Need help for engine stalling evo3 engine!!

Tom

TIMETOATTACK
Helmet Clan
Jul 6, 2000
5,562
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Kuala Lumpur
Bro cable tie your maf sensor connector , I had this problem , the connector was not tight, after I cable tie , everything was ok and check your turbo piping hoses ,it will become hard and leak air
good tip, I've had cars that were affected by a loose MAF socket.
Would either not start or would stall during driving.
Even if the connection breaks for a brief second, it would register as a broken MAF causing the engine to stall or to not start.
 

peterj

1,000 RPM
Senior Member
Apr 27, 2010
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Kuching
i have this problem from previous stock evo 4 engine, exactly the same when using vent to air b.o.v .... it is very common problem to stall and engine die off when u accelerate or throttle and press clutch for too long since it utilize MAF sensor, the theory here is that the MAF calculated the amount of air entered the engine and therefore calculated amount of fuel to put in as well.. but when you using vent to air b.o.v , MAF sensed for example 5 unit of air go in,therefore react with 5 unit of fuel to be put in engine, but the air that pass through MAF sensor is released through the b.o.v ... thus maybe with only 2-3 unit of air enter the engine to mixed with the 5 unit of fuel injected, then your engine is running rich and die off.. simple explanation is like this
 

Nicholasng925

Known Member
Jul 30, 2014
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I occationally have this problem as well, when the engine temperature is around 40-50 degree Celcius.

Engine die off suddenly, aircond is switched on, clutch engaged, trying to downshift and brake.

I suspect it's the ECU being tuned too lean at these temperature range, so not enough fuel being injected to keep the idling stable.

No such issue when engine reaches operating temperature (80-85 degree Celcius) though. :hmmmm:
 

peterj

1,000 RPM
Senior Member
Apr 27, 2010
1,321
258
1,683
Kuching
I occationally have this problem as well, when the engine temperature is around 40-50 degree Celcius.

Engine die off suddenly, aircond is switched on, clutch engaged, trying to downshift and brake.

I suspect it's the ECU being tuned too lean at these temperature range, so not enough fuel being injected to keep the idling stable.

No such issue when engine reaches operating temperature (80-85 degree Celcius) though. :hmmmm:
it is in reverse, engine running rich that is commonly will stall and die off not lean, engine can idle at airfuel that is as high as 16.0 afr, some even more, and when temperature higher, fuel easier to burn which will cause less trouble if running rich.. check you aif flow sensor see got faulty or not as well in that case
 

Nicholasng925

Known Member
Jul 30, 2014
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it is in reverse, engine running rich that is commonly will stall and die off not lean, engine can idle at airfuel that is as high as 16.0 afr, some even more, and when temperature higher, fuel easier to burn which will cause less trouble if running rich.. check you aif flow sensor see got faulty or not as well in that case
Another indication I forgot to write was, the idling was pretty rough and unstable at this temperature range also (40-50 degree C). I will normally switch off the aircond so that the idling won't get worsen.

I thought if the AFR is rich, the idling will be more stable? In that sense, it means the AFR is not rich enough that's why idling fluctuates? :hmmmm:
 

vr2turbo

Beyond 20,000 RPM!
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May 11, 2010
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Another indication I forgot to write was, the idling was pretty rough and unstable at this temperature range also (40-50 degree C). I will normally switch off the aircond so that the idling won't get worsen.

I thought if the AFR is rich, the idling will be more stable? In that sense, it means the AFR is not rich enough that's why idling fluctuates? :hmmmm:
You off air con then idling better? Like that is your IACV not compensating for air con load?
 

Nicholasng925

Known Member
Jul 30, 2014
51
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Kuala Lumpur
You off air con then idling better? Like that is your IACV not compensating for air con load?
But only at certain temperature (between 40 and 50 degree C)? When the temperature reaches operating temperature, everything is normal. I think it can be easily tuned at one of the parameters in Haltech software. :hmmmm:
 

vr2turbo

Beyond 20,000 RPM!
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May 11, 2010
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But only at certain temperature (between 40 and 50 degree C)? When the temperature reaches operating temperature, everything is normal. I think it can be easily tuned at one of the parameters in Haltech software. :hmmmm:
Oh! For me, my VR harder to start and idle when warmed up, but once started, one or two blip on the throttle then idling will be stable......lol:biggrin:
 

xtremeleo

3,000 RPM
Senior Member
Oct 18, 2005
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Hi sifus out there, pls enlightenme whats the problem with my engine lately, im using 4g63t evo 3 and im having bad engine stalling problem now, ive no problem when smooth crusing and boosting but the problem came when i off pedal and clutch release to neutral and brake engine seemed to stall and if lucky is rpm dropped to the lowest point and slowly climb back. When ive done at my side now is i took out IAC and replaced another and try and also my bov...both of these dont seem to have problem ..i also dunno whats wrong now..
What bov are you using? A vent-out or the original setup?
 

^pomen_GTR^

7,000 RPM
Senior Member
May 13, 2010
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sounds like idle servo not working perfectly...

edit....tried swapping maf sensor with friend first?


the other thing is... what bov model did you use?

-if sqv.. try adjust sqv for harder spring preload...

-if other than sqv..u need to adjust much harder spring preload...
 
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xtremeleo

3,000 RPM
Senior Member
Oct 18, 2005
3,247
464
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U must be using a vent-out bov, kan?

Edit : just realised ive asked this question several posts back, but op hasnt given his answer. Seldomly online ler these days
 
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