Hi all!!

I am a new member to the forum and appreciate the vast amount of information/help available on the site.

I have had a look through the forum pages in the hope of finding the same issue i am having with my glow plugs but haven't been able to find a thread that is similar to my fault.

I have a 2001 4 Life, 2.5 td.

The truck was starting fine until the other week when i went to replace my squeaking fan belts. When i went to start the engine but the glow plug light didn't illuminate.

I went through the system and found the switching signal from the ecu isn't live when you turn on the ignition.

I can switch the relay on using a test lead from the battery to the switching terminal, and this powers the glow plug plate. I've tried to start it using the test lead but even after leaving them on for a while the engine still won't start.

I am thinking the glow plug ecu is at fault but don't understand why the engine won't start even when i manually switch the plugs on.


Looking through the forum discussion it sounds like my plugs aren't in the best condition (2 ohms across each on when the plate is disconnected) but don't think this would cause the light not to illunmiate.


Is there a fuse that feeds the glow plug ecu?


I've done a few checks and other threads suggest the temp sensor may be the most likely fault but it is the only thing i've tested that is within spec (3.7K Ohm around 10 degrees, 5K Ohm around 2 degrees).

There is a hogher resistance across the relay switch terminal and body than expected (20 Ohms instead of 3 Ohms expected)

Would anyone be able to point me to a relevant post which discusses a similar fault, or know off hand what i should look at next as i am unsure if i should replace the ecu or the temp sensor?



Here are the reading i have taken so far;
Battery 12V
Relay input (from battery) 12.05V
Relay output (when switching using test lead) 11.31V
Plug plate voltage when relay is on - 11.21V

Any pointers at this stage would be very welcome as i am at a loss!!!

Thanks
Scott

so the truck dont start at all?

@scott.wilson5 does the engine light come on?

12v is a flat battery.

Thanks for the response,the starter turns over but the engine won't fire, even if I manually switch the relay on.
The 12v reading I took was after a few attempts starting it so it probably needs another charge

@scott.wilson5 does the engine light come on?

I think it did but when I just went to check the battery was flat as a pancake. I've got it on charge so will update when it's fully charged. Thanks again for the replies!!

no worries mate

Sorry for the lack of update - the symptoms changed after i had charged up there battery to check if the engine light came on. I've tried to investigate myself but i'm at a bit of a loss.

When i turned the ignition on, the glow plug relay was chattering on and off and the light was doing the same. The engine light didn't illuminate.

I realised the temp sensor was still disconnected after my last investigations, so i reconnected it but didn't make any difference - still flashing/chattering.

After a few more times of turning the ignition on to investigate the light and relay appear to be working as they should for the correct duration, but the engine still won't fire up. The chattering has happened a couple of times since then.

The battery had be ran flat before when i was trying to diagnose the issue with the glow plugs, and even after a full charge the light/relay still wouldn't come on.

Originally i was thinking is was the temp sensor but it doesn't appear to make much difference if its connected or disconnected.

Any thoughts as this has got me even more confused!!

Cheers,
Scott

Check under the intercooler make sure that the glow plug rail is clear of crud (when I got my truck I couldn't even see it). It is a live rail right next to the block/head so if something falls in there it may be shorting out the rail. Before replacing anything I'd be checking all the electrical connections are done up properly from the battery to the rail. Not sure exactly how to check the signal to relay - if that is constant but power from the relay is not, then guessing the relay is broken.

Thanks for the info. I had removed the rail before to check the resistance across each plug. I had another look today, took the rail off and sanded down the points of contact to make sure it was getting a good connection, also re-check the resistance across the glow plugs and they seemed to be between 1.3 & 1.5 ohms. Also had a look at all the connections and they seemed to be good.
Still unable to fire up the engine.
So as it stands the glow plug relay is now working as it should and getting the correct signal for the correct amount of time, power is getting to the plugs and they seem alright.

I'm starting to think it might be a issue of fuel supply but that wouldn't explain why the relay wasn't switching on in the first place which was the start of the problems....of it not starting

Does anyone know if the the glow plug ecu alters the fuelling for cold starts? Could it be a faulty temp sensor causing the issue?

so the engine lamp diffinaly does not come on with the ingnition and go off after a few seconds?

the engine light doesn't come on at all. The glow plug light comes on for about 5 seconds, then goes off. The relay then clicks off a couple of seconds after the light has went out.

ok id check the engine control relay first port of call then

Thanks!!! I'll give it a look to see if there is any issues. You given me some hope!!

Seen it before mate

Is it a non fbw pump. Just wondered if it was like mine wen it was 2.8 then when it is cold there is a lever position sensor that changes the timing to help cold stars.

This is quite good from the pajero forum. https://drive.google.com/file/d/0B737xMo...E14TWstek0/view
There is some other good threads on there there about the glow ecu

Simple test is if you know the plugs work then manually charge the bar for 10 seconds. If it still don't start then it's nothing to do with the plugs.

Thanks for the advice guys!!!
I removed the engine control relay this morning and found a bit of moisture and corrosion. Every place i tried didn't have a like for like replacement so i got the closest relay i could find but i think it was a bit too big and the control current couldn't throw the switch side. So this did work.

I put the old one back on and the glow plug light didn't come on, i tapped the relay with a screwdriver and it started chattering on/off again, removing the relay stop the plugs from coming on. So i knew Chef was right and the engine control relay was the issue.

I just used a cable in place of a relay and hey presto she fired right up. So it was the engine control relay at fault, and the reason why the glow plugs weren't coming on or were intermittently working, and why even when the plugs were on or i manually powered the glow plug rail she still didn't fire up.

Got a replacement ordered and that will hopefully mean i don't have to keep connecting and disconnecting the cable when i want to start it up.
Thanks again for all the advice and help - Chef (or Lee as I've learned from other posts) knows his stuff and i am very grateful as i would haven't never found that without his advice.



Excellent forum and members!!!

Now i can get round to my fan belts, flashing 4WD light, Turbo overboost at motorway speed (i suspect) and the knocking noise around the back end!!

Good to hear mate. 4wd flashing light is a vacuum leak in the lines. Crappy pipe somewhere. Replace them all for silicone for about £4. If it still persists then check the vacuum tank doodad on the chassis rail under the drivers bulkhead. It corrodes and leaks. 2nd cheapest. If still no go then Check vac pressure coming off the alternator. Most expensive

Quote: scott.wilson5 wrote in post #20

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Thanks for the advice guys!!!
I removed the engine control relay this morning and found a bit of moisture and corrosion. Every place i tried didn't have a like for like replacement so i got the closest relay i could find but i think it was a bit too big and the control current couldn't throw the switch side. So this did work.

I put the old one back on and the glow plug light didn't come on, i tapped the relay with a screwdriver and it started chattering on/off again, removing the relay stop the plugs from coming on. So i knew Chef was right and the engine control relay was the issue.

I just used a cable in place of a relay and hey presto she fired right up. So it was the engine control relay at fault, and the reason why the glow plugs weren't coming on or were intermittently working, and why even when the plugs were on or i manually powered the glow plug rail she still didn't fire up.

Got a replacement ordered and that will hopefully mean i don't have to keep connecting and disconnecting the cable when i want to start it up.
Thanks again for all the advice and help - Chef (or Lee as I've learned from other posts) knows his stuff and i am very grateful as i would haven't never found that without his advice.



Excellent forum and members!!!

Now i can get round to my fan belts, flashing 4WD light, Turbo overboost at motorway speed (i suspect) and the knocking noise around the back end!!

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