1986 doesnt start without starting fluid then runs perfect

[6-2DIESEL]

Originally Posted by IamDave0887

The military blazers ran 12 volt glow plugs.

The only things that were 24 volt was the starter, and the charging system.

There was a large inline resistor that would drop the voltage down to ~12 volts or so. The rest of the truck was powered after this resistor, so everything else remained a 12 volt setup.

If you have 24 volts at the glow plugs, and you are using 12 volt glows, they are dead. Not even worth testing them out. 12 volt glowplugs are actually rated at 10.5 volts due to the large drop that occurs when powering the glows(roughly 110 amps pulled from the batteries causes the voltage to drop down to ~10.5-11.0 volts).

Just imagine a 6 volt light bulb running on 12 volts. Imagine how long it would last before going poof. Same concept with double the voltage at the glowplugs. Regardless of the glowplug you are using, they aren't meant to take that voltage, so they will fail.

Odds are you ended up with Champion or Autolite glowplugs, which are pure garbage. Do yourself a favor and track down a set of Bosch Duraterm part # 80034 and install those. I've been running my first set of those since 2008 in my 6.5(with ~15 second glow times too) and since 2009 in my K-5(with up to 25 second glow times in the extreme cold) and all 16 are still good.

Keep away from the starting fluid. In fact take the can outside and either empty it, or throw it away and do not buy more.


I have one can of starting fluid at the house, and 3 diesels. My 6.5, my 6.2, and my fathers X595 3 cyl Yanmar diesel tractor. I always said if i found that ether can next to either of those 3 vehicles heads would roll by time i was finished.

That can sits in the cabinet with dust around it it hasn't moved in so long.

A properly running 6.5 or 6.2 will not need ether, or any starting aid to start, in any temperature. I started my 6.2 in 25*F weather, complete with wind and snow, yesterday leaving work. After the normal glow time plus ~5-7 seconds extra she fired right up with a lot of rattling and clacking, but she fired on all 8 right away and stayed running on all 8.

That's how a 6.2 or 6.5 should start in any weather.

Ether is to diesels like crack cocaine is to humans. The more you use it the more it is needed. It becomes an addiction that cannot be broken once it has begun.

If you can find a diesel compression tester(gauge has to go to at least 500 psi, mine goes to 1,000 psi) and a glowplug adapter, then un-hook the Pink wire on top of your injection pump and remove all 8 glowplugs. Thread the adapter into the glowplug hole, hook up the gauge, and crank the engine over to get ~6 "puffs" on the tester.

Check your compression numbers. 400 psi is the spec. When i bought my K-5 i had a few cylinder at 390-400 psi, and a few down to as low as 350 psi. This was after the engine sat dormant for 10+ years in the truck.

I've since put over 20,000 miles on this engine(with the last 10,000+ being turbocharged) and i'm sure the compression numbers have come up.

Very good post thank you!

So if I am getting 24v at the plugs I guess the ones in there are dead. Where do I go from here though? Should I fix it and make it a 24v system again and buy new plugs? Or should I re wire it so that i have a complete 12v system again with new plugs? Wouldn't this mean that I would need to buy a starter also then?

Im pleased to hear that all of you are leading me to something in the glow plug system, I really didnt want to buy an injection pump, but I also dont want to throw money at it for now reason, is my money best spent getting my plugs to 12v and buying the new bosh glows at the moment? And what do you guys think the odds are of this being my whole problem?

Thank you everyone!

[Fmiser]

Well, what do you want for a final system?

If you want a manual controlled system with a button to activate the glow, it should be trivial to get the power from onely one of the batteries and thus you could use easy to find 12V glow plugs. Sturdy, reliable, maintainable - decidedly non-stock.

Or you could rebuild/restore the original 24 V system. I have zero experience and data on the military 24 V systems so I don't even have a clue what that involves.

A third option would be a frankenstein merge. Use the original 24 V system to trigger a relay with 12 V supply.

All should work - but each will likely require different levels of skill on your part. The full manual control is pretty well documented and easy to understand.

So - what do you want?

[6-2DIESEL]

Originally Posted by Fmiser

Well, what do you want for a final system?

If you want a manual controlled system with a button to activate the glow, it should be trivial to get the power from onely one of the batteries and thus you could use easy to find 12V glow plugs. Sturdy, reliable, maintainable - decidedly non-stock.

Or you could rebuild/restore the original 24 V system. I have zero experience and data on the military 24 V systems so I don't even have a clue what that involves.

A third option would be a frankenstein merge. Use the original 24 V system to trigger a relay with 12 V supply.

All should work - but each will likely require different levels of skill on your part. The full manual control is pretty well documented and easy to understand.

So - what do you want?

thanks and ver good points, i think what im going to do for now is fix the 24v system and get my glows to 12v and also buy and install new ones, hopefully itll fire right up then.

does this seem like a good route for me to go at this point?

[smackzed]

Sure why not. You'll probably get some better info on the 12v system at steelsoldiers

[turbonator]

Did you ever test to actually see what, if any, voltage you are getting to the glow plugs ?

[6-2DIESEL]

Originally Posted by smackzed

Sure why not. You'll probably get some better info on the 12v system at steelsoldiers

Ill go back over there and check it out. I stumbled across that website but didnt spend much time there i felt that this one seemed more active lol

[6-2DIESEL]

Originally Posted by turbonator

Did you ever test to actually see what, if any, voltage you are getting to the glow plugs ?

I dont have a ohm meter so I brought it over to my local mechanic who im pretty good friends with and he threw the ohm meter on there to test voltage and it came back at 24v at the connector for the glow plug

[smackzed]

Originally Posted by 6-2DIESEL

Ill go back over there and check it out. I stumbled across that website but didnt spend much time there i felt that this one seemed more active lol

There are a few guys here who are familiar with the 24v system but I've found that there is also a lot of misinformation because many here, myself included, have only dealt with it peripherally

[smackzed]

Also something you can try instead of starting fluid is a plumbers torch or a hairdryer in the intake to heat the incoming air.

[zetan]

Getting 24v at the glow plug is strange

From this link: http://olive-drab.com/od_mvg_cucv_chevrolet.php

Temperature self-regulating AC 13G glow plugs operate on 12v supplied by the 24v circuit through a resistor to drop the voltage.