Hello everybody, I'm brand new to the forum and pretty new to the old Blazer game (bought it in November) and I am becoming frustrated with the beast.

The truck: 1986 military Blazer-Diesel

The problem: Unreliable starting

More details : Right when I got the truck, it was difficult to start. I discovered that the glowplugs on the passenger side of the engine were ALL disconnected. I reconnected them, but if I drive for any amount of time, they disconnect themselves and cause problems again. As long as the plugs were connected, it would start fine... for a while.

It got really cold about a month back and it wouldn't start again. I bought a new set of batteries and that helped a lot (as long as the glowplugs are plugged in it would start) until now. It was extremely cold again for a couple of days earlier this week, resulting in the truck not starting. I didn't try too hard though since I didn't want to drain the battery. I got the thing started (first crank) and drove the truck around a little yesterday and then went to work. I got off work and the darn thing wouldn't start. I tried for about ten minutes with zero luck. It was just cranking and cranking, not even trying to turn over. I tried again today and no dice. It's not that cold out so I'm really not sure what's going on, and the batteries seem to drain REALLY fast. it takes 2-3 cranks and it'll sound like its going dead.

I measured the voltage on both batteries and got about 10.1 on the back battery and about 13.5 on the front battery. It will barely crank, and certainly won't start.

Sorry for the long post, but I wanted to be as detailed as possible. Where do I start? I'm pretty mechanically enclined, but my area of expertise lies solely in 4 cylinder mkIII vws, so I'm out of my element here.

 

i really dont know that much about diesels but make sure each battery is grounded to the body along with the engine

 

you need 8 new glow plugs. i have a 6.2L and they need 2 things to start really well in cold weather. All glow plugs working and 2 great batteries. if one battery is weaker then the other they will equalize each other. the weak one will make the stronger one the same as it. which sounds like yours.plugging it in is a bonus but it still won't start worth a crap without good glow plugs.

so you'll have to break down and buy some nice ac-delco glow plugs.$$$

throw those puppies in there and let us know if that fixes it.

 

All right, I will give the plugs a try. Any suggestions on getting the batteries charged? I know its not possible to do a standard jump on a 24v system (or is it?) I've got 'roadside assistance' on my insurance so I'll probably just do that this time, but for future reference?

 

You should be able to be jumped by connecting the extra battery across the battery terminals of the battery that's known to be low. Or across either battery really, should work. Essentially, as long as the batteries are in parallel, you're not adding any voltage, only current.

 

i would look into converting that 24 to 12 volt system if you use it as a dd. that 24 volt stuff is getting harder and harder to find.

idk if those glow plugs are 12 or 24 volt. i think 12 but you should look into it. i didn't catch the military part

 

If you're interested in converting to 12V I found this some time ago it's a complete rundown of all available ways to convert and the benefits/drawbacks of each conversion.

 

I had an 82 with a 6.2 but it was a dual batter 12 volt system.

Glow plugs are important. You can check them, in the engine, but removing the wire and using an ohm meter to see if they are good or "burnt out".

Set the meter to the 1000 ohms setting, touch one lead to the engine block next to the glow plug and the other lead to the end of the glow plug you just took the wire off of. The resistance should go to zero. If it doesn't the plug is "burnt out" and needs to be replaced. They are expensive. Seems like the last time I priced them they were around $8 each (they were less than $2 each when I got my K5 diesel).

Once you've replaced the bad glow plugs and charged the battery you should still plug the block heater on any time it is forecasted to be down around freezing. It just makes the big sucker easier to start (which helps save on battery and starter wear and tear, too.) If you are going to park it anytime in the cold (32 or below) you need to start it and warm it up at least every 5 to 6 hrs. I used to come out, start mine up and drive it 4 or 5 miles down the road and back and it warmed up good and then started fine when I left work that evening. If you can plug the heater in at work that's even better, then there's no need to start it up half way through the day and warm it up. That's a big hunk of iron and it will stay warm for a few hours but not 8 or 10.

I also had problems with the switch/sensor on the rear of the intake on the driver's side that "tells" the glow plug system to come on when you turn the key on. If the glow plugs aren't coming on (just cause the light in the instrument panel comes on doesn't mean the glow plugs are working right) - be sure the glow plugs are cycling on/off.

Good luck with it. After my experience (and expense) with a diesel I'll stay with gas from now on.

 

if your glow plug relay is bad switch over to a push button with a relay. works alot better than the factor gpr.

 

^ that's my suggestion as well. if the relay is bad, it's be major source of the glow plugs not functioning correctly either. i've also come across a known problem of bad glow plug wiring being a big problem. check out the wire for corrosion.

as you can see in my sig, i have the same engine in my 'Burb.

while she has never seen the snow, i do open the garage every month 4 to 6 weeks and start 'er up.

never had it plugged in-for either a block heater or battery tender-and she's never had an issue starting.

even in the -30*C weather we had last week. mind you, the glow plugs did stay on for a few seconds longer than they do in the Summer.