Technical Glow plug troubleshooting

[nigelvan]

Hi guys,
We are currently in the south of Spain and I'm regularly seeing the glow plug symbol blink for 30 sec. I also experience more difficult starts in the morning when it's about 10 degrees C (not freezing). I have to keep the starter motor engaged for about 4 sec before the engine will fire up.
I disconnected the Bosch 0 281 003 039 glow plug relay to measure the glow plugs. All measure 1 ohm resistance but one reads 0.7 ohm. I don't know if that means this one is broken. Is there a way to test the relay in the field? I see pins G1-4, 30 (12V I think), 31 seems GND and 86 which could be the signal pin. There's also pin ST and DI. I don't hear a click when turning the key to ACC.
The van is a Citroen Jumper 3.0 from 2007. Help appreciated as always.

 

[Anthony489]

Hi nigelvan

The plugs are only active below a certain ambient temperature (10 degrees ?)

The relay also contains a current monitoring circuit. I suspect that one of your glow plugs has developed a partial short circuit. The current monitor will sense the excess current and trigger a warning. The trouble is, it will also cause the relay contacts to open again (trip-out) a very short time after closing, as a protection measure. This means that the three good glow plugs are only on for a brief instant and can't help with starting.

You could disconnect the faulty plug. I suspect you will still get a warning (this time due to low current) but not the trip-out, and with three plugs heated your starting will be easier. If the weather warms up above 10 degrees, after 5 or 6 engine starts the warning light will no longer come on but a fault code remains stored.

The long term solution is a new glow plug, but replacement is an operation which can be difficult and expensive due to the plugs often being seized in the head.

An alternative (which I adopted) is to wire a 1 ohm power resistor in place of the faulty plug. I still get three plugs working in cold weather, and the relay sees the correct current so no warnings.

For completeness, the connections to the relay are Ground, Low power 12V (For the internal electronics), High power 12V, Four outputs to the plugs, a Command signal from the ECU to turn the relay on and a Fault signal sent back to the ECU. I don't have the pin numbers to hand as I am in the middle of an office move !

 

[nigelvan]

Hi nigelvan

The plugs are only active below a certain ambient temperature (10 degrees ?)

The relay also contains a current monitoring circuit. I suspect that one of your glow plugs has developed a partial short circuit. The current monitor will sense the excess current and trigger a warning. The trouble is, it will also cause the relay contacts to open again (trip-out) a very short time after closing, as a protection measure. This means that the three good glow plugs are only on for a brief instant and can't help with starting.

You could disconnect the faulty plug. I suspect you will still get a warning (this time due to low current) but not the trip-out, and with three plugs heated your starting will be easier. If the weather warms up above 10 degrees, after 5 or 6 engine starts the warning light will no longer come on but a fault code remains stored.

The long term solution is a new glow plug, but replacement is an operation which can be difficult and expensive due to the plugs often being seized in the head.

An alternative (which I adopted) is to wire a 1 ohm power resistor in place of the faulty plug. I still get three plugs working in cold weather, and the relay sees the correct current so no warnings.

For completeness, the connections to the relay are Ground, Low power 12V (For the internal electronics), High power 12V, Four outputs to the plugs, a Command signal from the ECU to turn the relay on and a Fault signal sent back to the ECU. I don't have the pin numbers to hand as I am in the middle of an office move !

Hi Anthony489, Thanks again for helping out. Seems indeed like your solution is a good idea. We will see how it evolves when heading back up north to Belgium.

 

[nik233]

Hi Anthony489, Thanks again for helping out. Seems indeed like your solution is a good idea. We will see how it evolves when heading back up north to Belgium.

Hi nigelvan,
It would be a good idea to carry out some more diagnosis. I've been through this recently on my 2.2, and according to the eLearn manual the Glow plugs always come on when starting but for a shorter time and at lower current when the engine is hotter. This is probably a function of the element material which , I assume, increases its resistance as it gets hotter. Mine started at 16-17 Amps and decreased, and I would think yours would be similar. Would be a good idea to get some codes read if you are able, or perhaps check you've a) got 12V to each injector, and for how long b) put a current clamp on each injector cable. I did mine at the control module, but where-ever is easiest.
You will at least get a comparative reading.
Nick

 

[nigelvan]

A bit late to reply but his might help other people... I could hear the relay click by holding my ear next to it, so seems this part was good. When I got back in Belgium this March I disassembled the front and removed the throttle body (and broke off a bolt, yay) to get to the glow plugs. The one on the right (right under the old famous water ingress point) had a completely corroded connector. I did a test by disconnecting them all and see if I got 12V when switching on the contact, having only one plug connected each time, to rule out the bad ones. 2 of the glow plugs were faulty as power got cut immediately when the ignition was switched on.
With these 2 disconnected I do get continuous power to the other 2, still alive, plugs.
I drive now with 2 disconnected plugs and I definitely have a better start now in cold weather. I'll leave it there until I have to do some bigger job on the engine. I was able to start in freezing temperatures with no plugs at all, so I guess it's not that important.
Just measuring the resistance on the plugs didn't prove to work, results were all over the place, I don't remember if I disconnected the starter battery first, this could be the problem. Just measuring the voltage with one plug connected at the time and let the electronics of the relay decide is a better method...

As always, thanks for your help!

 

[Kadel]

Hi guys, i found this topic, when i searched for description how and when are glow plugs triggered by ECU (M010). I studied the service manual and el. diagram where is shown, that the pin 52 on M010 control the lenght of glow plugs being under voltage (glowing). But i was wondering what imput does the M010 processes to decide the engine needs to be preheated. I believe it must get an info about temperature, ,but not sure if it is from coolant (K036) or other temp sensore like diesel or air that gives info to M010 about low temperature.
My problem is that the Ducato in summer time starts perfectly, it starts perfectly once the engine is warm, but it is horible when it is cold. It takes several seconds, and usuall it stall at the first attempt. When successfuly started big cloud of white smoke comes from exauste (i am guessing not/badly burned diesel). Also when starting the glow plug dash light comes on only for a second or two. I measured resistance on each glow plug and found out that one could be faulty, but the 3 others should work (but they don t, since the dash light goes off very quickly). I checked also the relay M015 and it seems to be working too. So only thing that comes to my mind is that the ECU do not know the temperature outside is pretty low.

Hope I did not break any rules by reopening this topic.

 

[nigelvan]

Hi guys, i found this topic, when i searched for description how and when are glow plugs triggered by ECU (M010). I studied the service manual and el. diagram where is shown, that the pin 52 on M010 control the lenght of glow plugs being under voltage (glowing). But i was wondering what imput does the M010 processes to decide the engine needs to be preheated. I believe it must get an info about temperature, ,but not sure if it is from coolant (K036) or other temp sensore like diesel or air that gives info to M010 about low temperature.
My problem is that the Ducato in summer time starts perfectly, it starts perfectly once the engine is warm, but it is horible when it is cold. It takes several seconds, and usuall it stall at the first attempt. When successfuly started big cloud of white smoke comes from exauste (i am guessing not/badly burned diesel). Also when starting the glow plug dash light comes on only for a second or two. I measured resistance on each glow plug and found out that one could be faulty, but the 3 others should work (but they don t, since the dash light goes off very quickly). I checked also the relay M015 and it seems to be working too. So only thing that comes to my mind is that the ECU do not know the temperature outside is pretty low.

Hope I did not break any rules by reopening this topic.

Hi Kadel, the glow plug light coming on would seem it does power the glow plugs. Did you attach a multimeter to one of the glow plugs to see, when you turn the ignition on, if they get voltage and how long? Maybe a stupid question but do you wait a few seconds between contact and starting?
I have no idea where the ECU gets the temperature from, but my dashboards starts complaining about faulty plugs somewhere around 10C.
Another explanation might be a bad glow plug relay, but seems unlikely.
I can tell you when the ECU detects no shorts, the glow plugs get power between 5 - 10 seconds after putting the ignition (ACC) on, I don't remember exactly.

 

[Communicator]

Hi guys, i found this topic, when i searched for description how and when are glow plugs triggered by ECU (M010). I studied the service manual and el. diagram where is shown, that the pin 52 on M010 control the lenght of glow plugs being under voltage (glowing). But i was wondering what imput does the M010 processes to decide the engine needs to be preheated. I believe it must get an info about temperature, ,but not sure if it is from coolant (K036) or other temp sensore like diesel or air that gives info to M010 about low temperature.
My problem is that the Ducato in summer time starts perfectly, it starts perfectly once the engine is warm, but it is horible when it is cold. It takes several seconds, and usuall it stall at the first attempt. When successfuly started big cloud of white smoke comes from exauste (i am guessing not/badly burned diesel). Also when starting the glow plug dash light comes on only for a second or two. I measured resistance on each glow plug and found out that one could be faulty, but the 3 others should work (but they don t, since the dash light goes off very quickly). I checked also the relay M015 and it seems to be working too. So only thing that comes to my mind is that the ECU do not know the temperature outside is pretty low.

Hope I did not break any rules by reopening this topic.

I found the following info in eLearn for the x244 2.3jtd. Temperature sensing seems to be from the engine coolant as suggested. Perhaps the info may increase understanding.

"
eLearn - Contents

​ Heater plugs check​ The engine control unit, during the following stages: start-up post-starting applies a timer to the glow plug preheating control unit based on engine temperature. 1 - Engine coolant temperature sensor 2 - Engine management control unit 3 - Glow plug control unit 4 - Glow plugs Glow plug electronic unit​ The glow plugs are controlled by the preheating control unit under the direct control of the engine control unit. The preheating control unit contains a smart relay that sends a return response (feedback) to the engine control unit. The unit is thus notified of possible faults in the preheating control unit or short-circuits to earth in the glow plugs. The figure shows the connectors at the preheating control unit base and the pin-out. Unfortunately the diagrams did not copy as I hoped, perhaps the proven but time consuming method of printing to pdf, saving, and then attaching, would have been better. 31 - Earth K - Engine control unit 86 - Ignition switch (+15) ST - Not connected Di - Engine control unit 30 - Battery positive (+30) G1 - Glow plugs G2 - Glow plugs G3 - Glow plugs G4 - Glow plugs G5 - Not connected G6 - Not connected

 

[Kadel]

thank you for your reply nigelvan and communicator. I had a bit of time yesterday to play around the car and disconnected the coolant temp sensor K036 and the glow plugs light was on for a bit longer and car started much better, so i jump in a car and went buy new coolant sensor. Tested it and the glow plug light stayed on longer and it started better (no white smoke), but the coolant temperature was still on 20 deg. Today morning I tested it again. Coolant temperature was 6 deg. and it started almost perfect, but no white smoke. Almost, because of that one faulty plug (i am getting even flashing glow plug light now due to that, it did not do it before, because the M010 thought we have still summer and did not use glow plugs at all) I have new set of plugs with me for maybe 2 years, but I am affraid I will snap them in cyl.head, so i am hasitating with it :-(. Will see how it will start with even lower temperature, but if it will be like today morning I will be very happy
So the conlcusion is that M010 reads temp. values from K036 temp. sensor. In case someone gets in similar troubles as me

 

[nigelvan]

thank you for your reply nigelvan and communicator. I had a bit of time yesterday to play around the car and disconnected the coolant temp sensor K036 and the glow plugs light was on for a bit longer and car started much better, so i jump in a car and went buy new coolant sensor. Tested it and the glow plug light stayed on longer and it started better (no white smoke), but the coolant temperature was still on 20 deg. Today morning I tested it again. Coolant temperature was 6 deg. and it started almost perfect, but no white smoke. Almost, because of that one faulty plug (i am getting even flashing glow plug light now due to that, it did not do it before, because the M010 thought we have still summer and did not use glow plugs at all) I have new set of plugs with me for maybe 2 years, but I am affraid I will snap them in cyl.head, so i am hasitating with it :-(. Will see how it will start with even lower temperature, but if it will be like today morning I will be very happy
So the conlcusion is that M010 reads temp. values from K036 temp. sensor. In case someone gets in similar troubles as me

That's interesting Kadel, but doesn't the ECU use the same coolant temp sensor to show the temperature on the dashboard then? Was that still working ok?
Yes, snapping the glow plugs is a real risk. That's what's keeping me from replacing them too. The last time I checked, I had 2 working. It makes a difference in cold weather, although it will briefly run on 2 cilinders this way.

 

[theoneandonly]

That's interesting Kadel, but doesn't the ECU use the same coolant temp sensor to show the temperature on the dashboard then? Was that still working ok?

I believe there are 2 temperature sensors one for ecu one fo gauge

 

[Kadel]

That's interesting Kadel, but doesn't the ECU use the same coolant temp sensor to show the temperature on the dashboard then? Was that still working ok?
Yes, snapping the glow plugs is a real risk. That's what's keeping me from replacing them too. The last time I checked, I had 2 working. It makes a difference in cold weather, although it will briefly run on 2 cilinders this way.

the temp. dial in the dashboard worked ok. Holds 90deg nicely. Maybe it was working just in a certain range, not noticable on the dials. Lets say it never dropped bellow 20deg., so I could not see it on the dashboar, but ECU thought the engine is warm enough therefore no glow plugs needed.
Actually with new temp sensor it doesn't hold 90deg and i noticed it even dropped when I was coasting downhill. I thought termostat need to be replaced too. But maybe there was just air in the system. Since I removed the old sensor and a bit of coolant spilled out. I need to drive it more, I only drove it to MOT and back approx 50km.

 

[nigelvan]

the temp. dial in the dashboard worked ok. Holds 90deg nicely. Maybe it was working just in a certain range, not noticable on the dials. Lets say it never dropped bellow 20deg., so I could not see it on the dashboar, but ECU thought the engine is warm enough therefore no glow plugs needed.
Actually with new temp sensor it doesn't hold 90deg and i noticed it even dropped when I was coasting downhill. I thought termostat need to be replaced too. But maybe there was just air in the system. Since I removed the old sensor and a bit of coolant spilled out. I need to drive it more, I only drove it to MOT and back approx 50km.

I have the same symptom and fixed it partially: initially the gauge only reached the middle when the engine was under decent load, such as cruising on the highway or driving uphill/hard acceleration. It would drop back when just coasting or indeed driving downhill as you described. It happened a few times that it would climb a bit above the middle when driving on a hot summer day in France in heavy traffic, but it never really overheated. But I had the feeling it dropped back a bit too much when light cruising/downhill...
So, because the coolant was quite dirty I decided to drain and flush the system and replace the thermostat since it is quite cheap and is easy accessible.

With the new thermostat the temp gauge will stay closer to the middle than before but will still drop down a tiny little bit when taking the load off the engine. In Bulgaria last winter the gauge went all the way down again when coasting downhill a mountain. I guess this is to be expected as temperatures were sub-zero, was running the heater at full heat and the temperature sensor is right with the thermostat at the front of the engine and engine bay and takes all the cold directly.
In your case I would change the thermostat anyway, it's a cheap part and doesn't involve much mechanical work. But I wouldn't worry to much about the gauge moving a bit.

 

[Kadel]

so, after long time (i underwent a surgery) i could drive the Ducato again. The temp. dial gets max to 80deg, slighly higher when under load, like climbing a hill, But drops again when going downhill.
I would like to change the coolant and insert a heating element (DEFA for preheating engine from 230V), so it would be wise to chenge the thermostat too. What should be the openning temp.? I found only 79deg. KAMOKA, never heard about such a brand. Is it good or shall i search for specific brand?
Btw guys, what cooland do you use. I have currently (already bought the car with it) a red coolant, but the one i ordered, specifically for Fiat and it is green.