Non VW engine help needed...

[Justin & Muttley]

Dear All,
My wife's old banger is a Nissan Micra 1989 - it's only done 42k and until now has been a sweet little runaround for her but it's developed an irritating fault that has our local mechanic stumped...

The other day it started mis-firing and wouldn't tickover, we took it to the mechanic and he checked all the electrics (coil, points, plugs, dizzy etc) and all checked out OK. He thought it might be fuel starvation so he checked the carb, fuel pump, filter, vacuum hoses etc and again, all were fine.

We took the car away and it was fine for a week, then the same thing happened - he's checked it over again and can't find anything wrong? Any ideas...?

 

[Justin & Muttley]

OK, so it's a Nissan - but surely someone has some ideas???

 

[VWAIRCOOLED]

Mostly these types of fault are ignition related.What parts have you replaced so far to try and fix it if any?

 

[Justin & Muttley]

Mostly these types of fault are ignition related.What parts have you replaced so far to try and fix it if any?

Points checked, coil checked, leads and plugs checked, rotor arm and dizzy cap checked... all OK!

 

[VWAIRCOOLED]

Without seeing it I can only guess but most cars start missfiring as the cold damp weather sets in due to tracking in/on the distributor cap and also the spark plugs.Inspect them for black lines tracking to earth.

To start with replace the points and condensor if they're more than a year old.If the distributor cap looks old and dirty replace it.If the spark plugs have been in there more than two years change them.

You could also have a look at the ignition components in complete darkness,get someone to rev the engine and look for electricity tracking like a blue spark.Don't touch anything though! If something is tracking you need to replace it.

 

[Justin & Muttley]

Thanks for your advice dude - I'll charge up the battery and give it a go tomorrow!

Mucho apreciated...

 

[angus]

Dodgy earth?

Try running the engine and fiddling/moving everything, listening to the engine note - may be a loose lead on a sensor somewhere?

We traced a similar sort of problem on the caterham to the crank sensor lead passing too close to the main lead from the coil - the pulses from the coil were screwing up the signal from the crank sensor, causing lots of missing, stalling and general problems....

 

[Tintop]

I few years ago i have a calibra that had a similar fault and it turned out to be the leads becoming faulty when the engine was warm. (but not all the time) mainly after it had been driven agressively.

I freiend of mine owns a garage and we hooked it up to his machine and bingo he found it within 3 minutes other garages couldn't find it.