RR 1995 TD: engine stops but fuel pump doesn't!

Hi fellas just reading thro grrrrt are you absolutely sure you have tried some of the other relays in the one that feeds the pump ,and when you took the fuse and relay you said your battery was dead have you charged the battery to fully charged and done a drop test to see if it can hold charge on its own Sorry not interfering just want sure from what I had read .

defender300td1 said:

Hi fellas just reading thro grrrrt are you absolutely sure you have tried some of the other relays in the one that feeds the pump ,and when you took the fuse and relay you said your battery was dead have you charged the battery to fully charged and done a drop test to see if it can hold charge on its own Sorry not interfering just want sure from what I had read .

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Think the reason his battery was dead was because fuel pump would not switch off. Reason for that seems now to have been found. Time to get his soldering iron out. A £150.00 fuse box against a 20p diode does not take a lot of thinking about if your a handy lad.

Do the diode! You already said the fusebox was in excellent condition.

Here's how to take the fuse box to pieces.

Fuse Box Repairs

Ok I thought he said it also died after charging it and reconecting a second time with pimp fuse and relay out it died also never mind hope all is well

You sure they are Zener diodes Tony, can't think why they would be anything other than normal silicone diodes. Zeners are used for voltage limiting/regulating purposes, I would expect the diodes to be 1N4005 or similar.

Datatek said:

You sure they are Zener diodes Tony, can't think why they would be anything other than normal silicone diodes. Zeners are used for voltage limiting/regulating purposes, I would expect the diodes to be 1N4005 or similar.

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Well lets reduce that call out to diodes then Keith. You know electricery is alien to me.

Am having thoughts on this. Diode is orientated to allow current to flow from alternator to pin 6. But not to allow current to flow from glow plugs back to alternator and other diode vise versa. If that is the case the diode cannot be the problem maybe the alternator controller is leaking voltage. Thought Keith you are the leccy man.

defender300td1 said:

Hi fellas just reading thro grrrrt are you absolutely sure you have tried some of the other relays in the one that feeds the pump ,and when you took the fuse and relay you said your battery was dead have you charged the battery to fully charged and done a drop test to see if it can hold charge on its own Sorry not interfering just want sure from what I had read .

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Yes, tried a few of the other relays. Same outcome. Yes, battery held charge for 2 days on its own (in the shed.) I've been using other batteries I had lying around for the tests.

All seems to work as it should if I take the the positive off the alternator or the starter motor lead off the battery positive. Otherwise the pump whirrs. Even with fuse 39 out it lost voltage though. Testing overnight with starter lead removed to see if all drain through alternator.

My logic from Wammers posts was: battery connects to alternator; alternator connects to ignition / brain; brain is connected to fusebox. Diodes must stop current going wrong way. If diodes fail then could leak back past alternator to brain and in back of fuse box and then leak out on a number of other circuits.

If this logic is flawed then I'm in trouble!

Grrrrrr said:

Yes, tried a few of the other relays. Same outcome. Yes, battery held charge for 2 days on its own (in the shed.) I've been using other batteries I had lying around for the tests.

All seems to work as it should if I take the the positive off the alternator or the starter motor lead off the battery positive. Otherwise the pump whirrs. Even with fuse 39 out it lost voltage though. Testing overnight with starter lead removed to see if all drain through alternator.

My logic from Wammers posts was: battery connects to alternator; alternator connects to ignition / brain; brain is connected to fusebox. Diodes must stop current going wrong way. If diodes fail then could leak back past alternator to brain and in back of fuse box and then leak out on a number of other circuits.

If this logic is flawed then I'm in trouble!

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Read my last post. Diodes are there to stop the two possible feeds reacting with each other. Diode on line from alternator is supposed to allow current to flow from alternator. But there should not be any current unless alternator is running. So my thoughts now are alternator controller duff.

Would I not get a red light on the dash if the alternator wasn't working properly? To be fair it did flash a warning a few times but I've had the power connected and disconnected so many times at one stage there pretty much wasn't a single warning that didn't flash up, although the ABS was pretty persistent for a while.

ABS light stays on until you've got up to 4mph or something so don't worry about that one.

Grrrrrr said:

Would I not get a red light on the dash if the alternator wasn't working properly? To be fair it did flash a warning a few times but I've had the power connected and disconnected so many times at one stage there pretty much wasn't a single warning that didn't flash up, although the ABS was pretty persistent for a while.

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It's possible to have a duff diode in the alternator but for it to still charge so you would not see a red light on the dash. Sorry I have not had the chance to look at RAVE yet busy tiling the kitchen floor, but you have a leakage circuit somewhere, either in the fuse box or the alternator as Wammers has said, for get the "brain" as you call it. I'll try to go through the drawings but my copy of RAVE does not have the early diagrams.

Datatek,

Here are the correct diagrams. (I think!)

http://www.landyzone.co.uk/lz/attachment.php?attachmentid=33561&stc=1&d=1342338021

http://www.landyzone.co.uk/lz/attachment.php?attachmentid=33560&stc=1&d=1342338021

When they say Generator on the diagram, do they mean what I would call Alternator?

OK, downloaded Wammers version of RAVE (thanks Tony). I can't see that the diodes in the fuse box can cause the problem, the alternator certainly could.

Datatek said:

OK, downloaded Wammers version of RAVE (thanks Tony). I can't see that the diodes in the fuse box can cause the problem, the alternator certainly could.

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Yeah that is my way of thinking now Keith. Diodes in fuse box just stop interactive flow one power source to the other. If for instance diode on glow power supply went down, number six plug would be constantly powered when engine was running. Not a good scenario. So think it has to be down to alternator controller. Because no power is supposed to come down that line until engine is running.

After 10 hours with alternator positive removed the battery is within 0.1V of where it started so I'm happy with that. Battery to fuse to relay to pump seems fine. Battery to alternator fine. Alternator to whereever seems to be the fault - or the alternator.

Alternator connects to the starter motor. From there it appears it splits: part goes to the battery. The rest disappears into the dash.

Grrrrrr said:

After 10 hours with alternator positive removed the battery is within 0.1V of where it started so I'm happy with that. Battery to fuse to relay to pump seems fine. Battery to alternator fine. Alternator to whereever seems to be the fault - or the alternator.

Alternator connects to the starter motor. From there it appears it splits: part goes to the battery. The rest disappears into the dash.

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Think it is almost certain now after much thought that your problem is the voltage regulator/controller on the alternator. Change that, should be less than £30.00 from a factors dead easy to change. Comes with new brushes.

wammers said:

Think it is almost certain now after much thought that your problem is the voltage regulator/controller on the alternator. Change that, should be less than £30.00 from a factors dead easy to change. Comes with new brushes.

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I agree, one diode gone short circuit either in the regulator or the diode pack

can yu not remove the plug from the Alternator and check it?

He dissed the alternator, cured the problem