As i drive the rev counter will jump up and down and mainly read a lower reading than what the engine is actually running at, at the same time as this the engine develops a misfire,
to me it seems like theres a problem with whatever gives the rev counter its signal, i was guessing it would be the crank sensor but to me the crank sensor would either be working or not and couldnt rly cause this problem?
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Hi Chloe, the rev counter gets it’s input from the coil pack, and often there is a problem with a loose connection/bad earth in that area. However your problem sounds more like the HT leads failing, have they ever been changed?
hi, thanks for the info, ive tried cleaning up both the earths that i can see on the engine (inlet side), ive swapped the coil and leads making no change, ive had the instrument panel out just to check for loose connections
is there a seperate earth that i could be missing for the coil? the problem seems to be getting more and more common too, really bugging the hell out of me!
pretty much all the time now, cold, warm or hot, the car has pretty stiff suspension so i havent ruled out a loose connection somewhere but i have checked what i would say is the obvious
hmmm… ok, pull the plugs check them. is there condensation where the leads meet the plugs, it’s a great place for it to get trapped, and it only needs a drip or two. so when she’s hot pull the leads out and leave them on the hot block where any moisture can evaporate, i know it’s obvious but happens a lot. is there white smoke when she’s running (or blue for that matter)? do you have any heater problems? does the coolant need topping up all the time??
If it is doing it at roughly the same RPM’s it should be the crank angle sensor, but again, before you go down the leads/ plugs / coilpack route, try the sensor first.
The crank sensor is alot cheaper than a coil pack, I should know…
