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Discussion Starter · #1 ·
Truck would loose prime if parked on a incline (front tires higher than back). I didn't think it was getting harder to start over time, just one day went to start truck and wouldn't go without priming it.

Fuel filter primer seemed soft and I know they are a wear part. So I replaced the filter housing with a NAPPA brand one. I also replaced the fuel lines from the housing to the next joint (about 12 inches I Think)

Right away the new housing leaked out the top of the primer. The new filter housing also didn't come with a new water separater. Nappa had no replacemenrts in stock to exchange it with, so I left it on the truck and ordered one off amazon with a new water separator. I also picked a new fuel cap as someone said they sometimes wear and don't let oxygen into the tank???

For the week the leaky housing was on, the truck started fine but after a min of idle it started to die and I had to floor it until lines filled up again and then it ran fine until parked. Then started fine, but needed to floor it once it started dying while idling until lines filled up agian.


Put the new fitler housing, water separator one.. Truck kept losing prime again.. It came with a no name fuel filter which I planed on taking off anyways once my AC Delco arrived in the mail.

So put the AC delco one on.. Truck seemed to run "ok", but I noticed when cold idling the engine sort of chugged. It was very slight. Figured it had air in the lines and drove it.

Truck would still chug at cold idle a week later. So I turned on the rpm gauge on my edge cts. Rpms were going up and down by +- 60 rpms at cold idle.

Then yesterday (about 2 weeks after the new AC delco filter was put on) truck was parked on a flat surface and truck started great, but when I put it in gear and drove away, it started to die.. I put it in neutral and floored it until rpm's picked up and drove it home fine.

Today it started great, didn't die and then I drove it 15 mins to town where I had to park it on a very steep incline in a parking lot. I went into the store for 15 mins. Came out and it totally lost all prime and needed to be pumped.

Seems like its fine if sitting flat. Loses primes right away if parked at an incline though. And truck seemed to be fine for 2 weeks..

Whats my issue?

Do I have a leak in the lines between the tank and filter housing?

Do I have a leak in the lines between the housing and injector pump?

Or do I need a new injector pump?


*I will go out and tighten the hose clamps I used when I put on the new fuel lines from the housing to the first joint. My neighbor tightened the 2 clamps close to the engine, I tightened the 2 on the housing. He's pretty competent, but who knows??
 

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Discussion Starter · #2 ·

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'07 GMC LBZ
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I have an 07 with similar issues. For me it seems to be heat related. Started last summer, towing, went into limp. I took it to a shop that replaced the fuel pressure regulator and filter , didn't fix the problem. Limped it to another shop that eventually replaced everything from the tank to the injectors and still didn't fix the problem, limp within 50 miles. Now, when it's hot I have to pump the primer and bleed the filter carrier or she'll crank all day and not start.

Sorry I don't have a solution for you. Hopefully these are related and we will both get it figured out.
 

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Last summer my truck was losing prime over a couple days while parked in my driveway on a slight incline. Pumped the primer 5-6 times and it fired right up.

I put in a new Baldwin fuel filter and ACD water sensor along with new orings.

Have not had any problems since.

Good luck on yours.
 

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It certainly seems like there is a problem getting fuel into the engine. Often, the addition of a new fuel filter and the mount will solve the problem of air leaking into the fuel system. There are also a couple of connectors in the fuel line between the tank and the driver's side of the engine. You might see if you can find any problems there. Another thing that can be done at little cost is to make a setup like you were going to run fuel injector cleaner thru the fuel system, disconnecting the fuel line near the master cylinder and putting a tube into a container of fuel and the other end into the line to the fuel filter. If the truck starts reliably once you get it primed, that tells me that the problem is not between that connection and the engine, but it is further back towards the tank. If you still have problems running with this setup, your problem is likely between there and the CP3 somewhere. Doesn't cost much, is not hard to do, just takes a little time and effort. Alternatively, you could temporarily plumb a lift pump (fuel pump - like an Airtex E8153) into the system and see if that makes the truck start and run reliably. That doesn't fix the existing problem whatever it may be, but it may overcome the existing problem.

Theheder used a different fuel filter and that may be something to try. Many people have had problems with different brands of filters.

You could check the vacuum created on the test port near the front of the engine to see how much vacuum is created while pumping. Could it be your CP3, sure, but that is pretty expensive and likely you will need some professional advice.

And your problem COULD be electrical, COULD be in your fuel tank, Could be lots of things, unfortunately

Keep posting and let everyone know what's going on. There are LOTS of people with this same situation.
 
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