Slight throttle dies
09-15-15, 09:14 PM
#1
Slight throttle dies
Ok fellas, so here's the issue. And before you say it, yes I have researched and tried diagnosing.
This happens when:
Partial throttle is applied
In any gear, At rpm:
Afr - - -(dashes) out lean
Dies at idle
Face plants driving
If I baby touch the throttle its fine and drivable..ish except up hill not enough air flow/power:
- 1.6v to ~3.9+v
At ~4.5v partial throttle that's when dash out lean Afr hits
During idling it WILL cause engine to die.
While driving it will cause power loss and nose dive
When I press just past "dead zone" throttle, 4.5v half to full throttle, afr jumps back up to normal operation
So I'd say
0 to 10% throttle input gives normal afr
~15 to 25% is the "dead zone"
~30 to 100% throttle input gives normal afr
If that makes any more since.
I have checked for any possible vacuum leaks, all resolved.
Timing. No change.
Swapped around afm, tps, barometric pressure sensor. No change.
Put my rtek 2.1 to factory settings. No change.
Swapped around injectors. No change.
If any other info is need, please ask.
This issue makes it hell to drive slow in residential, or go from a stop without spinning wheels.
Thanks, Brendan
This happens when:
Partial throttle is applied
In any gear, At rpm:
Afr - - -(dashes) out lean
Dies at idle
Face plants driving
If I baby touch the throttle its fine and drivable..ish except up hill not enough air flow/power:
- 1.6v to ~3.9+v
At ~4.5v partial throttle that's when dash out lean Afr hits
During idling it WILL cause engine to die.
While driving it will cause power loss and nose dive
When I press just past "dead zone" throttle, 4.5v half to full throttle, afr jumps back up to normal operation
So I'd say
0 to 10% throttle input gives normal afr
~15 to 25% is the "dead zone"
~30 to 100% throttle input gives normal afr
If that makes any more since.
I have checked for any possible vacuum leaks, all resolved.
Timing. No change.
Swapped around afm, tps, barometric pressure sensor. No change.
Put my rtek 2.1 to factory settings. No change.
Swapped around injectors. No change.
If any other info is need, please ask.
This issue makes it hell to drive slow in residential, or go from a stop without spinning wheels.
Thanks, Brendan
Last edited by R.O.D; 09-16-15 at 02:17 PM.
09-16-15, 02:46 PM
#5
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Turbo or na
Also when you give it partial throttle i wonder if it somehow thinks its in decel mode and is cutting fuel to 1 rotor... i dunnno
Also when you give it partial throttle i wonder if it somehow thinks its in decel mode and is cutting fuel to 1 rotor... i dunnno
Last edited by FührerTüner; 09-16-15 at 02:49 PM.
09-16-15, 05:06 PM
#7
Sorry should've specified specs
86 frame 88 turbo swap
Stock ports all emissions removed
Bac valve installed, not plugged in
(Not a leak source, I've checked)
550s prime and sec for now
Modded tb
60-1 t04e .82 ar exhaust 3" outlet
Running +/- 5 psi for breakin period
2.5" tubing and large fmic
Stock coils and plugs
Avcr ebc
Rtek 2.1
Apexi neo (only for system monitoring)
Read rumors on here that they sometimes cause issues even being installed. May remove for testing.
Aem wb afr
I will disconnect tps and try swapping ecu at different interval.
What will disconnecting the tps do or show? Will it even start or run?
86 frame 88 turbo swap
Stock ports all emissions removed
Bac valve installed, not plugged in
(Not a leak source, I've checked)
550s prime and sec for now
Modded tb
60-1 t04e .82 ar exhaust 3" outlet
Running +/- 5 psi for breakin period
2.5" tubing and large fmic
Stock coils and plugs
Avcr ebc
Rtek 2.1
Apexi neo (only for system monitoring)
Read rumors on here that they sometimes cause issues even being installed. May remove for testing.
Aem wb afr
I will disconnect tps and try swapping ecu at different interval.
What will disconnecting the tps do or show? Will it even start or run?
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09-18-15, 05:40 PM
#14
I gotcha! Ya and I'm starting to think fuel psi as well. If I slowly let off the throttle that "dead zone" almost disappears. May be a hack job. But thinking of using a vice grib to slightly increase pressure by making the return side a little more restricted. Thoughts? BTW, this will NOT be permanent. Just for testing.
09-18-15, 05:54 PM
#15
that would only work if the regulator is stuck open and allowing pressure to bleed off. if the pump is weak or there is a bypassing leak inside the tank then that won't really accomplish much. you can usually rent a pressure tester from a generic auto parts store.
09-19-15, 02:49 AM
#17
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Boost leak or vac leak between turbo and throttle body...
AFM can't read the extra air drawn in as the throttle is slightly opened as it sucks air elsewhere.
Once the turbo starts spooling it draws air through the AFM and sorts itself out..
Probably runs a bit rich on boost too and a bit lean on idle too.
If it was fuel filter/pump/pressure it would hate any kind of load.
AFM can't read the extra air drawn in as the throttle is slightly opened as it sucks air elsewhere.
Once the turbo starts spooling it draws air through the AFM and sorts itself out..
Probably runs a bit rich on boost too and a bit lean on idle too.
If it was fuel filter/pump/pressure it would hate any kind of load.
09-19-15, 06:23 AM
#20
a large vacuum leak could do it but i'd be pretty surprised that the ECU didn't cut off the pump once started and that the car wouldn't just continually stall versus idle. but i guess it really depends where the leak is and whether it is able to act as a flapper valve with enough air movement.
09-19-15, 04:38 PM
#21
Pulled the fuel pump out. Inside looks either rusted or just dirty. Aaaaand the pump sock was destroyed. Looks like the pump ate it. Soooooo. Got an aeromotive 340 on the way, but gonna try this one again with a new sock and see how it does. Plus I'm gonna try to do the 12v pump rewire.
09-19-15, 09:09 PM
#23
I don't disagree, bit thought it might be worth a shot. Jury rigged some crap as a sock to prevent large contaminants from getting in. I think the pump is just shot. Between eating the old sock and more than likely because it sat in old fuel its probably just done. New pump should be in Wednesday. I'll report back then.
