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My new truck

ak diesel driver said:
Well it looks like my raptor pump has died. I've had to replace the fuse 3-4 times and just now driving home the pump quit. Changed the fuse but nothing, acts like instead of being shorted it has an open. My brother is on his way with some cardboard to lay on, a DMM, and another fuse. I have my stock LP on board.
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Remind me what the benefit of these aftermarket lift pumps was?
 
No clue Big T ..I've got a regular AC Delco in mine... As long as the pump gets enough fuel to the front of the truck I don't see the benefit of aftermarkets..
 
Installed it in 2017, on my 96 I went thru a pump a year for 3 years before I finally got one that lasted. Plus I was looking ahead towards more performance in the future. At this rate the after market pump cost me about the same as a lift pump per year. On a side note I discovered that my fluctuating fuel pressure readings weren't totally the raptors fault, getting some weird readings with the stock on too. Only getting about 3 psi running down the road.
 
I was just thinking that if you're having problems getting good pressure out of 2 different pumps then there must be a problem outside of the pumps, like a partial blockage before or after the pump. And maybe that is what killed the Raptor since it was working extra hard?
 
The strongest and longest life of the factory ones is the EP158 from AC Delco. I run them, but am entertaining the idea of the FASS or airdogg system with filters built in so that it eliminates air intrusion and FASS claims to stop flow once water separator is full. Not sure about airdogg on that. They also filter down to around 3 microns.
Most the older 6.2 had the mechanical lift pump that was abandoned duel to bladder failure causing fuel to get into oil. They tend to get 4-6 psi. I don’t suggest them.

An obstruction sounds likely. Like a flap of rubber inside the line.

Higher nitrate is not good for any radiator- wet sleeve diesel engines require really high nitrate, so guys running the wet sleeve cummins and an aluminum radiator just have to suck it up and replace radiator more often. 6.5 can run normal nitrate levels. Its a complicated enough issue it should probably be a thread y itself.
 
So just to be clear my LP issues were on my other truck, the 96. Never had any issues on this truck but my previous experience with stock LP's didn't leave a good taste in my mouth, and since I was looking forward to more performance and reliability I bought the raptor.
 
FellowTraveler said:
If my memory serves me right, the stock lift pump for the 6.2 diesel, actually made higher pressure than the one for the 6.5TD and held up better too.
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The 6.2 stock lift pump was a mechanical diaphragm fuel pump located where the turbo oil return fitting bolts to the block on the 6.5TD now. That was replaced by the electric lift pump we all know and love now.
 
Will L. said:
So Raptor isthe airdog- what is their pressure regulator system?
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They have a built-in, non-return style, adjustable regulator. I called to ask about bypassing the regulator years ago and the person I spoke to told me to just adjust the regulator screw to full pressure. I’m tempted to open mine up and try to gut the regulator since I’ll be running an external regulator now.
 
The reason I ask is - non Return regulated-
The pump itself is going to flow at full capacity. A blocking style regulator makes the pump work harder. Advantage of return flow is the pump runs not under a massive load because even though it is flowing full volume, the majority of flow it return to tank.

Imagine you cranking a hand pump and a regulator that lets one side of regulator build to 15psi, but 75% or more of the flowis free flowing to tank- thats easy to crank. But if you plug off the line so that it only gets to 15psi a d above that flow completely stops- that takes a lot of effort to crank.

Problem with cree flowing pump bypassing most it’s fuel is aeration or air entrapment into the fuel- hence the basis of their air removal systems. Ypu you aren’t just paying for getting rid of the fuel in you system stock . It is all the added air that will be introduced by return to tank bypassing regulator.
 
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