NA-T Stalling problem, can't get it right, HELP!
Thread Starter
Driver
Joined: May 2005
Posts: 105
Likes: 0
From: Ga
NA-T Stalling problem, can't get it right, HELP!
1993 Lexus SC300 NA-T
V8 MAF
Boostlogic 525cc injectors
SAFC-2 (low throttle is 49, high throttle is 50)
Open Atmosphere BOV
Finished turboing this car last year, after getting the SAFC2 installed correctly the car was driveable but with a stalling problem. If you accelerate in any gear up to about 2500rpm or higher and then pop it into neutral the rpms will dip and then almost hit zero and struggle to stay running...sometimes it would die. At this time I was not taking out any fuel using the SAFC2 at this moment. I also had only one O2 sensor hooked up as well.
I also noticed during this time, that when I started the car, it would rev to 1500 to warm up, them plummet to almost cutting off, catch itself and then back to 1500, repeat...it would eventually stop and level off but the car would really spit and sputter if I tried to drive it. After about 45 seconds of driving awful it would run just fine.
Started dialing out about 30% fuel and still had the same problem with the car stalling when going to neutral from 2500rpm and up, same thing if I just pushed the clutch back in when doing 2500 rpm+. But I did notice that the dipping/revving problem when I started the car was gone.
Got the first o2 sensor tapped into the same line as the second o2 sensor (getting the same reading using a meter for both so I know they are both working), but third sensor after the "cat" is still unplugged. I understand this does not control the mixture but only makes sure the "cat" is working. I still have the stalling problem and oddly enough the dipping/revving issue at startup is back.
I dial out 40% fuel and the stalling problem is much better, the car will catch itself when the rpms drop and will not let the car die....but the revving/dipping problem when starting the car is back. Experimenting even more, I dial fuel back in at 800 and 1000 rpm and the car's starting problem goes away but this puts me back to stalling when going into neutral. Maybe if I dial out more fuel in the 1600-2000 rpm range I won't have to take out more fuel at 800 and 1000. So I lean out 1600-2000rpm points and richen the 800 and 1000 up to get a smooth start, but the stalling problem continues.
At this point it's either lean the car out to 40% at the 800 and 1000 rpm points and have a starting problem or dial out about 32% and have a smooth start but stalling when going into neutral. The 800 and 1000 rpm set points are the only adjustments that seem to effect the revving/dipping and the stalling problems, so when I correct the fuel it's for these two points.
In summary:
No fuel correction = stalling when going to neutral and revving/dipping starts, starting problem eventually went away.
40% fuel correction = revving/dipping starts but will not stall going into neutral.
32% fuel correction= smooth start but stalling going into neutral.
I don't wanna have to buy something else (unless it's cheap) to correct this, I've tightened down the BOV, got both sensors reading and have tried multiple SAFC settings and i either have one problem or the other.
Any suggestions?
V8 MAF
Boostlogic 525cc injectors
SAFC-2 (low throttle is 49, high throttle is 50)
Open Atmosphere BOV
Finished turboing this car last year, after getting the SAFC2 installed correctly the car was driveable but with a stalling problem. If you accelerate in any gear up to about 2500rpm or higher and then pop it into neutral the rpms will dip and then almost hit zero and struggle to stay running...sometimes it would die. At this time I was not taking out any fuel using the SAFC2 at this moment. I also had only one O2 sensor hooked up as well.
I also noticed during this time, that when I started the car, it would rev to 1500 to warm up, them plummet to almost cutting off, catch itself and then back to 1500, repeat...it would eventually stop and level off but the car would really spit and sputter if I tried to drive it. After about 45 seconds of driving awful it would run just fine.
Started dialing out about 30% fuel and still had the same problem with the car stalling when going to neutral from 2500rpm and up, same thing if I just pushed the clutch back in when doing 2500 rpm+. But I did notice that the dipping/revving problem when I started the car was gone.
Got the first o2 sensor tapped into the same line as the second o2 sensor (getting the same reading using a meter for both so I know they are both working), but third sensor after the "cat" is still unplugged. I understand this does not control the mixture but only makes sure the "cat" is working. I still have the stalling problem and oddly enough the dipping/revving issue at startup is back.
I dial out 40% fuel and the stalling problem is much better, the car will catch itself when the rpms drop and will not let the car die....but the revving/dipping problem when starting the car is back. Experimenting even more, I dial fuel back in at 800 and 1000 rpm and the car's starting problem goes away but this puts me back to stalling when going into neutral. Maybe if I dial out more fuel in the 1600-2000 rpm range I won't have to take out more fuel at 800 and 1000. So I lean out 1600-2000rpm points and richen the 800 and 1000 up to get a smooth start, but the stalling problem continues.
At this point it's either lean the car out to 40% at the 800 and 1000 rpm points and have a starting problem or dial out about 32% and have a smooth start but stalling when going into neutral. The 800 and 1000 rpm set points are the only adjustments that seem to effect the revving/dipping and the stalling problems, so when I correct the fuel it's for these two points.
In summary:
No fuel correction = stalling when going to neutral and revving/dipping starts, starting problem eventually went away.
40% fuel correction = revving/dipping starts but will not stall going into neutral.
32% fuel correction= smooth start but stalling going into neutral.
I don't wanna have to buy something else (unless it's cheap) to correct this, I've tightened down the BOV, got both sensors reading and have tried multiple SAFC settings and i either have one problem or the other.
Any suggestions?
Thread Starter
Driver
Joined: May 2005
Posts: 105
Likes: 0
From: Ga
with my tial i ran a slightly stronger spring, and put the maf in blowthrough.
with v8 maf and close to 550s you shouldnt be changing much on the low settings. do you have a wideband?
if it is stalling when you are not in boost, then the high settings wont come into play at all. and you should not be adjusting your baseline fuel map to get around the stalling issue. you will create much worse driveability issues and starting problems. this is definately an air issue. even if you arent in boost if your bov opens, you can now loose air or even suck in air through that space. when you are at cruising speeds on the highway your car will be pulling more vac or less vac then at idle, depending on your throttle position. if your bov is adjusted correctly it will open whenever you let off the throttle, not just when you are in boost
put the maf in blowthrough or just recirculate with a ssqv or something. its the only way I could stand my safc when I had it. I almost crashed when the car stall on the highway once when it was in drawthrough. all turbo SC's have a rough idle when the ecu is reset, but if your low setting is close enough (for injector change) it will smooth out after 2-3 drive cycles.
Last edited by Ali SC3; Aug 11, 2009 at 05:05 PM.
Solution: Don't throw it in neutral. 
I have a 5spd T61 with MAF and my car never dies.
Yeah....of course its gunna die if i punch it and throw it in neutral...but why in the hell would i need to do that anyways?
Drive normally and it will run normal.
But then again u have V8 dunno the differences with that to be honest.
Oh and im praying for you tonight in my sleep hoping you have a wideband cus if your playing with numbers like that your next thread is gunna be asking why theres smoke and a thumping noise coming outta your engine.
DONT BLOW THAT S***!
I have a 5spd T61 with MAF and my car never dies.
Yeah....of course its gunna die if i punch it and throw it in neutral...but why in the hell would i need to do that anyways?
Drive normally and it will run normal.
But then again u have V8 dunno the differences with that to be honest.
Oh and im praying for you tonight in my sleep hoping you have a wideband cus if your playing with numbers like that your next thread is gunna be asking why theres smoke and a thumping noise coming outta your engine.
DONT BLOW THAT S***!
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Solution: Don't throw it in neutral.
I have a 5spd T61 with MAF and my car never dies.
Yeah....of course its gunna die if i punch it and throw it in neutral...but why in the hell would i need to do that anyways?
Drive normally and it will run normal.
But then again u have V8 dunno the differences with that to be honest.
I have a 5spd T61 with MAF and my car never dies.
Yeah....of course its gunna die if i punch it and throw it in neutral...but why in the hell would i need to do that anyways?
Drive normally and it will run normal.
But then again u have V8 dunno the differences with that to be honest.
????? You must be confused. Let me re-iterate.
Todd1225 clearly has found 3 solutions by tuning his car with the SAFC. BUT, now he clearly has a problem on each of those 3 solutions, therefore he is solving one problem but opening up another.
My solution was in regards to the car dying when he throws it in neutral after driving up to a certain rpm (or punching the throttle then letting it fall in neutral).
If you do a search (clubna-t, cl, sf...etc) CLEARLY people will tell you PER EXPERIENCE that the SAFC WILL NOT compensate for the lost air that the BOV dispenses.
Now some may argue this is the case for OBD1 cars because the *DEC AIR* feature was introduced in the OBD2 cars! There ya go! Problem solved ==> USE DEC AIR FEATURE?!?.....
Now IF you searched EVEN DEEPER you'll notice complaints of the DEC AIR feature on the OBD2 cars.
Not gunna go into it theres many threads about it already.
Why the hell do u needa punch the car then randomly throw it in neutral and not want it to die. I mean your using a piggyback here its tweaking your ECU...nobody said tweaking is a definitive and perfect solution.
Todd1225 clearly has found 3 solutions by tuning his car with the SAFC. BUT, now he clearly has a problem on each of those 3 solutions, therefore he is solving one problem but opening up another.
My solution was in regards to the car dying when he throws it in neutral after driving up to a certain rpm (or punching the throttle then letting it fall in neutral).
If you do a search (clubna-t, cl, sf...etc) CLEARLY people will tell you PER EXPERIENCE that the SAFC WILL NOT compensate for the lost air that the BOV dispenses.
Now some may argue this is the case for OBD1 cars because the *DEC AIR* feature was introduced in the OBD2 cars! There ya go! Problem solved ==> USE DEC AIR FEATURE?!?.....
Now IF you searched EVEN DEEPER you'll notice complaints of the DEC AIR feature on the OBD2 cars.
Not gunna go into it theres many threads about it already.
Why the hell do u needa punch the car then randomly throw it in neutral and not want it to die. I mean your using a piggyback here its tweaking your ECU...nobody said tweaking is a definitive and perfect solution.
check your TPS.. you should never tune close-loop as you want that on OEM settings.. only open loop you should tune..
The stalling is due to MAF location when giving it WOT and letting off the gas immediately.. MAF on TB side tends to help out, somewhat, but life expectancy of the MAF is cut short... MAF on Turbo side caused my NA-T project to keep cutting off.. until I moved it over to the TB side...
BTW - CLUBNA-T.com is your friend... Indepth information regarding your issue is covered several times and some ppl go blow through or blow by... different results for every car running KVF.
Also check for vac leaks.. engine idling up and down usually is due to a vac leak...
The stalling is due to MAF location when giving it WOT and letting off the gas immediately.. MAF on TB side tends to help out, somewhat, but life expectancy of the MAF is cut short... MAF on Turbo side caused my NA-T project to keep cutting off.. until I moved it over to the TB side...
BTW - CLUBNA-T.com is your friend... Indepth information regarding your issue is covered several times and some ppl go blow through or blow by... different results for every car running KVF.
Also check for vac leaks.. engine idling up and down usually is due to a vac leak...
????? You must be confused. Let me re-iterate.
Todd1225 clearly has found 3 solutions by tuning his car with the SAFC. BUT, now he clearly has a problem on each of those 3 solutions, therefore he is solving one problem but opening up another.
My solution was in regards to the car dying when he throws it in neutral after driving up to a certain rpm (or punching the throttle then letting it fall in neutral).
If you do a search (clubna-t, cl, sf...etc) CLEARLY people will tell you PER EXPERIENCE that the SAFC WILL NOT compensate for the lost air that the BOV dispenses.
Now some may argue this is the case for OBD1 cars because the *DEC AIR* feature was introduced in the OBD2 cars! There ya go! Problem solved ==> USE DEC AIR FEATURE?!?.....
Now IF you searched EVEN DEEPER you'll notice complaints of the DEC AIR feature on the OBD2 cars.
Not gunna go into it theres many threads about it already.
Why the hell do u needa punch the car then randomly throw it in neutral and not want it to die. I mean your using a piggyback here its tweaking your ECU...nobody said tweaking is a definitive and perfect solution.
Todd1225 clearly has found 3 solutions by tuning his car with the SAFC. BUT, now he clearly has a problem on each of those 3 solutions, therefore he is solving one problem but opening up another.
My solution was in regards to the car dying when he throws it in neutral after driving up to a certain rpm (or punching the throttle then letting it fall in neutral).
If you do a search (clubna-t, cl, sf...etc) CLEARLY people will tell you PER EXPERIENCE that the SAFC WILL NOT compensate for the lost air that the BOV dispenses.
Now some may argue this is the case for OBD1 cars because the *DEC AIR* feature was introduced in the OBD2 cars! There ya go! Problem solved ==> USE DEC AIR FEATURE?!?.....
Now IF you searched EVEN DEEPER you'll notice complaints of the DEC AIR feature on the OBD2 cars.
Not gunna go into it theres many threads about it already.
Why the hell do u needa punch the car then randomly throw it in neutral and not want it to die. I mean your using a piggyback here its tweaking your ECU...nobody said tweaking is a definitive and perfect solution.
So you're saying you have to adapt your driving to the way the ecu will react on a DD car with simple mods (and yes, all these are still considered pretty simple)? That's the most BS thing I have ever heard. I'm glad that you have such a vast knowledge of how all this works. But yet your elegant solution is... "Don't throw it in nuetral after throttle, (
)you're unable to do certain things with throttle and decel b/c that's just how it is." Lol. Don't mind my sarcasm though, I don't know anything about tuning.
Last edited by 2jzlex; Aug 14, 2009 at 01:42 PM.
Instructor
Joined: May 2007
Posts: 1,001
Likes: 64
From: ca
Epic post.
So you're saying you have to adapt your driving to the way the ecu will react on a DD car with simple mods (and yes, all these are still considered pretty simple)? That's the most BS thing I have ever heard. I'm glad that you have such a vast knowledge of how all this works. But yet your elegant solution is... "Don't throw it in nuetral after throttle, ()you're unable to do certain things with throttle and decel b/c that's just how it is." Lol. Don't mind my sarcasm though, I don't know anything about tuning.
So you're saying you have to adapt your driving to the way the ecu will react on a DD car with simple mods (and yes, all these are still considered pretty simple)? That's the most BS thing I have ever heard. I'm glad that you have such a vast knowledge of how all this works. But yet your elegant solution is... "Don't throw it in nuetral after throttle, (
)you're unable to do certain things with throttle and decel b/c that's just how it is." Lol. Don't mind my sarcasm though, I don't know anything about tuning.Obviously nobody will punch it and let off on the regular bases just for the hell of it. But if we assume he has to, like trying to get up to speed on the HWY then getting cut off for example, i sure hope he puts it in neutral before penetrating somebody's trunk!
Problems like that are the main reason i went standalone. Nevertheless, i still get some stalling, but that's because i haven't addressed the stupid drive by wire yet...
Epic post.
So you're saying you have to adapt your driving to the way the ecu will react on a DD car with simple mods (and yes, all these are still considered pretty simple)? That's the most BS thing I have ever heard. I'm glad that you have such a vast knowledge of how all this works. But yet your elegant solution is... "Don't throw it in nuetral after throttle, ()you're unable to do certain things with throttle and decel b/c that's just how it is." Lol. Don't mind my sarcasm though, I don't know anything about tuning.
So you're saying you have to adapt your driving to the way the ecu will react on a DD car with simple mods (and yes, all these are still considered pretty simple)? That's the most BS thing I have ever heard. I'm glad that you have such a vast knowledge of how all this works. But yet your elegant solution is... "Don't throw it in nuetral after throttle, (
)you're unable to do certain things with throttle and decel b/c that's just how it is." Lol. Don't mind my sarcasm though, I don't know anything about tuning.pretty simple? If it was so simple and the engine and ecu didn't take it as a big upgrade for performance then he wouldn't have problems now would he?
I dont care if you wanna assume... "Oh hes gunna throw it in neutral so lets solve that problem!".
Lets try this how bout you help him solve that problem of him punching the car then throwing it in neutral (stupidest **** ive ever heard needing to be done on a DD, LIKE WHY!?!?!?) and let me know when you come up with a solution (besides going standalone
). Get back to me on your conclusions/solutions!
Please quote me where i said you have to adapt your driving to the way the ecu will react on a DD car....
pretty simple? If it was so simple and the engine and ecu didn't take it as a big upgrade for performance then he wouldn't have problems now would he?
I dont care if you wanna assume... "Oh hes gunna throw it in neutral so lets solve that problem!".
Lets try this how bout you help him solve that problem of him punching the car then throwing it in neutral (stupidest **** ive ever heard needing to be done on a DD, LIKE WHY!?!?!?) and let me know when you come up with a solution (besides going standalone ).
Get back to me on your conclusions/solutions!
pretty simple? If it was so simple and the engine and ecu didn't take it as a big upgrade for performance then he wouldn't have problems now would he?
I dont care if you wanna assume... "Oh hes gunna throw it in neutral so lets solve that problem!".
Lets try this how bout you help him solve that problem of him punching the car then throwing it in neutral (stupidest **** ive ever heard needing to be done on a DD, LIKE WHY!?!?!?) and let me know when you come up with a solution (besides going standalone
). Get back to me on your conclusions/solutions!
Max,
On the DBW it's all about the idle adjustment screw and the base timing/idle timing offset if you actually keep it instead of going mechanical. Sadly enough the idle adjustments in the AEM (I'm assuming your still AEM from MyIS.right?) don't do jack if DBW is still enabled and have the 1050 box.
-Jon