Glow plugs keep blowing

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cristianoattie

New Member
Joined
Jun 27, 2020
Messages
8
Location
Reading, UK
Car
Jeep Commander CRD 3.0 2007 (Powered by Mercedes OM642)
Hi all

I've been having an issue with my Jeep Commander CRD 3.0 2007 powered with Mercedes OM642.

I was having some difficulties to start the engine first in the morning - since I have changed the glow plug and module 6 months I wasn't worried about those until this point.

So I did test all the fuel injectors and I noticed that 3 of them were returning too much fuel and I replace it - BTW I did not code the new fuel injectors.

The issue persists so I did change the crankshaft sensor, camshaft sensor and fuel regulator.

I did check the ground wire close to the fuel filter - I did not notice anything wrong with that.

I use the JScan app and noticed that I had errors in all the 6 glow plugs - I've replaced the glow plug module and cleared all the errors and nothing changed - so apparently the issue wasn't with the glow plug module.

I've bought a new set of glow plugs - I've tested them before with glow plug tester tool and they were fine.

Just after installing the new glow plugs I continue to have issues to start the engine - check for errors and all 6 glow plugs again - removed the glow plug and test with the tool and they're all dead.

I've tested again changing only one glow plug and right after I start the engine the glow plug dies.

What is causing a short circuit in the glow plugs maybe?

Thanks
 
CDI engines dont really need glow plugs to start.... Unless its freezing cold ..
Mine had 2 dead plugs for ages and never affected starting.
Do you still get glow plug light on after setting off?
Sure you dont have any fuel pipes that are cracked ?
 
What about the supply voltage , are you using the correct voltage plugs for the car as i believe there are a couple of options.

It is extremely unusual to fry six plugs at the one time.

K
 
fairly sure the om642 uses 4,4 v plugs. some are steel some are ceramic. i myself have put 12v across mine to make them glow and they didnt pop .
 
CDI engines dont really need glow plugs to start.... Unless its freezing cold ..
Mine had 2 dead plugs for ages and never affected starting.
Do you still get glow plug light on after setting off?
Sure you dont have any fuel pipes that are cracked ?

I don't know about all the CDI engine but this engine only starts after SEVERAL (5+) attempts without the glow plugs.

All the pipes look good, besides that doesn't explain the glow plug keeps blowing.

After the engine is warm I CAN start the engine the whole day without any issue.
 
Last edited:
What about the supply voltage , are you using the correct voltage plugs for the car as i believe there are a couple of options.

It is extremely unusual to fry six plugs at the one time.

K

I totally agree with you! Totally unusual.

This engine uses the 4.4v glow plugs and the glow plug module that originally with the car is #0522140709 BERU.

I saw someone from another forum mentioned that the MB Sprinter uses the 7v glow plugs with the same engine.
 
I was researching
Did your problems start after the tuning box was fitted ?

I'm not sure when it starts because I did several things at once when I service the car - I was thinking to remove the box tunning and see if that makes any difference - will do that tomorrow.

During a period of 1,5 year I've changed the fuel filter, transmission oil. transmission filter, transfer case oil, both differentials oil, serpentine belt, belt tensioner, two pulleys, coolant, all rotors, all brake pads, hand brake shoes, caliper guides (rusted!), both struts (one shock starts leaking), front differential CV joint, catch can install and other minor stuff.
 
Did your problems start after the tuning box was fitted ?


Mine did , think I twisted my knee.
 
I'm getting here - I was measuring the voltage in the glow plug connector. When I turn on the ignition - without starting the engine - I can see a peak of 9v something and goes down to ~2.2v again, after I start the engine it's always around 2.2v.

What could cause the peak of 9v?
 
The video with the 9v voltage peak
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The multimeter is connected to one of the glow plug connectors.
 
Hi
I have a b class w245 cdi, after I replaced 4 glow plugs I couldn't start the engine, it dose turn over but dosent start.
Battery it's OK and there is fuel coming
Anyone has similar experience?
Please help!
Thanks in advance
 

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