KV6 reluctant to start, things and don't laugh! But you will!

Bob Walker · 17th January 2024, 14:53

Dear All
i hope you are all well.
My ZT 190 isnt : (
Its very reluctant to start, this has got worse over the last few week and takes quite a few attempts to get it going (a bit like me!!), reading the forum suggestions have been the cam sensor which I swopped yesterday with a new one from DMGRS, this made even more reluctant to tick over once it had warmed up! Swopped the old one back at lunch time yesterday and at least it managed to tick over once it did start!
Got an new set of coils, replaced four of them then dropped my extension and socket down the back of the engine!! I can hear you all laughing all the way from North Yorkshire at this stage!! Just now, out of interest, I tried to start it and after many goes it did eventually tick over. Until I have left it for 5 minutes of so, as soon as you put your foot on the accelerator it dies!! Once warmed up, the engine starts first time and revs freely. Now I know how to get to the back plugs out I will replace them all when my magnets socket turns up tomorrow!
The other issue is the thermostat which leaks, if it doesn't rain this weekend I will do this (not the key hole method which ripped me to shreds last time!!), and I think the coolant sensor is kaput, as as soon as I start the car it reaches normal running temperature! Is the coolant sensor the source of all my troubles?? At least when I jack the car up to take off the under-tray off I can give the car an oil change and retrieve my tools!!!
Any suggestions and sarcastic comments welcome!!
Best wishes to all
Thawed out Yorkshire Bob : )

Matt_75 · 17th January 2024, 18:19

Quote:

Originally Posted by Bob Walker

I think the coolant sensor is kaput, as as soon as I start the car it reaches normal running temperature! Is the coolant sensor the source of all my troubles??

Hi Bob,

Yes, I think the coolant sensor could well be the cause. The ECU uses this information to control the fueling. If it thinks the engine is at operating temperature when its actually cold, it'll be providing insufficient fuel for a start up.

Let us know how you get on. Good luck!

xsport · 17th January 2024, 18:24

Sounds like you need to spend some time in the " V " i think. Once you get organised with parts and tools you can do the lot together. If your not doing the keyhole method then renew the inlet manifold gaskets as well whilst in there. If the temp gauge is receiving a message for a fully warmed up engine,then i suppose the mixture settings will suffer from a dodgy temperature sender. Renew that as well whilst in the "v" Crankshaft sensor can give erratic starts but should show on the rev counter nudging up and down, but your first port of call is in the "v" ... which wants sorting regardless ...

SD1too · 17th January 2024, 19:28

Quote:

Originally Posted by Bob Walker

I think the coolant sensor is kaput, as as soon as I start the car it reaches normal running temperature!

This has to be the first thing to tackle Bob, as Matt and Stefan have already said.

Quote:

Originally Posted by Bob Walker

The other issue is the thermostat which leaks ...

To clarify, the common fault here is flattening of the 'O' ring seals due to incorrectly set serrated clips on the straight pipe. All you'll need is four CDU 3858 seals which I recommend that you buy from an X-Part agent because the dimensions are critical.
You'll need to remove just one of the inlet manifolds so have a new gasket standing by and observe the torque setting for the bolts.
Please refer to my historic posts on how to set the serrated clips correctly or send me a PM if you have any questions.

Good luck!

Simon

Bob Walker · 18th January 2024, 05:26

Dear All
Many thanks for all your help and support.
Am I correct in thinking the torque settings for the aluminum inlet manifold bolts are 25Nm?
Very best wishes to all
Bob

SD1too · 18th January 2024, 07:22

Quote:

Originally Posted by Bob Walker

Am I correct in thinking the torque settings for the aluminium inlet manifold bolts are 25Nm?

Yes Bob.
If you haven't done it this way before, you'll need a selection of 3/8" drive wobble extensions to reach some of them.

Simon

P.S. As an aside, I think your computer needs the language setting changing from American to English.

Bob Walker · 28th January 2024, 17:25

Good evening everyone.
I thought I should give you all an update.
So today, I decided to tackle my starting problem and coolant leak.
Before I started this this afternoon, I got on the roof and fixed the mortar that had come out and then I started on the car. I thought today would be a good day as the forecast is not so good for the rest of the week!
I changed the coolant sensor and thermostat, got them out okay but could I get the tube behind the thermostat back, no! Fiddled around with it for an hour or so and noticed that DMGRS provided some spare o-rings, swapped it and hey presto all back together again in half an hour!! I did remove the throttle and battery box which meant I don't rip my arm to shreds like I did last time!!
Starts first time and the coolant temperature is no longer immediately half way up the gauge before its warmed up! Hopefully the drive to work tomorrow morning will be trouble free!!
At 64 my kids think I am on some special medication or steroids or both, I haven't stopped till it went very dark and I have even washed up after tea!
Thanks for all the advice and support, it is appreciated, just have the rest of the car to sort out!
Bob

TomTheTyke · 28th January 2024, 18:14

Coolant temperature failure, especially intermittent or 'non-complete' failure (i.e. it's faulty but still provides some signal) can definitely cause big running and starting issues, as per my thread here:

https://www.the75andztclub.co.uk/for...=325004&page=4

Glad your issues seem to have improved.

17th January 2024, 14:53	#1
Bob Walker Loves to post MGZT Join Date: Aug 2019 Location: Richmond Posts: 255 Thanks: 26 Thanked 80 Times in 45 Posts	KV6 reluctant to start, things and don't laugh! But you will! Dear All i hope you are all well. My ZT 190 isnt : ( Its very reluctant to start, this has got worse over the last few week and takes quite a few attempts to get it going (a bit like me!!), reading the forum suggestions have been the cam sensor which I swopped yesterday with a new one from DMGRS, this made even more reluctant to tick over once it had warmed up! Swopped the old one back at lunch time yesterday and at least it managed to tick over once it did start! Got an new set of coils, replaced four of them then dropped my extension and socket down the back of the engine!! I can hear you all laughing all the way from North Yorkshire at this stage!! Just now, out of interest, I tried to start it and after many goes it did eventually tick over. Until I have left it for 5 minutes of so, as soon as you put your foot on the accelerator it dies!! Once warmed up, the engine starts first time and revs freely. Now I know how to get to the back plugs out I will replace them all when my magnets socket turns up tomorrow! The other issue is the thermostat which leaks, if it doesn't rain this weekend I will do this (not the key hole method which ripped me to shreds last time!!), and I think the coolant sensor is kaput, as as soon as I start the car it reaches normal running temperature! Is the coolant sensor the source of all my troubles?? At least when I jack the car up to take off the under-tray off I can give the car an oil change and retrieve my tools!!! Any suggestions and sarcastic comments welcome!! Best wishes to all Thawed out Yorkshire Bob : ) Last edited by Bob Walker; 17th January 2024 at 15:51.. Reason: typo

18th January 2024, 05:26	#5
Bob Walker Loves to post MGZT Join Date: Aug 2019 Location: Richmond Posts: 255 Thanks: 26 Thanked 80 Times in 45 Posts	Thank you and torque setting for inlet manifold Dear All Many thanks for all your help and support. Am I correct in thinking the torque settings for the aluminum inlet manifold bolts are 25Nm? Very best wishes to all Bob Last edited by Bob Walker; 18th January 2024 at 05:34..

28th January 2024, 17:25	#7
Bob Walker Loves to post MGZT Join Date: Aug 2019 Location: Richmond Posts: 255 Thanks: 26 Thanked 80 Times in 45 Posts	Starting problem and thermostat Good evening everyone. I thought I should give you all an update. So today, I decided to tackle my starting problem and coolant leak. Before I started this this afternoon, I got on the roof and fixed the mortar that had come out and then I started on the car. I thought today would be a good day as the forecast is not so good for the rest of the week! I changed the coolant sensor and thermostat, got them out okay but could I get the tube behind the thermostat back, no! Fiddled around with it for an hour or so and noticed that DMGRS provided some spare o-rings, swapped it and hey presto all back together again in half an hour!! I did remove the throttle and battery box which meant I don't rip my arm to shreds like I did last time!! Starts first time and the coolant temperature is no longer immediately half way up the gauge before its warmed up! Hopefully the drive to work tomorrow morning will be trouble free!! At 64 my kids think I am on some special medication or steroids or both, I haven't stopped till it went very dark and I have even washed up after tea! Thanks for all the advice and support, it is appreciated, just have the rest of the car to sort out! Bob

17th January 2024, 18:24	#3
xsport Posted a thing or two rover 75 club se Join Date: Apr 2011 Location: Leicester Posts: 1,673 Thanks: 358 Thanked 419 Times in 310 Posts	Sounds like you need to spend some time in the " V " i think. Once you get organised with parts and tools you can do the lot together. If your not doing the keyhole method then renew the inlet manifold gaskets as well whilst in there. If the temp gauge is receiving a message for a fully warmed up engine,then i suppose the mixture settings will suffer from a dodgy temperature sender. Renew that as well whilst in the "v" Crankshaft sensor can give erratic starts but should show on the rev counter nudging up and down, but your first port of call is in the "v" ... which wants sorting regardless ...

28th January 2024, 18:14	#8
TomTheTyke Avid contributor Rover 75 2.5 Connoisseur, MG TF 80th Anniversary Join Date: Sep 2021 Location: Pontefract Posts: 157 Thanks: 12 Thanked 22 Times in 11 Posts	Coolant temperature failure, especially intermittent or 'non-complete' failure (i.e. it's faulty but still provides some signal) can definitely cause big running and starting issues, as per my thread here: https://www.the75andztclub.co.uk/for...=325004&page=4 Glad your issues seem to have improved.