GM 6.5 TD engine poof problelm

[Will L.]

Ah- I see how that could be true also.
Gotta measure at the wires
Or…
Do what I been saying for years. Put the meter back in the drawer.
Remove the plugs and plug the wires back on. Little jumper wire action for the ground and test them.
Element gets red hot, whiteish to the tip and it is good.
Element barely changes color- something is not good.
At that point attach a known good 60G and if it glows red- throw away the old plugs and move on with life.
New to you truck just invest $90 and install new plugs- test the old ones and keep the good ones, chuck the old. Many miles later or suspect a problem with the relay or control system- unplug one wire, plug onto the known good used plug from your parts shelf- and instantly diagnose in less time than reading one of my posts! Haha

 

[Bezzer]

This information a few of you wanted to know...especially dbrannon79.

Checked continuity on all 8 glow plugs. They all checked good.

Now remember- my first check for voltage at passenger side showed 6Volts about 10 days ago. I did not leave the key on long enough at that time to get a reading of 12 volts .

Today on the driver's side I checked the 4 connectors (unplugged): one read 10.70 volts....another read 10.68....another read 10.60....and the 4th read 10.64.
Started checking the batterys at 12.50 volts. After finishing .....the battery voltage was at 12.42 volts. After 1 1/2 hrs. the batterys are back up to 12.50.
At this time I believe the other 4 connectors (on the other side) should read 10 volts plus?

Also remember I checked the glow plug controller - it has 12volts going in and 12volts going out.

 

[dbrannon79]

reading around 10v at the glow plug connections with them plugged in is about right. remember all 8 connected and when the relay is on they will draw about 90 amps together.

looks like your wiring is checking out good. now time to start pulling glow plugs out one by one. mark each one to the cylinder you pulled it from. post a pic of their conditions so we can see. we will tell you if there is some swelling going on or if the electrodes have erosion.

you can also bench test them by using your jumper cables on a battery clamp the neg on the body and momentarily touch the pos on the spade terminal where the wires connected. the tip should glow red hot within a couple of seconds. also verify what the part numbers are on the glow plugs. having someone replace one or two leaving you with a set of mix matched glow plugs is not good.

these things are like spark plugs on a gasser. they need to be replaced in sets.

 

[dbrannon79]

A side note: I am sure we mentioned this before....

unscrew the glow plugs from the head and then pull straight out. do NOT try to wiggle / bend them. the tips will break off in the head and cause you a massive headache. if they do not pull out from the head. FULL STOP. you will need a special puller and a prayer.

I will let Will and others guide you if one seems to be stuck and won't come out with ease.

 

[WarWagon]

like a cummins. When they fail they don’t kill engines.

Err, Well, No. Grid Heater Bolt. When it gets loose and the bolt burns in half from the arcing ... the engine eats it. Rare but happens. It's a risk on my 2018. The newer RAM Cummins models just burn the truck down from a now recalled grid heater relay.

 

[jrsavoie]

This information a few of you wanted to know...especially dbrannon79.

Checked continuity on all 8 glow plugs. They all checked good.

Now remember- my first check for voltage at passenger side showed 6Volts about 10 days ago. I did not leave the key on long enough at that time to get a reading of 12 volts .

Today on the driver's side I checked the 4 connectors (unplugged): one read 10.70 volts....another read 10.68....another read 10.60....and the 4th read 10.64.
Started checking the batterys at 12.50 volts. After finishing .....the battery voltage was at 12.42 volts. After 1 1/2 hrs. the batterys are back up to 12.50.
At this time I believe the other 4 connectors (on the other side) should read 10 volts plus?

Also remember I checked the glow plug controller - it has 12volts going in and 12volts going out.

Did you disconnect each glow plug to test them for continuity?

The flickering voltage sounds normal.
I've had that frequently on multiple key hits. It seems to only cycle normally on the first hit of the key.
A bad temp sensor seems to also affect that. Seems it was the sensor on the passenger side. It's been many years since I had that issue. I'm sure there's a thread somewhere

 

[jrsavoie]

This information a few of you wanted to know...especially dbrannon79.

Checked continuity on all 8 glow plugs. They all checked good.

Now remember- my first check for voltage at passenger side showed 6Volts about 10 days ago. I did not leave the key on long enough at that time to get a reading of 12 volts .

Today on the driver's side I checked the 4 connectors (unplugged): one read 10.70 volts....another read 10.68....another read 10.60....and the 4th read 10.64.
Started checking the batterys at 12.50 volts. After finishing .....the battery voltage was at 12.42 volts. After 1 1/2 hrs. the batterys are back up to 12.50.
At this time I believe the other 4 connectors (on the other side) should read 10 volts plus?

Also remember I checked the glow plug controller - it has 12volts going in and 12volts going out.

Did you disconnect each glow plug to test them for continuity?

 

[jrsavoie]

This information a few of you wanted to know...especially dbrannon79.

Checked continuity on all 8 glow plugs. They all checked good.

Now remember- my first check for voltage at passenger side showed 6Volts about 10 days ago. I did not leave the key on long enough at that time to get a reading of 12 volts .

Today on the driver's side I checked the 4 connectors (unplugged): one read 10.70 volts....another read 10.68....another read 10.60....and the 4th read 10.64.
Started checking the batterys at 12.50 volts. After finishing .....the battery voltage was at 12.42 volts. After 1 1/2 hrs. the batterys are back up to 12.50.
At this time I believe the other 4 connectors (on the other side) should read 10 volts plus?

Also remember I checked the glow plug controller - it has 12volts going in and 12volts going out.

Did you disconnect each glow plug to test them for continuity?

The fluctuating glow plug voltage may be normal.
I've had instances of quick glow plugs after the first hit. First hit was normal duration. After that they would flick on and off.

I think it may have been mentioned that the glow plug controller can also act funny if the temp sensor on the passenger side is acting up.
I had that a couple times a long time ago.
Please correct me if I have something incorrect on that issue.

Regardless, I would get a set of 60G glow plugs from a trusted seller. I used to buy them at AutoZone.

As Will said. Save any good old plugs for emergency and testing your wires.

 

[Will L.]

Did you disconnect each glow plug to test them for continuity?

The fluctuating glow plug voltage may be normal.
I've had instances of quick glow plugs after the first hit. First hit was normal duration. After that they would flick on and off.

I think it may have been mentioned that the glow plug controller can also act funny if the temp sensor on the passenger side is acting up.
I had that a couple times a long time ago.
Please correct me if I have something incorrect on that issue.

Regardless, I would get a set of 60G glow plugs from a trusted seller. I used to buy them at AutoZone.

As Will said. Save any good old plugs for emergency and testing your wires.

Well- y’all are missing a key part of what I said. Maybe I didn’t state it clearly.

Ohm testing or voltage testing the glow plugs is ineffective. Depending on the wear or damage the glow plug sustains- the reading can be too high or too low.

I have had good ones test bad.
I have had bad ones test good.
I did the testing over hundreds of them and found it is frequent.
I used multiple testers.
I had others do the same and verified findings.
Using an ohm meter or voltmeter to test these style glow plugs is a waste of time that can have you chase other functional parts as bad that are working properly.

I showed it to the GM engineers that we were doing the testing of other issues for and they basically said “ya we know”.

If you want to test a glow plug- bench test only with applied power and monitor heat.

 

[Bezzer]

jrsavoie, dbrannon79, and Will L.: I did remove each glow plug wire to check continuity. With those small wires that go on the glow plugs and the controller putting out 12 volts...sure seems I should see more than 10 plus volts on my meter.
Will L.-How did you find the temperature sender was acting up?
I'll be getting 8- new 60G glow plugs.
Today I had to cut out the inner fender wall to get to the glow plugs. Been squirting the glow plugs with Blaster on and off this afternoon. Hope to pull them out tomorrow.
Here's three pictures of my project so far!
At 81 I'm done for the day!!

 

[Bezzer]

2-8-24 10:30am Got all four out on driver's side- no problem. No signs of any swelling. Calling O'Reilly's to see if they have them in stock. If so- they'll be installed today!
So far so good??

 

[Bezzer]

2-8-24 10:30am Got all four out on driver's side- no problem. No signs of any swelling. Calling O'Reilly's to see if they have them in stock. If so- they'll be installed today!
So far so good??

 

[ak diesel driver]

Can you see the markings on them?

 

[jrsavoie]

If they are 60G, I would test and reinstall

 

[Big T]

jrsavoie, dbrannon79, and Will L.: I did remove each glow plug wire to check continuity. With those small wires that go on the glow plugs and the controller putting out 12 volts...sure seems I should see more than 10 plus volts on my meter.
Will L.-How did you find the temperature sender was acting up?
I'll be getting 8- new 60G glow plugs.
Today I had to cut out the inner fender wall to get to the glow plugs. Been squirting the glow plugs with Blaster on and off this afternoon. Hope to pull them out tomorrow.
Here's three pictures of my project so far!
At 81 I'm done for the day!!

Why did you have to cut out the inner fender on the driver’s side? The driver’s side is the most accessible side. On the passenger side, the job is easier if you pull the inner fender.

 

[Bezzer]

ak diesel driver-
Yes, I see the markings. They are 11G. All 4 checked at 1400 plus degrees. Picking up the 8 - 60G's at O'Reileys this afternoon. Once I get these 4 in and button up everything I will go to the other side.

 

[ak diesel driver]

When you get those 60g in there if you so desire you can put in an override switch for extended glow time for cold weather

 

[Bezzer]

Big T: Something went wrong with the web page. It posted one reply I made twice and not the one above.
Why I cut out the inner fender on the driver side.....it's a motorhome. The motorhome company buys the chassis . They build the motorhome body and then lower the motorhome body down on the chassis... and the engine ends up behind this inner fender well where the glow plugs are. That's why I had to cut it to get to the glow plugs.

 

[Bezzer]

ak diesel driver: Thanks for your override switch suggestion.

 

[dbrannon79]

Depending on how much you had to cut out, maybe use a rubber mud flap from a big rig with some self tappers and fender washers to make up a inner fender that you can re-cover that area which can later be removed for future work. That will also help protect the engine bay from road and mud debris from the tire.