Lift Pump Lever Position Confusion?

[KEENO]

Hey Gang!



I'm prepin' my truck for a 2 1/2 week trip to Jackson Hole, Wy. & Canyonland area of Utah.



I replaced a questionable Lift Pump (Carter brand) w/ a new Cummins Lift Pump. Installation was straight forward.



My question is in regard to Lift Pump Manual Primimg Lever "position" after purging the pump & feed line of air thru the "low pressure bleeding screw".



IN WHICH POSITION SHOULD THE MANUAL PRIMING LEVER RESIDE DURING NORMAL OPERATION?



In section 14-114 FUEL SYSTEM in the '92 service manual under MECHANICAL LIFT PUMP it states: "During vehicle operation the pump lever must be in the down position. " Easy enough to understand.



Then: In section 14-134 FUEL SYSTEM - SERVICE PROCEEDURES (a few pages later) the manual states: "CAUTION: The lever must be returned to the locked position (pointing up) after priming. " I assume this means while the vehicle is in operation once again. Is this conflicting information or I'm I missing something?



LOOKING FOR THE STRAIGHT ANSWER!



Thank you in advance..... KEENO

 

[J DeMaio]

Not for sure on this KEENO, I think it should be in the up position, my primer doesn't seem to work. I push down or pull up and it is very easy to operate, there is no resistance whatsoever to show that it pumps and i have even tried to rotate the engine to other positions, when i replace fuel filter I just fill it with fuel and it starts right up. The theme here is to "NEVER RUN OUT OF FUEL!"

 

[AlK]

Keeno,

I asked that same question about a year ago and received no definitive answer. The lever on mine is in the up position. Would be nice to have an answer.

---

Al

 

[WestTN]

On my 1989 the pump lever normally resides in the up position. There is a slight detent to hold it in place.



To J Demaio- Did you loosen the air bleed screw to allow the air to escape? Piston type fuel injection pumps are so sensitive to damage due to extremely small clearances that I would never risk pouring fuel into the filter. Mine has always been purged by the book.

 

[J DeMaio]

Yes, WestTN, I loosened the air bleed screw to purge the air out once but it didn't work. I ended up having to roll the motor over by teh starter continuously till the fuel came out of the air bleed port. I know this wasn't that great on the starter but I had to get home. This ended up ruining my 1 month old battery, but i got a new one. That lever won't pump at all, there is no resistance against it in either direction.

 

[BushWakr - RIP]

The up position is the correct one. That is, lever at 3 o'clock.

regards, Bush'

 

[KEENO]

Thanks!

Thanks for all of the replys!



My truck is running well w/ the lever in "UP" detented position (3 O'Clock pos. as Bush' mentioned)



I did have some of the similar tendencies as "J" mentioned. I could not get the new lift pump to prime well even after spining the engine. However, w/ the engine running and cracking the "Low Pressure" bleed screw, fuel ran out like a banshee! This should make the injector pump very happy.



I finished w/ "High Pressure" bleeding the injectors & return line to insure everything was 'air' free.



Only another week of wrenching on my truck & it will be ready for it's western journey.



Keeno

 

[NuttyMopar]

Now everyone has me thinking about my fuel filter. I only change it once a year and that time is coming up soon. I usually just fill the new filter with fuel and carefully screw it on. I do pump the lever once or twice but the truck just starts right up without a problem. My question is: What would happen if air does get into the lines? I know it won't hurt the motor but will it take away performance? Is it better to bleed the lines starting at the filter and working towards the injectors? What is the proper procedure in doing that? Thanks.

 

[KEENO]

Hey Nutty!



Fresh from the pages of my '92 Service Manual in Section 14-134 Fuel System - Service Procedures:



"Some air enters the fuel system when filters or the injector pump are changed. This small amount of air is vented AUTOMATICALLY from the injector pump through the FUEL DRAIN MANIFOLD. "



The system will have to be bled manually if:



-The Fuel Filter is NOT filled before installation.

-Injector Pump is replaced.

-High Pressure Fuel Line connections are loosened or replace.

-Initial engine start-up or start-up after an extended period of no engine operation.



I always fill my fuel filters w/ fresh diesel before installing and then start & operate normally.



Just a few words from the manual... Amen!



Tim "KEENO" Keen

 

[WestTN]

lift pump confusion

NuttyMopar,

I always fill my filter too, but I do it by using the priming lever per the manual. Open the air bleed screw and start pumping. When fuel runs out around the screw, close it and you are ready to go.



Depending on where your engine has stopped, you may need to bump the starter to be able to stroke the pump. Usually it takes several, possibly a couple dozen pumps to fill the filter. This is therecommended procedure in the manual.



I know a lot of people pour fuel into their new filter, but it is still VERY risky. A particle of dirt far too small to see can score the pump and begin the failure process. It just isn't worth it for the few seconds you save. I have almost 223,000 miles on my '89 and the original pump still works fine. The only repair is a new pump seal last year.

 

[ggorremans]

. . per a Cummins tech, fuel filter change with every other oil change. Easy to remember.

gary