Oh Dear.... KV5.... but now KV6 again

stocktake · 19th April 2009, 19:47

Travelled the last 50 mile home from todays superb meet ...... on 5 cyl.

No nasty bangs or clunks just went on to 5 cyls.

out with the code reader
Cyl no 6 Misfire
Swapped coilpacks 4 & 6
Cyl no 6 Misfire
Put a spare plug in cyl 6
Cyl no 6 Misfire

Will buy a new set of plugs tomorrow when I get time, doesn't sound good, tickover is around a lumpy 1000rpm

Any ideas apart from a comp test?

Phil · 19th April 2009, 19:52

Sorry to hear this Dave. Do you have a multimeter?
As you have swapped the plug and coil pack over, I would check the resistances across the injectors, if you check all of them, then you will see if there is any difference on injector 6.
Sorry to hear this Dave, lets hope it isn't too serious. Was nice to see you again today.

Departed · 19th April 2009, 19:55

Injector? Or it could be wiring though I'd expect a fault code for open circuit.

stocktake · 19th April 2009, 20:03

Thanks gents, is that an inlet manifold off to check across injectors, what am I checking for and at what points

thanks again

Phil · 19th April 2009, 20:11

Providing they only have two wires going to them, unplug the plug off the injector and check the resistance over the two pins. I don't know the actual specs, 10 ohms rings a bell. I think you will probably have to take the manifold off.

Dragrad · 19th April 2009, 20:15

Sorry to hear of your woe, Dave, Not the best ending to a good meet.... At least you got home

Hope you her sorted soon

Fraser Mitchell · 19th April 2009, 20:16

Sorry to hear of your travails

You really do need to do a compression test, to see of this cylinder is down compared to the others.

Also as Phil says, the fuel injector may not be firing OK so no or little fuel is being injected. What did the plug look like when you got it out ? (you need to compare with a plug from one of the good cylinders)

If the injector's gone open circuit there should be a fault code registered, I would have thought, as each injector is fired individually by the ECU.

Departed · 19th April 2009, 20:17

I don't know the spec either, but a good check is to compare a good one and the suspect one. Like Phil says, measure resistance across the two pins once the plug is out.

You could swap injectors, in case it's some sort of blockage, but depressurise the fuel system before you do!

Phil · 19th April 2009, 20:19

Quote:

Originally Posted by Fraser Mitchell

If the injector's gone open circuit there should be a fault code registered, I would have thought, as each injector is fired individually by the ECU.

Not nescessarily, I've had one before with no fault other than the misfire code, the injector had shorted inside giving perfect continuity when tested. This had blown the ecu as the injector provided a direct short.

Departed · 19th April 2009, 20:24

Quote:

Originally Posted by Phil

Not nescessarily, I've had one before with no fault other than the misfire code, the injector had shorted inside giving perfect continuity when tested. This had blown the ecu as the injector provided a direct short.

I've also had a car (not a 75) where there were no fault codes, but wouldn't start. No sparks at all.
The supply to the coils was down (someone had unplugged it, don't ask) but the ECU doesn't see the supply, only the load on the trigger circuit. So fault codes aren't 100% reliable.

A short like that damaging the ECU though is pretty poor design. I take it it wasn't a Rover Phil?

19th April 2009, 19:47	#1
stocktake Vis Whiz Rover 75 2.5 auto Saloon Join Date: Jun 2007 Location: LEEDS Posts: 20,594 Thanks: 2,057 Thanked 3,056 Times in 1,621 Posts	Oh Dear.... KV5.... but now KV6 again Travelled the last 50 mile home from todays superb meet ...... on 5 cyl. No nasty bangs or clunks just went on to 5 cyls. out with the code reader Cyl no 6 Misfire Swapped coilpacks 4 & 6 Cyl no 6 Misfire Put a spare plug in cyl 6 Cyl no 6 Misfire Will buy a new set of plugs tomorrow when I get time, doesn't sound good, tickover is around a lumpy 1000rpm Any ideas apart from a comp test? __________________ Dave... Lost a few stones and a Gall Bladder and part of a bile duct and all of my dignity in the suppository incident Last edited by stocktake; 21st April 2009 at 10:53..

19th April 2009, 19:52	#2
Phil This is my second home Rover 75 CDT Connoisseur SE Join Date: Nov 2006 Location: Wales Posts: 12,227 Thanks: 469 Thanked 523 Times in 241 Posts	Sorry to hear this Dave. Do you have a multimeter? As you have swapped the plug and coil pack over, I would check the resistances across the injectors, if you check all of them, then you will see if there is any difference on injector 6. Sorry to hear this Dave, lets hope it isn't too serious. Was nice to see you again today. __________________

19th April 2009, 20:03	#4
stocktake Vis Whiz Rover 75 2.5 auto Saloon Join Date: Jun 2007 Location: LEEDS Posts: 20,594 Thanks: 2,057 Thanked 3,056 Times in 1,621 Posts	Thanks gents, is that an inlet manifold off to check across injectors, what am I checking for and at what points thanks again __________________ Dave... Lost a few stones and a Gall Bladder and part of a bile duct and all of my dignity in the suppository incident

19th April 2009, 20:11	#5
Phil This is my second home Rover 75 CDT Connoisseur SE Join Date: Nov 2006 Location: Wales Posts: 12,227 Thanks: 469 Thanked 523 Times in 241 Posts	Providing they only have two wires going to them, unplug the plug off the injector and check the resistance over the two pins. I don't know the actual specs, 10 ohms rings a bell. I think you will probably have to take the manifold off. __________________

19th April 2009, 20:15	#6
Dragrad This is my second home *None DROWNED** Join Date: Aug 2007 Location: Cardigan Posts: 33,339 Thanks: 1,257 Thanked 1,664 Times in 1,081 Posts	Sorry to hear of your woe, Dave, Not the best ending to a good meet.... At least you got home Hope you her sorted soon __________________ Andrew Ich Dien Problem solving is... lateral thinking SEARCH FIRST ...ASK LATER...

19th April 2009, 19:55	#3
Departed Retired -- Join Date: Jan 2007 Location: -- Posts: 3,785 Thanks: 0 Thanked 4 Times in 4 Posts	Injector? Or it could be wiring though I'd expect a fault code for open circuit.

19th April 2009, 20:16	#7
Fraser Mitchell Gets stuck in Rover 75 2.5 V6 Club Auto Join Date: Feb 2007 Location: Crewe Posts: 898 Thanks: 0 Thanked 0 Times in 0 Posts	Sorry to hear of your travails You really do need to do a compression test, to see of this cylinder is down compared to the others. Also as Phil says, the fuel injector may not be firing OK so no or little fuel is being injected. What did the plug look like when you got it out ? (you need to compare with a plug from one of the good cylinders) If the injector's gone open circuit there should be a fault code registered, I would have thought, as each injector is fired individually by the ECU.

19th April 2009, 20:17	#8
Departed Retired -- Join Date: Jan 2007 Location: -- Posts: 3,785 Thanks: 0 Thanked 4 Times in 4 Posts	I don't know the spec either, but a good check is to compare a good one and the suspect one. Like Phil says, measure resistance across the two pins once the plug is out. You could swap injectors, in case it's some sort of blockage, but depressurise the fuel system before you do!