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

PMD Fails In Cold Weather

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  #1  
Old 01-20-2011, 05:50 PM
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Default PMD Fails In Cold Weather

My 6.5TD ran fine all summer but when the temperature dropped it would start but while idling/warming up it would quit after running only a minute or two. It started again but again ran for a few minutes then quit. This would go on for 4 to 9 times before I got it to idle without stalling.

Everybody knows PMDs quit due to hot temperatures so I looked for other causes but nothing corrected the problem. Finally on a 20 degree morning I put a 60 watt lightbulb under the PMD for 2 hours and put a cardboard box over the bulb to keep the heat in (my PMD is mounted on a heat sink above the intake manifold). After 2 hours I started the engine and it ran perfectly without ever stalling. I've done this at least 8 times on very cold mornings and it worked every time.

Don't know if anyone has had probs with the PMD in cold weather but that's my solution if it happens. Of course, the PMD will be replaced.
 
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Old 01-20-2011, 06:01 PM
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before going after the PMD get OPS in and see what happens
 
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Old 01-20-2011, 06:09 PM
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I'm putting the OPS in tomorrow morning as you know from my other post about the lift pump so after that I'll see what happens on our cold mornings without the lightbulb. Current/voltage drops in cold temps so that could be a factor.
 
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Old 01-20-2011, 06:58 PM
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if you batteries drop that muck i say it time for new ones these engine need lot cranking speed to start and to work the glow plug system
 
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Old 01-20-2011, 09:41 PM
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pure heat actually doesnt really kill them its the large difference in temps that kill pmds. engine is same temp in winter and summer but in the winter the engine gets a lot cooler after you havent ran it for a long time for obvious reasons. in the summer the temp difference isnt as drastic as ambient air temp is a lot higher
 
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Old 01-25-2011, 01:04 PM
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I installed a new AC Delco Oil Pressure Switch (OPS) and that cured the problem I was having with the fuel lift pump not running but the engine still quits while idling on a cold morning. Today it quit 3 times before I could get more than 2 blocks from my house and the outside temp was 40*. Any other ideas out there???
 
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Old 01-25-2011, 01:17 PM
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are you getting any codes and do have spear PMD try
 
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Old 01-25-2011, 01:27 PM
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I don't have a spare PMD. My truck is a '94 so I have to use the blinking method to read DTC codes. I ran those yesterday and got only 12, the start up code. Ran them twice, cleared the codes and ran them again and got only DTC 12.
 
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Old 01-25-2011, 03:18 PM
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just may be your PMD where is your PMD mount at now
 
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Old 01-25-2011, 08:31 PM
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My PMD is mounted on the big heat sink made by SS Diesel, on top of the intake manifold. I installed it in March of 2006 and it has 8,748 miles on it. It is a Stanadyne. Remember that when I warmed the PMD with a 60 watt light bulb for a few hours before starting the engine on a cold morning, the engine didn't stall. Cold must be a factor in this problem.
 


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