New Member With A Broken M1008

[Amazed&Confused]

I'm very new to the surplus vehicle world and just recently bought a 1986 M1008 that has the Detroit 6.2 and a 24v system. Since buying I've put around 100 miles on it and everything was running and driving seemingly fine.

The only problems I knew it had before now was the exhaust on one side needed replaced, there was a small fuel leak that I think is somewhere low towards the passenger side of the engine, and there is a lot of wires coming from and leading to nothing. But a couple days ago I went to start it up and when cranking there was a loud rattling sound and the dash lights were kind of flickering.
I tried again after crawling around and trying to see if maybe the starter came loose, but when I went to cycle the glow plugs again I heard what sounded like a hissing or sizzling. That sent up red flags to immediately stop what I'm doing, I'm over my head, and to ask people who know better than me.

I'm probably the 3rd or 4th owner of the truck after it got sold off from a fire department so I'm not sure what has and hasn't been done to it over it's lifetime. I've tried looking through the different threads on here as well as other forums, but I haven't made any headway other than it's possibly starter or flex plate.

I'd really appreciate anything even if its just leading me to a specific thread I've probably missed.

 

[WWRD99]

I'm very new to the surplus vehicle world and just recently bought a 1986 M1008 that has the Detroit 6.2 and a 24v system. Since buying I've put around 100 miles on it and everything was running and driving seemingly fine. The only problems I knew it had before now was the exhaust on one side needed replaced, there was a small fuel leak that I think is somewhere low towards the passenger side of the engine, and there is a lot of wires coming from and leading to nothing. But a couple days ago I went to start it up and when cranking there was a loud rattling sound and the dash lights were kind of flickering. I tried again after crawling around and trying to see if maybe the starter came loose, but when I went to cycle the glow plugs again I heard what sounded like a hissing or sizzling. That sent up red flags to immediately stop what I'm doing, I'm over my head, and to ask people who know better than me. I'm probably the 3rd or 4th owner of the truck after it got sold off from a fire department so I'm not sure what has and hasn't been done to it over it's lifetime. I've tried looking through the different threads on here as well as other forums, but I haven't made any headway other than it's possibly starter or flex plate. I'd really appreciate anything even if its just leading me to a specific thread I've probably missed.

Oh the days of the first miles owning a truck with no idea what's been done to it!!

Welcome to the club and know it probably won't be your last one you have.

The sizzling noise kinda sounds like the glow plug relay goin nuts. Pretty common...makes a really fast clicking noise sounds like it coming from the top of the dash when you're sitting behind the wheel. There's a sensor on the drivers rear head that can make the gp control board do that. You can test that by unplugging it and see if that noise goes away. Should hear one click and the wait light on.

You mentioned the starter which can be a bad thing if it does not have the small bracket mounted to the front of it to the block. Check to see if that is there. If not don't try to start it until you get that on there.

Next take pics of the random wiring. Hopefully it's just left over from lighting etc. Post a bunch from under the hood.

These trucks are very simple...if you have time, look for the tm manuals in the first posts for these vehicles...thousands of pages of pictures and numbers to look at that tell you everything about these trucks.

We can do some basic voltage checks once some pics verify how its wired.

Sent from my SM-S906U using Tapatalk

 

[Amazed&Confused]

Oh the days of the first miles owning a truck with no idea what's been done to it!! Welcome to the club and know it probably won't be your last one you have. The sizzling noise kinda sounds like the glow plug relay goin nuts. Pretty common...makes a really fast clicking noise sounds like it coming from the top of the dash when you're sitting behind the wheel. There's a sensor on the drivers rear head that can make the gp control board do that. You can test that by unplugging it and see if that noise goes away. Should hear one click and the wait light on.
You mentioned the starter which can be a bad thing if it does not have the small bracket mounted to the front of it to the block. Check to see if that is there. If not don't try to start it until you get that on there.
Next take pics of the random wiring. Hopefully it's just left over from lighting etc. Post a bunch from under the hood.
These trucks are very simple...if you have time, look for the tm manuals in the first posts for these vehicles...thousands of pages of pictures and numbers to look at that tell you everything about these trucks. We can do some basic voltage checks once some pics verify how its wired.

Sent from my SM-S906U using Tapatalk

So I crawled underneath to look for the bracket that was mentioned and am fairly sure that it's there. But when it comes to the wiring to me all I see is rat's nests since I'm not very sure what exactly I'm looking at.

I'm fairly sure that in one of the pictures I have shows the slave cable connector inside of the cabin on the floor instead of out of the front of the truck.
There is also a panel missing in the dash that I'm guessing is where a radio of some sort went.

 

[WWRD99]

So I crawled underneath to look for the bracket that was mentioned and am fairly sure that it's there. But when it comes to the wiring to me all I see is rat's nests since I'm not very sure what exactly I'm looking at. I'm fairly sure that in one of the pictures I have shows the slave cable connector inside of the cabin on the floor instead of out of the front of the truck. There is also a panel missing in the dash that I'm guessing is where a radio of some sort went.

Pictures look great!! So to start under the hood it looks like there is 2 relays hooked up mounted to the rear battery. No idea what they have hooked to that but if there are no big wires running out I'd guess some sort of plow possibly.
I don't think you need those but more pics so I can see where it goes. Looks like you do have the starter front mount in place! Under the dash some one put in a few 12 volt things...I see a cig lighter hanging by the fuse box and some small wires and a cb antenna wire.
You could probably use the cig lighter to charge your phone or just remove it and the fuse they have put the wire under, just put the fuse back in.

The plug laying at the 4wd shifter is the diagnosis port. It is supposed to be bolted to the bottom of the dash. My guess is they took it off to mount a cb. The hole in the dash is normal since most of the dash covers didn't keep the radio delete plate. Not a big deal.

They do make repop radios that fit those mount holes with bluetooth etc. I see a doghead relay done...not a big deal. Doesn't look to bad though!! I have seen worse.
I'd say a few side pics of that rear battery so we can figure out if you need those relays! Could be one of those went nuts.

 

[Amazed&Confused]

Here's a couple of the battery like you had said. I'm wondering if either of the relays could be for the old siren?

 

[WWRD99]

Here's a couple of the battery like you had said. I'm wondering if either of the relays could be for the old siren?

I have no idea!! They must have needed relays for something but the way they did it doesn't make sense. Either way follow the fat wire on the bottom of the relay and see where it goes...could be capped off. Probably just remove it then. It looks to be feeding 24 volt to something.

Sent from my SM-S906U using Tapatalk

 

[nyoffroad]

I take it that this was at one time a fire truck? Nozzle nutz love their lights! Many years ago I worked on a few ambulance's and fire PU's converted to brush trucks and the wiring was always a mess. All you can do is start following the wires and keep a test light handy.

 

[Amazed&Confused]

Update on the truck, I bought a multimeter and was checking the batteries after watching a YouTube video and found battery 1 was only around 6v where battery 2 was 12.4v. After charging battery 1 everything seemed to work fine, there wasn't any noises when I cycled the glow plugs and it cranked and started up just fine. Now I need to figure out if I have a bad battery, a draw on the battery, and possibly a bad alternator. But at least the truck is starting and driving

 

[CARC686]

Since nobody addressed the fuel dribble, if it's coming from beneath the passenger side generator, it's probably your lift pump. If you're going to dig in, you might as well replace the hoses while you're in there. I didn't and lived to regret it.