M1009 No start/crank

[Assel]

Hey Steelsoldiers!

I did the Doghead relay mod and today I put the Batteries back into the CUCV. Voltmeter showed 25.6V with Ignition off.

So i got in the truck and put the key in, pushed it into "on" and glowplugs started cycling, like they used to do before the Winter. Everything normal so far.
Checklights went out & the Wait lamp did the same. I pushed the Key further into "start" position then.

But then the CUCV wont go "rattle rattle rattle" like it should. but the starter-relay did It sounded like it was engaging & disengaging very fast, about 3-4 times a second. Immediately I dragged the key back to "off" and went to check everything.

All Fuses are good, I had a loose ground cable so tightened this one, But now the Voltmeter showed only 24.5V
Because I found a loose ground-cable I thought this was the issue, attempted to try it again but this time:

As soon as the Key is in "on" position the starter Relay begins to "rattle" ...shouldnt it be doing nothing until the Key is in "start" ?

I wanted to fix the "prone to be faulty" relay ..and not to break another thing & get electrial gremlins

Possibilitys I think about are: bad connections on the relay, going to check this & renew them... or a broken relay. Maybe one of my Batteries is dead? but i had them in the Audi for weeks and never had problems... but why is the relay engaging as soon as key is in on-position? what could be the issue here?

Thanks for your help

 

[Assel]

Ok now i unwrapped the contacts on the doghead relay, recrimped the 24v supply (it was not 100% tight) , Voltmeter on Batteries shows 25V, red supply on starterrely shows 25V also, so cables & grounds should be good.

I then put key in "on" again and this time I found out that I misheard the "rattling" it was not the doghead relay, it is the glowplug-relay, top connection there shows 25v also. but as soon as key is in "on" it starts the machinegun-like rattle.

The first rattle from the starter-relay was way louder and not so fast. could this cause some components of the glowing system to fail? I assume the glowplug relay does not get enough power to stay engaged?

 

[firefox]

My guess is that it is the glow plug module or the glow plug relay.
Try pulling the module and looking for fried components. Also
clean the contacts on the board edge. Just use a pencil erasser to
shine them up.

 

[antennaclimber]

Sounds like you have a battery failing under load. Load test both batteries.

 

[Assel]

that was my first thought also, but I had them both in my daylie driver, there were never any issues, started good at -20°C etc. but I take them to a shop and see if ones bad...would be my preferred "fail" ...I really dont know how expensive & maybe impossible to get, GP controllers etc. are over here....

 

[joshuak]

Good morning, if I read correctly you measured 25v on your gp relay (top post). I don't think you should have more than 12.X volts there.
If I may suggest reading a thread called "muddy resistor bypass" or similar it might offer insight about that in particular. I would link it but I'm not as smart as my smart phone.

Good luck.

 

[firefox]

If you end up needing a GP controller, I suspect you could buy one from antennaclimber.
I wouldn't think shipping would be that bad, and his prices are excellent. Also,
they are new, not refurbished.

 

[Assel]

I think the voltage on the GP relay top post only drops to 12.x V when current is flowing? ..thought I read somewhere something like that. I measured it with ignition off, as soon as is go into "on" that relay goes rattling... and ye, shipping from US might be again the better idea... when done via Bonvu.com there should be no problems for people to ship.

 

[firefox]

The relay is activated by a 12 volt source, but switches the 24/12 volts to the glow plugs.
Disconnect the contact portion of the relay and see if it still chatters. If it still chatters,
then remove the relay and hook the coil of the relay up to the battery with a good cable
and see if it chatters. if it does, then load test the battery. If that passes, then replace the
relay. Since the relay is pretty cheap, it might be easier to just replace the relay. Be
aware that you still may end up having to load test the batteries.

 

[Assel]

I take both batteries to the shop tomorrow, and im gonna take a look for the controller & check the relay, thx for the help anyways

 

[Assel]

Batteries are ok, but I get only 9v to the GP Relay (the small stud), if I manually ground it then it does nothing. Hooked it directly to a batterie then and it still did nothing. Measured resistance between the small studs: Endless Ohm. I guess the relay is broken ...

 

[MarcusOReallyus]

Good morning, if I read correctly you measured 25v on your gp relay (top post). I don't think you should have more than 12.X volts there.

I think the voltage on the GP relay top post only drops to 12.x V when current is flowing? .

You are 100% correct, sir. When the relay is NOT engaged, you should see full battery voltage there, 25 volts or so. When the relay IS engaged, you should read about half of battery voltage there.

Batteries are ok, but I get only 9v to the GP Relay (the small stud), if I manually ground it then it does nothing. Hooked it directly to a batterie then and it still did nothing. Measured resistance between the small studs: Endless Ohm. I guess the relay is broken ...

Yep. Bad relay. Good news? It's an easy fix, and the part isn't hard to find. Should be available even in Germany. Any 12v, 100 amp relay with 4 terminals will do the job.

This would be a good time to do the resistor bypass!

 

[Warthog]

It may also be time to take the wiring harness firewall connection apart and clean it. Many times the connections are so dirty with all the black goo that electricity will not flow correctly.

A wire brush and a can of electrical contact cleaner will help a lot.

Make sure the batteries are disconnected before starting. There is voltage present when the connection is apart.

 

[Assel]

I ordered a Relay rated 12V /150amp, should do the job. And yeah, clean connections is a must.

 

[Assel]

cleaned all cable connections again, put the 2 fresh loaded batteries, a new GP-Relay and the new Controller Card into it. Fine glow, no chattering relays. Light went out and i turned the key into start:

And sudenly there was the long missed "rattle rattle rattle" from the 6.2 Diesel Engine I didnt even crank for a full second, im impressed about that great startup after ~7 months of "winter sleep".

Thx for your help all !