Misfire

[Guest paul boatman]

Before i venture onto Curborough again can anyone help with my misfire problem - only when given total abuse ie. start of a circuit or when cornering hard and accelerating hard the car misfires with a puff of blue smoke.

 

running normally or pushed hard on the road its fine - no smoke no noises and no misfire.

 

standard sierra carb

 

my thoughts include fuel surge/starvation, oil surge in sump? but these all seem a bit far fetched

 

any suggestions?

[Guest Simon cooper]

hi Paul,

Forget oil surge, (through the pump anyway).

The most likely cause is lack of throttle enrichment. This is when the carb gives a squirt of juice directly into the throat of the carb as the throttle is opened.

without the engine running, look down the carb and open the throttle. You should see a squirt from a small jet mounted near the top inside the carb. if you see nothing then, either the jet is blocked or the enrichment diaphragm is stuffed.

Blue smoke is normaly oil, but in this case i think it is just enrichment.

hope this helps. If it doesn't, then more info on the prob is needed.

Simon

[Guest paul boatman]

thanks Simon

 

I have checked it and it seems to be working fine, chuckng fuel in no problem . - wouldn't a blocked jet mean too little fuel not enrichment?

 

any yhoughts?

[Robbie 2B]

Paul

 

I have the same problem but only when you floor it in first gear, very embarrassing when coming out of the pub. :angry:

 

I have a 2 lit 2B with the standard pinto carb' and ECU. I have checked for blocked nozzles, enrichment, etc all seams OK and I think it may actually be fuel starvation.

 

The fault appears to be more prevalent when making a swift get away from a side road (pub car park), thus exerting a cornering force as well as the acceleration force, than when dragging away from traffic lights.

 

Can anyone confirm this hypotheses or propose a solution. I am debating whether altering the height of petrol in the float chamber will have an effect.

 

Robbie