Thread: Rough running analysis?

condensor, running too rich or the advance mech ias dodgy

Originally Posted by RaggedJoe

Hi all

1976 SIII 2 1/4 petrol, LWB, in the family since new.

Hasn't been out much in the last 6 months. Last couple of drives have been a bit rough, worse today.

Seems to be fine at first, then under load, she starts losing power the surging and backfiring. Once over the top of the hill, comes right and all is well.

Full tank of fuel, but I suspect a fuel problem. Dirt? Pump playing up going up hill? Any ideas or similar experience?

Cheers RJ

I had this issue with mine 1976 game....

i found it was a faulty coil pack.

I also thought it was fuel as well...

if the fuel is 6 months old it has probably gone off. Either drain off or drop in some high octane unleaded.

if the fuel is 6 months old it has probably gone off. Either drain off or drop in some high octane unleaded. Change the fuel filter and check for water/condensate.

This happened to me and was solved by replacing the inline fuel filter. Maybe a good thing to replace if present.

Could be a faulty fuel pump. Run the engine and then look underneath to see if there is any fuel dripping from the bottom of the fuel pump. If so the diaphragm is stuffed and you either need a new one to overhaul the existing pump, or a new fuel pump (the latter is easier and quicker).
These symptoms were what I experienced with an identical vehicle (except it hadn't been in the family since new...).
I could keep going if I lifted off and changed to a lower gear so that the engine was unloaded somewhat. If it is the fuel pump, then the problem occurs because with the throttle open wide the pump can't deliver enough fuel and the mixture gets way too lean and generates rough running. As soon as you back off, the problem goes away....
The other suggestions may also apply, but if the fuel pump has never been replaced, then it's probably on the way out by now.

Coop

Thanks to all for the replies.

I need to check:
Condensor
Coil
Fuel filter (in line one looks okay visually)
Dripping from fuel pump.

Actually I will probably drop if off to my freindly mechanic, he can test the electrical and perhaps the fuel pump better than I can.

The symptoms are so specifically up hill under load, that I am most suspicous of fuel pump but I bow to the great kwnoledge here, it could well be electrical.

Thanks again for trh responses, will advise diagnosis when done...