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Thread: Warm start problem 1990 8V GTI Digifant

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    Default Warm start problem 1990 8V GTI Digifant

    Hi All
    I have just purchased an 8v GTI Digifant & have a problem where it's difficult to start when warm. It idles & drives well once running. No problems starting from cold & it will start warm if I disconnect the blue sensor. So far I have replaced the blue sensor with a new OEM item, replaced dizzy cap & rotor arm & checked all of the earths. I'm guessing from the fact it starts with the blue sensor disconnected it is more likely to be a fueling problem.
    Any ideas where I should start please?

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    Possible areas without seeing the car myself are, faulty AFM, damaged fuel pressure regulator, low fuel pressure or poor engine set up.

    Vague as I said because the car is not in front of me.

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    Thanks. It runs really well when going. Was going to try fuel pressure regulator next anyway, so will start with that.

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    Unlikely to be fuel pressure if unplugging the blue ecu sensor changes things. I'd like suspicious of the ecu or the track on the AFM.

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    We've now tried a known good AFM, a new lift pump, spark plugs & fuel pressure regulator & still very difficult to start when warm. I'm now not sure the blue sensor makes much difference when disconnected. Sometimes when its disconnected it will instantly start & other times it makes no difference. I've checked there's fuel flowing to the injectors when the key is turned & the engine cranked, although I have not measured the amount of fuel. Should I keep looking at the fuel system or now widen the search to ignition/timing/ecu etc?
    I must say it does run well & idle nicely when running. It actually feels responsive when it runs.

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    The blue sensor is for the ECU. Do you have to crank it for long when it's hot?

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    Yes lots of cranking required before it will catch

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    Try a quick squirt of easi-start or similar when it's next hot. If it starts, you'll know it's a fuel issue. If it doesn't, it's spark or other mechanical.

    It shouldn't be valve clearances on a Digi... Them having hydraulic tappets.

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    Problem now seems to be resolved. Firstly we noticed the earth from the top of the gearbox was missing, so reinstated this. This did not resolve the problem but obviously needed doing. We then tried a spare ECU & the car now starts up instantly both from cold & when warm.

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    We really do appreciate when folk like you come back to report on their findings.
    Happy motoring.

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    Very true, it's rare people close out a thread after a fix has been found.

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    Thanks. I know what you mean, when you read through a thread & don't see the outcome!!

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