Fouling of plugs in '86 Volvo 240GL

My 1986 Volvo 240GL has suddenly started fouling the plugs in a very short time. I have brought it to the local mechanic, discovered it was getting too much fuel and has replaced the fuel injection ECU, however it hasn't solved the problem. He indicated the sensors were OK and I don't like to disagree with him, but finding the actual problem is difficult for me. Anyone have any suggestions?

I have recently replaced the high tension leads, distributor cap & rotor - could this be a contributing factor?

Regards,

Anton

Reply to
Anton Sather
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plug type cold or hot can make a difference I remember once I put a new set of plugs in they were all faulty do you think that didnt confuse me ?Naturally I looked everwhere else that I had touched till disparate I found the plugs klg were useless

Reply to
John Robertson

Reply to
John Robertson

If the engine wiring harness has not been replaced it needs to be, these always rot out and fail. I've never even heard of a 240 ECU failing, that part is probably the most reliable component in the whole system.

Reply to
James Sweet

Check the vacuum hose from the fuel pressure regulator to the intake manifold. If the diaphragm is ruptured or cracked, raw fuel is admitted to the manifold and will ful the plugs in short order.

Bob

Reply to
User

The car worked fine then suddenly started fouling plugs. The car worked fine on the local fuel before, I think its in the injection system where something (and it is driving me and the mechanic crazy trying to find out exactly what!) isn't working and it defaults to a 'get home' mode. I've used injector cleaner, use a quality oil withut going overboard and don't scrimp on the routine maintenance/repairs. This happened suddenly, even tho it took a bit to discover the plugs were actually fouling regularly - all that needs to work out is why!

Reply to
Anton Sather

In addition to the pressure regulator, you could also check the mass air flow sensor.

It sounds as though your mechanic is replacing expensive parts and not really diagnosing the problem. Try to avoid the temptation to start pulling and replacing parts on your own as the suggestions roll in on this forum. If there is not an obvious problem with the pressure regulator you should consider switching to a mechanic who is familiar with Volvo cars.

Reply to
Roadie

I would bet money the problem is the engine wiring harness, these

*always* fail on Volvos made during this time period, if it has not been replaced already with the upgraded harness I can assure you it is bad. Look at it closly for insulation crumbling off the wires, if you see any of that, it is deteriorating badly within the outer sheathing and it will only get worse. Dave Barton sells replacement harnesses or you can do what I did and rebuild the original. Fortunately replacement is quite easy, hardest part is working with the crusty hardened original.
Reply to
James Sweet

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