plugs while I was there, but saw no improvement in mileage on the return trip. Gapped to just under 35.
EDIT2:
Does seem like temperature might be a factor, as the car ran decently this morning while it was cool outside, but is running worse at the noon hour. It was so bad on the way home last night that I decided I didn't want to wait until the weekend to dick with it. Have not double checked the temp sensor connections.
Once car gets past the hesitation, it continues to pull decently, so I'd think that rules out a restriction in the fuel system, since those seem to lock you down at lower engine speeds since there's no fuel to keep up.
I don't have a logger, but I'll be looking for one here today. Just curious what you guys thought. Posted in Newbie because I found dozens of threads on this issue by other FNGs over time. Kinda hoping a little more pre-post troubleshooting might appeal to the kind mercies of the veterans. /ubbthreads/images/graemlins/worthy.gif
Thank you.
Symptoms:
Part throttle hesitation under acceleration. Typically around 2500-3500rpm. Tach climbs, boost gauge climbs (steady, no twitching), speed climbs, and pulls like a raped ape on Opposite Day. Noticeable loss of power under loads at part throttle.
Usual suspects:
Boost leak - I don't have a tester. I've never needed one. Did a thorough once-over of the plumbing last night. Stock IC and "piping" is secure. One of the two lines to the EGR had come off, but replacing it didn't mitigate symptoms. The only other questionable vac location I could find is the little BCS-looking solenoid on the front of the airbox. This was a California car until I opened up the ECU last summer. No CEL at this time. If I recall, I'm pulling down closer to 20in vac at idle.
Dirty MAF - Before the trip to SoCal this past weekend, I swapped out the dirty K&N for a clean one. I am generally very light with the oil, but the MAF got a good cleaning anyway.
Running rich - On the way to SoCal Friday night, I added a can of Seafoam to the tank, as it has probably been a while. Added to low tank, filled up on top.
Fuel filter - I wonder if getting rear-ended at 50 might have knocked some shiz loose inside the gas tank, which is now trying to make its way through the system. Don't know how long the current filter has been installed, but I dunno...
Fuel pump - Sometimes they overheat. Sometimes they just get old. Sometimes they suck up so much loose shiz in the gas tank that the pre-filter gets clogged and they can't flow enough. It's barely getting into the low 90s here in Phoenix and this pump did just fine last summer at 120* with the AC on in traffic. I doubt it's suddenly started bitching about its job. Although, shiz in the tank...?
EDIT:
Also, replaced the plugs prior to the trip. NGK BPR6ES looked good, despite being installed in January 2008, 17k+ on them. Nobody local had the right plugs, so I tried NGK BPR6EYs, which are their V-Power jobbers. I lost 4mpg on the way to SoCal. Sourced the right plugs while I was there, but saw no improvement in mileage on the return trip. Gapped to just under 35.
EDIT2:
Does seem like temperature might be a factor, as the car ran decently this morning while it was cool outside, but is running worse at the noon hour. It was so bad on the way home last night that I decided I didn't want to wait until the weekend to dick with it. Have not double checked the temp sensor connections.
Once car gets past the hesitation, it continues to pull decently, so I'd think that rules out a restriction in the fuel system, since those seem to lock you down at lower engine speeds since there's no fuel to keep up.
I don't have a logger, but I'll be looking for one here today. Just curious what you guys thought. Posted in Newbie because I found dozens of threads on this issue by other FNGs over time. Kinda hoping a little more pre-post troubleshooting might appeal to the kind mercies of the veterans. /ubbthreads/images/graemlins/worthy.gif
Thank you.
Last edited: