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DTT Assassin not pumping!


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Hello ladies and gents!! Hope everyone is ready for Christmas and New years and everything is going well for everyone.

 

Now, on to the problem.

 

My brother has recently purchased a very clean 2002 Ram 2500 CTD. It is a five speed and completely bone stock from bumper to bumper. He is going through the motions of basic bullet-proofing (Gauges, Lift Pump, Etc.) I talked him into getting an Assassin mechanical lift pump because that is what I will probably end up getting if and when my Raptor gives up. He also went with the beans diesel sump at my suggestion versus the draw straw.

 

My father and brother are working at installing the entire system this weekend and just got it all buttoned up. One slight problem... they cant get the lift pump to move any fuel!! They had assembled the entire fuel system but left the line off that goes into the VP. They were going to prime the fuel system then hook that line to the VP very last. To prime the lines they just put an electric drill on the lift pump shaft and used that to turn the pump.

 

They never could get fuel to the VP. Not even air!! So they pulled the lines off of the Assassin and sucked on the fuel line coming from the tank. They had fuel in less than 30 seconds just from manually sucking on the fuel line. Hooked it all back up, and still wont pump any fuel.

 

They have triple checked that they are in fact driving the pump the correct way, and even tried turning it the other way with no luck. I have never heard of anyone having such an issue with the Assassin. It is such a simple design I just cant figure out what could be wrong with it.

 

Anyone have any kind of a clue as to what they could try next?? They are in central WA state working on this and I am in western MT state so I am trying to help them over the phone. Thanks a bunch as always!!

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Maybe peanut from packaging got inside of pump, I would take it apart and check, unless it requires special tools and gaskets, also maybe put some 5-30 engine oil in pump and assemble the rest excepted to vp, then see if it primes. If it does run it to flush engine oil out and you're done. Every oil pump I put in for gas engines I take apart, clean and fill with straight 50 weight to help prime. Few times I found small metal shavings in new oil pump.

Sounds like its cavitating.

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  • Owner

Some oil should help it out to prime. Be be warned this problem will happen again if there is a air leak problem. So if you lose prime on the pump you'll be cranking till the cows come home to get it primed again. Fuel Boss uses the stock lift pump for system priming and them runs on the mechanical pump after starting. So you keep your bump the starter prime system but as soon as pressure is seen the electric pump is disabled.

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I hope that I am wrong here but, the DTT Asasin may require a high spin to do any priming since it is belt driven and has a reduced or small size pulley. I think therefore it is a pump requiring a high spin. This may be one advantage in priming a fuel system that electric pumps have over it.

 

I am staying with the electric pumps and just carry an extra one with the truck. Seems simpler than worrying about a single belt drive. JMHO.

Edited by JAG1
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Well I asked them about that and they said they had cleaned everything out real good. When they couldn't get any fuel to move with the pump they ended up just sucking on the line manually to see if they could get fuel and it came rushing out real quick. Since that happened I am thinking there isn't a restriction in the line. I am going to have them try putting some fuel/oil straight into the pump to see if that gets things moving.

 

Thanks again for everyones help on this!

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  +1  AND   I'd loosen  or remove the  outlet  from the pump too..  and let  any air out quickly.    Soon as  you see  fuel,  bingo.

 

If you just pressurize the tank  without doing this,   both sides  of the pump will be  'high',  and  nothing  can move.

 

 

This may be really dumb question to ask..  but are they sure they  took out the  cap plugs..   I realize it'd be pretty hard to  thread up  the fittings...  but   sometimes   something like this   can be  overlooked!

 

This  problem  should  be  a  'one time deal'...  since  they had EVERYTHING  bone dry..         next time    a  filter is  changed,  or even run out of  fuel,   there will at least be  something  in the  lower parts of the lines   for the  next  prime-up.

Edited by rancherman
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It does have the return line that connects to the pressure regulator after the pump. They did try to pressure up the tank and they couldn't even get air to come through the assassin. They put the project on hold for the time being just until either I or someone else can assist and get it finished up.

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   I do not like the design of the assassin pump. I think It is too small for taking such a high spin resulting in heat build up, poss. bearing failure. .Are those little bearings going to last with so much stress from the high spin and the constant belt tension?

 

Such a small piece of equipment to have to dissipate the heat and stress.

 

Time will tell......

 

Sorry if I've offended anyone.... To me, they are too expensive to not know what any published test results are with continual service.

Edited by JAG1
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I've like the idea/concept of this style pump and know sooner or later mine will need to be changed. So this is why I like these discussions. But I'm hesitant on buying one due to these issues.The pump concept is good, in principal, and might be exceptional in practice. But they are limited to certain venue. How many other vehicles, besides the Dodge Cummins can use them. So they either have to be good and reliable or they will be out of business very soon, if nothing else but by word of mouth. 

 

Why not call the manufacture and explain the issue ? If you try more than they will consider normal, won't they not back their products then ? And of anyone knows of problems like this, they should and what was the remedy was to correct it. Then if there is a product issue, you should get a replacement without cost.If not, I would assume most people would like to know so they won't go to them. And as I said, under those conditions, they would go out of business.

 

As for the bearing size, I can only hope it was engineered properly and tested properly before being out up for sale. I've seen bearings on pumps in refineries that I thought were improper for their size that run 12/7 for years without issues. So I'm listening and still learning. I do have one slight advantage, I still have some time before I have to cross this threshold.

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Time will tell on these pumps.

Awhile back I used to read a little about different types of pumps and remember some where self priming. Meaning they were able to lift whatever liquid they were designed for, from dry to a self prime with a vertical lift rating of say 6 feet, or a self priming capability of 8 feet. They were all rated more or less, depending on design, with a particular amount of self priming capability. All had the commonly stated GPM rating too but, always stated weather it had self priming capabilities. Some pumps were not self priming and always stated that.

Now in the case of the Assassin being that it is mounted below the tank level esp. with a full tank, or maybe somewhat even with the bottom of the tank, depending on ground slope, this pump does not need much in the way of a self priming capability. It does need to be able to build and hold pressure up to the injection pump. Therefore I cannot understand why Will and his brother are having trouble unless it's high spin design is allowing tank drain back but then again, it should be getting enough fuel just from gravity to prime up to the VP. I just don't know other than saying something is wrong with the pump or air coming in from somewhere is allowing an immediate tank drain back past the pump. How can that be?

Another question is would I want to rely on a single pressure regulator to not ever allowing extreme pressure to damage the the VP in any way or causing other problems. I hate to sat it.... there might be some advantages to having the electric pump back near the tank... just not sure of anything much these days.

Will, I would say have your brother put the electric pump back in place and see if it starts except that comes with a lot more work having to back track.

Edited by JAG1
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This style of pump was originally  designed to be driven  with a  love-joy  style coupler.    spider drive lug and rubber star..  all inline.   No   radial   pressure..     I see they  really  don't run too much  belt  tension however.

 

I've read posts  where  guys  have run several   hundred k  miles... and  the next one  has    issues  right out of the box..  and  after  many  calls to the  manufacturer,   still no  satisfaction.   Back in the box it goes.

 

as far as  the  priming part..    any pump  that  is  'self priming'   MUST  be able to  push the air out  DOWNSTREAM of the pump.    If that air  cannot  be  moved,  then   there is no way  liquid  can be  drawn into the   impeller.

 

So  when we look at this system,  there is  a  pressure regulator  on the  downstream side.        The only way   air  can  get past  this  is if   it  is  greater than the   pre set on the  regulator.      

These  roller pumps  are NOT  the  most efficient  air pump.     The are  a pretty  good liquid pump.

Edited by rancherman
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Now this might be going a bit far on this, but:

If there were a check valve on the liquid discharged line, then when liquid was pulled from the tank, when not in use, the liquid would not recede back to the tank holding the liquid in the line and pump assembly, (if no line/fitting leaks).

Then a temp bleed after the pump to allow liquid to flow, proving no air restriction after the pump and verifying the pump is working correctly ... to that point. (extra parts and testing to prove pumps mechanical ability is with in tolerances)

Then any restrictions would be from that point on and proving the pump is fine.

 

Like I mentioned, extra parts and time to verify.

 

But I'd like to mention, when I was installing my fuel pre / final filter setup, I could not obtain a flow. A brand new setup. And after completely disassembling the unit, I found a small piece of red plastic in the inlet fitting that was wedged enough to restrict all flow of liquid. Even though the manufacture said they verified everything was correct before shipping and have no red plastic in the building, something happened and gave me a few minutes extra work. Might had been from the shipping material ? Been after I cleared it, it's been fine since. Someone mentioned this before (debris in unit) and I highly recommend a complete check, if not dismantling it to verify it's clear of debris prior to the next test. Also it can be verified that the impeller tolerance is close enough to cause the liquid to flow. If not, then the impeller will spin and be the source of cavitation.

 

Almost enough variables as there are parts involved ?

 

(Note: sorry I had to edit this, haven't finished my first cup of coffee yet.)

Edited by anoldbiker
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Sorry for not getting back sooner guys. Been crazy with the holidays and what not.

 

They did get the pump working correctly after all. I gave them the idea of putting some fuel down the downstream side of the pump and leaving the hose off the VP. They had fuel coming out in less than a couple seconds of spinning the pump with a drill. Got it all hooked back up and everything is running well! They just need to hook the fuel pressure gauge back up to see where its at but other than that everything is working how it should.

 

On the contrary, they have a serious leak from the front of the oil pan now. They had torqued the pan bolts back up to 10 ft lbs orginally. The pump bracket kept coming loose at 10 ft lbs so of course just like any good little brother, he just wrenched down the bolts tighter HAHA! I think this might have caused the pan gasket to crack/split because he is getting oil everywhere now. The truck has just over 200k on the clock and I would bet that gasket is the original. Probably needed to be changed anyway.

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