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83 GMC 6.2 priming question

16K views 10 replies 5 participants last post by  acesneights1  
#1 ·
Afternoon all, This is my 1st post so excuse me if I don't get everything right. I am a do it yourselver that gets himself in trouble by not reading the fine print.. I can usually get myself out of trouble but this one has got me.. I aquired a 83 GMC 6.2 Deisel pick up.. Knowing the previous owner I knew the fuel filter needed changing of which I did but being the idiot I am I didn't prefill the new filter with fuel before starting the engine. It ran great until it sucked in the air..I have tried everything I can think of to prime the fuel system but not quite getting.. Can anyone point me in the right direction on how to prime this engine. I would be so ever gratefull....Thanks
 
#3 ·
This may not be the safe way to do it. But I use to spray starting fluid in the air box and keep it running until the mechincal pump primed it self....its real simple. But dangerous.:woohoo
 
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#9 ·
Dude ,
That is about the worst advice you could give some one espcially someone in experienced with diesels.
NEVER I repeat NEVER use Ether on a glowplug equiped engine. At the very minimum you will wipe out the glow plugs. Catostrphic engine damage can result.
 
#5 ·
Square filter or round filter?

Credit to "High Sierra 2500" off another site:

Round filter:
Hook an air compressor hose into the return line at the injection pump (IP). The line you want is the rubber one that goes into the front of the IP. Alternatively, you can stick the air hose into the filler neck, but that is not as effective. You can also modify a fuel cap with a valve stem off of a tubeless tire and use an air chuck to supply the air, which works good. Whatever way you choose, the next step is to loosen the fitting on the outlet side of the fuel filter. Loosen it enough that fuel will come out readily, but don’t take it all the way off as you will need to be able to tighten it fairly easily. Put a pop bottle with a funnel stuck in the neck under the fitting to collect the fuel. With the fuel cap on tight, turn on the air to about 4 psi. Give it some time to fill the fuel tank. Fuel will start to run out of the fitting and into the pop bottle. When the pop bottle is about full, tighten the fitting. Then turn off the air. Disconnect the air line, wait for any remaining pressure to bleed out of the tank, and then reconnect the return line to the IP. If you used the modified fuel cap or the hose in the filler neck, you can ignore these last few steps.

Once you have bled the air out of the system to that point, you may need to crank for a while to get it to start. It is not necessary to loosen injector lines to bleed the system to the injectors on the 6.2. Simply crank until it starts. You will need to do this in several cranking sessions of about 15-25 seconds in length so that you do not burn out the starter.
 
#6 ·
Square filter:

These trucks were equipped with a combination fuel filter/water separator/fuel heater ("square" filter). If your truck is equipped with a "round" filter, see the procedure for early model trucks.

Hook an air compressor hose into the return line at the injection pump (IP). The line you want is the rubber one that goes into the front of the IP. Alternatively, you can stick the air hose into the filler neck, but that is not as effective. You can also modify a fuel cap with a valve stem off of a tubeless tire and use an air chuck to supply the air, which works good. Whatever way you choose, the next step is to open the air bleed valve. It is located on the top of the fuel filter mounting block. There is a hose fitting right next to it. Hook a hose onto that, and run the hose into a pop bottle (this will collect whatever fuel you bleed out). With the fuel cap on tight, turn on the air to about 4 psi. Give it some time to fill the fuel tank. Fuel will start to flow out of the bleed valve and into the pop bottle. When the pop bottle is about full, close the bleed valve. Then turn off the air. Disconnect the air line, wait for any remaining pressure to bleed out of the tank, and then reconnect the return line to the IP. If you used the modified fuel cap or the hose in the filler neck, you can ignore these last few steps.

Once you have bled the air out of the system to that point, you may need to crank for a while to get it to start. It is not necessary to loosen injector lines to bleed the system to the injectors on the 6.2. Simply crank until it starts. You will need to do this in several cranking sessions of about 15-25 seconds in length so that you do not burn out the starter.
 
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#8 ·
once again, not mine. credit goes to user High Sierra 2500 on DP. but i hope it works out for ya
 
#10 ·
First off, this is why on any 6.2s I have ever owned, I converted them to electric fuel pumps. Problem solved. Now if running the stock mech fuel pump there is two accepted way to do this(BTW not disagreeing with you fastcr just not every one has shop air availible, I have used the shop air trick many times on a stubborn 6V92 i used to have).
If you have the square filter there is a bleeder on top with a nipple. There is a special tool which you might as well buy that is made for them. I don't remember who makes it but I want to say Matco or Mac. It is a hand vacuum pump that pulls the fuel through. If you have the round filters just take them off and fill them to tippy top with fuel and spin them back on. Have two good strong batts and hold your foot to the floor while cranking. It shou,d go on it's own. Another trick i have used it hooking a hand push pull pump (Like Oil burner techs use ) on the inlet line of the IP to pull fuel to that point and then screw it back on. I did it on my diesl van but can't remember exactly where I hooked it. But it was post filter. DO NOT USE STARTING FLIUD.
 
#11 ·
I just noticed you have an 83. IIRC 83 is the round filters. Notice Plural. There is a hidden small one practically under the rear of the intake. it's a royal PIA to get to but must also be filled with fuel.