Another Misfire problem

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Andy
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Another Misfire problem

Post by Andy »

Hi

This intermittent misfore happens mainly when the engine has warmed up and when accelerating after a period of slow driving. Usually after turning a corner.

The car 'judders' a few times, then carries on as normal. I can drive along at 50/60 with no trouble and for most of the time the car behaves perfectly. I've replaced the HT leads and dizzy cap but this had no affect. All the ingnition components seem to be in good condition and were replaced recently (although not recently enough that you'd think they were the cause).

The vacuum advance unit works (tested by sucking on the other end of the tube).

I've partially stripped down the carb and cleaned it up, but again, this had no effect.

Does this sound to you like a fuel. or an ignition induced problem?
bmcecosse
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Post by bmcecosse »

If it's after a corner then it's likely fuel surge as fuel either spills over into the carb causing extreme rich mixture - or falls away from the jet causing starvation. The older SUs are infamous for this -the newer HIF design eliminates it! It may be your fuel level in the float bowl is marginal anyway - could be worth check - see Haynes.
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Andy
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Post by Andy »

Thanks for that.

I thought it might be something along those lines. I'm going to replace the carb with an old spare at the weekend to see if that makes a difference.

Andy
bmcecosse
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Post by bmcecosse »

Hopefully a NEW spare!
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8009STEVE
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Post by 8009STEVE »

Hopefully a NEW spare
New as in new or new to the car?
Packedup
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Post by Packedup »

I spent a lot of time mesing with the carb on a Metro once cue to it stuttering on/ just after left handers and under heavy braking. Never did cure the fault.

When I stripped teh car (terminal rot and extreme pressure to get rid) I found one of the LT wires had burnt the insulation off - So it's almost certain the problem was electrical, not fuel. Might be worth checking for a similar fault.
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