A couple of weeks ago i believe i put too much lead additive into the fuel on my car, within a matter of days my car started to miss fire and run rough. so i replaced the spark plugs and emptied the fuel tank which didnt help as it was still running awful. After a close inspection from a local mechanic i was told it needed a new carb, so I got hold of a good second hand one and fitted that and still it miss fires, it appears to be running too rich, i have been told its not the values as compression is good. Yet even altering the mixture the car still missfires and refuses to rev up at all.
Any Ideas would be appreciated as its been 3 weeks now without a car,
Thanks
Tom
Help!!!! Unknown Missfire Cause
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minorsrule
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minorsrule
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mike.perry
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Unlikely to be too much additive and I wouldn't have wasted a tank full of petrol finding out.
Carbs go on for ever until you get serious problems so first try adjusting the mixture before you bin it.
Check plugs (gap, tight, undamaged), HT leads (tight on distributor, plugs and coil), connections to coil and distributor, check points gap
Try running the engine in total darkness and watch for any stray sparks from short circuits. If you are in a closed garage a few seconds is long enough
Try replacing and testing one at a time, coil, condenser, distributor cap (carbon brush in top, cracked cap).
When you have checked that lot, if you still have a problem come back
Carbs go on for ever until you get serious problems so first try adjusting the mixture before you bin it.
Check plugs (gap, tight, undamaged), HT leads (tight on distributor, plugs and coil), connections to coil and distributor, check points gap
Try running the engine in total darkness and watch for any stray sparks from short circuits. If you are in a closed garage a few seconds is long enough
Try replacing and testing one at a time, coil, condenser, distributor cap (carbon brush in top, cracked cap).
When you have checked that lot, if you still have a problem come back
[sig]3580[/sig]
Amazing the 'mechanics' who suggest getting a new carb! It's almost NEVER the problem, and even then the SU carb is so simple - whatever is wrong can be easily reconditioned. Steady misfire like this is almost certainly ignition related - especially as it continues with a different carb - Mike's advice above is spot-on. Although I would start with a new rotor arm - after checking the points gap.
You say the compression is good - do you have the figures ? And - forget the 'additive' - it doesn't need it unless being regularly hammered on M/ways.
You say the compression is good - do you have the figures ? And - forget the 'additive' - it doesn't need it unless being regularly hammered on M/ways.
