CUCV-II No Start

[Nico]

the common 6.5l diesel problems where not waiting too long...
on the 4th day test driving (after a short 20min stop) the engine stalls,
sure in the middle of the intersecton.
running again after cranking 4 times.
same agains after the next 10 min. stop.
i bet there is some air in the diesel system.
after several days working on the truck and not driving it wont fire up at all.
first thing i tryed, like recomendet from serveral diesel experts and warthog i installed a new pmd...no differnce.
i checked all the connectors. looking for loose cable and so on. nothing.
the batteries where almost dead. dryed after cranking 2 times. i replaced them with red top optimas. still not starting.
i opened the water in fuel drain valve, some diesel came out like it should while crankin. so the diesel pump should be ok.
next thing i thougt was to change the diesel fuel filter. the parts dealer said: use only oem ac delco filter. the other aftermarket filter often dissolve and damage the ip, lot of problems here because of the ethernol diesel over here.
so i tryed to change the filter but
i got a wix filter...completed with a ring nut to bolt on the housing... the original filter needed a seperat element nut, that was missing...bought a new one on ebay.
i hope that`s it but i still belive there must be some air leak in the diesel system. i also removed a glowplug to see if some diesel deliverd, unfortunatly not.
View attachment 509853

 

[Warthog]

Hello Nico.

I started a new thread for you and I copied your post from you other thread.

The CUCV-II 6.5L engine is all 12v except for the starter which is 24v.

The standard GM repair manuals cover all repairs.

I was thinking about the no start issues. The 6.5L TD is similar to the 6.2L but the injector pump is electronic instead of manual.

I had a no start issue with the truck last year. Here is the thread.
http://www.steelsoldiers.com/showthread.php?116374-CUCV-II-won-t-start

The issue ended up being a bad ground wire.

Here is a picture that I found that will help locate items on the system.



One of the areas that I had issues with in the past was the Main Ground connection. The military had broken the ring connector. I cleaned and replaced it. Double check the connection.

Second area to check is the connectons and wiring harness extention for the relocated PMD. As you found the PMD has been relocated behind the bumper. Check the pin connections on the harness.

Third. When you install the new PMD did you install a new resistor? The unit that I installed had the #9 resistor. It is installed inside the PMD connector

 

[Warthog]

Other items to check.

Make sure the ground wire for the PMD is clean and tight at the IP.



The fuel flow is controlled by the Fuel Shutoff Solenoid on the top of the pump.



You may want to disconnect the wiring plug and test the wiring and the solenoid. The pink wire is the 12v hot from the ignition switch. It should be hot at all times with the key on. The dark blue/white wire is the ground and is controlled by the PCM (Power Control Module) behind the glovebox.



Disconnect the plug and check for 12v at the pink wire with the key on.

You may also want to use a couple of jumpers wires and wire the solenoid directly to the battery. Pink wire to the 12v positive terminal, dark blue wire to ground.

 

[Nico]

at first thank you for this thrad and the support!
yes,
i forgot the resistor!

i got a new gray one...i hope the old resistor will fit in.
ok the internet said i need a new one.
but this is just a tuning part so the engine should start also without a resistor

i will go throu all other points tomorrow
thx!!!

 

[Nico]

checked
-main ground OK
-new oem diesel filter
-shutoff solenoid wire connecton ok and does make a clicking nosie when pluged in again

What about that "hammering" noise from the diesel lift pump. is that normal or should i replace?
https://www.youtube.com/watch?v=JVm5yiz4RQQ&feature=youtu.be

 

[FMJ]

That sounds just like an aftermarket lift pump, Not sure if the CUCVll uses the same style, but if it does, that sounds normal. Are you getting fuel to the filter with the key in the run position?

 

[Stonepicker1]

Sounds like all of my CUCV-II's.

 

[Nico]

That sounds just like an aftermarket lift pump, Not sure if the CUCVll uses the same style, but if it does, that sounds normal. Are you getting fuel to the filter with the key in the run position?

i did "air bleed" after replaceing the diesel filter and the lift pump delivers diesel.

 

[Nico]

Sounds like all of my CUCV-II's.

ok, that`s good to know.
thx.

-i´ll get some professional help soon. a service with a diagnose-computer will see the truck next week. i hope that will targeting the problem.

 

[Warthog]

Hello Nico.

I was thinking about the truck and why it won't start.

Since the Customs agents decided to rearange some of the items, it is possible that they disconnected/bumped some of the wiring.

Pull the glove box and check the wiring connectors on the Engine Control Module. It is the silver box that is about the size of a cigar box. Remove the three connectors and reinstall them. It is possible that they bumped the connectors.

When you jump started the truck how did you do that? 12v or 24v? When the truck came from the the Iowa National Guard, they sent 24v thru the 12v side of the wiring. It damaged the ECM. It had to replace it.

 

[Nico]

Warthog,
thank you for your advise.
the truck is running again!
...and it was almost to easy.
i pluged the old pmd directly to the original connection location...the truck started at once!
i will order a new extension cable now.
maybe ill post a pic of the "corpus delicti" if will find the broken part.

DANKE!

 

[Warthog]

Great news!!!

Thank you for the update.

I did not think about the cable.

Make sure you do not run it long without the heat sink block. The transistors in the module get hot and will be damaged by the heat.

 

[Nico]

I had a second no start.

the solution was to clean all battery terminal bolts.

 

[cucvrus]

Good job. How cold is it in Germany where you are at? It was below 0 F here this morning in Pennsylvania.

 

[Nico]

Hi! i checked my 12V --> 24V converter today. both fuses were wrong.
15A & 25A instead of 20A & 30A.
the 15A was also blown alredy.
stonepicker wrote that this may be the reason my driverside battery was comlpetly dry.