For the advanced guru. Strange, Car rev's in Start up mode, not in running mode?
11-10-2014, 02:39 PM
#1
For the advanced guru. Strange, Car rev's in Start up mode, not in running mode? Hey guys.
2009 Z06 with Procharger F1 with strange issue.
Recently did a engine transplant, (original engine lost oil pressure, and spun 5&6 bearings). Customer bought a modified LS7 from another customer of mine as well as his Procharger.
Upon first fire up the car runs and sounds perfect, but would not rev past 3000 rpms, it would rev up then fall on it's face at 3k. O2's reading a lean condition, so I added some fuel, now engine hesitates and flutters at 5000 rpms.
no SES light.
Now here's the strange thing, in start mode (first 2 seconds of run time) engine revs freely and and sounds beast to 6500 rpms. Then same issue again, after 2 seconds no longer in start mode, flutters at 5k rpms. Feels like it's running on 4 cylinders at that rpm, like a 2 step without the 2 step.
Checked fuses, good.
No missing grounds, everything plugged in fine.
No tuning issues.
I'm at a little loss here
Pulled 02 sensor fuse, now SES states open injector circuit.
Injectors 1, 5, 6, 8. Put fuse back in ses light goes away.
Any thoughts anyone ?
Thx
Clint
2009 Z06 with Procharger F1 with strange issue.
Recently did a engine transplant, (original engine lost oil pressure, and spun 5&6 bearings). Customer bought a modified LS7 from another customer of mine as well as his Procharger.
Upon first fire up the car runs and sounds perfect, but would not rev past 3000 rpms, it would rev up then fall on it's face at 3k. O2's reading a lean condition, so I added some fuel, now engine hesitates and flutters at 5000 rpms.
no SES light.
Now here's the strange thing, in start mode (first 2 seconds of run time) engine revs freely and and sounds beast to 6500 rpms. Then same issue again, after 2 seconds no longer in start mode, flutters at 5k rpms. Feels like it's running on 4 cylinders at that rpm, like a 2 step without the 2 step.
Checked fuses, good.
No missing grounds, everything plugged in fine.
No tuning issues.
I'm at a little loss here
Pulled 02 sensor fuse, now SES states open injector circuit.
Injectors 1, 5, 6, 8. Put fuse back in ses light goes away.
Any thoughts anyone ?
Thx
Clint
11-12-2014, 10:36 AM
#3
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No mention of fuel pressure at the rails?
I don't think you should claim "no tuning issues" when
there is this sort of misbehavior. Maybe "no -known-
issues".
Seems like maybe you're falling off the end of after-
start enrichment, and need way more fuel. Might have
a look at the fuel plumbing situation, and whether the
injector flow rate matches (like, having a table for a
boost referenced regulator but using one from a tank
regulated vehicle, stockish, could maybe act this
way).
Consistency of sensors w/ tune & boosted - right MAP
sensor vs tune/OS (multi-bar MAP for boosted? Or is
this some "MAF will handle it" 1-bar boosted cobble?).
I don't think you should claim "no tuning issues" when
there is this sort of misbehavior. Maybe "no -known-
issues".
Seems like maybe you're falling off the end of after-
start enrichment, and need way more fuel. Might have
a look at the fuel plumbing situation, and whether the
injector flow rate matches (like, having a table for a
boost referenced regulator but using one from a tank
regulated vehicle, stockish, could maybe act this
way).
Consistency of sensors w/ tune & boosted - right MAP
sensor vs tune/OS (multi-bar MAP for boosted? Or is
this some "MAF will handle it" 1-bar boosted cobble?).
11-12-2014, 01:09 PM
#4
No mention of fuel pressure at the rails?
I don't think you should claim "no tuning issues" when
there is this sort of misbehavior. Maybe "no -known-
issues".
Seems like maybe you're falling off the end of after-
start enrichment, and need way more fuel. Might have
a look at the fuel plumbing situation, and whether the
injector flow rate matches (like, having a table for a
boost referenced regulator but using one from a tank
regulated vehicle, stockish, could maybe act this
way).
Consistency of sensors w/ tune & boosted - right MAP
sensor vs tune/OS (multi-bar MAP for boosted? Or is
this some "MAF will handle it" 1-bar boosted cobble?).
I don't think you should claim "no tuning issues" when
there is this sort of misbehavior. Maybe "no -known-
issues".
Seems like maybe you're falling off the end of after-
start enrichment, and need way more fuel. Might have
a look at the fuel plumbing situation, and whether the
injector flow rate matches (like, having a table for a
boost referenced regulator but using one from a tank
regulated vehicle, stockish, could maybe act this
way).
Consistency of sensors w/ tune & boosted - right MAP
sensor vs tune/OS (multi-bar MAP for boosted? Or is
this some "MAF will handle it" 1-bar boosted cobble?).
Thanks for the input.
Pressure at the rail is consistent at 58 to 60psi. No drop off. Fuel system is fine.
I'll restate as I agree, "no -known-issues" in the tune.
Agreed, after afterstart enrichment, then need more fuel.
1 Bar Map with Card style MAF, tried Maf tune only and combo Maf/Map no effect.
Next were trying pcm swap, among other things, running out of options..
12-03-2014, 11:15 AM
#5
Just for the record. Found the issue. We were shipped Low Imp injectors instead of the High Imp we ordered. Car is fixed and running now. Got them replaced, but it screwed up the injector driver in the pcm at the same time. Just for for thought for everyone that could have a mystery issue like this. 
Clint
Clint
