VW 1.8 hot starting problem.

This has happened 5 times in the last week, so something is going wrong somewhere. VW 1.8 20v non-turbo. Engine starts fine cold. Runs well, no problems at all. Come back to it after being parked for 10 mins or so, and it wont start. Smell of petrol, and after turning over for a few minutes, or left for a minute or so, then turn over again and again, it will eventually start.

Once started, it runs well, once the initial excess petrol has been burnt off.

Reading a few online forums, there are a few options that it could be (it seems to be a common fault, that doesn not show up as an error code).

The temperature sensor for the cold start injector could be faulty, The cold start injector is stuck open.

Other suggestions were a faulty starter motor (apparently they have to crank over at above 280rpm to start). Seeing as it'll start fine at the

-3 degrees we had last Sunday, I cannot see how it could be a starter problem, - surely the engine will turn over faster when the engine is warm? Correct me if I'm misinformed.

Another distinctly strange possibility was a faulty ignition switch. I'm discounting this, as the only time it happens is when the engine is hot, so most unlikely to be an intermittent switch problem.

Which leads me to the cold start sensor and injector.

Are these cheap, so I could just buy them and fit them to make sure it wasnt them?

Anything else I may have missed?

Thanks for your thoughts Alan.

Reply to
A.Lee
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Well you can see on the diagnostics if the temperature sensors think it's cold

Reply to
Duncan Wood

As a matter of interest, have you tried hot-starting with the throttle pedal held to the floor?

This used to work like magic as a means of clearing flooded carbys. There's no reason for it to work on fuel-injected systems except that some manufacturers have preserved the method by making a wide-open starting throttle lean out the mixture deliberately.

John

Reply to
John Henderson

Yes, I found a bit of pumping of the pedal tended to work eventually.

I've investigated further, and think it is probably the temperature sensor. Even though the guage reads correctly on the dash, it is telling the ecu it is cold. I tested this by unplugging the lead when running - the engine ran better immediately, so discounting my thoughts that it was running well - only slightly worse when connected, but a noticeable difference.

Ta Alan.

Reply to
A.Lee

When the sensor was disconnected it goes back to a set value on the computer. So your correct in thinking its the sensor. There not very expensive to replace.

r
Reply to
Rob

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