When cold = full boost but no acceleration?

[jdemara]

When my car is cold, for the first 3-4 minutes or so of driving, it is almost as though the injectors are not providing enough fuel to the cylinders.

I do realize it is not advisable to be boosting when the car is not warmed up yet, but even so, minimal amounts of boost don't increase the acceleration what so ever.

Boost will go straight up to 8-9 psi and the turbo is audible, but it doesn't even feel like I'm boosting.


Does anybody know if this would be the cause of bad injectors? Possibly fuel pump? (dont see why, it only does this when cold). I have tried running fuel injector cleaner, and checked for codes (there is none).

Let me know what you think!
Thanks guys!

 

[arizzle]

yes i would like to know also my supra does this in really cold days though but it doesn't go that high. mine sits at 0 like its spooling lol. and its only for probably 2mins until the temp needle moves.

 

[lagged]

check codes.

possibly a bad coolant temperature sensor.

 

[IwantMKIII]

The ECU won't let you boost quite yet. its too cold. you shouldn't be boosting if the engine is this cold anyway.

 

[jdemara]

The ECU won't let you boost quite yet. its too cold. you shouldn't be boosting if the engine is this cold anyway.

i realize this. but even so when im normally accelerating say just up a hill, and it approaches 0, there is no change in acceleration. its hard to explain, but i know for sure its not supposed to do this, cuz when i first got my car it didnt do this.

 

[IwantMKIII]

^i can assure you, it does this. Especially in cold ambient temerpatures, mine does the same thing.

 

[arizzle]

yep mines only done this is -0 temps, but on warm days its fine. i guess its normal lol.

 

[supraguy@aol]

Mine is fine when cold, though a bit more like an on-off switch.
It sounds like the fuel ratio is lean.

 

[jetjock]

OP: You're right. It's not supposed to do that...

 

[gaboonviper85]

OP: You're right. It's not supposed to do that...

Care to explain?...

 

[jetjock]

What's to explain? The poster claims his engine didn't do this before and he's right when he says it's not supposed to. Can't get much clearer than that...

 

[lagged]

Care to explain?...

the behavior the OP described is NOT normal contrary to what all the other geniuses in this thread have posted.

like i said, check this ECU coolant temp sensor. check codes.

 

[super.secret.supra.club]

I have tried running fuel injector cleaner, and checked for codes (there is none).

Let me know what you think!
Thanks guys!

 

[Nghty89]

I doubt there will be codes. Mine did the same thing. Before I knew anything about my car, I actually tried to punch it one day for the hell of it (and i was in a hurry) and the turbo would just spool and the car would go nowhere.

 

[gaboonviper85]

Again I ask "care to explain"...I don't know what's normal and what's not but I want to know why his car is doing this....by all rights if he is showing positive boost then there should be more power...what could cause this issue?

 

[Nghty89]

It doesn't appear to be a boost leak. It's almost as if the ECU was limiting it until the temps rose. Could this be a safety feature?

 

[MA70_Powa]

I get the same thing with my car too, happens before the car has warmed up - especially when I try and go up a hill. Boost will go to 0 or like 1-2psi (I try not to push the accelrator very hard) and car goes slowwww. When it's warmed up it's fine tho.
Mine will do it in any temperature too... (also have no codes and no leaks that i could find)
I'd be interested to know if it was a safety feature!

 

[jdemara]

exactly what MA70 just said!! same symptom here...
I DO know, last winter when i first bought this car, it did NOT do this what so ever. I do think it is most likely running lean when it does this, because of the positive boost pressure and not much power!

no boost leak, the car pulls like mad once warmed up! and once again no codes. runs like a champ, except for the first 3-4 min when its cold.

possibilities:
coolant temp sensor?
a really dumb safety feature (dont know what it would keep my engine safe against?)
fuel pump?
bad injectors? (maybe when they are too cold they are unable to deliver enough fuel somehow)

 

[supradjza80]

As I understand it, the boost sensor signal only goes to the boost gauge, so the ECU is unaware that the motor is cold and you are boosting it based on boost pressure alone. It may use the AFM signal but I think that is pretty unlikely.

 

[jdemara]

or possibly maybe bad o2 sensor? when it's cold it is not understanding that the engine is running lean, therefore not able to tell the computer to provide more fuel?

i don't know!! :S