Car nearly dies when pressing clutch

[Anadinolin]

Replaced the idle control valve, this has exacerbated the problem, it is now every time I drop the clutch to change down a gear. Idle is still OK and the car recovers itself before stalling.

Could it also be a vaccume problem somewhere? When im changing down I am on the brakes aswell most of the time...

[Clan]

Originally Posted by Anadinolin

Replaced the idle control valve, this has exacerbated the problem, it is now every time I drop the clutch to change down a gear. Idle is still OK and the car recovers itself before stalling.

Could it also be a vaccume problem somewhere? When im changing down I am on the brakes aswell most of the time...

I take it the throttle did NOT open when you turned the engine off then as you replaced the throttle control motor .. ? does it do that now ?
If the throttle has a lot of carbon around the edge it may well be open as far as it can go , it can only makes minor alteration to the air flow at idle . Try cleaning the bore of the throttle body , OR you could have an air leak into the manifold of course .

[Anadinolin]

I changed the complete throttle unit (butterfly valve, idle controller) that bolts onto the top of the manifold system, this was a know working unit and had been taken from the engine I had in the car previously and had new injector and idle control valve a month before swapping engines over to rectify what now turned out to be a burnt valve and fractured piston.

The butterfly did not open after shutting off the engine and both units where cleaned with brake cleaner.

Are these engines prone to manifold leaks or warped manifolds etc?

[Clan]

Originally Posted by Anadinolin

I changed the complete throttle unit (butterfly valve, idle controller) that bolts onto the top of the manifold system, this was a know working unit and had been taken from the engine I had in the car previously and had new injector and idle control valve a month before swapping engines over to rectify what now turned out to be a burnt valve and fractured piston.

The butterfly did not open after shutting off the engine and both units where cleaned with brake cleaner.

Are these engines prone to manifold leaks or warped manifolds etc?

No the manifold isn't prone to leaking ..
the very fact that the motor does not open the throttle ready for the next start when you turn the engine off means it is not working for what ever reason ... there is a pair of contacts in the switch which after 20 years out of production could be corroded / worn on every single B18U engine out there .
There was a mod on the early B18U around 1994 which added a small "amplifier" to the ECU wire near the ECU to help the throttle operation but was standard after 1995 i believe .

Also over the years someone could have opened up the throttle manually with the stop screw to get over the failed motor !

[Anadinolin]

Is there an adjustment procedure? The stop screw (if it is the one I'm thinking of) that the injector taps against is fairly well in and the injector "ticks" when you switch tue car off after adjusting it, which I would guess is the motor looking for its new alignment. There was an etch mark on it that would suggest that it has been tampered with to account for a bad motor? Unfortunately I cannot be sure.

After that are there any other checks I can make? The throttle does open back up. When putting my foot down in neutral the engine stutters then revs up no matter where that stop is.

The car is back at its storage untill the mot on Tuesday.

[Clan]

Originally Posted by Anadinolin

Is there an adjustment procedure? The stop screw (if it is the one I'm thinking of) that the injector taps against is fairly well in and the injector "ticks" when you switch tue car off after adjusting it. There was an etch mark on it that would suggest that it has been tampered with to account for a bad motor? Unfortunately I cannot be sure.

with a hot engine idling , the throttle stop should be resting against the pad on the throttle motor , this closes the contacts inside and enables the idle control . If you always have a gap between throttle stop and pad on the Motor it can never work . The only time you have a gap is when you turn the engine off , the throttle opens ready for the next start sequence .