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misfire with engine under load
Posted: Sat Jun 02, 2007 8:41 pm
by spotdoc
Hi,
can anyone help with this problem.
My engine is mis-firing badly when under load (going up a hill for instance).
I've changed the plugs, condensor, rotor arm and checked the timing.
The plugs were very black so I tried weakening the mixture but nothing seems to work.
any ideas?
many thanks
spotdoc
Posted: Sat Jun 02, 2007 9:10 pm
by bmcecosse
First check must be general engine condition - to do this first check and reset the valve gaps - and then use a compression tester and report back with the result! It may of course just be blocked air filter - so take it off and try running the car without a filter - is there an improvement ? Could be many other things - coil/dizzy cap/dizzy advance-retard stuck/dizzy vacuum advance broken - stuck/carb needing oil in dashpot/carb flooding - it goes on and on. How did you 'weaken' the mixture ?? The adjustment on the carb is for the idle mixture and has very little effect on the running mixture - to change that you need to change the needle - did you ?
Engine misfire
Posted: Sun Jun 03, 2007 12:01 am
by southerly95
I am having similar probs so last weekend I replaced plugs, rotor arm, dist cap and coil and it improved alot. However it has come back in a different guise (today) - after 20 or so miles in traffic the engine suddenly loses power and tries to stall but more go pedal stops it although fluffs a bit, preceding that is rapid fuel pump clicking (new a month ago) so wondering if that is caused by a fuel blockage higher up on the piump side or possibly a vacuum in the tank? After awhile it stopped doing it.
Posted: Sun Jun 03, 2007 12:43 am
by Dominic
A rapid clicking of the fuel pump suggests fuel starvation - it is sucking on air. A most annoying event when the needle is on empty and you just know that you should have refuelled at that last garage you passed a mile back......
misfiring
Posted: Sun Jun 03, 2007 3:28 pm
by Willie
Your rapid pumping tick suggests, since it occurs after 20 miles in traffic that you are suffering from fuel evaporation. route the fuel pump to float bowl pipe as far away from the manifold as you can get it. If the engine runs ok once you are able to cruise out of the traffic jams it would definitely suggest evaporation problems. Or some other problem associated with heat.