86 6.2 diesel crank no start

[pmehringer001]

I’ve just bought 1986 K30 CUCV with the 6.2 Diesel in it. It’s really low mileage, only 20k original, I bought it from a local fire dept. it has a new or rebuilt injection pump, and glow plugs look fairly new from the outside. It has been a little cold around here lately, (only as low as about 25 degrees in the morning) but it will just crank and crank, I know it’s not good but it will only start cold if I spray a little starting fluid in it. Once warm if you shut it off it will start right up no problem.

I plan to replace glow plugs (just to be sure), maybe glow plug controller and relay, and maybe a new starter to spin it faster.

Anything I need to look for or check first before I do any of this?

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[Rickf]

Use starting fluid if you want to blow the head gaskets. 6.2's don't like to start without functioning glow plugs or fair to poor batteries spinning the starter. It probably still has the 24 volt starter & glow plug system. Get a multi meter and figure what's 24 and 12 volt.

 

[Blue Ox]

Ditto on Do NOT use starting fluid. Do you get smoke from the exhaust while cranking? Test the glowplugs with a test light. Pull the connector off and attach test light to battery positive. If it lights the plug is good. Test all of them. The glowplug light on the dash is powered by the glowplug circuit, so if it's coming on for a reasonable time, approx ten seconds on a regular cold start, they should be working okay.

Test and report back.

 

[Craig Nedrow]

Also, when you first turn on the key, you will here a click which is the glow plug controller, locater on drivers side rear of engine. I had to replace mine. Also if your block heater is not working, replace it, had to do that to, not a terribly job.

 

[vr1967]

Been dealing with these IDI diesels since 78, when the old 5.7s came out. We’ve had at least one in the family every since, and I’m fixing an 84 up with a 6.2 that will go back to being my daily driver. I tried to buy the truck new when it hit the lot in Nov 1983, not knowing a buddy had ordered it, and it was waiting on a Banks turbo before David took delivery. Remember when we were getting the new CUCVs to replace the Dodges in units on post.

Pull the glow plugs one by one, ground the body (i grip them with vice grips and hold the vice grips to a good ground) and cycle the key. Should see the tip get glowing red. Check every one. Just because the circuit works, doesn’t mean the plug itself is heating up.

I’ve gotten bad new plugs out the box. Use Delco 60G (self limiting plugs). I have not had much luck with any other ones.

Check the starter and make sure it has the front brace. If changing the starting system back to 12v, use a later 6.5 starter and corresponding brace.

Check the harmonic balancer thoroughly. I’d probably just change it due to age.

 

[pmehringer001]

Ditto on Do NOT use starting fluid. Do you get smoke from the exhaust while cranking? Test the glowplugs with a test light. Pull the connector off and attach test light to battery positive. If it lights the plug is good. Test all of them. The glowplug light on the dash is powered by the glowplug circuit, so if it's coming on for a reasonable time, approx ten seconds on a regular cold start, they should be working okay.

Test and report back.

Yes it does have some white smoke after cranking for a bit, exhaust currently is like an axle dump so hard to really see it while I’m in the truck. As soon as I get a chance I’ll check each wire for the glow plugs and replace the plugs themselves. Hopefully that helps it, thanks!

 

[pmehringer001]

I also think my starter may be going out soon, might be a large part of the problem. I’ve replaced both alternators and the batteries are from 2021 and test good. If I shut off to get fuel when I start it up again it barely turns enough to start. However when it’s cold it cranks faster but still not very fast. It has 13.13 volts at the starter, which is the same as what the batteries have so I’m pretty sure it’s getting enough power. It also has a remanufactured starter on it already so wouldn’t surprise me if that went bad.

Does that sound about right? Still new to the diesels and just getting into it.