Misfire under acceleration - Only when warm!

[72elan1304]

Will check the coolant and the leads and get back to you both.

[72elan1304]

Coolant level fine, BUT it didn't want to start!

Dash lighting up fine, but I didn't hear the fuel pump prime and nothing from the starter, not even a click. Reset the alarm using the fob a couple of times, messed about with the fob for the immobiliser switching it on and off. Nothing.

Then, started searching on my phone for an answer, tried the ignition again and it started.

I'm thinking there's an earthing issue. Could it all tie in; incorrect temp reading on the stack, misfire when warm and not starting?

[robin]

When you turn the ignition on but don't crank/start the engine is the red charge warning light on or off (the one with a picture of a car battery on it)? It should be on.

When the engine does start, I'm guessing the charge warning light must be off as you would have pointed that out already otherwise.

How old is your car? Is the ECU in the engine bay or in the boot? You need to check that security of the battery and the battery leads. On an S1 you must be ultra careful as there are two risks:

(1) If the battery is not well supported it is possible for it to bounce about and for the negative terminal to touch the chassis.
(2) If you are not very careful you can touch a spanner from the positive terminal to the chassis. To derisk this process it is imperative that you disconnect the -ve battery terminal first and then the positive terminal second. Refitting is the reverse. Connect positive first, negative second.

When it is running is the fuel pump whine strong and constant or does it change in pitch and come and go?

I'm struggling to see a single point of failure that could accurately cause this set of symptoms.

That said, bad earthing is always a place to start with this sort of problem.

Cheers,
Robin

[ronin]

It sounds like you have condensation in the spark plug tubes, when the engine is hot enough the water vapor will short out the spark plug...If you have a rust colored residue use dielectric grease in the boots and wire..

[72elan1304]

I had another look at this today. There was some moisture in the spark plug tube on the first cylinder. I dried it out best I could and it seems to have cured the misfire.

Thanks for the help.

[dirkpitt]

I had another look at this today. There was some moisture in the spark plug tube on the first cylinder. I dried it out best I could and it seems to have cured the misfire.

Thanks for the help.

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