CUCV starting (or, actually, NOT!)

[dremu]

My '09 is starting to, well, not start, on cold mornings ... cold here being defined as mid-30's, early 40's F. Once either the weather warms up or the truck finally starts, it's fine, and will restart happily.

I would imagine the first step is to replace the glow plugs. However, I hear horror stories about them swelling and being impossible to remove ... and my truck is still 24V, so I don't know if I can use the stock 60G's or have to use some other part?

So, is my diagnosis correct, i.e. I should be replacing the glow plugs? Do I need a magic tool to extract them? And do I need a funny part for 24V?

Thanks all!

-- A

 

[Rob 85K5]

The glow plugs are still 12 volt. The only thing 24 volt on the CUCV is the starter.

 

[tRustyK5]

You can quickly test the glow plugs you currently have without removing them. All you need is a test light. Attach the alligator clip to the spade terminal of the GP in question, then touch the probe end to the positive side of the battery. If it lights up the GP is functional.

I'd look into a set of quick heats from Kennedy Diesel, they're constant duty and reach 'surface of the sun' glow in 5 seconds or less. This makes them work well with stock GP controllers...

All you need to do is unscrew each GP and hope none have swollen on you. You may be able to keep untreading it until the swollen part starts to thread out...worst case is the tip will break off and you'll have to remove that injector and retreive the broken bits. Where the piston is shouldn't have any bearing on the difficulty because the busted tip will be in the pre-chamber.

Rene

 

[DieselDan]

Not all glow plugs are hell to remove. Take you time, read up on the tricks, know your worst case options. Yes, the GP use 12V (reduced from 24V). I have no idea if 60G will work, but it sounds like a good match

First thing to do is check your voltage at the solenoid. Should be 24V (24-28 battery voltage) in and drop to 12V with the GPs cycling and the GPs WORKING. If it's just 24V cycling out of the solenoid your GPs are all dead.

 

[dremu]

You can quickly test the glow plugs you currently have without removing them. All you need is a test light. Attach the alligator clip to the spade terminal of the GP in question, then touch the probe end to the positive side of the battery. If it lights up the GP is functional.

I'd look into a set of quick heats from Kennedy Diesel, they're constant duty and reach 'surface of the sun' glow in 5 seconds or less. This makes them work well with stock GP controllers...

All you need to do is unscrew each GP and hope none have swollen on you. You may be able to keep untreading it until the swollen part starts to thread out...worst case is the tip will break off and you'll have to remove that injector and retreive the broken bits. Where the piston is shouldn't have any bearing on the difficulty because the busted tip will be in the pre-chamber.

Rene

Good info, Rene, thanks. I note that Kennedy's web page says

This plug fits all civilian (12 volt) GM 6.2, and 6.5 diesels with flat blade terminals.

Which makes me concerned about the 12V vs 24V thing. I thought I read somewhere, though, that there's a big ballast resistor to drop to 12V on the GP's ... maybe that's not on the HMMWV's and only on the CUCV's?

-- A

 

[tRustyK5]

DieselDan will hopefully have more accurate info on that. My junk is all civi and all 12 volt...so anything i told ya would be second hand and prolly wrong.


Rene

 

[dremu]

DieselDan will hopefully have more accurate info on that. My junk is all civi and all 12 volt...so anything i told ya would be second hand and prolly wrong.


Rene

Works for me. Tomorrow when it's light and warmer, I'll check all eight for resistance, and check out the controller and relay. Electrical stuff I can do, when I know how it's supposed to work

Thanks all!

-- A

 

[DieselDan]

Must be the CUCV curse I had to replace a set today. Weird thing is they were replaced just this past spring .

Yes, CUCVs have a ballist resistor to drop the 24V to 12V (on the firewall, behind the air cleaner). Makes it real easy to tell if they're (the GPs) are working: the voltage drops to 12+V (if they're not you get 24+V).

Personally I don't know why the Army didn't modify the GP system by using 24V plugs (from the HMMWV), modify the harness (HMMWV GPs are post not spade), and do away with the resistors.

Will the 60Gs work? I don't know. I would guess that the 60Gs might be more resilent to higher voltages than the "quickheats". The 60Gs are PTC (positive temperature control) also, I think. Could be an expensive lesson
CUCV glowplugs are 15G or 13G I can't remember. They're NOT PTC and like to burn out. If you're really interested I can cross reference the part numbers tomorrow.

 

[dremu]

Must be the CUCV curse I had to replace a set today. Weird thing is they were replaced just this past spring .

Yes, CUCVs have a ballist resistor to drop the 24V to 12V (on the firewall, behind the air cleaner). Makes it real easy to tell if they're (the GPs) are working: the voltage drops to 12+V (if they're not you get 24+V).

Personally I don't know why the Army didn't modify the GP system by using 24V plugs (from the HMMWV), modify the harness (HMMWV GPs are post not spade), and do away with the resistors.

Will the 60Gs work? I don't know. I would guess that the 60Gs might be more resilent to higher voltages than the "quickheats". The 60Gs are PTC (positive temperature control) also, I think. Could be an expensive lesson
CUCV glowplugs are 15G or 13G I can't remember. They're NOT PTC and like to burn out. If you're really interested I can cross reference the part numbers tomorrow.

Well, I replaced the 13G's with 60G's today. Won't know until the morning how the cold start goes. Did have to replace the spades on the wires with wider ones, was easier for me than grinding down all the plugs. I also see that she runs rough at first, when cold, like she's missing... if it were a gasser I'd be checking spark plug wires right off. Does this bring to mind anything? -- A

 

[tRustyK5]

My only problem with the 60G's is they take longer to heat up, so with a stock controller cycling them they'd never get hot enough to get an easy start. I finally got fed up and went manual control for my GP's...

Running rough when it first fires is a cylinder not firing. Mine runs on 5 or 6 for a little bit and eventually it smooths out. I know i have at least two dead 60G's though...

Rene

 

[dremu]

My only problem with the 60G's is they take longer to heat up, so with a stock controller cycling them they'd never get hot enough to get an easy start. I finally got fed up and went manual control for my GP's...

Running rough when it first fires is a cylinder not firing. Mine runs on 5 or 6 for a little bit and eventually it smooths out. I know i have at least two dead 60G's though...

Rene

Dangit. She started right up this morning, 35 F, after one glow from the OE controller... ran rough for a bit, rrrr RRRR rrrrr RRRRRRR, but smoothed out pretty quick. -- A

 

[imiceman44]

Well, I replaced the 13G's with 60G's today. Won't know until the morning how the cold start goes. Did have to replace the spades on the wires with wider ones, was easier for me than grinding down all the plugs. I also see that she runs rough at first, when cold, like she's missing... if it were a gasser I'd be checking spark plug wires right off. Does this bring to mind anything? -- A

When it runs rough it means you DO have dead GP's, like Rene said that cylinder will not run right until the engine warms up and get's going.
I need to get mine going, it's just sitting in my driveway dead, not sure what is wrong yet.
Wanna come by and work on it with me and see how a 6.2l with a TURBO runs?

 

[dremu]

When it runs rough it means you DO have dead GP's, like Rene said that cylinder will not run right until the engine warms up and get's going.
I need to get mine going, it's just sitting in my driveway dead, not sure what is wrong yet.
Wanna come by and work on it with me and see how a 6.2l with a TURBO runs?

Dangit ... the plugs are brand new! I wonder if the wiring harness is suspect. Thought you had a Perkins -- A

 

[imiceman44]

Dangit ... the plugs are brand new! I wonder if the wiring harness is suspect. Thought you had a Perkins -- A

Hey I have the perkins but that Suburban in my driveway is a Turbo 6.2

Yesterday I got my 57 willys wagon running so I can move it around, I also got my C&C frame from my friends place and have it on my side yard waiting to become a trailer.

That sub had supposedly a problem in the IP and the guy replaced it and couldn't get it to start.
I have started to check compression and I showed 280, 290 PSI on the couple I saw and I thought that was too low but now I know at that pressure it should at least start but not run very good so i am going to try and get it to run.

 

[tRustyK5]

You could check all the new GP's and verify that they're all good...but probably they could use an extra couple of seconds to fully heat up and the factory controller won't do that for you. The 60G's is the sole reason I went with manual control on my GP's. It'd start with the factory controller but it was a real beotch!!!

Rene

 

[DieselDan]

The CUCV uses an unique controller (not on any civvy GM). And seams to cycle the plugs pretty long. Unlike the civilian GP controller the WAIT light is not wired from the actual GP voltage (harness) but uses a seperate signal from the controller. If you watch the voltmeter you will see the plugs stay on after the WAIT light goes out. CUCV savvy soldiers will wait until the volmeter jumps back out (you'll hear the solenoid click too) before they crank the engine. The plugs seem to last longer this way and the engine will start/run smoother.