1.8T cutting out and now dead

Eric_m · 26th December 2020, 15:50

I've not used my 75 a lot this year due to working from home and my motorsport fun being reduced this year (towcar), so I thought a drive to Bedford last Saturday to pick up some parts for a project would be good excuse for a run out in the Car. It passed its MOT a month ago (just needed new rear pads and discs) and hasn't moved since. It started straight away, and drove great for the first 5 miles or so. It then started to miss every now and again, a stumble about once a mile. This gradually got worse until, just approaching the A14 , it cut out completely. I coasted along, restarted it and carried on for a few hundred yards, where it cut out again and I rolled to a stop. I got out, opened the bonnet and wobbled a few wires (as you do) and got in and it restarted it. I was 30 yards from the A14 roundabout so I decided to turn around and go home. I ran, not well, but got me about a couple of miles before it died completely and i coasted nicely into a large layby on the A6 just south of Market Harborough. One thing I noticed, was that as soon as it stumbled, the rev counter dropped to 0. Again I looked for anything amiss and couldn't really find anything. As my journey back home involves a lot of country lanes I decided to cal the RAC out to see if they could diagnose it. He arrived in about 45mins and proceeded to hook up his box of tricks. It started okay but was still stumbling at idle, the engine would falter for a sec and then pick up. Again the rev counter would drop to zero during the stumble. He found a few legacy errors but nothing to help pinpoint the problem. He cleared all the old errors and then restarted it, again stumbling and completely cutting out completely a few times. No new errors appeared on his box-o-tricks. After a time it refused to start, just turning over. He then put a spark tester on and we definitely had no spark. I then got towed home. Once arrived home, it still wouldn't start, and as my drive has a bit of a slope on, we managed to push it into a nearby car park. Next day, I returned to the car and it started fine and I managed to drive it up my drive.

My simple diagnostics of this was the crank sensor. The revcounter dropping to me meant it was electrical more than fuel (the RAC man did remove the fuel pipe and it did squirt fuel when turned over). It can't be plugs or coil packs as it would run rough if any of those failed (4 plugs and 2 coil packs). The only other thing could be the crank sensor, so I ordered one from DMGRS and it arrived on Christmas Eve.

I fitted the sensor and it won't even start now - any Idea what to check next.

Wires to the crank sensor?, they look like they have a hard life close to the turbo (wrapped in heat protective stuff)
Any fuses that could be bad connections? (any numbers it is worth changing?)
Duff Relays, immobiliser problem?

Anybody had anything similar, or got any ideas?.

Cheers

Eric

GaryGee · 26th December 2020, 16:08

Mine died a while ago, the wires to the crank sensor were as you describe, they actually fell apart whilst investigating 😔
Swapped loom over and still couldn't get it going
Ended up at mates garage, eventually having second hand ECUs as I think the wires had shorted and blown them
Prob worthwhile stripping back the wiring as far as possible to see if same may have happened

planenut · 26th December 2020, 16:09

Might be worth checking the wiring to the crank sensor. A wizard from the Club found a break in mine a few years back, in the loom where it lies beneath the engine bay fuse box. The wires there turn through 90degrees and are open to the elements.

Good luck

Yorkshire GOC · 26th December 2020, 16:25

So she is dead in the water now following cut outs - so when you turn her over does the rev counter move ? If not then that clearly points to the crank sensor - now i have had a new one (BMW Siemens) fail after a few weeks following replacement so you may have a duff replacement.

As you say the wiring is close to the turbo on the front bell housing and i would advise re-sheathing the crank wiring with new heat resistant cladding.

Finally has your MPG fallen dramatically ?- when i had a failing crank sensor leading to hot cut outs my MPG fell to 18 mpg on the trip comp - following replacing the sensor/re sheathing the wiring with new heat resistant sheath it went back up to 31 MPG within a few days. A failing crank sensor will send duff data to the ECU affecting the fuelling mix.

I came to the view that heat from the turbo and a generally hot engine was affecting the crank signal to the ECU -but hey ho that's just my conclusion.

Eric_m · 26th December 2020, 16:36

Thanks guys, 4 views and 3 answers, brilliant service

The rev counter doesn't move when cranking.
It looks like it would be worth swapping the wires and replacing the heat shielding.

Does anybody know if you can get replacement connectors or at least the terminals?

Eric

marinabrian · 26th December 2020, 17:12

It is a common problem, the wiring to the CKP will be cooked where it is routed past the turbo, the insulation bakes hard, disintegrates and eventually shorts out taking the ECM with it.

Talking of ECM it is an NNN000500 that is required, and the coding transferred from your old unit.

Brian

GaryGee · 26th December 2020, 17:28

Quote:

Originally Posted by Eric_m

Thanks guys, 4 views and 3 answers, brilliant service

The rev counter doesn't move when cranking.
It looks like it would be worth swapping the wires and replacing the heat shielding.

Does anybody know if you can get replacement connectors or at least the terminals?

Eric

If you can get pic and sizes it may be worth contact auto supplier or someone like frost auto restoration
Mine had all turned black with age, so couldn't patch in a repair and they'd all broken off at same points

Eric_m · 27th December 2020, 11:01

checked the wires out = not good

One was broken and the rest are black and the insulation cracked. I had to cut the other two to remove the insulation - after noting which terminal they go to. I will see if I can remove the terminals from the plug and solder on new wires.

Cheers

Eric

GaryGee · 27th December 2020, 11:07

Quote:

Originally Posted by Eric_m

checked the wires out = not good

One was broken and the rest are black and the insulation cracked. I had to cut the other two to remove the insulation - after noting which terminal they go to. I will see if I can remove the terminals from the plug and solder on new wires.

Cheers

Eric

Exactly what mine was like, hopefully they’ve not shorted and fried anything

Yorkshire GOC · 27th December 2020, 12:37

This is the stuff i re-sheathed the wiring with

https://www.ebay.co.uk/itm/SILICONE-....c100005.m1851

26th December 2020, 15:50	#1
Eric_m Regular poster Rover 75 Club 1.8T Join Date: Apr 2013 Location: Countesthorpe Leicester Posts: 80 Thanks: 10 Thanked 42 Times in 20 Posts	1.8T cutting out and now dead I've not used my 75 a lot this year due to working from home and my motorsport fun being reduced this year (towcar), so I thought a drive to Bedford last Saturday to pick up some parts for a project would be good excuse for a run out in the Car. It passed its MOT a month ago (just needed new rear pads and discs) and hasn't moved since. It started straight away, and drove great for the first 5 miles or so. It then started to miss every now and again, a stumble about once a mile. This gradually got worse until, just approaching the A14 , it cut out completely. I coasted along, restarted it and carried on for a few hundred yards, where it cut out again and I rolled to a stop. I got out, opened the bonnet and wobbled a few wires (as you do) and got in and it restarted it. I was 30 yards from the A14 roundabout so I decided to turn around and go home. I ran, not well, but got me about a couple of miles before it died completely and i coasted nicely into a large layby on the A6 just south of Market Harborough. One thing I noticed, was that as soon as it stumbled, the rev counter dropped to 0. Again I looked for anything amiss and couldn't really find anything. As my journey back home involves a lot of country lanes I decided to cal the RAC out to see if they could diagnose it. He arrived in about 45mins and proceeded to hook up his box of tricks. It started okay but was still stumbling at idle, the engine would falter for a sec and then pick up. Again the rev counter would drop to zero during the stumble. He found a few legacy errors but nothing to help pinpoint the problem. He cleared all the old errors and then restarted it, again stumbling and completely cutting out completely a few times. No new errors appeared on his box-o-tricks. After a time it refused to start, just turning over. He then put a spark tester on and we definitely had no spark. I then got towed home. Once arrived home, it still wouldn't start, and as my drive has a bit of a slope on, we managed to push it into a nearby car park. Next day, I returned to the car and it started fine and I managed to drive it up my drive. My simple diagnostics of this was the crank sensor. The revcounter dropping to me meant it was electrical more than fuel (the RAC man did remove the fuel pipe and it did squirt fuel when turned over). It can't be plugs or coil packs as it would run rough if any of those failed (4 plugs and 2 coil packs). The only other thing could be the crank sensor, so I ordered one from DMGRS and it arrived on Christmas Eve. I fitted the sensor and it won't even start now - any Idea what to check next. Wires to the crank sensor?, they look like they have a hard life close to the turbo (wrapped in heat protective stuff) Any fuses that could be bad connections? (any numbers it is worth changing?) Duff Relays, immobiliser problem? Anybody had anything similar, or got any ideas?. Cheers Eric

26th December 2020, 16:25	#4
Yorkshire GOC I really should get out more....... Rover 75 connoisseur se v6 auto Join Date: May 2014 Location: Hull Posts: 2,069 Thanks: 1,842 Thanked 623 Times in 469 Posts	So she is dead in the water now following cut outs - so when you turn her over does the rev counter move ? If not then that clearly points to the crank sensor - now i have had a new one (BMW Siemens) fail after a few weeks following replacement so you may have a duff replacement. As you say the wiring is close to the turbo on the front bell housing and i would advise re-sheathing the crank wiring with new heat resistant cladding. Finally has your MPG fallen dramatically ?- when i had a failing crank sensor leading to hot cut outs my MPG fell to 18 mpg on the trip comp - following replacing the sensor/re sheathing the wiring with new heat resistant sheath it went back up to 31 MPG within a few days. A failing crank sensor will send duff data to the ECU affecting the fuelling mix. I came to the view that heat from the turbo and a generally hot engine was affecting the crank signal to the ECU -but hey ho that's just my conclusion. __________________ She came off the Longbridge Line on 20-05-2003 The Silver Machine was the 13th of 160 Rover 75's to come off the production line that day and is the 100th of 527 Starlight Silver Rover 75 2.5 V6 Connoisseur SE Auto saloons listed in the build records produced world wide.

27th December 2020, 12:37	#10
Yorkshire GOC I really should get out more....... Rover 75 connoisseur se v6 auto Join Date: May 2014 Location: Hull Posts: 2,069 Thanks: 1,842 Thanked 623 Times in 469 Posts	This is the stuff i re-sheathed the wiring with https://www.ebay.co.uk/itm/SILICONE-....c100005.m1851 __________________ She came off the Longbridge Line on 20-05-2003 The Silver Machine was the 13th of 160 Rover 75's to come off the production line that day and is the 100th of 527 Starlight Silver Rover 75 2.5 V6 Connoisseur SE Auto saloons listed in the build records produced world wide.

26th December 2020, 16:08	#2
GaryGee Avid contributor MG ZT-T Join Date: Dec 2020 Location: Crewe Posts: 102 Thanks: 9 Thanked 47 Times in 36 Posts	Mine died a while ago, the wires to the crank sensor were as you describe, they actually fell apart whilst investigating 😔 Swapped loom over and still couldn't get it going Ended up at mates garage, eventually having second hand ECUs as I think the wires had shorted and blown them Prob worthwhile stripping back the wiring as far as possible to see if same may have happened

26th December 2020, 16:09	#3
planenut Regional Secretary Rover 1.8T Tourer Join Date: May 2007 Location: Heathrow Posts: 6,955 Thanks: 1,551 Thanked 2,036 Times in 1,264 Posts	Might be worth checking the wiring to the crank sensor. A wizard from the Club found a break in mine a few years back, in the loom where it lies beneath the engine bay fuse box. The wires there turn through 90degrees and are open to the elements. Good luck

26th December 2020, 16:36	#5
Eric_m Regular poster Rover 75 Club 1.8T Join Date: Apr 2013 Location: Countesthorpe Leicester Posts: 80 Thanks: 10 Thanked 42 Times in 20 Posts	Thanks guys, 4 views and 3 answers, brilliant service The rev counter doesn't move when cranking. It looks like it would be worth swapping the wires and replacing the heat shielding. Does anybody know if you can get replacement connectors or at least the terminals? Eric

26th December 2020, 17:12	#6
marinabrian MG ZT Join Date: Jan 2011 Location: Newcastle Upon Tyne Posts: 20,151 Thanks: 3,565 Thanked 10,837 Times in 5,718 Posts	It is a common problem, the wiring to the CKP will be cooked where it is routed past the turbo, the insulation bakes hard, disintegrates and eventually shorts out taking the ECM with it. Talking of ECM it is an NNN000500 that is required, and the coding transferred from your old unit. Brian