Engine just conked out!

trax · Jun 29, 2015

if this turns out to be a blown fuse, can someone get the noose ready for the op

TheMunster · Jun 29, 2015

If it is a fuse I might have a little giggle; been there done that!

Landlover99 · Jun 29, 2015

I have actually checked all the fuses and relays. First thing I did. I even hooked the relays out and bench tested them fully; they were fine in all respects. I freely admit I don't understand that section of the wiring diagram, though. It's nothing like I'm accustomed to.

sierrafery · Jun 29, 2015

yes we all got carried away with parallel discussions and forgot about the simple things

... at least we ruled out the ECM, also when i come into such kind of debate i'm always presuming that the OP at least has checked the fuses and relays

the gist is that you need feed on those brown/orange wires with ignition on

trax · Jun 29, 2015

time for some continuity tests to the fusebox methinks

Landlover99 · Jun 29, 2015

trax said:
time for some continuity tests to the fusebox methinks

One of the first things I did.

Landlover99 · Jun 29, 2015

sierrafery said:
yes we all got carried away with parallel discussions and forgot about the simple things ... at least we ruled out the ECM, also when i come into such kind of debate i'm always presuming that the OP at least has checked the fuses and relays

the gist is that you need feed on those brown/orange wires with ignition on

Are you SURE about that? I did ask the auto-electrical bloke about those brown/orange wires when I had him on the phone this afternoon and he called up the diagram on his computer. Told me they should NOT be live with the ignition on!

sierrafery · Jun 29, 2015

if you have the RAVE you can watch the diagram note down the connector's number then go to Electrical library - connectors and you should get the pic of it with pin disposals and wire colours then chase on the circuit where the feed stops... anyway in that section there must be "How to use ..." and "wire coluour codes" chapters , read them then chase on the circuit where that feed to those pins is missing... even if the main relay is tested on the bench you must make sure it gets feed on the coil as well to close the circuit to pins 3, 22, 27 cos that's your problem

sierrafery · Jun 29, 2015

Landlover99 said:
Are you SURE about that? I did ask the auto-electrical bloke about those brown/orange wires when I had him on the phone this afternoon and he called up the diagram on his computer. Told me they should NOT be live with the ignition on!

then dont go with your car to him , i'm wondering if they should be live with ignitionh off then as long as the main relay is normally open???

see attachment

trax · Jun 29, 2015

just chucking stuff out there.

td5 has leccy fuel pump doesn't it? you should be able to hear it priming with ign on. can you?

also doesn't it have a safety fuel cut off switch on the rear bulkhead.. this isn't on or the wires are knackered?

Landlover99 · Jun 29, 2015

sierrafery said:
if you have the RAVE you can watch the diagram note down the connector's number then go to Electrical library - connectors and you should get the pic of it with pin disposals and wire colours then chase on the circuit where the feed stops... anyway in that section there must be "How to use ..." and "wire coluour codes" chapters , read them then chase on the circuit where that feed to those pins is missing... even if the main relay is tested on the bench you must make sure it gets feed on the coil as well to close the circuit to pins 3, 22, 27 cos that's your problem

OK, well we've been down so many false rabbit holes in this investigation so I'll reserve judgement on that for now. I've had it up to here today (pointing at my arse) and I'm not making any more excursions outside 'til tomorrow. I'll focus in on that area and find what's amiss with any luck. Quickest test is just to bridge a +V wire over from the battery and energise that part manually; see if that makes it fire up.

sierrafery · Jun 29, 2015

here is the description of the main relay for D2 Td5 which has the same kind of ECM and also Td5 engine as i dont have RAVE for defender, the only difference can be with connector number and the position of the relay

The main relay is located in the engine compartment fuse box and supplies battery voltage to the following:
l ECM.
l MAF.
l Fuel pump relay.
l Cruise control master switch.
l Cruise control RES switch.
l Cruise control SET+ switch.
It is a 4 pin normally open relay and must be energised to provide voltage to the ECM.
Input/Output
The earth path for the main relay is via a transistor within the ECM. When the earth path is completed, the main relay
energises to supply battery voltage to the ECM. Interrupting this earth path de-energises the main relay, preventing
battery voltage reaching the ECM.
Input to the main relay is via pin 1 of connector C0632, located at the engine compartment fuse box. Output from the
main relay is via fuse 1 to the ECM connector C0658 pins 3, 22 and 27. The earth path is via pin 21 of ECM connector
C0658.
The main relay can fail in the following ways:
l Relay open circuit.
l Short circuit to vehicle supply.
l Short circuit to vehicle earth.
l Broken return spring.
In the event of a main relay failure any of the following symptoms may be observed:
l Engine will crank but not start.
l If the engine is running it will stop.
For the ECM start up to take place the ignition 'on' (position II) voltage must be greater than 6.0 volts.

sierrafery · Jun 29, 2015

if you want to give direct feed give it to the relay's coil circuit to make it close then measure voltages at the ECM cos if you give feed only to those brown/orange wires it will not start cos the main relay gives feed to the pump relay's coil too...but you better start from C0063 and see if you get voltage on pins 85-86 with ignition on or remove the relay and put a bridge instead it's contact 30-87 then if that's the only problem it should start

Landlover99 · Jun 29, 2015

Many thanks for that info, Sierrafery. I'm suffering from diagnostics exhaustion right now so will peruse it in the morning. If what you say is correct, the fault should be readily detectable I'd have thought.
Enough for now!

Landlover99 · Jun 29, 2015

sierrafery said:
if you want to give direct feed give it to the relay's coil circuit to make it close then measure voltages at the ECM cos if you give feed only to those brown/orange wires it will not start cos the main relay gives feed to the pump relay's coil too...but you better start from C0063 and see if you get voltage on pins 85-86 with ignition on or remove the relay and put a bridge instead it's contact 30-87 then if that's the only problem it should start

Noted, thank you. May I please lie down in a darkened room with an ice pack now? Thank you.

sierrafery · Jun 29, 2015

welcome and good luck, i'll lie down too

, i have the feeling that you'll find the culprit tomorrow, i'll try to help you when i have the chance cos tomorrow i'll be working 12 hours shift

sierrafery · Jun 29, 2015

for the morning and to prove the incompetence of that electrician here's a link with defender main relay description Land Rover Workshop Manuals > TD5 Defender > ENGINE MANAGEMENT SYSTEM > RELAY - MAIN

Landlover99 · Jun 29, 2015

I hope you're younger than I am, then, if you have to do hours like that.
Hopefully I shall have better news soon. Until then!
Tune in again tomorrow, kids.

Landlover99 · Jun 30, 2015

Cut long story short. Now have power to the pins aforementioned by Sierrafery and the dang thing still won't so much as splutter. I made a final attempt to check for signals to the injectors at the ECU end just in case the wiring between ECU and injector harness had been somehow severed, but still nowt.
So it's booked in now for a code-reading at a different auto-electrician who says he has dedicated td5 diagnostics and did used to work for the LR main-dealers before going it alone. It should be picked up this afternoon. I'll report back here when I know anything further but it will be a few days most likely. Sorry it didn't work out and thanks for all your help.
Once again: I suspect ECU failure!!

trax · Jun 30, 2015

Landlover99 said:
Cut long story short. Now have power to the pins aforementioned by Sierrafery and the dang thing still won't so much as splutter. I made a final attempt to check for signals to the injectors at the ECU end just in case the wiring between ECU and injector harness had been somehow severed, but still nowt.
So it's booked in now for a code-reading at a different auto-electrician who says he has dedicated td5 diagnostics and did used to work for the LR main-dealers before going it alone. It should be picked up this afternoon. I'll report back here when I know anything further but it will be a few days most likely. Sorry it didn't work out and thanks for all your help.
Once again: I suspect ECU failure!!

"naw mate, your fuse was blown at F3. That'll be £60.82+vat + 10p for the fuse"

Engine just conked out!

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