Bad HFCM, I think
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From: PA
Bad HFCM, I think
Hey, it's been a while since I've been on here. I've been crazy busy and my truck has been dependable as hell, until this week.
I was doing my maintainance changing out my fuel filters and draining the water from the HFCM, but while I was putting the plug back in I realized that it was stripped, so instead of buying $160 manifold I decided to drop the HFCM clean it up and run a 3/8 NPT tap into the stripped hole and replace that plug with a brass pipe cap. It worked and sealed well, so I reinstalled the HFCM, primed it 10 times and tried to start my truck, NO DICE. So I primed it a couple more times and tried again, STILL NO DICE.
I could hear the pump so I knew it was working. So I crawled underneath the truck and double checked that everything was connected and that the filter cap was tight and seated. Tried priming and starting the truck again, NOTHING. At this point I started getting frustrated, I pulled the upper filter and attempted to prime, air bubbles were gurgling out of the housing but fuel never came no matter how many times I tried to prime it. So I crawled under the truck and pulled the line that runs from the pump to the engine tried to prime it again and nothing came out of that line, so I crawled back under the truck and pulled the filter and it was as dry as it was when I put it in. Absolutely no fuel had been sucked out of the tank and into the pump/filter housing with all of the priming I had done. I reinstalled the filter, tried to prime it again and relized that I could hear air gurgling in the tank while the pump was turning.
So my theory is that fuel pump has worn out, allowing the pump motor to spin but not pump fuel, but because the system was primed full of fuel it was able to keep the truck running and flowing fuel. But now that I broke that seal and the system lost it's prime the pump doesn't have enough ***** to pull the fuel out of the tank and reprime the system.
Does this make sense to any of you techs or gurus? Has anyone ever ran into this? I felt confident enough in my conclusion that I ordered a pump and it will be here tomorrow, I would have rather got the Airdog II, but funds are low due to the skyrocketing price of home heating fuel.
Sorry for the long post and thanks in advance for any input.
I was doing my maintainance changing out my fuel filters and draining the water from the HFCM, but while I was putting the plug back in I realized that it was stripped, so instead of buying $160 manifold I decided to drop the HFCM clean it up and run a 3/8 NPT tap into the stripped hole and replace that plug with a brass pipe cap. It worked and sealed well, so I reinstalled the HFCM, primed it 10 times and tried to start my truck, NO DICE. So I primed it a couple more times and tried again, STILL NO DICE.
I could hear the pump so I knew it was working. So I crawled underneath the truck and double checked that everything was connected and that the filter cap was tight and seated. Tried priming and starting the truck again, NOTHING. At this point I started getting frustrated, I pulled the upper filter and attempted to prime, air bubbles were gurgling out of the housing but fuel never came no matter how many times I tried to prime it. So I crawled under the truck and pulled the line that runs from the pump to the engine tried to prime it again and nothing came out of that line, so I crawled back under the truck and pulled the filter and it was as dry as it was when I put it in. Absolutely no fuel had been sucked out of the tank and into the pump/filter housing with all of the priming I had done. I reinstalled the filter, tried to prime it again and relized that I could hear air gurgling in the tank while the pump was turning.
So my theory is that fuel pump has worn out, allowing the pump motor to spin but not pump fuel, but because the system was primed full of fuel it was able to keep the truck running and flowing fuel. But now that I broke that seal and the system lost it's prime the pump doesn't have enough ***** to pull the fuel out of the tank and reprime the system.
Does this make sense to any of you techs or gurus? Has anyone ever ran into this? I felt confident enough in my conclusion that I ordered a pump and it will be here tomorrow, I would have rather got the Airdog II, but funds are low due to the skyrocketing price of home heating fuel.
Sorry for the long post and thanks in advance for any input.
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Elder User
Joined: Feb 2009
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From: PA
Yup, almost a full tank, and i also put the clean diesel white bottle in it when it was filled so its not gelled either. I checked all of the connections multiple times and blew them out with my compresser so i know that they are clean and fully connected.
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Full tank of fuel and you didn't have it running all over the place when changing the filter? I would say your issue is between the tank and the pump.
Also, I cannot imagine cycling the key that much could be any good for the FICM.
Josh
Also, I cannot imagine cycling the key that much could be any good for the FICM.
Josh
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Elder User
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From: PA
I just had the FICM rebuilt by FICM.com and its warrantied, but i know what your saying. I pick up the new pump and housing tomorrow morning, there isn't a core charge so ill be able to tear the old pump apart and see whats going on inside. I'll post my results. I am pretty positive that i covered all the bases, i spent the last two days cleaning it and making sure it was sealed and the connections were good.
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From: PA
Well, that was it, I installed the new unit and cracked the upper filter housing open, turned the key twice and fuel was flowing.
I got the whole new HFCM for $260 plus tax at Napa, the guy told me I saved more than $40 on it because I reserved it online and picked it up at the store.
Its a Carter Unit part# P76115M, I'm pretty impressed with it because it came with a new harness that deletes the obsolete fuel warmer connection and when I opened it up it had a genuine FoMoCo filter with the water seperating membrane already installed.
I had not noticed any significant difference in performance when the old pump took a dump, but I do not have a way to moniter fuel pressure or else I probably would have caught the problem ahead of time.
I have pics of the new unit if anyone is interested, but it is Identical to the OEM.
I got the whole new HFCM for $260 plus tax at Napa, the guy told me I saved more than $40 on it because I reserved it online and picked it up at the store.
Its a Carter Unit part# P76115M, I'm pretty impressed with it because it came with a new harness that deletes the obsolete fuel warmer connection and when I opened it up it had a genuine FoMoCo filter with the water seperating membrane already installed.
I had not noticed any significant difference in performance when the old pump took a dump, but I do not have a way to moniter fuel pressure or else I probably would have caught the problem ahead of time.
I have pics of the new unit if anyone is interested, but it is Identical to the OEM.
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