3.5 swap.hesitating/misfiring
03-05-2009, 08:35 PM
#1
3.5 swap.hesitating/misfiring
well, im sorry for the repeated posting of threads but ive searched and searched and have not found an answer.
I just recently finish a 3.5 swap on my cousins car and it starts on the 1st crank and idles fine around 7-900rpm.
THE PROBLEM
under load or any throttle over 30% under 2.5k rpms the car bucks and hickups and hesitates like its on a 2 step or something then smooths out then right back to the problem again.
We've changed new sprakplugs, known working UIM,TPS,MAF,ECU,injectors and coilpacks and still the same problem. Also redid all the injector wire splices.
Tried running the car at idle and shaking/moving the engine harness around and couldnt get it to manually misfire or run smooth.
Any idea what this might be? doesnt bother him as much but its killing me that its running this weird
The car is a 95 SE, 3.5l motor 3.0l timing, AFRP,z32 fuel filter,warpspeed ypipe and PFTB
I just recently finish a 3.5 swap on my cousins car and it starts on the 1st crank and idles fine around 7-900rpm.
THE PROBLEM
under load or any throttle over 30% under 2.5k rpms the car bucks and hickups and hesitates like its on a 2 step or something then smooths out then right back to the problem again.
We've changed new sprakplugs, known working UIM,TPS,MAF,ECU,injectors and coilpacks and still the same problem. Also redid all the injector wire splices.
Tried running the car at idle and shaking/moving the engine harness around and couldnt get it to manually misfire or run smooth.
Any idea what this might be? doesnt bother him as much but its killing me that its running this weird
The car is a 95 SE, 3.5l motor 3.0l timing, AFRP,z32 fuel filter,warpspeed ypipe and PFTB
03-06-2009, 12:37 AM
#3
all 4th gen sensors on 3.5 upper oil pan. one thing I noticed though. The motor is out of a 04-05 altima and the CPS on the tranny is actually mounted at the bottom of the block, so all I had to do was drill the opening a little bigger.
one thing I noticed though, the flywheel timing ring look like it might have been bent and about 5 teeth were broken off/bent. could this or too many metal shavings on the cps cause it to do this? im asking right now because im not near the car at the moment to try these out before I post
LMK
one thing I noticed though, the flywheel timing ring look like it might have been bent and about 5 teeth were broken off/bent. could this or too many metal shavings on the cps cause it to do this? im asking right now because im not near the car at the moment to try these out before I post
LMK
03-06-2009, 02:00 AM
#4
all 4th gen sensors on 3.5 upper oil pan. one thing I noticed though. The motor is out of a 04-05 altima and the CPS on the tranny is actually mounted at the bottom of the block, so all I had to do was drill the opening a little bigger.
one thing I noticed though, the flywheel timing ring look like it might have been bent and about 5 teeth were broken off/bent. could this or too many metal shavings on the cps cause it to do this? im asking right now because im not near the car at the moment to try these out before I post
LMK
one thing I noticed though, the flywheel timing ring look like it might have been bent and about 5 teeth were broken off/bent. could this or too many metal shavings on the cps cause it to do this? im asking right now because im not near the car at the moment to try these out before I post
LMK
Thats odd, but your issue sounds RPM dependent or throttle dependant? In either case, I had the same exact issue as you. It would hesistate and buck and wouldnt really pull. So I got an adjustable FPR with a gauge and lowered the fuel pressure down and everything smoothed out.
Any codes at all?
03-06-2009, 06:59 AM
#5
all 4th gen sensors on 3.5 upper oil pan. one thing I noticed though. The motor is out of a 04-05 altima and the CPS on the tranny is actually mounted at the bottom of the block, so all I had to do was drill the opening a little bigger.
one thing I noticed though, the flywheel timing ring look like it might have been bent and about 5 teeth were broken off/bent. could this or too many metal shavings on the cps cause it to do this? im asking right now because im not near the car at the moment to try these out before I post
LMK
one thing I noticed though, the flywheel timing ring look like it might have been bent and about 5 teeth were broken off/bent. could this or too many metal shavings on the cps cause it to do this? im asking right now because im not near the car at the moment to try these out before I post
LMK
03-06-2009, 07:48 AM
#7
gayness...ok about to go grab another flywheel. ill let you guys know the verdict.
also,TJ_Max we tried calling from a 301 9*6 8**8 number but no answer but we play with the fuel psi and samething
also,TJ_Max we tried calling from a 301 9*6 8**8 number but no answer but we play with the fuel psi and samething
03-06-2009, 11:22 PM
#8
Shyt, i must have missed it. Call back, we'll troubleshoot it. Sad to say my issue is still there though. I've got a slight random misfire at idle, it sucks so bad.
03-07-2009, 08:12 PM
#10
03-07-2009, 08:46 PM
#11
what would you suggest if it was only when the car was warming up? My car is very erratic at part throttle light acceleration when its not fully warm...holding the throttle steady it doesnt accelerate smoothly and lately I get one or two jolts out of nowhere as if I just dropped the clutch or something.
03-10-2009, 07:14 PM
#13
what would you suggest if it was only when the car was warming up? My car is very erratic at part throttle light acceleration when its not fully warm...holding the throttle steady it doesnt accelerate smoothly and lately I get one or two jolts out of nowhere as if I just dropped the clutch or something.
04-17-2009, 04:11 PM
#15
was this problem ever solved? I'm having an issue almost identical to the OP's in a swap I just completed. Only under load, at around 1500 rpm does the car hesitate, and then smooth out. I didnt recall any missing teeth on the flywheel, and the fuel pressure is just under 50~. The tps was almost perfectly in spec and the bracket holding it is very sturdy as well.
04-20-2009, 03:49 PM
#16
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was this problem ever solved? I'm having an issue almost identical to the OP's in a swap I just completed. Only under load, at around 1500 rpm does the car hesitate, and then smooth out. I didnt recall any missing teeth on the flywheel, and the fuel pressure is just under 50~. The tps was almost perfectly in spec and the bracket holding it is very sturdy as well.
04-20-2009, 03:52 PM
#17
that seems so low though. I did lower it to more in the 40's though and changed the TPS. Apparently the problem was solved, or then became throttle-dependent which screams "tps" to me. Not in my hands anymore.
i'm still running my car around 50 myself. I was trying to get that extra little timing but...who knows if its worth it.
i'm still running my car around 50 myself. I was trying to get that extra little timing but...who knows if its worth it.
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