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Discussion Starter · #1 ·
Have any of you ever run into an occasion when the primer pump wouldn't do anything? I have the upgraded primer pump. A little background to my issue; last week I topped off my tank and found out that my WVO filter had failed. Now I have some sediment in my tank which I've been dealing with until I can get up to Farm & Fleet for a new filter. Up until today, I've just had to drain my prefilter every so often and prime the system. Today I did this, but the primer pump wouldn't suck any fuel into the pre-filter. I'm fully aware of the possibility of a clogged tank screen, which I'm going out to check shortly. The thing is, I don't think it's even possible that I got enough sediment in my tank to obstruct the tank screen, so I'm wondering if maybe the problem could be somewhere else. My entire fuel supply line is new and it's highly unlikely that I'm sucking in air anywhere. I did, after an hour of pumping and cranking on the engine get the system primed so I could limp the car home; but it's still starving for fuel.
 

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Sometimes when industrial diesels are primed the pumps fail tp prime, either because the sealing ring on the primer fails, and sometimes because of back pressure. The latter is easier to deal with, just open up the outflow side and pump. The former is sometimes caused by the ring failing or by the priming rod or lever not moving in the full range. Sometimes (once) there was not fuel to prime with. This is gathered form Industrial units, but I believe the principles are the same. Good luck
 

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Discussion Starter · #3 ·
Thanks, I'm still waiting for the tank to finish draining so I can check the tank screen. I bought a new filter housing, so I'll be starting again with a fresh screen, a clean mixing tank (cleaned it after the other filter failed), and a brand new filter. I honestly can't see why my WVO filter failed, the housing appears to be in good shape, maybe I just had a bad cartridge; I'll probably just run the two filters in series now.
 
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Stevenpfaff said:
Have any of you ever run into an occasion when the primer pump wouldn't do anything? I have the upgraded primer pump. A little background to my issue; last week I topped off my tank and found out that my WVO filter had failed. Now I have some sediment in my tank which I've been dealing with until I can get up to Farm & Fleet for a new filter. Up until today, I've just had to drain my prefilter every so often and prime the system. Today I did this, but the primer pump wouldn't suck any fuel into the pre-filter. I'm fully aware of the possibility of a clogged tank screen, which I'm going out to check shortly. The thing is, I don't think it's even possible that I got enough sediment in my tank to obstruct the tank screen, so I'm wondering if maybe the problem could be somewhere else. My entire fuel supply line is new and it's highly unlikely that I'm sucking in air anywhere. I did, after an hour of pumping and cranking on the engine get the system primed so I could limp the car home; but it's still starving for fuel.
hey steven, i just had to chime in on this one.......this goes back to the discussion we all had over my CONTROVERSIAL elimination of the tank screen........

during the job, the tank was never really cleaned out, so it had some sediment still........the advantage i have now is that with 2 pre-filters up front, i can see how its doing, and she's been clean now for a while...........using a clear prefilter BOSCH helps........

but yeah, if u went ahead and did this now, u wouldnt have to EVER deal with the problem again, putting it permanently behind you...........

just my 2 cents
 

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Stevenpfaff said:
My entire fuel supply line is new and it's highly unlikely that I'm sucking in air anywhere.
I agree but what you're describing is a classic symptom of an air leak.
 

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Discussion Starter · #6 ·
AMSOIL300CDT said:
hey steven, i just had to chime in on this one.......this goes back to the discussion we all had over my CONTROVERSIAL elimination of the tank screen........

during the job, the tank was never really cleaned out, so it had some sediment still........the advantage i have now is that with 2 pre-filters up front, i can see how its doing, and she's been clean now for a while...........using a clear prefilter BOSCH helps........

but yeah, if u went ahead and did this now, u wouldnt have to EVER deal with the problem again, putting it permanently behind you...........

just my 2 cents

The screen was fine, I'm certainly not taking it out; there's a reason it's there. Without a sediment screen you run the risk of obstructing the fuel line. Checking the sediment screen is an easy job, I always have plenty of veggie oil containers around and I'm able to pull the hose without spilling more than a few ounces.
I know that this problem was a classic sign of an air leak, but if there was an air leak keeping the system from priming it never would have primed. Once I finally got it to prime, there were no bubbles coming into the prefilter and no leaks after the prefilter. The only place there could be an air leak is in the two flare-fit brass unions in the middle of the steel line, and if either of them were leaking I would have seen air bubbles.
 

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Another possibility would be the valves in the fuel pump under the primer pump. If they are not seating, your just pushing the fuel back and forth between the pump and the tank. Are you hearing the releif valve "buzzing", meaning your getting fuel pressure after the pump?

Jamie
 

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Discussion Starter · #8 ·
Before I finally got it to prime, there was nothing; no noise or even resistance on the primer pump. Once It finally primed, I could hear the fuel go through the bypass valve and then the relief valve hissing; and there was normal resistance on the pump. After it finally primed, everything was normal; it worked just like it always has. I have to put in a fresh prefilter today, I'll see what happens when I prime it this time.
 

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Little tip ..........I've had that happen before as well. What did I do? Pull off the cigar hose from the filter housing and blast a little compressed air into it...pressurizes the tank a little and forces fuel up through the line and filters...saves a lot of futile pumping.
 

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Discussion Starter · #10 ·
It wouldn't have been a big deal had I been at home; but I just happened to be twenty miles from home at a restaurant.
 

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Discussion Starter · #14 ·
I probably wouldn't have been too embarrassed, except my car was first parked on an uphill incline so I thought maybe the primer wasn't able to suck the WVO up that extra height due to the higher viscosity; so I decided to push the car over to a more level part of the parking lot. I don't know why but having to push any car is always embarrassing to me, and I'm not easily embarrassed.
 

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Discussion Starter · #15 ·
Well it turned out that this problem was due to a bad fuel pump. For any of you who may find your way into this thread in a later search, the online parts stores call this a primer pump assembly. If this fails, you can buy the whole pump for around $150 or you can buy a repair kit for roughly $5. The repair kit is a dealer item and the part number (thanks to member JamieK) is 000-090-02-10. My problem started as a poor idle, then progressed to a lack of idle when the engine was warm, then I had problems getting the fuel system to prime; after some time it got to the point that the engine would barely run once it got warm. The symptoms I suffered pointed to an air leak in the fuel system, which I addressed before I replaced the pump by replacing all the crush washers on the IP and fuel filter housing. I hope this thread someday saves somebody the cancelled roadtrip and three weeks of greif I suffered. Here's a picture of the culprit; the part is rotated 90' so that the roller mechanism can be seen. You can see the primer pump screws into the top of this part.
 

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