Uneven running

[wclough]

Hi. When I collected my ebay purchase the car drove home at about 60mph but at lower speeds it felt to hesitate intermittently. On getting it home I have replaced 2 very dodgy plug leads which had corroded ends and green oxide. I had a new Distributor cap and rotor in stock so put these on. Still misfiring, possibly worse. Checked points gap which was a bit tight so set correctly. Worse still. The car starts immediately. It pulls away no problem. When cruising there is that slight misfire feel all the time. Any ideas before I have to start throwing money at it. Thanks

 

[jjad]

Well, the condenser doesn't cost much to replace. Try that?

 

[jcarruthers2]

Well, the condenser doesn't cost much to replace. Try that?

Hi

Typical condenser or coil symptoms. These two components would be my first line of enquiry. I would change the condenser first as cheapest.

Best Regards

 

[jcarruthers2]

Hi

Almost forgot, check spark plugs first before the above if you have not done so already.

Best Regards

 

[wclough]

Thanks. I did check the plugs and they were awful. The worst I have ever seen. Clogged with hard light beige clay with the electrode heavily worn and hollowed. Bought a set of new NGK's. Unfortunately it has made no difference so now I am really stumped. Does the plug colour and condition indicate a fuel mixture problem? Mines an 1100cc engine with, I think, the Zenith. Just 2 screws, an idle and a mixture. May need to pay for some professional help next

 

[ecurb.renots]

Did you try a new condenser and clean and regap the points, if the plugs were that bad i would not mind betting the points will require attention and i think this will resolve your problem.

 

[AdamWilkes]

Replace/clean/reset everything in the ignition system (as above) - including wired connections - bit by bit until it gets better, coil etc if needed too.

Faults do get worse when you improve other areas in the same system, as load on the whole system changes; when you find the root cause, everything may suddenly fall into place.

One of us on this site said "80% of fuel problems are electrical". I find this is pretty close - well worth bearing in mind!

 

[wclough]

New condenser today. Some worn wires and looked hopeful. All nicely back together with cleaned connections and new bolt. No change. Only the coil to go now. What I have not made clear up to now is how it runs well at full throttle.

 

[ecurb.renots]

Have you cleaned/replaced and regapped the points only you have not mentioned it, I would certainly do that before replalcing the coil,

 

[Richnd1974]

I did a carb clean on mine, changed the diaphragm. jets and all gaskets, as it was running lumpy on de-acceleration and lumpy on acceleration - it now drives 100%, this was after I changed the plugs, leads, coil, condenser, rotor, cap, points and fuel filter. Only cost me a few pounds and about 1 hour to do it.

 

[ecurb.renots]

I did a carb clean on mine, changed the diaphragm. jets and all gaskets, as it was running lumpy on de-acceleration and lumpy on acceleration - it now drives 100%, this was after I changed the plugs, leads, coil, condenser, rotor, cap, points and fuel filter. Only cost me a few pounds and about 1 hour to do it.

which carb and where did you get the parts, were they are kit. I need to do mine sometime as the float valve sticks sometimes.

 

[malcolm]

Vacuum related problems are quite common and would put the ignition timing out by 10 degrees on low throttle. If you take the distributor cap off and see if the base plate moves and holds while you suck through the little vacuum pipe to the carb. Also the hose from the engine breather to the manifold should have a restrictor with a 1mm hole inside. Lacking that would mess the mixture up.

 

[Richnd1974]

which carb and where did you get the parts, were they are kit. I need to do mine sometime as the float valve sticks sometimes.

I've got the zenith 28if on mine, pretty standard and bought the kit from franzose for not much money

 

[wclough]

Ex mechanic neighbour has been out in the car with me and is of the opinion that the way it pulls on full throttle it is not the coil. He was think a carb issue. Advance working OK when sucking on pipe. Decided to take above advice and do a carb clean. Might be some time before I can report back. Thanks

 

[wclough]

OK, I have now had the carb off and the jets out. Sprayed WD40 equivalent down all the orifices in the jets and where they had come out of. Couldn't see anything come out. Blew through them. All OK. Reassembled and was delighted that the engine now running well