Thanks. I think I see now. The silver bar over the top is the glow plug fuse and it's burnt out.

Now, the left side of the knackered fuse shows 12v at all times. That can't be right can it?

G~
 
  • Like
Reactions: Nig
Thanks. I think I see now. The silver bar over the top is the glow plug fuse and it's burnt out.

Now, the left side of the knackered fuse shows 12v at all times. That can't be right can it?

G~

Yes, it is a direct feed from the battery, the relay switches this to the glow plug wires through a timer. The relay is switched by the ECM so the glow lamp will light but no power will go to the plugs if fuse is blown. Check all the wires/plugs for a dead short before you replace fuse. Think the fuse is 80 amp from memory.
 
Last edited:
Zero impedance from the RHS of the knackered fuse. What is the approx routing of the wiring from the base of the ECM to the glow plugs. I know that sounds dumb but I don't really know what weight of cabling I'm looking for.

Also, there is impedance at the glow plug heads. This makes no sense to me because it suggests that the cable must have burnt right through.

G~
 
  • Like
Reactions: Nig
Zero impedance from the RHS of the knackered fuse. What is the approx routing of the wiring from the base of the ECM to the glow plugs. I know that sounds dumb but I don't really know what weight of cabling I'm looking for.

Also, there is impedance at the glow plug heads. This makes no sense to me because it suggests that the cable must have burnt right through.

G~

Look at Rave, Electrical trouble shooting/Circuit/Section A6, Diesel/ Page 6.
 
Lovely. Thanks. Now if it could just stop raining for a few minutes, I could try and see which one it is.

If I can identify the short to one g/plug, is it OK to just snip that one for the time being and to replace the fuse to get the bugger started? I can then run a patch lead to to the g/plug showing the fault later.

G~
 
  • Like
Reactions: Nig
Lovely. Thanks. Now if it could just stop raining for a few minutes, I could try and see which one it is.

If I can identify the short to one g/plug, is it OK to just snip that one for the time being and to replace the fuse to get the bugger started? I can then run a patch lead to to the g/plug showing the fault later.

G~

I think it may make more sense to disconnect it rather than snip it off to be honest.
 
Measurements taken from back of relay multiplug (in situ)

There are six leads that look to be around 15 amp. Black/Brown, Black/White, Black/Red, Black/Yellow, Black/Purple and Black/Green. All show 0.03.

Four very thin wires at the other end of the block.

Black/Red - 0
Red/White - 0
Black/Yellow - 0
Black 0.03 (This one worries me because if it is an earth as black tends to be, the all the g/plugs are open circuit!)

Do I need to disconnect the battery before unclamping the megaplug into the ECM proper so that I can pull the multiplug from the relay and see what I get then?

G~
 
  • Like
Reactions: Nig
Measurements taken from back of relay multiplug (in situ)

There are six leads that look to be around 15 amp. Black/Brown, Black/White, Black/Red, Black/Yellow, Black/Purple and Black/Green. All show 0.03.

Four very thin wires at the other end of the block.

Black/Red - 0
Red/White - 0
Black/Yellow - 0
Black 0.03 (This one worries me because if it is an earth as black tends to be, the all the g/plugs are open circuit!)

Do I need to disconnect the battery before unclamping the megaplug into the ECM proper so that I can pull the multiplug from the relay and see what I get then?

G~


Might be a good idea. Look at the wiring diagram. It tells you which wire goes to which plug. Work it out from that it tells you all you need to know.. The lead from number six plug also feeds the fuel pump to run it whilst glow plugs are on.
 
Last edited:
Another wet weekend approaches and I will be tracing the short. I now have another worry. One of the old g/plugs came out incomplete. The heating part had sheared off at the base of the thread. I had no way of extracting it so just replaced the threaded bit. Looking at a g/plug diagramme I can't see how the lodged bit could fall into the cylinder because the housing has a funnel shape but have read a couple of nightmarish articles. Is there a danger of the small bit that protrudes into the cylinder having come away? If so, is it likely to blow out the exhaust port if/when I get the thing fired up? Would something that size damage the turbo on the way out?

G~
 
  • Like
Reactions: Nig
Another wet weekend approaches and I will be tracing the short. I now have another worry. One of the old g/plugs came out incomplete. The heating part had sheared off at the base of the thread. I had no way of extracting it so just replaced the threaded bit. Looking at a g/plug diagramme I can't see how the lodged bit could fall into the cylinder because the housing has a funnel shape but have read a couple of nightmarish articles. Is there a danger of the small bit that protrudes into the cylinder having come away? If so, is it likely to blow out the exhaust port if/when I get the thing fired up? Would something that size damage the turbo on the way out?

G~

Only thing i can suggest is take out the threaded bit put a little Easit or Plus gas in the hole and let it soak a while keep doing this and starting engine after each application. DON'T put loads of Plusgas in and let it run into cylinder. Starting engine should blow the offending bit out after a while. But stand clear it will come out like a bullet so use some rags to catch it. That is the old time way of removing stuck injectors.
 
Last edited:
Thanks. I'll try that once I've got the thing started. I do hope that No5 is one that can be got at without removing the manifold!!

G~
 
  • Like
Reactions: Nig
Measurements taken from back of relay multiplug (in situ)

There are six leads that look to be around 15 amp. Black/Brown, Black/White, Black/Red, Black/Yellow, Black/Purple and Black/Green. All show 0.03.

Four very thin wires at the other end of the block.

Black/Red - 0
Red/White - 0
Black/Yellow - 0
Black 0.03 (This one worries me because if it is an earth as black tends to be, the all the g/plugs are open circuit!)

Do I need to disconnect the battery before unclamping the megaplug into the ECM proper so that I can pull the multiplug from the relay and see what I get then?

G~

Measurements with the box removed:

All bar one glowplug reading 0.6 ohm. The broken one 40 ohms.

The low amperage wires:

Red/White
Black/Yellow
Black/Red =========All no reading but they connect to the ECM

Black 0.3 - earth

Do these readings look right?

G~
 
  • Like
Reactions: Nig
Started!!! Will provide further details in the next day or two. Thanks to everybody who assisted, particularly Wammers.

G~
 
  • Like
Reactions: Nig
Only thing i can suggest is take out the threaded bit put a little Easit or Plus gas in the hole and let it soak a while keep doing this and starting engine after each application. DON'T put loads of Plusgas in and let it run into cylinder. Starting engine should blow the offending bit out after a while. But stand clear it will come out like a bullet so use some rags to catch it. That is the old time way of removing stuck injectors.

Late to bring this back to life but it was glowplug renewal day today.

My mechanical mate and I agreed to give this a try.

Shot it into a piece of 3x2. It worked!

Three cheers for @wammers and many thanks !

The mate, who is a diesel mechanic by trade was well impressed.
 
  • Like
Reactions: Nig

Similar threads