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Discussion Starter #1
started having longer cranking times last week till finally truck didn't start after refueling. pushing the primer bulb didn't help.it never got hard. used ether to get started ( was 200+ miles from home) and got going. truck runs fine once started. Ordered new filter head since the one i had was rebuilt 2 times. replaced head and still couldn't get system primed. uses shop vac to push fuel from tank to filter, truck started and i test drove for 20 mins.no issues. cutoff truck and restart but cranking still longer than normal and truck starts. let sit over night and no prime and will not start. pushing primer bulb i'm constantly getting air from bleeder. i do not see any fuel leaks anywhere but i know it's sucking air. i have a kennedy pump so i figure once it gets started the pump is keeping a constant fuel flow, but stlll no visible signs of fuel leaks. i tested the primer bulb before installing on truck by placing finger over intake tube and it had good suction. Is there a way to test for where air is entering the lines?
 

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To answer your question directly, NO, not that I have ever heard of. However, I do have a question for you. Does the Kennedy pump setup run as soon as you turn the key to the RUN position, or does it require oil pressure to be present before starting the fuel pump? My pump (not Kennedy) is wired so that when the key is on or start, the pump runs. That makes it very handy for priming the fuel system when changing fuel filters and in situations like yours where there is a leak somewhere, but who know where it is.
 

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started having longer cranking times last week till finally truck didn't start after refueling. pushing the primer bulb didn't help.it never got hard. used ether to get started ( was 200+ miles from home) and got going. truck runs fine once started. Ordered new filter head since the one i had was rebuilt 2 times. replaced head and still couldn't get system primed. uses shop vac to push fuel from tank to filter, truck started and i test drove for 20 mins.no issues. cutoff truck and restart but cranking still longer than normal and truck starts. let sit over night and no prime and will not start. pushing primer bulb i'm constantly getting air from bleeder. i do not see any fuel leaks anywhere but i know it's sucking air. i have a kennedy pump so i figure once it gets started the pump is keeping a constant fuel flow, but stlll no visible signs of fuel leaks. i tested the primer bulb before installing on truck by placing finger over intake tube and it had good suction. Is there a way to test for where air is entering the lines?
If the rubber lines under the truck are dry rotted they can let air in before the filter. The lift pump compensates for this but when the truck sits over night the fuel lines drain back to the tank as the fuel above the tank is replaced by air. My guess would be air leak between the tank and filter head.

you could SLIGHTLY pressurize the tank and go over the lines and connections with soapy water looking for bubbles, i doubt you have a very large leak since the truck runs, odds are its a tiny pin hole or crack thats just seeping slightly, which is all it takes to loose prime over night.
 

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Discussion Starter #4
just to add,the new filter head came with filter and WIF sensor.

my pump is wired to the oil pressure sensor.
 

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just to add,the new filter head came with filter and WIF sensor.

my pump is wired to the oil pressure sensor.
In that case, your pump isn't actually running until the engine is started, so you're getting no priming from it. I can't remember; is the Kennedy self-priming?
 

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In that case, your pump isn't actually running until the engine is started, so you're getting no priming from it. I can't remember; is the Kennedy self-priming?
I dont think it is since its a centrifugal pump not a positive displacement pump, however if its below the fuel level in the truck gravity should prime it. and if there is fuel at the filter head, the pump is primed.

It might just be easier though to switch the activation source for the pump from the oil pressure switch to switched ignition power. Whats the point of a lift pump that doesent run until after the trucks started? Odds are good that will bandaid the issue and give you time to find the problem without getting stranded. That said, since its not a positive displacement pump, if the tank runs down enough where the pump sucks in air, your back to where you are now.
 

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No, not self priming. Pump is relay on with key on.
The sensor is a shut down, wired into the relay, not a start up check.

Next stop for a leak, on the way back to the tank, is the quick connect seal on the flex line, driver's side top.
 

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Discussion Starter #8
correct. the pump doesnt do anything until the oil pressure is up. I haven't heard that the kennedys are self-priming. I've read where some say they have some type of button that causes the pump to run for a few seconds but I didn't see that on mine
 

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Button is on the relay, next to the red light. But that's for if the pump is already primed, as it's not a self priming pump.
 

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Discussion Starter #10
thx i didnt think it would prime the system. just saw the button. my relay is mounted upside down :(
 

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LHN...We ARE the Joneses
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There's also the possibility of a leak in the fuel module, back at the tank.
Usually appears with lower tank levels.
 

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LHN...We ARE the Joneses
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Edit;.....wait. You replaced the filter head, but didn't swap out the two lines to/fro it?


That flex line on the driver's side that makes the transition from the hard line up to the engine topside, is a potential fuel blockage at the bends (TSB issued) for one (it tends to kink and collapse), and a leak source on the O-ring in the quick connect.

TSB remedy was to cut it off and replace with 1/2" bulk fuel line and hose clamps.
 

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Discussion Starter #14
last year when I 1st experienced the dreaded p087 I changed the 2 lines to and fro the filter head. I removed those lines today and did discover one of the clamps was a little warped(worm gear clamps). it's possible air was being pulled in while pumping the bulb. I picked up some parker hose and fuel injection clamps. will install tmrw. my next step is to replace the hose you mention with parker hose and clamps. that is a tight spot where the 2 lines change from hard to soft but wouldn't I theoretically only need to change the feed line?
 

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LHN...We ARE the Joneses
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Yes, just the larger 1/2" supply line...next to it is the smaller 3/8" return line.
At the other end (hard line) down below is a crimp to cut/slice and peel back.
 

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I had the same issue a few years ago after my truck broke down. It would start to prime then lose it. I ordered a fuel filter housing rebuild kit from Amazon. Fixed the problem and no issues since.
 

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Discussion Starter #17
found the leak!!!!! pressurized the tank and found a broken clamp on the hose going into my FWS on the frame. (clamp was stuck to the fuel hose so it looked good). changed that clamp (used fuel injection clamp since they have the solid inner band) and after forever got all the air out and starts and runs good. after all that ,the test drive spit out anther issue. frozen piston on the right front caliper. UHHHGGG!!!!!. will be changing that caliper today.

thx for the help and suggestions
 
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