Patch request discussion: rev-down maf clamp (stalling issue)
Evolved Member
Joined: Mar 2008
Posts: 730
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From: Lattitude 48.38°, Longitude 17.58°, Altitude 146m = Slovakia, for common dude
I think collection of criteria is a hard part in this approach as well.
I would rather implement dynamic correction of MAF according to MDP (actually takiing advantage of both MAP and MAF worlds), but I cannot tell the consequences.
I would rather implement dynamic correction of MAF according to MDP (actually takiing advantage of both MAP and MAF worlds), but I cannot tell the consequences.
My .02
The idle dip, from my experience, has been related to the 0 load cell timing and the decel fuel cut delay tables. If you remove the 0 load cell the engine tries to interpolate where it should be. The conditions are always different during decel so the ECU never has a series of timing cells to go by. Also, if the decel tables are too high or too low there is issues on run down.
I see that a lot of "tuners" remove the 0 load cell, and several other drivability region loads. I do not recommend this.
I may be completely wrong....but this is what I believe the issues are from.
For me, I believe that anyone can basically tune for a WOT pull, but tuning for drivability seems much more important. After all, most people want both.
Paul
The idle dip, from my experience, has been related to the 0 load cell timing and the decel fuel cut delay tables. If you remove the 0 load cell the engine tries to interpolate where it should be. The conditions are always different during decel so the ECU never has a series of timing cells to go by. Also, if the decel tables are too high or too low there is issues on run down.
I see that a lot of "tuners" remove the 0 load cell, and several other drivability region loads. I do not recommend this.
I may be completely wrong....but this is what I believe the issues are from.
For me, I believe that anyone can basically tune for a WOT pull, but tuning for drivability seems much more important. After all, most people want both.
Paul
I agree speed density is the ultimate solution. As a matter of act, when I had this problem with my DSM, I compeltely solved it by installing a GM MAF in blow-though.
However, I think we should be able to code this relatively simply. One of the devices that I was mentioning that does this sort of thing is the HKS EIDS. All it has is an input for the MAF Hz and TPS. So, I'm sure it's doing something along the lines of what I was mentioning above.
I think it would be good to include coolant temp and AC on/off just so cold start and AC conditions wouldn't be affected.
Eric
However, I think we should be able to code this relatively simply. One of the devices that I was mentioning that does this sort of thing is the HKS EIDS. All it has is an input for the MAF Hz and TPS. So, I'm sure it's doing something along the lines of what I was mentioning above.
I think it would be good to include coolant temp and AC on/off just so cold start and AC conditions wouldn't be affected.
Eric
Edit, here's a page from the manual on how the ECU+'s version works.
http://cid-a5ff1875a08be401.skydrive...anti-stall.pdf
Last edited by honki24; Jan 21, 2010 at 05:37 AM.
Evolving Member
Joined: May 2008
Posts: 346
Likes: 0
From: Dallas, TX
My .02
The idle dip, from my experience, has been related to the 0 load cell timing and the decel fuel cut delay tables. If you remove the 0 load cell the engine tries to interpolate where it should be. The conditions are always different during decel so the ECU never has a series of timing cells to go by. Also, if the decel tables are too high or too low there is issues on run down.
I see that a lot of "tuners" remove the 0 load cell, and several other drivability region loads. I do not recommend this.
I may be completely wrong....but this is what I believe the issues are from.
For me, I believe that anyone can basically tune for a WOT pull, but tuning for drivability seems much more important. After all, most people want both.
Paul
The idle dip, from my experience, has been related to the 0 load cell timing and the decel fuel cut delay tables. If you remove the 0 load cell the engine tries to interpolate where it should be. The conditions are always different during decel so the ECU never has a series of timing cells to go by. Also, if the decel tables are too high or too low there is issues on run down.
I see that a lot of "tuners" remove the 0 load cell, and several other drivability region loads. I do not recommend this.
I may be completely wrong....but this is what I believe the issues are from.
For me, I believe that anyone can basically tune for a WOT pull, but tuning for drivability seems much more important. After all, most people want both.
Paul
I would really love to see a fix for this for us MAF users as I have no interest in going SD at this time.
Last edited by tnt1106; Apr 28, 2010 at 10:30 AM.
Evolving Member
Joined: May 2008
Posts: 346
Likes: 0
From: Dallas, TX
convert to SD still same issue (only with a/c on) rock solid with a/c off since SD. I have tried every posted suggestion thus far I have found.
edit: ISCV tables with rpm control suggested from another thread seem to be helping.
edit: ISCV tables with rpm control suggested from another thread seem to be helping.
Last edited by tnt1106; Apr 28, 2010 at 10:23 AM.
Reviving this thread. Any solutions besides SD or a blow thru MAF? I run 94170715 My car consistently stalls if I clutch in after giving a little gas (happens in parking lots or the driveway).
Look at a stock timing map. Notice a strange bump in timing thats completely out of place in the 0-1000rpm/60load area? This is for decel catch. If you have cams, large injectors or both, this area can SOMETIMES be adjusted to aid a bit as the fuel is being re-applied by the ECU.
-Jamie
(jack_of_trades)
-Jamie
(jack_of_trades)
I tried this as well. Adding the zero load row back to the bigmaps does not affect the idle stumble.
it seems like there are a lot of us with this problem 
coming to a stop next to some ladies is usually awesome....unless I stall or my wife is in the car (I'm pretending she isn't over my shoulder right now)
coming to a stop next to some ladies is usually awesome....unless I stall or my wife is in the car (I'm pretending she isn't over my shoulder right now)
Post a log of your car stumbling at idle during decel. DataLog the following: Timing, Airflow HZ, RPM and Load. I will see if I can't help out. The key is to find the engine load your car is seeing during the 'stumble'. It will most likely be between 60-90 load, around 500-1000 rpm.
-Jamie
-Jamie
Last edited by Dynotech Tuning; Aug 11, 2011 at 05:55 PM.