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Discussion Starter #1
has anyone installed a FASS fuel pump system on their truck. just want to make sure i buy the system that is going to work the best!
 

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You can search the subject and should come up with alot of info. I will tell you that I have one and like it fairly well but I am not convinced it is the best for a duramax. If I go under a 1/4 tank of fuel it sucks in air and misses a little. I personally like it cause I got used to filling up once it gets that low It does supply all the fuel you need in my experience.
 

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What bigblackdmax said. :exactly:

The pump itself and filters work good and it supplies plenty of fuel but that is it's downfall, it supplies so much (and returns most of it) that it will actually suck the fuel cup that's in the fuel tank dry and suck air in instead and could stall the truck if you get below 1/4 tank or so.

Do a search of FASS it's been talked about many times.

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A "stand alone" FASS pump is also an option. It does not have the two filters built into it and serves just as a fuel pump. It's also a couple hundred bucks cheaper than a full FASS system. It does not have a problem under a 1/4 of a tank like the regular FASS units with the filters do. It also comes with a 4 year warranty, so its hard to beat. We have sold lots of these "stand alone" pumps and havent had any problems with them. We had a single FASS "stand alone" keeping up with two CP3's just fine on kyle's pulling truck last summer:ro) .
 

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I like mine as well. I have the 150gph plus installed So Cal billet pickup.
 

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I should of mentioned that mine's the 150 with the filters.

This past Saturday I was at a dyno and we hooked up a pressure recording line from the dyno to the fuel test port at the front of the engine.

During idle my pump was putting out 7.5 psi and all through the dyno pull the pressure never really dropped below 5 psi. :ro)

Here's a graph of the pull with the fuel pressure colored in pink at the bottom of the graph.





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Discussion Starter #8
so if im going to buy a fass pump i need to get the 95gph not the 150 or i will be filling up when i hit 1/4 tank!
 

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Fass 150 And What Not To Do

Gonna tell you all a little story, actually very stupid one on my part about my FASS 150. EIMPMG ( love all these acromyms over half of which I don't understand). I made this one up, Early In My Personal Mod Game, I was running a Quadzilla that felt like it was starving for fuel on the high setting when you were getting on it. A little research, (but not on this page) and I decided I needed a lift pump. Someone told me the FASS was the best and being the Mad Crazed Wild Ass Know Nothing Diesel Neophyte (MCWAKNDN, another one to add to your list) that I am bought a 150 with the filters and me and my Cummins buddy installed it. Install looked really good, had to fab a bracket to mount on the frame just in front of the drivers side rear tire. The bracket they sent and the suggested mount location were for a long bed. Turned on the key and it sounded like a washing machine. Drove it and it didn't feel like it solved the problem but decided it might be something else.

Fast forward about a year to summer of 05. Getting serious about this modded Duramax additiction by now, I've added lots of stuff, big injectors, turbo, propane, water meth, head studs about everything you can except N2O. I got to Montana to get involved in the 'Pull-Off" sponsered by another GM diesel site and meet Kennedy and MotoVet. I don't know how many of you have ever met John Kennedy but he gets one look at the ATS stickers on my truck and I feel like he has decided I'm the enemy. I find out later after getting to know him a little better he is really a nice guy, but getting info out of him that weekend was not too easy. One thing he did say was if I was running a FASS that I had better have more than a 1/4 tank of fuel or it may die on me. I ran down the mountain and got some more fuel. Didn't beat him or MotoVet but had a good time and learned a lot.

Fast forward to last October at the Fast Specialities Diesel Dyno Days in Vancouver, WA. I meet some great guys with some really hot trucks in Max Payne, Top Hog and Los Lobos. I'm soaking up the info like a dry sponge does water, but being so ignorant I'm not retaining but about a third of it. The one thing I did learn was after one of the guys blew his engine into a thousand pieces after the dyno day and on his way home I decided the race with drugs was over for me and was going to go striaght on #2 only.

This is getting like a book huh? Anyway over the course of this winter Max Payne and IdahoCTD have totally rebuilt my truck. When I went to pick up my truck from Max Payne in late December he was checking my buddies LLY fuel pressure to see if his filter was getting bad and I asked him to put the gauge on mine to check my fuel pressure. ZERO! NOTTA! ZILCH!! What is going on?? Can hear the FASS running, sounds at times like a washing machine but no pressure. This remains a big mystery for another month. Thinking that I may be sucking the fuel pickup line flat we disconnect the intake of the pump from the tank and using another hose try to pump from a bucket of fuel. Again, nothing..... I finally take off the FASS and reconnect the fuel line. Put the FASS on the bench and hook it up and it pumps like crazy.

I say screw it and decide to go in another direction and install one of the new MITUSA lift pumps. I have the truck back with Max Payne and he is installing a transfer flow fuel tank. He calls me and tell me he knows why my FASS wouldn't work and informs me that I had it plumbed into the return line not the supply line!!!!! Think about that, for almost two years the FASS was pumping 10psi of back pressure to the return line and the truck still ran pretty darn good. Max Payne had checked it when we were doing the dyno last Oct and said my big injectors were not getting enough fuel. I still dynoed 499hp and about 1138 ftlbs of TQ. Engine was asking for 25,000 psi and the CP could only deliver 14,000. I pulled out the big injectors and everything else I had installed except the head studs. Still blew a head gasket but that is another story on another thread.

Anyway, don't know if this add or subtracts from you thread on FASS lift pumps, probably should have been in the dumb s$$t thread but it does speak to just how strong the CP pump is.:duh: :banghead:
 

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Discussion Starter #10
dang. now you got me thinking about injectors again! hmm well I am planning on getting a pump first and then putting some injectors in. When i am installing the pump i will be sure to put it on the right line! how big were the injectors you had!
 

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dang. now you got me thinking about injectors again! hmm well I am planning on getting a pump first and then putting some injectors in. When i am installing the pump i will be sure to put it on the right line! how big were the injectors you had!
I'll bet ALOT smaller than his avatar! Sorry, couldn't resist but rest assured I read EVERY one of his posts! :ro)
 

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dang. now you got me thinking about injectors again! hmm well I am planning on getting a pump first and then putting some injectors in. When i am installing the pump i will be sure to put it on the right line! how big were the injectors you had!
Can't tell you the % over, ATS advertised them and 95hp.
 

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over a 100k on my fass.................little noisey......will hiccup below a 1/4 tank but does a nice job suppling clean fuel
 

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subman

So you were sucking the fuel out of the tank by using the return nipple on the sending unit ?

That could work because the return line actually goes down into the fuel cup near the pickup, but not very well because the fuel line is smaller and there's no real pickup just a small diamater manifold.

And you were pushing fuel Backwards through the return line up to the engine ?

If fuel was running backwards in your system how did the CP3 work that way ?

If the fuel was running backwards how was your fuel getting filtered ? I don't think it was.

Very intresting.

(note to self: keep subman away from my fuel system) ;)

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subman

So you were sucking the fuel out of the tank by using the return nipple on the sending unit ?

That could work because the return line actually goes down into the fuel cup near the pickup, but not very well because the fuel line is smaller and there's no real pickup just a small diamater manifold.

And you were pushing fuel Backwards through the return line up to the engine ?

If fuel was running backwards in your system how did the CP3 work that way ?

If the fuel was running backwards how was your fuel getting filtered ? I don't think it was.

Very intresting.

(note to self: keep subman away from my fuel system) ;)

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DD you ask very good questions, but yes to where the fuel was being picked up. The CP pump was pulling fuel the normal way and since I had the big injectors I don't know what was going on in the return line except that the FASS was pressurizing it at least to some extent. There was a lot of noise coming from the FASS at times, like a washing machine that is running out of water on the empty cycle. Never saw anyh fuel flowing back into the fuel filler line from the pressure bypass line on the FASS so I may not have been getting much fuel and therefore much pressure. Had I had a fuel pressure gauge when we installed it we would have know there was something wrong. But since it was trying to pick up fuel through the return line it may infact was sucking that line flat and therefore not getting much fuel. I sure the stock fuel filter was working because Kennedy's fuel pressure gauge showed the fuel pressure to be what you would expect with no lift pump. As I said, the truck ran pretty good. After Max Payne took off the big injectors the checked the rail pressure with the TECH 2 and everything looked good. I also had a Duramaximizer on the truck and you could tell no difference with it on or off. We all assumed it was the big injectors but maybe the incorrect plumbing of the FASS contributed to that as well. Anyway sold the FASS and it works well, give the new owner a good warning on getting the plumbing right. MITUSA this weekend and get the twins tuned and KATTIE BAR THE DOOR!!!!:grd:
 

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You should check out SuperDiesel's lift pump set up as well...fuel on demand only. It doesn't run all the time so you get more life out of it.
 

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Discussion Starter #17
checking out superdiesel
 

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Discussion Starter #18
bought the FASS intstalled it saturday. works well the gauge shows just over 8psi. also put on the cool duals. smokes like a sum B
 

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I just bought the fully-filtered FASS for my 05 LLY due to some problems I've been having with the fuel rail and lean conditions. I have the Transfer Flow 45-gal underneath and the American Tank 45-gal in the bed. So you guys are saying the I really need to limit my driving to just 1/4 tank to prevent it from sucking air? I usually switch tanks (or fill up) at 1/4 tank, but on long runs if I'm pushing it I might take each tank to just less than 1/4. I don't know what to expect from the FASS then? Also, I'm worried that it's going to be loud. Does it interrupt conversation in the cab?
 
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