Chevy/GMC 6.2L and 6.5L Discussion of Chevy and GMC Trucks with 6.2L and 6.5L Diesel Engines

91 Suburban w/6.2 Head cracked

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  #21  
Old 04-16-2014, 07:14 AM
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Hey again guys, the engine's running good on this old burb, but a couple questions-

Sometimes when I go to start it hot the glow plugs wouldn't cycle. however it still started, just cranked longer. so, I bypassed what I thought was the "inhibit" switch? it's the one behind the ex manifold on the passenger side head.

Things had been working fine until yesterday morning. it was 25 degrees and I went to get the old girl started. I cranked and cranked and it smoked and smoked and wanted to fire, but acted as if it wasn't getting the glow plugs, even though the light was cycling... finally it did start, but I'm wondering, did I bypass the wrong switch?

Thanks!

DF
 
  #22  
Old 04-16-2014, 07:57 AM
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Sounds like you got the correct temp switch. Are the glow plugs good? Maybe they are weak.


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  #23  
Old 04-16-2014, 08:59 AM
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brand new kennedy quick heats
 
  #24  
Old 04-16-2014, 10:56 AM
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Check the glows for power when the light cycles-perhaps the relay is bad or a fusible link or several are burnt out?
 
  #25  
Old 04-16-2014, 03:01 PM
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Yes i see the crack in the cylinder as racer55 pointed out time for new motor
 
  #26  
Old 04-16-2014, 03:38 PM
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This thing I'm wondering now if it's a fuel issue.

found out the switch I had unhooked was the switch for the cold timing/throttle advance. hooked that back up. Tried to start it today at 40 degrees, and same blasted thing. crank and crank. white smoke out both sides till it fired.... once fired up it ran great. Took it to the shop, tested glow plugs. Glow plugs are coming on and off with the light. However, I'm not seeing that the cold advance is working. should the little plunger on the bottom of the IP be pulled in towards the pump when cold? or out? I can move it manually, but I don't think it's moving on its own.

What's strange is none of this was going on until I took it out to the shop the other night to put 2.5 inch lift blocks under the rear springs. since then I've got this cold start issue.
 
  #27  
Old 04-16-2014, 03:53 PM
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Damn your right, that temp switch is for cold advance. I was thinking for glow plugs for some reason. That would leave glow plugs on until engine warmed up.
As far as plunger for cold advance, can't you jump it and see if it moves? Ground the body and 12v to connector and see if it pulls in or pushes out. I have a couple pics of the cover off my DB2 pump but its hard to tell which way that sucker moves.

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The pen in the pic was referencing fuel shut off solenoid for someone else.

Maybe try running a jumper to cold advance when engine is cold if you don't have power to it and see if it starts easier.


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  #28  
Old 04-16-2014, 06:34 PM
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