High load at idle
05-15-2018, 10:05 AM
#1
Cpt. Slow
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High load at idle
I've been attempting to remote tune a highly modified MSM and am coming across something I don't think I've encountered before, and am wondering if anyone else has. It's warming up nicely but we're still working on warm restarts, as rpm is currently fluctuating like crazy.
My main concern is that it's idling at 60kpa. I've looked over a number of my datalogs from other vehicles and usually see low 30s. Idle valve is in a normal range of ~30%, and the car refuses to idle leaner than ~13.0, which was apparently similar with his Hydra. Am I missing the reason for this?
Yes I have CL idle, idle VE, and a number of other features disabled as we try to work on just warming up and restarting.
.msq and log attached.
Shoot log is too big, I'll get a shorter one soon
My main concern is that it's idling at 60kpa. I've looked over a number of my datalogs from other vehicles and usually see low 30s. Idle valve is in a normal range of ~30%, and the car refuses to idle leaner than ~13.0, which was apparently similar with his Hydra. Am I missing the reason for this?
Yes I have CL idle, idle VE, and a number of other features disabled as we try to work on just warming up and restarting.
.msq and log attached.
Shoot log is too big, I'll get a shorter one soon
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05-15-2018, 10:15 AM
#2
SADFab Destructive Testing Engineer
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Sounds like a vacuum leak? The other time I recently dealt with a high kpa idling car the intake came was off a tooth.
60kpa of vacuum at idle is way too high, something is wrong.
60kpa of vacuum at idle is way too high, something is wrong.
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05-15-2018, 10:36 AM
#4
Cpt. Slow
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It does supposedly have big cams. Adjustable exhaust cam was 6* advanced, I had the owner return to zero advance with no change in idle load. I'll have him double check for any vacuum leaks.
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05-15-2018, 01:47 PM
#13
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This is what the car has. (Curly is helping me)
Skunk2 throttle body, Garrett GT3170R turbo with a 3” exhaust out the back. Wideband
sensor and 1000cc injectors
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05-15-2018, 02:34 PM
#17
Cpt. Slow
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He said he sprayed carb cleaner everywhere without an increase in RPM, I'd be doing a smoke test, but that's out of the typical home mechanic's abilities.
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05-15-2018, 10:49 PM
#18
Tweaking Enginerd
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What is the idle RPM? Do throttle changes result in reasonable MAP/RPM changes? Is MAP stable? Unless the ignition timing, cam timing, or something else is totally fubar, I would expect the torque to prevent it from getting down to anything a normal person would call idle.
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05-15-2018, 10:58 PM
#19
Tweaking Enginerd
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Continued...
I would start by targeting a stable afr of like 12.5. If the CAM profile really is that aggressive, you are probably getting all sorts of sporatic combustion behavior at 13 or higher. Once you get the AFR/rpm stabilized, you can try leaning it out.
I would start by targeting a stable afr of like 12.5. If the CAM profile really is that aggressive, you are probably getting all sorts of sporatic combustion behavior at 13 or higher. Once you get the AFR/rpm stabilized, you can try leaning it out.
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