engine don't want to rev...

[Badcow]

I'm "blessed" with a new problem that I can't resolve... on my 390, the engine start and run ok for 2 or 3 minutes, and after that it remain idle (around 1000 rpm) even if you floor the throtle pedal. The only thing is that if you try to accelerate, there is a lot of "pop and bang" in the exhaust pipe... I changed the fuel pump but with no success... any ideas ?

[Chassis 33]

Air flow meter?

[Badcow]

Could be, but it seems to be Ok...

[Chassis 33]

Ok, sorry out of ideas, unless the ECU is defaulting to "limp home mode" after a couple of minutes of an error being flagged up? I know Rover 800's did this and you had to go thru a dance routine on the pedals to reset the ECU, dont know if the V8 boxes have a simular function.

Regards
Iain

[boosted ls1]

Is the fuel pressure ok, is the vac hose attached to the fuel pressure regulator? Does the dizzy advance in mechanical mode or are the weights jammed?

Boosted.

[boosted ls1]

Is the fuel pressure ok, is the vac hose attached to the fuel pressure regulator? Does the dizzy advance in mechanical mode or are the weights jammed?

Boosted.

[350matt]

sounds like fuel or rather the lack of it, is the pressure regulator working OK, try crimping the return line to the tank and see if that does anything

Matt

[dickymint]

Does sound like fuel pressure dropping. But first I would check the coolant temperature sensor. Either swap it for a new one (£12) or short out the plug with a 170 Ohm resistor, if this works then the sensor is duff.

[chunder]

I doubt if a faulty sensor would cause this - sounds like it's getting enough fuel and air to start with. I assume AAV open and CSI firing but then closing and shutting off - can it be revved higher than idle in the first minute or so ?

Are you sure the throttle linkage is moving with the pedal ?

Is the throttle butterfly loose and just sitting in the closed position ?

Is the air filter blocked ?

Is the AFM flap free to move ?

If there's no big obstruction to airflow and plugs are all firing and in the right order then fuel pressure would be next to check.

[Badcow]

Thx for all those answers, I will need the following week to check for everything...

I think that I will begin with the fuel pump and the air flowmeter, just to see if the entry / exit signals are ok or not...