LB7: Lb7 no start story

[OregonDMAX]

Maybe think about switching out your sending unit. And this is one of the main reasons why I think its dumb some people run cat filters. Water in the fuel reads havoc. Also I use 1/2 in steal braided fuel line with AN fittings I believe the brand is Vibrant super easy to make up the lines you need and very durable.

I have fuel up to the cp3, I am going to run that line though since I have everything apart

I sure hope it isn't the pump bud if so I have a friend with a 02 and a bunch of spare stuff including stock pump if you need one I could get it for a bargain. His is all built but he saves everything. I'd just have to give him a ring and ask. Let me know.

If it's the cp3 I'm going to get a sportsman, any cp3 that has been removed is instantly only worth it's weight as a core imo,you never know how the person removed it and stored it.

I have seen one run with a sheared gear pump shaft. As long as there was positive supply pressure it would continue to run. Just would only build about 8k/26k psi.

Easiest way to dead head the pump on an lb7 is to take the 2 old injector lines and cut off the rail ends. Weld the tube shut so you now have a block off plug. Disconnect both rail feed lines from the fprv/rail pressure sensor block on the drivers side intake clam and install your block off plugs. Now you have effectivly dead headed the pump into the rail sensor. Crank the engine over and see if you have rail pressure. If you do then you have a fubard injector. Hook up one side at a time to isolate it to driver or pass. If you still have no rail pressure then check the fprv. It could be pinned open from a piece of trash or something or broken spring. Disconnect the big return banjo from that block. If you have any fuel come out of the fprv it's bad. If nothing leaks from it, you have fuel going into the cp3, and no rail pressure when dead headed it's got to be a dead cp3.

Dang that is alot of testing, I'll do what I can. In the end I'm pretty sure it's the cp3 it's been weak for a while and it's surged several times on the freeway and has a bad lope at idle, either way I need one I guess haha

 

[JRein]

Maybe think about switching out your sending unit. And this is one of the main reasons why I think its dumb some people run cat filters. Water in the fuel reads havoc. Also I use 1/2 in steal braided fuel line with AN fittings I believe the brand is Vibrant super easy to make up the lines you need and very durable.

Sent from my STV100-2 using Tapatalk

How often do you drain your GM filter? He has a water separator already inline and the CAT filters are just as much a water separator as the GM filter just without a drain but have more surface area.

In all technicality, the GM filter is nearly worthless as a water separator after adding a lift pump anyways as you want them on the vacuum side of the pump because the water becomes emulsified after going through the pump. Also going the CAT filter can be fine over a period of time because of the cost savings and the pain of removing the bottom sight glass.

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[2008lmmchopper]

How often do you drain your GM filter? He has a water separator already inline and the CAT filters are just as much a water separator as the GM filter just without a drain but have more surface area.

In all technicality, the GM filter is nearly worthless as a water separator after adding a lift pump anyways as you want them on the vacuum side of the pump because the water becomes emulsified after going through the pump. Also going the CAT filter can be fine over a period of time because of the cost savings and the pain of removing the bottom sight glass.

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I drained it every now again you don't actually drain the filter. Just the water which sometimes there's some and sometimes there's none. I rarely had any water. I have had water in my fuel system before and its not fun. But I have a lift pump a good low micron filter a water separator and I still use my stock filter on the motor I just don't change it often anymore and no need to check and drain it. And that's false the cat filter is not "as much of a separator as the stock gm" because it's literally not a water separator at all. The stock gm filters worked for me I see that he has a water separator and a lift pump lol clearly I only was referring to all the corrosion in his filter from water. I only meant that's exactly why I think its dumb people use a cat filter in place of their stock filter because all of the water if any that caused the corrosion would be going through your system and again cat fuel filters do not separate water. There is a reason cats have a fuel filter then they use a spin on water separator like a lift pump on a truck.

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[2008lmmchopper]

Dang I didn't know that we'll good luck bud I hope it's better then you think.

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[OregonDMAX]

How often do you drain your GM filter? He has a water separator already inline and the CAT filters are just as much a water separator as the GM filter just without a drain but have more surface area.

In all technicality, the GM filter is nearly worthless as a water separator after adding a lift pump anyways as you want them on the vacuum side of the pump because the water becomes emulsified after going through the pump. Also going the CAT filter can be fine over a period of time because of the cost savings and the pain of removing the bottom sight glass.

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I deleted the factory filter it's worthless after a liftpump imo

 

[BrandonLLY]

I was getting a p0089 code on my truck when I would get on it. My fprv was popping so I plugged it and been fine since.

 

[OregonDMAX]

I was getting a p0089 code on my truck when I would get on it. My fprv was popping so I plugged it and been fine since.

I've had it for a few years, still ran a 12.7@104 with a the code coming up haha