glow plugs clicking in and out while engine running and hot

[Green1]

While driving around today I noticed the glow plug relays clicking in for a couple of seconds at random intervals, this is happening quite frequently (as in every block or 2 while driving, or even more frequently)

I have troubleshot the following:
- Engine starts fine with glow plugs doing all the usual stuff both before and after start.
- This issue was after the engine was up to temperature and I had been driving around for a while (this isn't just the normal "engine still cold" stuff)
- Never seems to do it at idle.
- Doesn't seem to do it while braking.
- Doesn't seem related to cornering.
- Bumps don't seem to make a difference.
- Seems mostly on acceleration (or while easing off the acceleration).
- Have tried a "spare" (Thanks Erebus!) glow plug controller box and that seems to have no effect.
- have wiggled all wires I could find without any reproducible effect.

It seems to me like it should be something loose somehow (because it never seems to do it at idle, only while moving) but I can't find anything that I can wiggle to reproduce it, nor does it seem to be reliably reproduced on any specific driving manoeuvre.

.... ummm... HELP?

[mararmeisto]

Coincidentally enough, Moon Machine has seemed to have developed the same problem... weird.

Only thing I would add, I thought it might have had to do with the cooler temperatures of late, but I didn't think it was THAT cool.

Also, not exactly sure, but it would seem the temp gauge in the dash is not quite registering correctly either. I will sometimes, not often, dip WAY down, almost to 'C' and then climb back up. I haven't gotten under the bonnet yet, but I'm going to do the same thing as Green1: wiggle wires, tap on things, etc. It definitely seems to be an intermittent fault though, which are always the worst to fault-find.

As anybody really figured out just what signals are going into the ECU?

[Green1]

my temperature gauge seems to be working fine, as do all other instruments, and the temperatures here couldn't really be classified as "cool" yet.

[mararmeisto]

Of course, when I type 'cool' I mean 15-17C instead of 23-25C.

I'm also wondering if the dampness might be a factor... it's been raining of late. Green1? Wet and damp there in Cowtown?

[Green1]

hot and dry here.. only about 20-22c today

[Schwa]

Could be the sensor that tells the ECU that it's hot enough, I believe it's a different sensor than the one the temperature gauge uses... Dunno how they act when on their way out.

[mararmeisto]

Could be the sensor that tells the ECU that it's hot enough, I believe it's a different sensor than the one the temperature gauge uses... Dunno how they act when on their way out.

Problem is, I just had that replaced a couple of months ago when I changed the glow plugs (and the alternator, and the ECU). The ECU I got was from another vehicle, not a refurbished one...

[Green1]

Could be the sensor that tells the ECU that it's hot enough, I believe it's a different sensor than the one the temperature gauge uses... Dunno how they act when on their way out.

that was one of my thoughts, however it seems odd that that would be related to movement...
I do have a spare, though I'm not entirely sure on how to do the replacement, first I need a deep socket 17mm (which I don't seem to have) secondly (and more importantly) I need to figure out how to seal the new one in place, it looks like they have some form of paste on them to seal?

[jessef]

I tried two different ECU's in my van once. One had a similar plug clicking like yours is doing.

It was out of an Exceed and not out of a Chamonix.

Turns out there are different boards with the same numbers on the outside. You have to open them up to check if replacing them.

Put one out of a Super Exceed in and all was good. I put the Super Exceed one into the Exceed and same problem.

Quite possible they are not all inter-compatible.

[Green1]

mine was working fine and then suddenly developed this issue (without getting a new "ECU") once I had the problem I swapped my ECU for a known good one (from Erebus' van (we both have Super Exceeds with the same glow plug system)) and the problem remained.
As such I'm convinced the ECU isn't the problem, but that the problem lies elsewhere.

[Green1]

As the general consensus appears to be that I do not know what I'm talking about, and cause more harm than good, I am removing this post so that others are not tricked in to following my ill-advised instructions.

[FalcoColumbarius]

Another disturbing thing happened today though, and I'm not sure what to think of it, I can only hope it's related.
When I went to start the vehicle from cold today I heard the glowplugs go through their cycle, and then i tried to start the vehicle, it cranked for a good 30-45 seconds or more before catching... I don't know what's going on there, but I know I don't like it...

There is a post about this somewhere. I believe the average start time is after three seconds. I discovered this (with the help of Christine of the Tardisdeli) when I was setting up the remote start system on the Miss Lil' Bitchi. Mistakenly I thought the preheat time was nine seconds and the remote start would start the engine during the day but not first thing in the morning. This puzzled me. Then one day I actually counted steamboats from when I turned the key on to the first click ~ reset the timing on the remote system and it works fine now. When the first click happens (3 secs) the plugs are hot, then they cool off. When the engine is running, the computer readjusts a couple of times (additional clicks after the fact).

If you are waiting for all the clicks to happen before turning the engine over then I would think that the glow plugs have cooled off ~ or have I misunderstood your post... smiles.

Falco.

[Green1]

or have I misunderstood your post

in a word... yes.
I know how to start a Delica, I've had it for a while now...

The problem today was that after the glow plugs finished (on, 2-3 seconds, then off again) I then cranked the engine for nearly a minute before it would catch at all... it's not that bad at -20! something else is going on here....

I hope it's related to the other issue I have, but I don't really see how it could be considering that I'm relatively certain that the problem there is the temperature sensor, and even with no glow plugs at all the Delica shouldn't have been that hard to start.

It is acting more like it couldn't get fuel maybe? I'll have to look at it more tomorrow.

[FalcoColumbarius]

Question:

• 1/ What are you running the engine on (i.e.;diesel or wvo)?
  2/ Could it be a condensation issue?

Falco.

[mararmeisto]

Another disturbing thing happened today though, and I'm not sure what to think of it, I can only hope it's related.
When I went to start the vehicle from cold today I heard the glowplugs go through their cycle, and then i tried to start the vehicle, it cranked for a good 30-45 seconds or more before catching... I don't know what's going on there, but I know I don't like it...

Sounds like what Moon Machine was doing before I changed the glow plugs. Even after the starting cycle, are you getting a big cloud of smoke out the rear? Could be a compression start. The timer only 'counts steamboats' (thanks Falco, now you got me doing it) - I don't think it actually checks to see if the glow plugs get hot.

Of course, not having a proper description of the circuit makes it much more difficult to troubleshoot anything wrong with it. I think we're getting along fine as we are: a military weapons electronic technician, a rescue coordinator, a painter, etc.