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M20 high rev jumping
Posted: Tue Jan 06, 2015 2:16 pm
by shabalake
Hi guys just need some help, seems when the car is at a high rev if I let of the accelerate feels like the car is jumping back and forth?
Cheers
Posted: Tue Jan 06, 2015 2:38 pm
by shabalake
The car is a 2.5
Thanks
Re:
Posted: Tue Jan 06, 2015 7:12 pm
by Brianmoooore
When the throttle is closed at high revs., the fuel injectors should shut off, leaving the engine just as a spinning flywheel/air compressor, until the revs. drop below 1800(?) RPM, when they start firing again.
The engine management is told that the throttle is closed by the TPS, so that would be my first check.
Re:
Posted: Sun Jan 11, 2015 11:23 pm
by ezagood
I thought they work on air flow and the tps was just a switch to say its at wide open throttle
Re:
Posted: Sun Jan 11, 2015 11:32 pm
by Brianmoooore
ezagood wrote:I thought they work on air flow and the tps was just a switch to say its at wide open throttle
E30 TPS is fairly primitive, and just switches between three states - throttle closed, throttle part open and throttle wide open, each with their own map. The 'throttle closed map' shuts off the injectors completely above fast idle, as there is absolutely no point in injecting fuel under these conditions.
The LPG system on my red touring has a connection to the closed throttle switch for exactly the same purpose.