P6 3500 is back firing

Ricky43

Member
My p6 rover 3500 is back firing and keeps cutting out what could be the problem can any one help ? Please
 
What have you done so far? what have you tried? My initial thoughts would to look at engine timing and ignition.

Graeme
 
Check the distributer cap is not tracking/cracked between two adjacent plug leads. Seen that a few times, usually on the inside, in the early days. Engine can then try to fire at same time on opposite banks, giving a backfire, knocking and all sorts of other effects
 
backfiring is fuel being burnt too late. eg in exhaust system . have we removed refitted dizzy? check. firing on cylinders against dizzy leads. and TDC but ideally remove No:1 plug and rotate until firing point 6 degrees BTDC? gently. use a plastic straw or other no engine damaging stiffish probe until it touches top of cylinder .carry on by hand. rotating crank. to TDC. straw ought to go UP and them pause at TDC going back down bore as we go past TDC point.
if that is oK? then DO check BOTH valves at that point for that cylinder are Closed? as we may be. out on basic timing. ? if. valve timing and spark timing is OK? then other remote possibility is unburnt fuel vapour being drawn into inlet manifold is being ignited as. valve opens on an exhaust stroke on another cylinder. thus igniting it .(heat of burnt /burning exhaust gas) bearing in mind valid point made by roverp480 about dizzy cap ad spark tracking.
 
Check the distributer cap is not tracking/cracked between two adjacent plug leads. Seen that a few times, usually on the inside, in the early days. Engine can then try to fire at same time on opposite banks, giving a backfire, knocking and all sorts of other effects
Also check the metal clamp holding the distributor in place. I once had similar symptoms, stuck on the road not far from home, and it took the RACV (similar to RAA) mechanic an hour of frustration until he tracked it to the broken clamp which allowed the dizzy to rotate freely at will.
 
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