Bypass valve compensation
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Newbie
Joined: Sep 2011
Posts: 42
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From: Moscow
Bypass valve compensation
I heard about an algorithm in a MMC Colt Ralliart flash that is likely to be bypass valve compensation - when you release the throttle it somehow affects load. Such a thing should be also present in Evo flashes. Does anybody know about it? Does it use some maps or constants?
My problem is that on throttle release while the airflow Hz is lowering, the load raises and the engine goes very rich and tries to stall. The more time bypass vents, the richer it goes. It's connected to bypass valve - with stock plastic one the problem almost disappears, but with RS (metal) or other (GFB Deceptor) one it's really takes place. So maybe correcting bpv compensation will help me.
I use 80700010, but I think I'll manage to find the corresponding snippet of the code by analogy to any Evo 7-9 flash, maybe someone have these maps.
My problem is that on throttle release while the airflow Hz is lowering, the load raises and the engine goes very rich and tries to stall. The more time bypass vents, the richer it goes. It's connected to bypass valve - with stock plastic one the problem almost disappears, but with RS (metal) or other (GFB Deceptor) one it's really takes place. So maybe correcting bpv compensation will help me.
I use 80700010, but I think I'll manage to find the corresponding snippet of the code by analogy to any Evo 7-9 flash, maybe someone have these maps.
Newbie
Joined: Nov 2012
Posts: 43
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From: Czech rep.
Nice, i found this about month ago, when i finally solved idle stalling by installing original plastic bov(after huge tries on ecu idle remapping, throttle body sealing+biss calibration,ect).
To your teory, it happening also if there is no bov=no air venting. There is surge going reversed throught MAF. Nothing strange on datalogs, only huge injectors PW when rpm dropping under target idle.
It also can be connected to acceleration enrichment(throttle pump compensation) mean especialy deceleration situation. This according my experience with standalone managements on other cars(also only speed density).
To your teory, it happening also if there is no bov=no air venting. There is surge going reversed throught MAF. Nothing strange on datalogs, only huge injectors PW when rpm dropping under target idle.
It also can be connected to acceleration enrichment(throttle pump compensation) mean especialy deceleration situation. This according my experience with standalone managements on other cars(also only speed density).
Thread Starter
Newbie
Joined: Sep 2011
Posts: 42
Likes: 2
From: Moscow
This is related to MAF, but not only to it - airflow Hz is falling and there isn't any noticable spikes during vent. Maybe it falls not as fast as with plastic BPV, but anyway rich afr is caused by load, which is controlled by ecu.
Newbie
Joined: Nov 2012
Posts: 43
Likes: 0
From: Czech rep.
Its impressive, this must cause problem on all cars with changed bov, and nobody from this forum noticed it during all the years. Just letting their car stalling and think that is normal or i dont know 
Probably there must be difference in potential compensation table between normal VIII with plastic and MR edition with metal. Do you have skills to understand&compare binnaries and search for it?
Probably there must be difference in potential compensation table between normal VIII with plastic and MR edition with metal. Do you have skills to understand&compare binnaries and search for it?
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