Misfire after injector install?
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From: Reynoldsburg, Ohio
Misfire after injector install? Recently, I've added 50# Delphi injectors scored from nbm00ws6 and have been tuning with billiumss. The car picked up for sure, and it seems to run decent at cruising/part throttle (some occasional stumbling and ****, all tuned out in time). WOT is amazing with no noticeable problems except lack of traction at anything under 50mph 
However, the car seems to be thinking it's misfiring, specifically on the #8 cylinder and occasionally on the #6 cylinder. There's no noticeable performance loss or stumbling around. However, it flashes the SES light only at cruising between 1500-2000 RPMs, and usually only in 4th gear. It never sets the light permanently, and usually a quick blip of the throttle kills the flashing.
Bill has been using the HPTuners scanner on my car, and that's how we know the PCM is seeing misfires in the 6/8 cylinders. At idle, the #8 cylinder is counting misfires like mad according to the scanner, but there's no SES and the car doesn't feel like it's missing.
I've checked the #8 plug wire, reseated the injector harness connector to the injector, and made sure the injector was seated in the intake.
On a side note, Bill cannot seem to get my trims zeroed for part-throttle. But my WOT trims go right to zero every time.
Anyone have any ideas or run into this before? Thanks.
However, the car seems to be thinking it's misfiring, specifically on the #8 cylinder and occasionally on the #6 cylinder. There's no noticeable performance loss or stumbling around. However, it flashes the SES light only at cruising between 1500-2000 RPMs, and usually only in 4th gear. It never sets the light permanently, and usually a quick blip of the throttle kills the flashing.
Bill has been using the HPTuners scanner on my car, and that's how we know the PCM is seeing misfires in the 6/8 cylinders. At idle, the #8 cylinder is counting misfires like mad according to the scanner, but there's no SES and the car doesn't feel like it's missing.
I've checked the #8 plug wire, reseated the injector harness connector to the injector, and made sure the injector was seated in the intake.
On a side note, Bill cannot seem to get my trims zeroed for part-throttle. But my WOT trims go right to zero every time.
Anyone have any ideas or run into this before? Thanks.
Might check for vacuum leak about the #8 injector seat,
perhaps an O-ring got cocked or lost? Also swap #8 injector
with #2 (or whatever) if the vac leak doesn't pan out and
see if the misfire moves. Always a chance that a used
injector (or any non-virgin-wrapped) inhaled a hairball.
perhaps an O-ring got cocked or lost? Also swap #8 injector
with #2 (or whatever) if the vac leak doesn't pan out and
see if the misfire moves. Always a chance that a used
injector (or any non-virgin-wrapped) inhaled a hairball.
Thread Starter
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From: Reynoldsburg, Ohio
Yeah, I planned on removing the fuel rail again and checking everything carefully. I made sure to coat the o-rings with oil and tighten everything down (3rd injector install for me). I'm hoping it's something stupid, like it usually is. I'm gonan change plugs too, even though the current ones only have 1500 miles on them.
Just in case, though. Can I clean the injectors myself? Or do I need to send them off somewhere?
Just in case, though. Can I clean the injectors myself? Or do I need to send them off somewhere?
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From: Reynoldsburg, Ohio
After doing some checking around and playing with the car, I'm gonna do one last plug change since I may have fouled them out. If that doesn't work, the code will be turned off. That flashing light is annoying as all hell.
You can raise the misfire detection threshold. However
if you have one cylinder that's out of bed with the rest
it's probably trying to tell you something. Going that
way might be better than just killing the code.
I have a 3000RPM stall, maybe a little heavier than yours
but not by much I think, and I see current misfire counts
of only 2-6 (but I also have stock F-body cam etc.). But
a loose plug wire gave me like 115.
if you have one cylinder that's out of bed with the rest
it's probably trying to tell you something. Going that
way might be better than just killing the code.
I have a 3000RPM stall, maybe a little heavier than yours
but not by much I think, and I see current misfire counts
of only 2-6 (but I also have stock F-body cam etc.). But
a loose plug wire gave me like 115.
