Still stalling!
Jun 6, 2004, 09:27 PM
#31
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but only at a certain rpm, (around 2k), and only if the clutch isnt let out all the way and u take ur foot off the gas abruptly??
the theory with the bigger intakes is that it is true it doesent make that much of a difference or shouldnt as far as the maf is concerned, somehow the air swirls inside the tube and thats what the messes up the maf at a certain rpm under certain conditions.
im thinking of throwing the stocker back on, but then gotta redo the bov and it might need a retune...i dont know.
the theory with the bigger intakes is that it is true it doesent make that much of a difference or shouldnt as far as the maf is concerned, somehow the air swirls inside the tube and thats what the messes up the maf at a certain rpm under certain conditions.
im thinking of throwing the stocker back on, but then gotta redo the bov and it might need a retune...i dont know.
Jun 7, 2004, 07:00 AM
#32
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Originally Posted by GBEvo
I did try adding up to +8 at 1800-2200 rpms with the AFC II and noticed that the car was catching itself at 500 rpm most of the time before stalling out. It still doesn't run right though and still stalls occassionally.
Jun 7, 2004, 08:53 AM
#34
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[QUOTE]If you are adding fuel and it was helping, this sounds like it is a lean stalling condition. I need more info. The people with this problem, do you all have a differnt intake pipe as well as filter? Or do some of you just have a aftermarket filter and mas adaptor? Did the stalling start right away after installing an intake or did it take some time to develop? Does it only happen when letting off the throttle or will it stall just at an idle? Does it stall regaurdless of clutch position? Please post, thanks
i have buschur intake with i believe k&n filter... the stalling started right after installation of intake...well, we installed intake, filter, intercooler, and turbo back exhaust at same time...
seems to happen only when letting off throttle abruptly, if u give it a little rev first, even if its in the rev range where it likes to die it is fine...it happens much more often when clutch is partially released and ur creeping it forward like in traffic, a tollbooth, etc.
the car does NOT just stall at idle....
when it stalls it just stalls like someone flicked a lightswitch off, sometimes when it almost stalls the idle gets funny and it catches itself or u can give it a rev and its fine...but when it stalls it just stalls like someone just turned it off....
thanks for trying to help
i have buschur intake with i believe k&n filter... the stalling started right after installation of intake...well, we installed intake, filter, intercooler, and turbo back exhaust at same time...
seems to happen only when letting off throttle abruptly, if u give it a little rev first, even if its in the rev range where it likes to die it is fine...it happens much more often when clutch is partially released and ur creeping it forward like in traffic, a tollbooth, etc.
the car does NOT just stall at idle....
when it stalls it just stalls like someone flicked a lightswitch off, sometimes when it almost stalls the idle gets funny and it catches itself or u can give it a rev and its fine...but when it stalls it just stalls like someone just turned it off....
thanks for trying to help
Jun 7, 2004, 09:29 AM
#36
I have it occasionally too.. But basically its the low MAF reading.. the lowered restriction causes the MAF air flow to "Stall" in the sensor.. I haven't figured out a way to compensate for it.. Yet.. but I'll post when I do.. (I didn't have this happen until yesterday 2 days after making a few upgrades such as intercooler, intake pipe, and intercooler pipes) Previously with just the filter, it never happened..
EDIT: Its actually not a low reading, but the new intake and lowered restriction in the buschur air filter lowered my idle maf reading from 30-32hz to 25-27hz which may contribute slightly to it under some circumstances.. See my LATER posts for some better thoughts, I didn't have enough info at the time I originally posted this..
EDIT: Its actually not a low reading, but the new intake and lowered restriction in the buschur air filter lowered my idle maf reading from 30-32hz to 25-27hz which may contribute slightly to it under some circumstances.. See my LATER posts for some better thoughts, I didn't have enough info at the time I originally posted this..
Last edited by MalibuJack; Jul 27, 2004 at 08:05 PM.
Jun 7, 2004, 09:32 AM
#37
Kinda pointless for me to recirculate my Diverter valve if this happens no matter what..
You can raise your idle slightly if you want at the throttle body, not sure how much that would help though.. I do know a blowthrough MAF sensor or speed density conversion will solve your problem since the MAF reading will never go below the stall threshold..
You can raise your idle slightly if you want at the throttle body, not sure how much that would help though.. I do know a blowthrough MAF sensor or speed density conversion will solve your problem since the MAF reading will never go below the stall threshold..
Jun 7, 2004, 11:27 PM
#38
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malibujack....are those parts available for our cars? if they are ill gladly buy one....
hey, i heard that if we raise the idle the computer will just compensate for it over time.....it worked with the older evos, but not ours...or so ive been told
hey, i heard that if we raise the idle the computer will just compensate for it over time.....it worked with the older evos, but not ours...or so ive been told
Jun 9, 2004, 04:16 PM
#41
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As far as I know, all larger MAF/ cold air intake pipes will cause these stalling issues(AEM, K&N, HKS). I just came back from my oil change at Mitsu. and talked to the Evo tech about the problem. He said it is definitely due to the larger intake and if adding the more fuel via the AFC-II or adding the hyperground cables don't work, our only other bet is to look for an aftermarket MAF sensor that can adjust to the greater airflow. Let me know if anyone goes this route or who even sells an aftermarket MAF sensor for the Evo.
It was funny watching them stall the car out while driving it up to the hoist.
It was funny watching them stall the car out while driving it up to the hoist.
Jul 27, 2004, 07:53 PM
#44
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I have the HKS Racing Suction Intake, and yes, after I installed it my car started bogging and almost stalling in situations like creeping through traffic or pulling into a parking space (quick blip of throttle followed by depressing the clutch). After I got DynoFlashed, I have had it actually stall a few times...probably because it's running a bit leaner now.
The whole time I thought it was my BOV...now you all are saying it's my intake???
Do you all think the HKS EIDS would fix the problem???
The whole time I thought it was my BOV...now you all are saying it's my intake???
Do you all think the HKS EIDS would fix the problem???
Jul 27, 2004, 07:58 PM
#45
Yeah, I FINALLY got a snapshot of the data when it begins to stall.. Its actually not a low maf reading, but an unusually high.. ok.. let me explain my theory so far..
You get on the gas, just enough to build a small amount of boost, but not enough to allow the diverter valve to open and purge.. so you get a small amount of surge (reversing of airflow) into the intake pipe.. the stock pipe is kinda small and probably doesn't allow it to pass through to the MAF sensor as easily.. anyway this is what I logged (and this also goes with my earlier theory that evolved over time)
at idle, MAF frequency is around 26-32hz you load and accellerate so the MAF frequency is up at 100 to 115 hz (obviously enough to build a small amount of manifold pressure) then suddenly let off the gas and clutch.. it drops to 90, idle drops to so low that it doesnt register on the UTEC, but the MAF reading is 120hz or so.. which means there's airflow traveling through it.. Though I was under the impression that if the airflow through the sensor reverses it would read erratically and the level would be random, in this case its not, it always seems to fall to about 100hz..
Ok, what makes this significant? Well, the engine is barely running, the MAF is telling the ECU there's the airflow of about 1200rpm, but the throttle is closed.. There are only two things that can cause that, compressor surge, or the DV, both would have to send enough air into the intake and out through the MAF sensor and not into the turbocharger snail, which leads me to believe its probably coming through the turbo..
Ok.. Whats the solution? Well, ultimately you can put your stock MAF pipe back on, it seems to have a tapered shape that dampens the small amount of airflow to prevent it from reading much higher than the stock idle airflow.. It doesnt prevent it from reversing through, just seems to choke it enough that it stays about the same leve.. you remove the restriction, and it goes higher and therefore causes the stalling.
Bad news is almost all aftermarket pipes lower the restriction, so its safe to say that most if not all of the aftermarket pipes will cause this stalling..
You can try the HKS EIDS and see if it helps.. The symptoms of this MAF pipe issue, seem to have similar characteristics to the BOV when you vent to the atmosphere, only it seems to last longer, and therefore might be harder for the EIDS to work with..
I'm going to make some recommendations to TurboXS as to a solution to this that they can possibly add through a UTEC firmware upgrade, it likely won't make the new firmware release if they do like the suggestion though..
So what options to you have now?
1) Put your stock MAF pipe back on, it will likely go away..
2) Convert to a blowthrough MAF setup (not cheap, around $600-700)
3) Convert to a Speed density setup (currently only available with a standalone system)
4) Try the HKS EIDS, it might work... might as well VTA also if you do this.
Now its up to you guys..
Basically in order to prevent the engine from stalling, the ECU needs to see airflow consistent with engine RPM at idle.. more percieved airflow, and you get a rich condition and a shift in timing that is enough to cause stalling, but usually it results in very low idle until it recovers.
From a technical standpoint, the solution is
1) A device that provides a 30hz signal when TPS is under 1% and engine idle is below 800rpm
2) Prevent the reversion of airflow through the MAF sensor (any ideas that won't introduce a restriction??)
3) Produce a 3" intake pipe with a steep "S" curve in it.. the extra length and sharper curve should be enough to supress the airflow enough to prevent it.. (Anyone want to make me one to try out??)
Ok guys, here's your ammo..
You get on the gas, just enough to build a small amount of boost, but not enough to allow the diverter valve to open and purge.. so you get a small amount of surge (reversing of airflow) into the intake pipe.. the stock pipe is kinda small and probably doesn't allow it to pass through to the MAF sensor as easily.. anyway this is what I logged (and this also goes with my earlier theory that evolved over time)
at idle, MAF frequency is around 26-32hz you load and accellerate so the MAF frequency is up at 100 to 115 hz (obviously enough to build a small amount of manifold pressure) then suddenly let off the gas and clutch.. it drops to 90, idle drops to so low that it doesnt register on the UTEC, but the MAF reading is 120hz or so.. which means there's airflow traveling through it.. Though I was under the impression that if the airflow through the sensor reverses it would read erratically and the level would be random, in this case its not, it always seems to fall to about 100hz..
Ok, what makes this significant? Well, the engine is barely running, the MAF is telling the ECU there's the airflow of about 1200rpm, but the throttle is closed.. There are only two things that can cause that, compressor surge, or the DV, both would have to send enough air into the intake and out through the MAF sensor and not into the turbocharger snail, which leads me to believe its probably coming through the turbo..
Ok.. Whats the solution? Well, ultimately you can put your stock MAF pipe back on, it seems to have a tapered shape that dampens the small amount of airflow to prevent it from reading much higher than the stock idle airflow.. It doesnt prevent it from reversing through, just seems to choke it enough that it stays about the same leve.. you remove the restriction, and it goes higher and therefore causes the stalling.
Bad news is almost all aftermarket pipes lower the restriction, so its safe to say that most if not all of the aftermarket pipes will cause this stalling..
You can try the HKS EIDS and see if it helps.. The symptoms of this MAF pipe issue, seem to have similar characteristics to the BOV when you vent to the atmosphere, only it seems to last longer, and therefore might be harder for the EIDS to work with..
I'm going to make some recommendations to TurboXS as to a solution to this that they can possibly add through a UTEC firmware upgrade, it likely won't make the new firmware release if they do like the suggestion though..
So what options to you have now?
1) Put your stock MAF pipe back on, it will likely go away..
2) Convert to a blowthrough MAF setup (not cheap, around $600-700)
3) Convert to a Speed density setup (currently only available with a standalone system)
4) Try the HKS EIDS, it might work... might as well VTA also if you do this.
Now its up to you guys..
Basically in order to prevent the engine from stalling, the ECU needs to see airflow consistent with engine RPM at idle.. more percieved airflow, and you get a rich condition and a shift in timing that is enough to cause stalling, but usually it results in very low idle until it recovers.
From a technical standpoint, the solution is
1) A device that provides a 30hz signal when TPS is under 1% and engine idle is below 800rpm
2) Prevent the reversion of airflow through the MAF sensor (any ideas that won't introduce a restriction??)
3) Produce a 3" intake pipe with a steep "S" curve in it.. the extra length and sharper curve should be enough to supress the airflow enough to prevent it.. (Anyone want to make me one to try out??)
Ok guys, here's your ammo..