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· Junior Member
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Discussion Starter · #1 ·
I was reading a post by Tony that said to grind out the openings in the fuel filter base, and take off the hand pump, just wondering if anybody had any luck with that and will it work with just the stock draw pump, meaning no pusher electric pump? Also will I lose my prime if I take the hand pump off? Any body know if the late 80s kw had a electric fuel pressure gauge factory or mechanical, I seen one in the truck paper an 89 and thought about going that route for a gauge, seeing how I cant keep the isspro mechanical working right very long with a snubber
 

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As long as your fuel system is sound and you dont have any lines sucking air you should not loose prime, but should that happen you will not have very good luck getting it primed.

I run an autometer electric guage for my fuel pressure, the T600s we had did not have pressure gauges in them, the had fuel restriction gauges.
 
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· Junior Member
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Discussion Starter · #4 ·
As long as your fuel system is sound and you dont have any lines sucking air you should not loose prime, but should that happen you will not have very good luck getting it primed.

I run an autometer electric guage for my fuel pressure, the T600s we had did not have pressure gauges in them, the had fuel restriction gauges.
So you did this and gained fuel pressure? Just don't want to waste my time porting on things and removing things that might screw me later.. thanks- Troy
 

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I was reading a post by Tony that said to grind out the openings in the fuel filter base, and take off the hand pump, just wondering if anybody had any luck with that and will it work with just the stock draw pump, meaning no pusher electric pump? Also will I lose my prime if I take the hand pump off? Any body know if the late 80s kw had a electric fuel pressure gauge factory or mechanical, I seen one in the truck paper an 89 and thought about going that route for a gauge, seeing how I cant keep the isspro mechanical working right very long with a snubber
Losing the primer will gain some flow, but no more pressure. Get the block off cover from Cat and drill it out to 1/2". If you increase pressure too much, the side cover (fuel manifold) on the pump will blow the gasket. 35-40 psi is all it needs anyway.
 

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No, my fuel system is completely different than the factory system and is built for volume.
 
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Sounds like the pump is starting to get a little weak, or your lines are degrading.
 

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Its not meant to gain you pressure, opening up tose holes with only let more volume thru and actually drop pressure, and if I remeber right the fuel pressure port on the filter base is before the jack pump so any increase in flow after that port will lower pressure.
 

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I didn't think long enough about it, I forgot that the fuel flows into the front of the base as it sits on the engine.
 

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This is what I did on my B model. I pull fuel with an electric pump (Airdog Raptor 150) thru the first filter (Parker Vormax) then on to the stock transfer pump, then to the stock filter head/filter and primer pump. I have a liquid filled gauge on the output side. When my filters are clean and new I get about 50-55 lbs. at idle. My mileage and power take a nose dive when pressure drops to anything below 40.

My first filter, on the Vormax, is a System One with a 35 micron screen that can be cleaned and replaced on side of the road if need be. The final filter is from the Cat store. It is now listed as an industrial filter rather than a road filter. By getting the Cat 1R-1712 you will get much longer life from your filters. I go about 2 months and write the date of change on the filter can with a Sharpie. The 1712 is a 10 micron filter media whereas the road filter is only 4 microns Four microns is too restrictive for an older engine.

Everyone in the filter business will sell the 4 micron filter because it "fits" all engines, meaning it screws onto the filter base. Ive done lots of checking and found only the Cat 1712 has the proper media restriction. If you use any other Cat filter number or ANY other brand, it will be 4 micron and restrict the flow causing you to change filters every week or more.
 

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I should also say, I put on the electric pump to "help" the stock pump. I bought a rebuilt transfer pump that did little better (30-35psi) than the one it replaced. They wouldnt give me a different one because it "was in spec," even tho the engine would not run properly. I was told that Cat pumps were good pushers but terrible suckers. I experimented with pump pressures on the electric pump and settled on 18 going to the transfer pump. This is how I end up with 50 or so after the 10 micron filter. I found that increasing pressure to 60 psi hurt mileage so I backed it off.
 

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Discussion Starter · #15 ·
I should also say, I put on the electric pump to "help" the stock pump. I bought a rebuilt transfer pump that did little better (30-35psi) than the one it replaced. They wouldnt give me a different one because it "was in spec," even tho the engine would not run properly. I was told that Cat pumps were good pushers but terrible suckers. I experimented with pump pressures on the electric pump and settled on 18 going to the transfer pump. This is how I end up with 50 or so after the 10 micron filter. I found that increasing pressure to 60 psi hurt mileage so I backed it off.
Is that filter what they used to run on those motors back in the day? 10 micron seems a little big for the main filtration?
 

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Went thru more or less the same thing -30-35psi, etc, etc. replaced my primary filter head (frame mount which may have been leaking a little air in, guess
I will never know now) with a fass 150hd. Had changed fuel lines, went to bottom draw, transfer pump,primer pump, pulled tanks off and cleaned.... Was getting 40-42psi just off idle with fresh filters. Give 'em a couple thousand miles and it would drop from 30 down to 22 or so. Drove me nuts.:gaah And yep my power and mileage would drop like a rock when it got anywhere near that low. Haven't had the fass very long , but so far really like it. It uses a high volume hydraulic filter as a primary. Runs about 17psi to t pump resulting in a little over 50psi up top. My numbers are very similar to yours. Interesting about the 10 micron 1712.
 

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Someone will have to explain to me how increasing the fuel preasure in the injection pump will effect anything?
If the fuel system is sound and the restrictor is open the system should be as good as it gets.
Increasing the flow to a restrictor that is what .020.
We found that if you put on to fine a primary fuel filter it will affect flow. The very best filter, is the Davco system, the best stock combination we found was a FF1212, primary and a FF211 secondary.
The fuel preasure port is before the secondary fuel filter, so if your preasure is dropping the primary is too restrictive.
I am not a fan of removing the priming pump, that side of the system is under preasure, and if you have to change a filter on the side of the road or loose you prime you are killing your batteries to prime it.
Just a thought!
 
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