6.2 starting issues

[brown82]

Took them out and put a + and - on them u until they got hot. Which was super quick.
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[hatzie]

Geez. These GM/Navistar/AMG 6.2L & 6.5L Diesels are pretty simple. They need fuel at pressure, compression, and Glow plugs below 70degrees make it an easier start. But. They can and will kick off without glows.

You've got fire in the glow plugs. No question there.

The only item you haven't verified is compression #s... But you stated it ran well before you ran out of fuel... I assume there was no smoke after the initial start-up puff when the engine was still cold? If this is all true the compression should not be an issue.

This brings us back around to fuel.


You've got fuel at the injector fittings with the fittings cracked open. Did it spray out with authority or just dribble out? A good DB2 Injection Pump is capable of 10,000 psi fuel pressure off the distributor head. Your injectors should pop at 1,800- 2,000 psi. I set my 76 & M1008 injectors to pop at 2,000 give or take a few psi.
Just in case you nobody told you... Crack the fuel lines and stand way back as you crank it.
DO NOT EVER get any part of your body near that high pressure fuel spray unless you are looking for mods via amputation. This is deadly serious. The pressures involved will inject fuel into your lower skin layers and kill large areas of your skin from the bottom up.

[brown82]

It leaks out of the lines. Thats it nothing more
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[legendman]

Originally Posted by brown82

Took them out and put a + and - on them u until they got hot. Which was super quick.
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Did they glow red after about 5 seconds?

Just a dribble should be good, when I was test firing the 6.2 in the K30
it was just a dribble and then it fired up, took a while though.

You might want to start a thread over at Dieselplace and see if maybe they can add something to help.

http://www.dieselplace.com/forum/forumdisplay.php?f=20

[brown82]

They started smoking, so I stopped heating them up. Besides they are about 3 months old.

How do you check if the injector pump is bad' it wouldn't push fuel to the lines right?
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[legendman]

Originally Posted by brown82

They started smoking, so I stopped heating them up. Besides they are about 3 months old.

How do you check if the injector pump is bad' it wouldn't push fuel to the lines right?
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Unless you take it off and have a diesel shop test it there is no real way to tell on the truck.

I doubt running it out of fuel did anything to it, sounds like there is still air somewhere.

[brown82]

Does the dual tank switch make much of a noise when switching tanks? I had a friend come over and assist me yesterday. He told me the switch seemed not to be working cause it wasn't locking into place. I have only been placing fuel into one tank. Should I be putting fuel into the other to the other tank to see if the fuel is just being feed by what's in the filter??
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[legendman]

Originally Posted by brown82

Does the dual tank switch make much of a noise when switching tanks? I had a friend come over and assist me yesterday. He told me the switch seemed not to be working cause it wasn't locking into place. I have only been placing fuel into one tank. Should I be putting fuel into the other to the other tank to see if the fuel is just being feed by what's in the filter??
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If you suspect the tank switch, I would hook up a jug to gravity feed right to the filters, the injection pump will pull fuel.
Then see if you can get it running.

If it does run then move the jug to were the line runs to the fuel pump from the tank switch. Process of elimination, it's a hassle but need to rule out as you go.

[brown82]

I have yet to try the latest advice.

Just an update. I moved it back into the driveway (wife didn't like that) to make it a motivator to keep working on it.
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[86c20]

Originally Posted by hatzie

Geez.


Crack the fuel lines and stand way back as you crank it.
DO NOT EVER get any part of your body near that high pressure fuel spray unless you are looking for mods via amputation. This is deadly serious. The pressures involved will inject fuel into your lower skin layers and kill large areas of your skin from the bottom up.

when i was in school a teacher had pics of a guy that worked for him that got injection with fuel. lost 2 fingers and they cut his arm up to the elbow.

cold it be a broken cam or off timeing on the pump? just speaking out load lol
the only other thing i can think of is that the pump is not putting out the min pressewr to open the injectors

[brown82]

My father swears by his mechanic s words that there is a manual fuel prime pump on this truck. Is this accurate?
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[86c20]

Not that I have ever known of
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[hatzie]

Originally Posted by brown82

My father swears by his mechanic s words that there is a manual fuel prime pump on this truck. Is this accurate?
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Not stock. If the mechanic installed one ask him where it is... It's a possible air leak location.

[brown82]

Back to working on truck. Discovered a "hot" wire that seems to be hot at all times. Can you help?

Connects to that block and runs over by the glow plug relay

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[brown82]

I also found those purge valves, they are stock and built into the frame by the rear axle
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[86c20]

have you tryed just unpluging the glow plugs and hiting it with a little either?

[hatzie]

That J block is supposed to be hot all the time. It's real easy to find it on the electrical diagrams.

I'm not sure what the black wire with the blue strain reliefs is for... It's not stock looking. I'd cover up the loose end or remove the hot end from the J block. If that loose terminal shorts against something it'll blow the fusible link at the starter.

[legendman]

Originally Posted by 86c20

have you tryed just unpluging the glow plugs and hiting it with a little either?

Not a good idea.

Best to get the glows working.

Head over the dieselplace.com they have a 6.2 section with some knowledgeable guys that will get fixed up.

[legendman]

Originally Posted by brown82

My father swears by his mechanic s words that there is a manual fuel prime pump on this truck. Is this accurate?
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No mechanical primer on these trucks, wish there was... would save a lot of grief and wear on the starter and batteries.

[86c20]

I no its nit a great idea but it will help to narrow it diwn to the plugs or fuel. I am not saying feed it with either just a shot ti get ut going. Why is every one so scard of either. If used right it is great. And if u are in to motors you no how ti use it. I know that detroit used either as a cold start aid abd same as cat
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[legendman]

Originally Posted by 86c20

I no its nit a great idea but it will help to narrow it diwn to the plugs or fuel. I am not saying feed it with either just a shot ti get ut going. Why is every one so scard of either. If used right it is great. And if u are in to motors you no how ti use it. I know that detroit used either as a cold start aid abd same as cat
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Ok just this one time

I would get it cranking then hit it with ether.

Don't spray the ether then try to start, it may lock up and the force will break the bolts off the starter.
Ether fires before TDC that's why it is bad.

[86c20]

Originally Posted by legendman

Ok just this one time

I would get it cranking then hit it with ether.

.

yes I knew you knew how to use it right. Lol
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[legendman]

Originally Posted by 86c20

yes I knew you knew how to use it right. Lol
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LOL I have an old Massey-Ferguson that won't start unless I give it a shot.
Lots of ether practice plus it smells good lol

[86c20]

lol. i have seen some of the old diesel be rebuilt do to being either whores and still wont start with out it.

anyway back to the 6.slow lol. when mine would not start it was the plugs where burnt out now i am thinking with this one he is not geting fuel. just seems to be the only thiing he has not shecked but cant see why runing it out of fuel would junk the pump but what about the lift pump? not enough suplie? i no the cummins get really wierd when they lose the lift pump.

[hatzie]

I agree that the lift pump is probably suspect. It's just a camshaft eccentric mechanical fuel pump like a good ole 350 with a carb. The diaphragm can fail.

The engine will run without a lift pump because enough fuel will continue to siphon from the tank to keep the injection pump happy. If you let air into the system, like changing fuel filters or running out of fuel, the injection pump is not capable of drawing fuel forward from the tank.

If they're good the mechanical lift pumps work just fine. I've put electric lift pumps on my older trucks because I'm a darn lazy engineer. It makes priming fuel filters without pre-charging them bloody easy.