hey all. i dont usually have any question on working on these engines, but today im a little puzzled. i changed the stock lift pump on my 2001 with a raptor 100. i had this lift pump on my other 2001, but i just got that one an air dog 150. 

anyhow, ive changed lift pumps/filters on these trucks 20+ times and have done the bleeding procedure as anyone would. crack lines 1,3,4 bump a couple times till you get some fuel, crank until air is gone and fuel is clear, close lines, start.

today after i got done finishing my lift pump install i did just as i stated and i was getting some fuel/air from all three. line 4 started to get good fuel and it was acting like it wanted to start. all the sudden lines 2 and 3 went from fuel/air bubbles to nothing. i cracked the vp44 line and was getting good fuel there. i then started to crank again and again with fuel only coming out of line 4 and not 1 or 3. i then opened line 5 and got good fuel from 4 and 5 still but none from 1 and 3. it isnt even trying to act like it wants to start. no engine codes. im guessing vp is toast. whats your thoughts. 

22 minutes ago, dripley said:

I never sprayed it straight into the motor, just on air filter. It might awful concentrated straight into the manifold. But don't really know.

ya figured better be safe than sorry

Out of desperation with a difficult prime, on one occasion I reversed the hose on a shop vac and blew air down in the fuel tank fill neck.  You don't need to do it for long... just short blasts of air and I pressurized fuel all the way to the engine and it started just fine. I also found a leak that way on another occasion. You'll get it to run this way if the VP is good but you better have fuel pressure showing on a gauge to make sure your lift pump is working or your killing the VP.

 

BTW, during the time you've been trying to get this truck going, even when just bumping the starter, your fuel pressure gauge should be showing at least14-19 fuel pressure.

Edited July 8, 20186 yr by JAG1

1 minute ago, JAG1 said:

Out of desperation with a difficult prime, on one occasion, I removed the filter out of a shop vac, cleaned the shop vac inside, reversed the hose so as to blow and blew air down in the fuel tank fill neck. I pressurized fuel all the way to the engine and it started just fine. I also found a leak that way on another occasion. You'll get it to run this way if the VP is good but you better have fuel pressure showing on a gauge to make sure your lift pump is working or your killing the VP.

 

BTW, during the time you've been trying to get this truck going, even when just bumping the starter, your fuel pressure gauge should be showing at least14-19 fuel pressure.

sadly, i dont have a gauge on this truck, just a low pressure warning light. ive been wanting to get one but this is #3 out of my 3 cummins and doesnt get driven much, and it all stock so unless a raptor completely fails it shouldnt have a problem supplying fuel. you just blew it down into the filler neck?

Yes, using my hand to kind of hold air the air in there and pressurized the tank. Do it in short blasts, just a few seconds each time, you don't want to over stress the fuel tank. When you remove the vac hose after just a few seconds you'll be amazed how much pressure comes blowing out the filler neck. You'll see it doesn't take a whole lot.

Just now, JAG1 said:

Yes, using my hand to kind of hold air the air in there and pressurized the tank. Do it in short blasts, just a few seconds each time, you don't want to over stress the fuel tank. When you remove the vac hose after just a few seconds you'll be amazed how much pressure comes blowing out the filler neck. You'll see it doesn't take a whole lot.

are you cranking while doing this or no

Usually I have no help for that. It would be better to have someone starting it at the same time.

 

I have also used an air hose but difficult to keep the air in there with a rag or piece of foam.

 

Other time I suspected dirt was clogging my draw straw in the tank so I removed a fuel line connection closest to the tank and blew air backwards in the fuel line.

Edited July 8, 20186 yr by JAG1

24 minutes ago, cumminsVP2001 said:

just a low pressure warning light.

 

Need a gauge... (Priority!)

 

Most low pressure light come on a 3 to 5 PSI which is way too low. You should keep at least a minimum of 14 PSI as a bottom pressure no more than 20 PSI is needed.

3 minutes ago, Mopar1973Man said:

 

Need a gauge... (Priority!)

 

Most low pressure light come on a 3 to 5 PSI which is way too low. You should keep at least a minimum of 14 PSI as a bottom pressure no more than 20 PSI is needed.

yes yes i know.  

22 hours ago, cumminsVP2001 said:

even if im for sure getting good fuel to the vp? it can still not be primed?

Good flow to vp should be spraying everywhere not barely trickling out make sure there is no air in the line going into the vp before doing the injector lines.. also u can try bleeding one line at a time instead of cracking them all.. I apologize I got busy yesterday.. I hope you get this figured out.. seems most in the thread know what they talking bout so u didn’t need me that much haha.. from person experience with water pumps u can prime em easily hundreds of times and that one time too much water / fluid excapes the chamber it will still pump just not to full potential it is practically vapor locked can’t push the bubble out.. same can happen in the radiator if u fill it too fast.. also if u have a spare battery laying around u can run pos and neg directly to the pump so ur not constantly waiting on it..

Just realized ur pump location is under the hood behind the filter housing.. one of the worst spots cuz the pump gets way too hot.. if this is the case the pump is way diff than what I was picturing in my head more than likely explains the confusion still concepts are the same also wouldn’t need a battery just two pieces of wire long enough to reach ur battery 

6 hours ago, snoogett said:

Good flow to vp should be spraying everywhere not barely trickling out make sure there is no air in the line going into the vp before doing the injector lines.. also u can try bleeding one line at a time instead of cracking them all.. I apologize I got busy yesterday.. I hope you get this figured out.. seems most in the thread know what they talking bout so u didn’t need me that much haha.. from person experience with water pumps u can prime em easily hundreds of times and that one time too much water / fluid excapes the chamber it will still pump just not to full potential it is practically vapor locked can’t push the bubble out.. same can happen in the radiator if u fill it too fast.. also if u have a spare battery laying around u can run pos and neg directly to the pump so ur not constantly waiting on it..

Just realized ur pump location is under the hood behind the filter housing.. one of the worst spots cuz the pump gets way too hot.. if this is the case the pump is way diff than what I was picturing in my head more than likely explains the confusion still concepts are the same also wouldn’t need a battery just two pieces of wire long enough to reach ur battery 

thank you all for the help. i just got back inside from trying to bleed it for an hour and no luck. i did get fuel to lines 1 and 3 which is a plus, but its just not high enough pressure i think..at one point it started hiccuping like it wanted to but then stopped.then after that i couldnt get any fuel out of line 3, a slight dribble/flow from line 1 and line four was getting the most, but still not spraying out.  i am getting high pressure fuel at the injection pump (it sprays everywhere when you loosen the banjo bolt.

Just get the lines slllllightly loose and crank that mofo! While it’s cranking slowly tighten the lines as tight as you can hand tight and see if it’ll sputter to life.

2 minutes ago, notlimah said:

Just get the lines slllllightly loose and crank that mofo! While it’s cranking slowly tighten the lines as tight as you can hand tight and see if it’ll sputter to life.

ive done it all, slightly cracked, 2-4 turns loose. like i said it just doesnt seem like its getting enough pressure to the injectors

So sometimes this happens with a diesel can be hella hard to get fully primed seems u got the pump for sure primed and need to get all injector pipes filled.. don’t give up.. 

1 minute ago, snoogett said:

So sometimes this happens with a diesel can be hella hard to get fully primed seems u got the pump for sure primed and need to get all injector pipes filled.. don’t give up.. 

just keep cranking? i feel like im getting no where and am going to eventually ruin a lift pump, injection pump, starter, batteries or the engine as a whole

Don’t just continue to crank the truck pull one pipe completely loose from the intake manifold.. turn key on and off twice should start pump for filter refil when fuel comes out of that one put it back completely tight I usually start with the front one going to the back.. one at a time when u have fuel coming out of all of them u should try to crank it

I’ve actually had to block the pipe with my finger for it to start with deisel out of it I guess it can get vapor locked somehow

Just to clarify if fuel doesn’t come out first try turn the key on and off twice again u should hear the pump running don’t overheat the pump trying.. 

I never heard of turning the key on and off twice to get the pump running. Mine, I just bump the starter, no engine start, and it runs for 30 seconds or so.

Just bump the starter and the lift pump will run 25-30 seconds. (Reprime program).

well..another day failed to start. just got back in from another hour of trying to get it going. this time i bled in every place i could till i got good clean fuel. at the injectors i was getting a small stream from #1, #4 and #5 were getting pretty good fuel but it was foamy and a mix of spray/running out. still no fuel from #3. no matter how much i bumped or cranked or bled the fuel coming out of 4/5 was foamy. i then decided to throw on my stock IP and bleed from everywhere again. same situation. decent fuel from 4 and 5 but foamy, a little from 1 and none from #3

I would check your fittings again on the suction side and be sure they are tight. It sounds like you are sucking air in somewhere with all the foamy fuel you are seeing.