occasional non starter MG ZR 1.4

[rapidyellow]

sometimes our mk2 1.4 ZR wont start, turns over fine but doesnt fire, if I apply Wide Open Throttle it will, it might splutter for a second but then its all ok. [its not coolant or HG related, its just been done]

fuel pump primes - but not every time

I have tried FP relay, swapped for a known good one, and also a bridged one [FP runs all the time], cant really say for sure if it made a difference due to the fact that once it has started, switching off and trying again it starts fine

mostly does it when cold, or when stood for a few hours

fuel pump is noisy, compared to a mk1 ZR we also own

new fuel filter put in yesterday


otherwise when it is running, its running sweet, really strong, good on fuel, doesnt miss or owt, theres no fault codes showing with my scanner.

has anyone got any advice on what I could check - please bear in mind the above that it starts if Wide Open Throttle is applied until it goes, and its only occasional.

thanks

[taurus]

Not sure about MGs - but on others I've played with when the fuel pump prime is intermittent it's either been a dud relay or a bad ECU earth. If you've checked the relay I'd double check the ECU earth, especially if you've just done the HG.

[rapidyellow]

I will check the ECU earth but would it not have a problem all the time if that was faulty?

[vitesseefi]

Holding the throttle wide is normally "flood clear" mode when it's not injecting any fuel at all so it sounds a bit like you might be getting too much fuel going in in the first place. Maybe dodgy coolant temp sensor of connection to it?

Nick