12 Valve 2nd Gen Dodge Cummins 94-98 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with P7100 Injection Pumps

priming procedure

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  #1  
Old 02-20-2013, 05:32 PM
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What is the proper priming procedure for a 1997 cummins? I just replaced the injectors and put it all back together. I cracked the injector lines on the pump and got fuel. then I cracked the injector lines and no fuel. What is the right way to prime the system?

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I think either the fuel shut off is bad or the lift pump is bad. Im getting presure at the fuel filter and at the inlet of IP but no fuel coming out of IP. Please help I have to put this truck back to work ASAP. Yesterday I did get fuel to come out of the IP and almost had the truck started but no fuel came out today
 

Last edited by 1993firstgennewbie; 02-20-2013 at 05:32 PM. Reason: Automerged Doublepost
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Old 02-20-2013, 06:55 PM
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bleed it at the injection pump at the holders, then bleed it at the injectors. if it was working fine before the new injectors nothing is is broke. did you have the shut down solinoid off? sometime this can get in a bind and only give you partial or no fuel. its will take several cranking sessions to get the whole IP bled if you allowed the fuel to drain completely back to the tank. you may want to prime the lift pump a bit to getthings pumping and gurgling around.
 
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Old 02-20-2013, 07:59 PM
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You might need to prime the LP start/run and repeat 2-3 times before all the chugging and dying subsides. ...and make sure there is fuel in the tank. I ran dry for the first time the other day, while believing a gauge that said 1/4
 
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Old 02-21-2013, 04:48 PM
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how do you prime the lift pump?
 
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Old 02-23-2013, 08:27 AM
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I just dealt with this recently. it was very frustrating and I did not cope with it very well. and in the end what worked for me was I fabricated a device to pressurize my fuel system using a piece of 1" drain hose a 1/2" nipple and a wall hydrant. I then stuck the plain end of the hose into the fuel filler and wrapped a shop rag round the hose and tamped it into the gap around the hose. then with the front banjo fitting loose on the fuel filter/water separator I blew through the hose hydrant (wall hydrant same thing) as hard as I could then closed off the hydrant then went to the primer on the lift pump and pump it. I had to do this a couple times cause it wasn't exactly air tight. n e hoo when bubbly fuel started coming out of the bolt. then I piddled around to let the air and fuel settle then pump some more till no bubbles came out and closed the banjo fitting tight. NOW BE AWARE it is wise to know that your over flow valve is good(front of injector pump inboard near the head at #1 cylinder) and letting off at around 20psi before you start doing all this. a diesel shop near me did it and shimmed it for me for a high five and a thank you. I the went back to priming and continued till the primer was hard to push. now this is not in the dodge repair manual but I saw a guy do it in a vid on this or another forum. I did not do any injector line cracking business. I got in the truck and cranked the motor holding my throttle to the floor. It took a 15 count and it spun like it wanted to fire up. ten I checked the starter and fuel shut off solenoid to see if the got hot. then I did it again and it freakin started. It idled about 205 rpm low and climbed till it was at around 705. now this I believe is unrelated t. prior to this method I tried the cracking method and I have fuel and bubbles coming from injector 3 at the o ring and I roll coal at any load including gear changes. so im going to have the injectors tested at the same shop that did my OFV but I have to hold off till I have the money in case I have to replace the injectors. so the truck is still parked for two weeks now which is over a month of dealing with this crap. freakin diesels. I love them but they are whiney spoiled little princesses man. shhhh don't tell her I said that.

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oh and I hope you disconnect the batteries prior to air getting in to the fuel system. if you haven't dealt with it yet you can burn the element in the fuel heater and cause more prollems
 

Last edited by NEWBIE 98; 02-23-2013 at 08:27 AM. Reason: Automerged Doublepost
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Old 02-23-2013, 08:47 AM
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i use air in the tank as well when truck loses prime. just watch and dont get too much pressure.
 
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Old 02-24-2013, 02:05 PM
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Interesting
 
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Old 02-28-2013, 10:14 AM
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Ok I almost had it. I put a wet vac on the blowing attachment and stuck it on the fuel tank. The I pumped the **** out of the lift pump and I got 1 2 5 and 6 to prime and just as 4 was gurgling, the starter goes bad and it was just starting to fire. So I went and had the starter replaced under warranty and started cranking on it and the thing lost prime again WTF. also I have to manually pull the fuel shut off to get it to engage I thought that was the problem for sure but still no success. We are now renting a penske truck until I get it fixed
 
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Old 02-28-2013, 06:27 PM
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blue wire at the battery terminal is a common failure for the solinoid. kinda sounds like you have a faulty OFV or have a hole or cracked line somwhere letting things bleed back.
 
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Old 03-01-2013, 11:33 AM
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where is the ofv
 


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