Timing randomly being pulled in upper RPMS
#1
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Timing randomly being pulled in upper RPMS
I've been banging my head against the wall trying to figure this out. From 7400 RPMS on up, timing keeps being randomly pulled to 5* from what it is supposed to be set at{7-8*). There is no knock in the logs, AFR is 10.7-10.8. Timing in the logs looks like this:
6-6-6-7-7-7-5-5-7-7-7-5-5-8-8-5-5-8-8-5-5
I've double and triple checked for loose things in the engine bay and tighten every bolt/nut, checked grounds, replaced IAT, replaced cam position sensor, and just replaced the crank position sensor. There are no blown fuses. I've tried a stock ignition, iridium plugs, copper plugs, my mini battery is new as of May-June, and has been on a trickle charger when the car is sitting since day 1. Car was boost leak tested to 35psi with no leaks. I've done multiple compression tests as well and the numbers are exactly what they were last summer.
Im out of ideas. Has anyone experienced this before? I can attach logs/rom if someone would be willing to take a look. Car is being tuned remotely by a very reputable tuner, I highly doubt the tune is the problem, but I guess you never know.
6-6-6-7-7-7-5-5-7-7-7-5-5-8-8-5-5-8-8-5-5
I've double and triple checked for loose things in the engine bay and tighten every bolt/nut, checked grounds, replaced IAT, replaced cam position sensor, and just replaced the crank position sensor. There are no blown fuses. I've tried a stock ignition, iridium plugs, copper plugs, my mini battery is new as of May-June, and has been on a trickle charger when the car is sitting since day 1. Car was boost leak tested to 35psi with no leaks. I've done multiple compression tests as well and the numbers are exactly what they were last summer.
Im out of ideas. Has anyone experienced this before? I can attach logs/rom if someone would be willing to take a look. Car is being tuned remotely by a very reputable tuner, I highly doubt the tune is the problem, but I guess you never know.
#6
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Won't hurt to zero the rest out just to see, but i don't think it'll fix this one.
This triggered me to ask him once again if he has any break up or misfire at WOT. before he said no, this time he said yes when i asked on facebook. maybe the o2 sensor is recording leaner than it really is due to the location of the sensor, and it is rich enough to break up. lets hope its that. thats an easy fix if so. typically misfires create lean conditions though and i dont really see any of that occuring uptop.
Either way, i leaned it out more and we will see what that does. The target afr for the car in general is around 11.5ish on 93oct.
I will report back new findings. Thanks for helping guys.
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#10
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the spool is amazing for this setup with a 2.1L and 6766 on 93oct.
Just need to figure out whats causing the timing to scramble. its not the AFR. I leaned the car out to be 11.5 straight across still does it.
I think its something to do with the crank trigger plate.
Just need to figure out whats causing the timing to scramble. its not the AFR. I leaned the car out to be 11.5 straight across still does it.
I think its something to do with the crank trigger plate.
Last edited by tscompusa; Sep 20, 2013 at 03:21 AM.
#12
You can have the issue were ecu will pull timing so quick it wont pick up on logger, as well as you can see knock voltage getting high at the point it pulls timing. Have you tried turning knock background noise table up to say 30 and do a pull and see what it does?
#13
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Its at stock filter uptop at 20 and the roms set to flash cel at 3 counts low and 6 counts high.
no we haven't tried to jack the filter uptop high to see what it does. i dont think thats going to fix this issue but worth a shot. we will try it then report back. knock voltage is normal no spikes.
i personally think this is something to do with the trigger plate / crank / cam signal.
or maybe bad ground or ignition.
i personally think this is something to do with the trigger plate / crank / cam signal.
or maybe bad ground or ignition.
#14
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This is a long shot, but the ECU adjusts timing to 5 degrees if it gets the start signal input. Maybe there is some wiring fault/short that causes that input to go "live" at higher rpm due to vibration etc. You could disconnect the pin from the ECU connector as a test and see what happens.
Another possibility would be if the vss is working intermittently and the launch maps are enabled and happen to have 5 degrees in those load cells (I have seen something like this before).
Another possibility would be if the vss is working intermittently and the launch maps are enabled and happen to have 5 degrees in those load cells (I have seen something like this before).