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Discussion Starter #1
Yesterday after a 30 mile drive and a 15 minute idle the truck went into limp mode. Paper clip brought up codes 17,18 and 35. GM service wants $3,760 to replace injection pump. Truck has 156,000 miles and previous owner had the injector pump replaced three times. Don’t know what brand PMD but it was on a heat sink on the firewall which I relocated to the front bumper.
Should I try a new AC PMD before having a new injection pump? Thank you in advance.
 

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Welcome,

Start by going through all of your grounds: Grounds-Grounds-Grounds The importance of good grounds.....
Install a piece of clear fuel line on the return side of the Injection Pump to look for air in fuel, as shown here:
 
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Discussion Starter #3
Checking my ground connections found only one wire coming of the passenger side frame to the firewall but it has another ground wire coming from the firewall to the block. The wires on the back of the engine are trapped under the transmission fill tube bracket and the stud turns with the nuts.
 

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Discussion Starter #5
635041
 

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I think the one on the first picture is good. It is a ground strap and it is connected on both ends.

The 2nd picture, it is not connected. Not good.
I think it needs to go to the bolt near the firewall where another ground is already there coming from the bottom.

Glagulator can confirm it or you can check the ground thread in the FAQ.
 

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Discussion Starter #7
I cleaned the grounds, added a ground wire from the frame to the engine passenger side and purchased a PMD kit from Leroy Diesel. The old PMD had been relocated but didn’t have a resistor and was made in China. Truck starts fine now without a cloud of white smoke and I don’t have to push the accelerator to make it stop stumbling. Thank you all for your input and help.
 
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I cleaned the grounds, added a ground wire from the frame to the engine passenger side and purchased a PMD kit from Leroy Diesel. The old PMD had been relocated but didn’t have a resistor and was made in China. Truck starts fine now without a cloud of white smoke and I don’t have to push the accelerator to make it stop stumbling. Thank you all for your input and help.
Glad you resolved the issue.
Thanks for giving us an update!

(y)
 

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Discussion Starter #9
Truck stumbled when starting, after a short drive went back to limp mode, codes 18 and 35 again. I’ll be checking for air in fuel leaks. What size are the stock o-rings on the lines to the lift pump? Also this connector came out of hiding and I can’t find where it goes.
635235
 

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Do you have a 2wd or 4wd?
 

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That is for a 4wd, you don't need it.
 

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Discussion Starter #13
Thank you
 

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Plugs into the 4wd harness, for front diff activation.
 
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