Sudden Mis-firing

Post by **3rustateers** » 12 Aug 2007, 19:18

Drove to Tatton Park today without a hitch. Stuck in the traffic trying to get out for about 1hr. Finally got out, pulled away and the van started to mis-fire. Did this all the way home, but I noted that it was mainly when the van was under load ie when pulling off or going up hills. The van revs up OK so I think its not fuel blockage. Any ideas?

1.9 DG 1989

Post by **HarryMann** » 12 Aug 2007, 20:43

I replaced the dirty fuel filter in case there was a problem with this. No difference. Dont know whether to run van with alternate 1-4 plugs disconnected to see if its a problem with one particular cylinder. Is this a good way to find out which is causing the mis-fire?

Not really, unless it's obviously running on 3 which is not a misfire per se but a dud cylinder..

When were these vans last serviced?

Drove to Tatton Park today without a hitch. Stuck in the traffic trying to get out for about 1hr. Finally got out, pulled away and the van started to mis-fire. Did this all the way home, but I noted that it was mainly when the van was under load ie when pulling off or going up hills. The van revs up OK so I think its not fuel blockage. Any ideas?

This one sounds like a plug or spark problem, fouled due to oily idling, or whiskered up.. revving up under load no-load doesn't tell you a lot generally, unless it really does rev quickly and cleanly to max revs, but even then has little bearing of consitions under load

Post by **big red bus** » 12 Aug 2007, 20:45

start by checking all obvious things. Plugs, leads,dizzy cap+rotor arm, could be coil breaking down, could also be dirt in carb, need to elimate the obvious before going in to deep. I would suspect that probably an ht lead is breaking down and causing miss fire under load. good luck

Post by **3rustateers** » 12 Aug 2007, 20:53

When the mis-fire occurs I can dip the clutch and it will rev up perfectly. Got home, tick over OK, removed each lead and it runs on all cylinders

When I wiggle the plug connector to the distributor the engine cuts out. Would I be getting that much movement when the engine is under load that this connection is being disrupted?