Low boost

[Macrobb]

I'll throw in a lift pump in the morning doesn't take more than like an hour to do so why not? I can probably warrantee this one and they won't ask me questions anyway lol

Go for it. 50/50 shot it'll fix the problem.

If you can, using compressed air to push any crud back up the line and into the tank is a good idea as well.
Third problem/solution is that you have a bunch of crud in the tank(disintegrated pickup?) And you'll need to drop the tank / remove the bed and pull the sender unit. Then you can replace the pickup and blow out the lines at the same time.

You might also have an air leak instead of a blockage, if so, you'll want to check the rubber hose at the lift pump, and anything else that you can.

One check you can do is to hook a jerry can of diesel right up to the lift pump with a short hose. If your pressure is good, it's obviously pre-lift pump.

 

[Thewespaul]

I call BS on some of this. The leaf spring is simply there to keep the plungers from filling further than they are 'limited' to. The leaf spring won't break from being 'maxed out', it's just pushed against the (çurved) rotor below it. If the spring was removed completely, I'd bet the pump would still work(I'll have to try this), because it would be limited by the cam ring instead - like a DB4 rotor(I think).
On a worn pump, well, you are dealing with leakage due to the wear... but I see no reason why it would "fail sooner" or have the output drop depending on the leaf spring position. What usually happens is either the advance piston wearing out(unrelated to fuel flow), or hot starting issues due to head/rotor clearance(again, not something that the plungers would really affect).
I'Ve maxed out several pumps, and I have had no issues doing it.

Well I respect your opinion, you should come down to Texas some time and we can spend some time on the test bench, always enjoy exchanging ideas and doing testing. Next time I have a pump seize on the stand I’ll set it aside and do a post Mortem writeup or a video on it

 

[03wr250f]

Ill be honest I do think that you are lacking fuel, but I also think that there could be another leak of boost, or even drive pressure.
I can tell you I had a large exhaust leak at the wye and crossover joint, and it cost me 2.5 mpg and .5psi of cruising boost.
I have a factory turbo pump, and a set of stage 1s I have not messed with the pump and I can make 15 psi intercooled. I find it hard to believe with a bigger ip than me, you are making less boost than me even if you are intercooled now.

 

[pelky350]

I would think with a boost leak though I'd have more black smoke, I hit 7 psi like right off the line then it seems like I have no more fuel to burn after that

 

[Thewespaul]

Ill be honest I do think that you are lacking fuel, but I also think that there could be another leak of boost, or even drive pressure.
I can tell you I had a large exhaust leak at the wye and crossover joint, and it cost me 2.5 mpg and .5psi of cruising boost.
I have a factory turbo pump, and a set of stage 1s I have not messed with the pump and I can make 15 psi intercooled. I find it hard to believe with a bigger ip than me, you are making less boost than me even if you are intercooled now.

Exactly!

 

[pelky350]

I've tried searching all over multiple times now on hot and cold side, my castings are new from typ4 as well. I'm going to search over the fuel system now for problems, maybe even my fsv could be plugged up? someone had mentioned blowing compressed air down the line before the lift pump to possibly dislodge stuff that could Ben plugging it? I'm only using front tank now because my rear tank had disintegrated and been plugging my fuel filters. Only use front tank now which appears to be newer than rear. Both fuel guages don't work either but I know front tank is full and rear tank is empty/unused. I do have o rings leaking on my injectors but that's probably now causing the issue other than my choppy starting right now. The fuel line going into my lift pump I know was never changed at any point so that probably a good place to start?

 

[pelky350]

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to my fuel pressure guage movement video may help?

 

[79jasper]

Barely revved it. Lol Go all the way.

Sent from my SM-G892A using Tapatalk

 

[pelky350]

My pump will let it go to like 4K if I did that lol but fulk throttle snap makes it drop to like 2-3ish

 

[Macrobb]

Aka... you aren't getting enough fuel to the IP!

 

[no mufflers]

i didn't think the factory lift pump was meant to make much psi. from what i remember 2 psi at full throttle is fine, as long as its getting enough fuel the psi doesn't really matter.

if he was running out of fuel driving i don't think there would just be a low boost issue. at some point it would stall or run terrible.

 

[centennial60]

Video isn't working for me but if your fuel pressure is fluctuating at idle I'd say you have an issue with the lift pump. Maybe a piece of junk from your rear tank got into the inlet or outlet check valves and is holding it open. I would get some 1/8" plastic line and some fittings so that you can temporarily move your fuel pressure gauge into the cab. Then you can see what your fuel pressure is at wot when the demand is greatest.

 

[hesutton]

if he was running out of fuel driving i don't think there would just be a low boost issue. at some point it would stall or run terrible.

Exactly.

Starving the IP of fuel (lift pump, blockage, restriction) has more symptoms than boost changes.

Heath

 

[Macrobb]

Exactly.

Starving the IP of fuel (lift pump, blockage, restriction) has more symptoms than boost changes.

Heath

Not in my experience, depending on the restriction. If the fuel being starved is replaced with air, you get big changes(surging, bucking etc). If it's just drawing a vacuum... it tends to just be anemic because the plungers can't push fuel. It also becomes somewhat retarded due to less internal pressure.

Remember, the metering valve limits fluid in effectively the same way - letting less fuel pass through to the plungers.

 

[HS108]

I didnt see it mentioned before, but what are your pre intercooler boost numbers? Are you maybe having a loss of psi in the cooler, it is possible to loose 1-3 psi through the system. tho not likely, but never know

Also the 2.5 inch DP opening could be choking you a little, maybe isnt flowing the max airflow it could be, hard to say tho.

I make 8psi MAX uphill unloaded, and im smoking a pretty good haze. Im on a factory pump and injectors unknown miles on both and unsure if pump its turned up, but doubtful it is. Waste gate in factory setting.

Specs on truck in sig