Difficult to describe, hesitation possibly?
Discussion
I'll describe the symptom and see if anyone knows what on earth I am talking about!
It is a minor niggle, and is the only thing I can fault with my new pride and joy. I am rather pleased to be back in a griff and have missed it.
Anyway, here goes.
It does not matter if the engine is hot or cold, but a very light application of throttle from idle decreases the revs to just above stalling, cured by not being so gentle with my right boot (slipper!).
It does not happen above idle and is only really noticeable when stationary and preparing to pull away.
It pulls really well, idles steadily at about 900-1000 rpm and everything else seems great.
I thought it might be the throttle cable being loose, but I don't think so, mainly because of the spring contraption on the throttle body keeping everything tight.
Vacuum advance U/S? Stepper motor need a good clean?
Anybody know ahat I am talking about?
Ta
Karl
It is a minor niggle, and is the only thing I can fault with my new pride and joy. I am rather pleased to be back in a griff and have missed it.
Anyway, here goes.
It does not matter if the engine is hot or cold, but a very light application of throttle from idle decreases the revs to just above stalling, cured by not being so gentle with my right boot (slipper!).
It does not happen above idle and is only really noticeable when stationary and preparing to pull away.
It pulls really well, idles steadily at about 900-1000 rpm and everything else seems great.
I thought it might be the throttle cable being loose, but I don't think so, mainly because of the spring contraption on the throttle body keeping everything tight.
Vacuum advance U/S? Stepper motor need a good clean?
Anybody know ahat I am talking about?
Ta
Karl
Hi Karl,
I had very similar problems on my 4.0 Chim. Though it would only happen at idle on a cold engine. First off, clean the stepper anyway. Can't hurt and may cure your problem by itself - Just be careful not to overtighten it.
I also changed my plug leads to Magnecor performance ones which has done wanders for this and I've had no problems with it since.
There may well be other causes but doing these worked for me.
Tony
I had very similar problems on my 4.0 Chim. Though it would only happen at idle on a cold engine. First off, clean the stepper anyway. Can't hurt and may cure your problem by itself - Just be careful not to overtighten it.
I also changed my plug leads to Magnecor performance ones which has done wanders for this and I've had no problems with it since.
There may well be other causes but doing these worked for me.
Tony
Hum.
Not a spot on the stepper motor.
The throttle cable is very loose though, should it be? (I can move it about with one finger).
Funny thing is that I started the car with the bonnet open, didn't touch the accelerator pedal and moved the throttle from the engine side and it did it then, once, now I can't repeat it with the pedal either.
Maybe I've fixed it. Hope so.
Not a spot on the stepper motor.
The throttle cable is very loose though, should it be? (I can move it about with one finger).
Funny thing is that I started the car with the bonnet open, didn't touch the accelerator pedal and moved the throttle from the engine side and it did it then, once, now I can't repeat it with the pedal either.
Maybe I've fixed it. Hope so.
My guess would be that the car is becoming lean when the throttle butterfly opens possibly you have an air leak that is letting un metered air into the plenum chamber or you have insufficient fuel pressure. Does the Speedo work normally ? I think the road speed sensor allows the ECU to enrich the mixture when under way. One thing worth trying is to reset the ECU by disconnecting the power supply for a few seconds.
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