More help needed re mine of Dec15 - Mega battery problem

Navylark · 18th December 2008, 16:25

Well my high hopes of having solved the problem by draing the lower plenum have proved false!
The basic problem is that a fully charged battery still drains to near 'dead' in about 2 hours..
I decided their must be a short circuit somewhere and set about trying to find it as follows - bear in mind the car is the diesel model :-

1) battery removed and put on charge
2) ohm meter applied to the positive and negative battery connections
3) result was zero resistance
4) assumed there must be a dead short to earth somewhere on the car
5) removed fuses one at a time - from the engine fuse panel and rechecked the resistance between battery leads
6) with fuse F6 removed - the 100 amp Glow plug one - resistance increases dramatically to 15 k ohm

Thus I assume there is a short circuit somewhere on the glow plug circuit.

Does the above sound 'common sense' and if so has anyone an idea where the short circuit could be - in a glow plug itself or elsewhere.

Many thanks for help so far

Navylark

stocktake · 18th December 2008, 16:31

Not a diesel man myself but would there be a relay that operates the glowplugs? if so this could have failed with its contacts welded to create a permanent curcuit.

Navylark · 18th December 2008, 16:36

Thanks Dave
I guess you could be right - sounds sense - but I cannot locate the glow plug relay
Haynes does not even list the fuse correctly
Does anyone know where the relay is?
Many thanks so far

Greeners · 18th December 2008, 16:36

The glow plug relay lives below the ECU. If the plenum has been water logged at any time, the relay usually cops it.

stocktake · 18th December 2008, 16:40

Sounds like we are getting somewhere

patrolman pete · 18th December 2008, 16:51

To check for a drain you need to disconnect the battery neg and connect a multimeter set to amps between the lead and terminal , this will measure the drain (which should normally be about 0.15 amps once the ecu etc has shut down -it can take up to 15mins on some cars) then start removing fuses and relays until the amps drop. Even 1 bulb on can draw 0.7 amps which is a lot.:xmas:

Navylark · 18th December 2008, 16:54

The lower plenum was flooded - so that fits.
Is the glow plug relay a separate unit or part of the ECU?
Does anyone know
Thanks so far
Navylark

Greeners · 18th December 2008, 17:13

It's seperate, lives in a grey box.

You could simply unplug it to test the circuit.

It's readily available and similar to land rover ones

Have a search and you'll find part numbers and prices

Navylark · 18th December 2008, 17:22

Many thanks - I feel we - actually you - have cracked it.
So one final question - if I remove the large 100 amp fuse - thus dissarming the glow plugs - will the diesel still start - I appreciate it may take a bit longer than if the glow plugs were working - also is there any problem in runing this way.
Many thanks
Navylark

Greeners · 18th December 2008, 18:05

Have a look at this thread

The glow plugs only operate at 5 degrees or colder, so if you disconnect it, it should start normally unless there temperature drops.

18th December 2008, 16:25	#1
Navylark Newbie Rover 75 saloon CDT SE Diesel Join Date: Feb 2008 Location: Teddington Middx Posts: 18 Thanks: 0 Thanked 0 Times in 0 Posts	More help needed re mine of Dec15 - Mega battery problem Well my high hopes of having solved the problem by draing the lower plenum have proved false! The basic problem is that a fully charged battery still drains to near 'dead' in about 2 hours.. I decided their must be a short circuit somewhere and set about trying to find it as follows - bear in mind the car is the diesel model :- 1) battery removed and put on charge 2) ohm meter applied to the positive and negative battery connections 3) result was zero resistance 4) assumed there must be a dead short to earth somewhere on the car 5) removed fuses one at a time - from the engine fuse panel and rechecked the resistance between battery leads 6) with fuse F6 removed - the 100 amp Glow plug one - resistance increases dramatically to 15 k ohm Thus I assume there is a short circuit somewhere on the glow plug circuit. Does the above sound 'common sense' and if so has anyone an idea where the short circuit could be - in a glow plug itself or elsewhere. Many thanks for help so far Navylark

18th December 2008, 16:31	#2
stocktake Vis Whiz Rover 75 2.5 auto Saloon Join Date: Jun 2007 Location: LEEDS Posts: 20,593 Thanks: 2,057 Thanked 3,056 Times in 1,621 Posts	Not a diesel man myself but would there be a relay that operates the glowplugs? if so this could have failed with its contacts welded to create a permanent curcuit. __________________ Dave... Lost a few stones and a Gall Bladder and part of a bile duct and all of my dignity in the suppository incident

18th December 2008, 16:36	#4
Greeners Moderator MG-ZTT Join Date: Mar 2007 Location: Ware, Herts Posts: 19,798 Thanks: 161 Thanked 1,249 Times in 1,036 Posts	The glow plug relay lives below the ECU. If the plenum has been water logged at any time, the relay usually cops it. __________________ *David* Impecunity is the mother of ingenuity Useful how to's for common problems Car Of The Month Jan 2014 [SatNav Power Down] [Coolant Level] [SatNav Repair] [Diesel Non Starting] [Paint Codes] [Rear Light Seals] [Reversing Light Switch] [Bleeding Brakes][Sunroof Drain] [Early ZT's][Instrument Pack Diagnostics][ATC Diagnostics]

18th December 2008, 16:40	#5
stocktake Vis Whiz Rover 75 2.5 auto Saloon Join Date: Jun 2007 Location: LEEDS Posts: 20,593 Thanks: 2,057 Thanked 3,056 Times in 1,621 Posts	Sounds like we are getting somewhere __________________ Dave... Lost a few stones and a Gall Bladder and part of a bile duct and all of my dignity in the suppository incident

18th December 2008, 17:13	#8
Greeners Moderator MG-ZTT Join Date: Mar 2007 Location: Ware, Herts Posts: 19,798 Thanks: 161 Thanked 1,249 Times in 1,036 Posts	It's seperate, lives in a grey box. You could simply unplug it to test the circuit. It's readily available and similar to land rover ones Have a search and you'll find part numbers and prices __________________ *David* Impecunity is the mother of ingenuity Useful how to's for common problems Car Of The Month Jan 2014 [SatNav Power Down] [Coolant Level] [SatNav Repair] [Diesel Non Starting] [Paint Codes] [Rear Light Seals] [Reversing Light Switch] [Bleeding Brakes][Sunroof Drain] [Early ZT's][Instrument Pack Diagnostics][ATC Diagnostics]

18th December 2008, 16:51	#6
patrolman pete Posted a thing or two Rover 75 club se tourer CDT and a Connoisseur SE Diesel Auto Saloon Join Date: Nov 2006 Location: Houghton - le - Spring Posts: 1,422 Thanks: 618 Thanked 333 Times in 197 Posts	To check for a drain you need to disconnect the battery neg and connect a multimeter set to amps between the lead and terminal , this will measure the drain (which should normally be about 0.15 amps once the ecu etc has shut down -it can take up to 15mins on some cars) then start removing fuses and relays until the amps drop. Even 1 bulb on can draw 0.7 amps which is a lot.:xmas:

18th December 2008, 16:54	#7
Navylark Newbie Rover 75 saloon CDT SE Diesel Join Date: Feb 2008 Location: Teddington Middx Posts: 18 Thanks: 0 Thanked 0 Times in 0 Posts	The lower plenum was flooded - so that fits. Is the glow plug relay a separate unit or part of the ECU? Does anyone know Thanks so far Navylark

18th December 2008, 17:22	#9
Navylark Newbie Rover 75 saloon CDT SE Diesel Join Date: Feb 2008 Location: Teddington Middx Posts: 18 Thanks: 0 Thanked 0 Times in 0 Posts	Many thanks - I feel we - actually you - have cracked it. So one final question - if I remove the large 100 amp fuse - thus dissarming the glow plugs - will the diesel still start - I appreciate it may take a bit longer than if the glow plugs were working - also is there any problem in runing this way. Many thanks Navylark

18th December 2008, 18:05	#10
Greeners Moderator MG-ZTT Join Date: Mar 2007 Location: Ware, Herts Posts: 19,798 Thanks: 161 Thanked 1,249 Times in 1,036 Posts	Have a look at this thread The glow plugs only operate at 5 degrees or colder, so if you disconnect it, it should start normally unless there temperature drops. __________________ *David* Impecunity is the mother of ingenuity Useful how to's for common problems Car Of The Month Jan 2014 [SatNav Power Down] [Coolant Level] [SatNav Repair] [Diesel Non Starting] [Paint Codes] [Rear Light Seals] [Reversing Light Switch] [Bleeding Brakes][Sunroof Drain] [Early ZT's][Instrument Pack Diagnostics][ATC Diagnostics]