Whoever said fuel pump......IS A GENIUS!

[Bilkob]

AT LAST!
I changed the fuel pump and the filter today, in extremely hot and muggy conditions. The car ran for a good 20-25 minutes at idle with no hint of cutting out, in humid 30 degree ambient. The heat it chucks out, jeez!
Anyway, as I tried to move it off the drive, any load prompted a cut, but if you coaxed it with a bit of clutch it was ok, then, as soon as I was able to get a bit of momentum it ran just fine. So, it will now idle, but still cuts with load initially but can be coerced into running ok. Gotta be a clue there somrwhere?!

[Sloppysod]

Vacuum, sucking in air when it does not need much, but when the vacuum is increased then what ever is leaking seals it self, something like the air filter box lid or any part of the the same pipework.

[xantia_v6]

I think that was me...

If it dies when applying load, I would be suspecting a faulty MAP sensor or if there is a hose between the manifold and MAP sensor, then maybe that hose is blocked. There is probably also a throttle potentiometer but I would not expect it to have much effect.

[Peter.N.]

I don't think they had them on CX's ... or is it the C15?

Peter

[wurlycorner]

MAP sensor on CX Turbo's outlined by me previously here
Can only affect timing, not air/fuel mix.

[wurlycorner]

It may be worth fitting a fuel pressure gauge at the rail and seeing what that shows. If it's not correct, or varies with heat, could point to the regulator.

[Peter.N.]

Ah, showing my ignorance again, I'm thinking diesel, don't know anything about petrol engines, the last one I drove had a carburettor and probably a dynamo.

Peter

[xantia_v6]

As the system has an air flow meter (which I had not noticed before), that would have to be the prime candidate for the current symptoms. Assuming (due to its vintage) that it is a mechanical flap type of AFM, then any stickiness in its operation would cause a stumble when the throttle is opened.

[wurlycorner]

It's a mechanical flap and 'wiper' type VAR AFM, yes.