Re: Twin Spark cutting out

["Masters, David DJ" <Masters.David.DJ@domain.elided>]

Last Friday Rob asked:

>I am currently experiencing some problems with a twin spark from a 75. 

Is this motor in another car?

>The car will run fine for a while and then suddenly start miss firing. >This starts off minor but within a kilometer starts to get worse until the
>engine eventually cuts out. Leave the car overnight, try to start it in
>the morning and, after running rough for a minute or two, cleans up. The
>problem will then re-occur after an undefined period of driving from 5
>minutes to half an hour.

Cutting out is a standard feature of TS's that have about 8 years on them. The culprit is usually a bad earth in the connector behind the cardboard behind the throttle butterfly.  Another contributor I have found is the rotor on the dizzy on the front of the engine.  The obvious test is to check that each plug wire will fire your timing light.

>I am assuming that this is a fuel related
>problem as when the car is running rough at idle both ignition systems
>appear to be working fine.

The only fuel problem I have had was a mysterious bad connection on the fuse.  I do however reseat the relays (the 4 together) regularly. The whole problem could have been the connector, above. I haven't heard of too many fuel problems, either.  Use Techron or Wynns every 10k kms.

>Anyone else had this problem. There is no inertia cut off to the fuel pump
>system so this not the problem. Current thought is the possibility of
>vapour lock in the return line.

This shouldn't be an issue with the recirculating fuel, etc.  If the pump was failing I guess it could be an issue, but I would check the High Tension electric's first.

>The fuel tank has recently been removed
>and cleaned and new fuel filters fitted.

And we all know that what we touch is usually the problem   :-0
It might be worth pulling the filter again and shaking it out to check that some large piece of crud hasn't blocked it.

Good luck!

Cheers,
david
- ---
David Masters
1989 Twin Spark, 140000 kms
Newcastle AUSTRALIA
 mailto:david@domain.elided



>Any suggestions would be great
>Thanks
>Rob

EOM 

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