One bank not firing but wet with fuel and getting a spark.
Discussion
I all,
I have a 93 Chim, was driving perfectly fine. Stopped briefly and restarted, it sounded a little lumpy before producing alot of smoke out of the exhausts and cutting out. It will now start but only seems to be firing on one bank. The spark plugs on the misbehaving bank are soaking wet, but I do get a spark on all four. The manifolds are also cold and there is alot of fuel in the cylinders. The other bank seems to be firing fine, manifolds get warm, not fuel anywhere it shouldn't be, plugs look a healthy colour etc etc.
I am struggling to work out what is only affecting one bank and not the other, are just being completely flooded beyond the ability to fire?
Any suggestions welcomed!
I have a 93 Chim, was driving perfectly fine. Stopped briefly and restarted, it sounded a little lumpy before producing alot of smoke out of the exhausts and cutting out. It will now start but only seems to be firing on one bank. The spark plugs on the misbehaving bank are soaking wet, but I do get a spark on all four. The manifolds are also cold and there is alot of fuel in the cylinders. The other bank seems to be firing fine, manifolds get warm, not fuel anywhere it shouldn't be, plugs look a healthy colour etc etc.
I am struggling to work out what is only affecting one bank and not the other, are just being completely flooded beyond the ability to fire?
Any suggestions welcomed!
No idea why only one bank is working if your getting spark on the offending bank but now your washing the bores with excess fuel it will be reducing compression to the point where that bank won’t fire in any case.
Try leaving it over night then disconnecting fuel, remove all plugs and then turn the engine over throttle wide open repeatedly for sometimes a good 20 mins to re oil the bores and gain some compression on that (wet) bank.
I had this issue on a Jag V8 using the XK engine of the late 1990’s where it would start ok but if it’s a cold day and the ecu is adding fuel to enrichen it then I’d turn it off before it warmed sufficiently the engine would flood and cause low compression and no amount of spark would fire it up until I’d done the above and built up compression.
On those engines it was a known problem and the only solution.
Keep an eye on the starter motor temp and stop for a while if it’s getting to hot.
That doesn’t account for why you have lost firing on that bank in the first place but well worth considering if you keep getting wet plugs.
Remove the plugs now and leave overnight will help evaporate the fuel in those effected bores.
I once had an AA man doing this for 1hr on the Jag before the car finally fired and ran as if nothing was wrong with it!
It happened twice in my 10 years with that car and both times it was due to me starting the car cold on a winters day then turning it off within only a few seconds of starting it.
It never happened again once I’d learnt that lesson.
Try leaving it over night then disconnecting fuel, remove all plugs and then turn the engine over throttle wide open repeatedly for sometimes a good 20 mins to re oil the bores and gain some compression on that (wet) bank.
I had this issue on a Jag V8 using the XK engine of the late 1990’s where it would start ok but if it’s a cold day and the ecu is adding fuel to enrichen it then I’d turn it off before it warmed sufficiently the engine would flood and cause low compression and no amount of spark would fire it up until I’d done the above and built up compression.
On those engines it was a known problem and the only solution.
Keep an eye on the starter motor temp and stop for a while if it’s getting to hot.
That doesn’t account for why you have lost firing on that bank in the first place but well worth considering if you keep getting wet plugs.
Remove the plugs now and leave overnight will help evaporate the fuel in those effected bores.
I once had an AA man doing this for 1hr on the Jag before the car finally fired and ran as if nothing was wrong with it!
It happened twice in my 10 years with that car and both times it was due to me starting the car cold on a winters day then turning it off within only a few seconds of starting it.
It never happened again once I’d learnt that lesson.
Worth checking the ECU for water ingress too seen this previously , one of the reasons why it winds me up when owners think water leaks are amusing or you get ......... "well its a TVR what do you expect? " like mentioned check the loom first they are well past their sell by date now and get crispy and chaff on metal objects if not internally between wires
These cars have the Lucas 14CUX ECU I think.
Classically these overvolt spike if you turn off the ignition with the engine running at revs and then turn it on again before the engine has stopped.
That surge fries the output circuit of whichever bank of injectors was firing at the time of the surge.
I'd try to get hold of a replacement working ECU before getting down and dirty with the loom.
Repair is not difficult, but not cheap either.
Classically these overvolt spike if you turn off the ignition with the engine running at revs and then turn it on again before the engine has stopped.
That surge fries the output circuit of whichever bank of injectors was firing at the time of the surge.
I'd try to get hold of a replacement working ECU before getting down and dirty with the loom.
Repair is not difficult, but not cheap either.
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