8 replies to this topic

[cottersmead]

I would appreciate any advice on a strange problem when my '85 mayfair progressively dropped in speed along the main road and barely had enough power to pull into a layby.
This time last week and again today I noticed a gradual loss of power, but after a few minutes of waiting at the side of the road the car seemed to have cured itself and was running fine again.
I was travelling at a fairly constant 30 in fourth in both instances, noticed a slight deceleration, so changed down to third, but from there it slowed down almost to the point of stopping completely.
In between these two events it has covered many miles without a problem.
When it happened the second time I put the choke to full, although it made no difference and the guage indicated that it was running at normal temperature.
Throughout the engine sounded fine, just like it was under a very heavy load or that the brakes were sticking.
My suspicions include ignition and vacuum advance although I would be very grateful for any suggestions as I don't really know where to look for this fault.

Nick.

[Willthewelder]

Sounds like a coil or lead breaking down and weakening the spark under load on one cylinder causing misfiring and lack of power?

[richw911]

Could be the brakes binding? Have you put your hand on the wheels to see if they are hot?

[cottersmead]

The HT leads have been replaced very recently and the engine didn't misfire, so It probably wasn't that. Next time it happens I will check the wheels in case it is the brakes. Another suggestion I have been given is that there are bits in the fuel bowl that blocked the jet and when I stopped they fell back to the bottom as there was little suction, which would explain how the fault seemed to cure itself. Any opinions as to the validity of this suggestion? I intend to check the fuel bowl tomorrow but I am doubtful that that is the sole cause of the problem.
Thanks for all the advice
Nick

[richw911]

The HT leads have been replaced very recently and the engine didn't misfire, so It probably wasn't that. Next time it happens I will check the wheels in case it is the brakes. Another suggestion I have been given is that there are bits in the fuel bowl that blocked the jet and when I stopped they fell back to the bottom as there was little suction, which would explain how the fault seemed to cure itself. Any opinions as to the validity of this suggestion? I intend to check the fuel bowl tomorrow but I am doubtful that that is the sole cause of the problem.
Thanks for all the advice
Nick

Could well be fuel related as you said or a faulty pump?

[cottersmead]

OK, thanks, I'll investigate that as well.

[KernowCooper]

Are you on points or electronic ignition, points could be the condenser over heating or the coil but thats not very often, but put your hand on the coil is is really hot is a indication. Sounds heat related as your able to pull away a short time after.

You don't have a vacuum in the tank building up do you, when it dies away remove fuel cap big rush of air means air vent is blocked

[Gulfclubby]

Check fueling first before going for the less likely sources of failure like the coil. It seems people suspect them to be faulty all the time, when in fact they hardly ever fail.

[KernowCooper]

Coils as I pointed out rarely go as you said just wondering about the condenser if its points or the fuel starvation symptom ?