Please help just replaced fuel lines fuel cooler and filter housing

[ethan18p]

I just replaced the fuel lines and filter housing on my 2003 duramax i believe i have air in the system at first when i went to go crank the truck up after replacing everything it fired right up ran for 10 seconds then died i primed the filter using the bleeder screw cranked it up ran perfect had it sitting outside my shop for a hour and a half then i went 5 miles down to road cut it off tried to start it back up it cranks fine but won't run i just primed it again with the bleeder next to the alternator got it to run for 5 seconds then it cut off i'm thinking i have a lot of air in my fuel system if anyone can point me in the right direction i appreciate it.


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[Ron Nielson]

I'd keep pushing the primer button and see if you can let some of that air out. It make take 10 or 20 or 30 pumps. Helpful to have a helper; one to turn the key, one to pump the primer

 

[2004LB7]

As ron said, prime and crank at the same time. If you can't get to fire, try cracking one of the high pressure lines loose and try again until you get fuel coming out.

 

[ethan18p]

I'd keep pushing the primer button and see if you can let some of that air out. It make take 10 or 20 or 30 pumps. Helpful to have a helper; one to turn the key, one to pump the primer

i've tried that already boss i pumped it for around a hour one time then i went back at it for another 30 minutes


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[ethan18p]

As ron said, prime and crank at the same time. If you can't get to fire, try cracking one of the high pressure lines loose and try again until you get fuel coming out.

i did open up one the high pressure line it just does the same thing as the primer just bubbles come out not a high flow of fuel sprays out like you would think


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[2004LB7]

You need to prime and crank over and over. If you crack an injector line open you prime and crank until you get clear fuel out of the line. Then tighten it back up and start over with priming and cranking.

Normally you prime with the bleeder screw loose until you get fuel. Then tighten the bleeder and prime until the bulb is stiff. Crank for a few seconds. If the engine doesn't fire then you start again with the priming with the bleeder closed and the bulb getting hard.

If the bulb doesn't get hard then you are pumping air, have a vacuum leak, bad seals or check on the housing or fuel line

 

[TheBac]

Moved to LB7 section.

 

[Chevy1925]

ill bet you got an air leak somewhere. either that new fuel filter housing or that fuel filter you put on is not 100% sealing up and pulling air in. For as long as you ran it, there is no reason there should still be air in the lines.

 

[ethan18p]

You need to prime and crank over and over. If you crack an injector line open you prime and crank until you get clear fuel out of the line. Then tighten it back up and start over with priming and cranking.

Normally you prime with the bleeder screw loose until you get fuel. Then tighten the bleeder and prime until the bulb is stiff. Crank for a few seconds. If the engine doesn't fire then you start again with the priming with the bleeder closed and the bulb getting hard.

If the bulb doesn't get hard then you are pumping air, have a vacuum leak, bad seals or check on the housing or fuel line

okay i'll try that again later but i believe i have a air leak somewhere possibly the housing this is the second one i got from autozone the first on i returned it cause i heard every time i pressed the primer a squirting sound from the primer


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[ethan18p]

ill bet you got an air leak somewhere. either that new fuel filter housing or that fuel filter you put on is not 100% sealing up and pulling air in. For as long as you ran it, there is no reason there should still be air in the lines.

that's what i'm thinking to this is my second housing i got from autozone the first one i returned because i heard fuel coming from the primer every time i pressed it and now this one's doing the same thing and the primer doesn't get all the way hard to where i can't push it anymore i replaced all the seals on the new primer to and it does the same thing


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[darkness]

My perhaps unpopular opinion is ditch the factory filter head and put a lift pump on with built in filtration.

 

[ethan18p]

My perhaps unpopular opinion is ditch the factory filter head and put a lift pump on with built in filtration.

i would do that if i didn't dump all this money in the new fuel lines housing and filter already


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[Chevy1925]

bad fuel filter housings are pretty common, new or not. i wouldnt doubt its leaking still but we are not there to say for sure. a clear peice of hose going into the housing and out of it while looking for air bubbles when you get it started. if you have air prior to the housing, you know its not the housing and a line or something prior. if its after the housings, its either the housing or the fuel filter. keep in mind, fuel filters can be known to cause this as well. verify you have all the o-rings in place and its properly seated.

 

[mriley1215]

There are two places that I have found the filter housing tends to leak. The first and least likely is the o-ring on the filter. The new design which is more of a v-shaped instead of round is much better at sealing but I have had one that gave me problems and just tightening it a little bit solved it. The second and more likely spot that I have found is the hand pump seal. I have an 04 LLY and have changed my filter annually (maybe 17 times now). The filter housings only lasted two to three filter changes and then I would have to buy a new one because of an air leak. I suspected the hand pump was the problem. The way I solved it is I put a couple of drops of oil around the hand pump base and let it run down around the seal before I start pumping it. Even pushing the hand pump down just a little and getting some oil down in there helps. Since I have started doing that approximately 6 years ago I have never had to replace the housing due to an air leak.

 

[2004LB7]

In line with what James said, check the water in filter sensor at the bottom of the filter too. Those have been known to leak and cause this problem. But you would normally have fuel leaking there. But not always if the CP3 is sucking fuel and this air at that pont.

 

[ethan18p]

There are two places that I have found the filter housing tends to leak. The first and least likely is the o-ring on the filter. The new design which is more of a v-shaped instead of round is much better at sealing but I have had one that gave me problems and just tightening it a little bit solved it. The second and more likely spot that I have found is the hand pump seal. I have an 04 LLY and have changed my filter annually (maybe 17 times now). The filter housings only lasted two to three filter changes and then I would have to buy a new one because of an air leak. I suspected the hand pump was the problem. The way I solved it is I put a couple of drops of oil around the hand pump base and let it run down around the seal before I start pumping it. Even pushing the hand pump down just a little and getting some oil down in there helps. Since I have started doing that approximately 6 years ago I have never had to replace the housing due to an air leak.

i noticed the o ring for the filter is like the v shape i've never seen that before but yea the filter is sealed good i even switched out the o rings around the pump with new ones and it's still doing the same thing if that doesn't work i'll most likely get another housing what housing do you recommend?


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[ethan18p]

In line with what James said, check the water in filter sensor at the bottom of the filter too. Those have been known to leak and cause this problem. But you would normally have fuel leaking there. But not always if the CP3 is sucking fuel and this air at that pont.

i will check that to thanks


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[Ron Nielson]

I don't think I've ever heard of testing the fuel supply side by vacuum, but why not? A small vacuum pump capable of 10 lbs is applied to either side of the fuel filter and see if you get bubbles. Depending on which side of the fuel filter you attach the vacuum to, you will be testing for leaks in different places, so think about that.

 

[Bdsankey]

Also check to make sure the soft lines on the driver side that feed/return fuel are not kinked/collapsed. It is not uncommon for the OEM feed line to collapse after ~2 decades. I know when I did my injectors (and many customers trucks) we've had that happen. Easy test would be to unhook the fuel feed line and put it into a bucket/jug of fuel and repeat the same procedure that resulted in a no-start.


My truck took a little bit of air in the fuel tank to get it started then it ran great. Shut it off for 10min and it wouldn't restart without doing the same. Primer felt hard etc.

 

[ethan18p]

I don't think I've ever heard of testing the fuel supply side by vacuum, but why not? A small vacuum pump capable of 10 lbs is applied to either side of the fuel filter and see if you get bubbles. Depending on which side of the fuel filter you attach the vacuum to, you will be testing for leaks in different places, so think about that.

i'll keep that in mind thanks


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