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suction leak problem

N

nealpellecchia

Active Member
Messages
349
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41
Location
Visalia, Ca.
1993 6.5 turbo hd 4x4 automatic.

Diesel guy says it sometimes takes him 3 weeks to find the problem. I've read that excessive fuel tank suction is caused by a clogged sock. Makes sense but he says that would cause no fuel flow and mine will run great until the suction causes a backfire and dogs. Yes it runs better with out the cap but why the problem? And hot or overnight bleed down causes a start and stall problem with air bleed necessary. Has anyone ever focused in on some findings? It's hard of course cause the fuel line is so in-excessable. New o rings in the cannister mgr. new hoses connecting it. tight clamps, steel lines no leaks. Just crazy amount of suction at tank for just a little driving. Seems like bi-pass sender could be related if sock is clogged. How else would it get fuel and expose the upper tank to so much suction? How about rusted lines on top of tank from backing truck into the bay to retrieve boat. Help before I drop tank.
 
You have a plugged tank sock or kinked hose. I had the same issue and the tank cap being loose did help, but wasn't the problem. Diesel will boil under a vacuum and you will be purging 'air' that is evaporated diesel as the IP can pull enough suction to find an air leak or boil diesel.

I suggest the following cure to eliminate the tank sock.

Get a Walbro FRB-5 from http://leroydiesel.com/
It has a built in strainer on the bottom of the pump.
Drop the tank. Replace the pickup assy if rusted. Throw away the tank sock and DO NOT REPLACE IT! Unless you enjoy dropping the tank.
Replace the lift pump with the fittings and the Walbro pump.
Excess tank suction would be "normal" or a bad fuel cap. I ALWAYS get a hiss when I open the tank caps and I have a new one.

Depending on what is plugging the sock you may want to run some biocide in the diesel or replace the tank if the silver lining is flaking off.

I assume you have tested your lift pump and OPS per the technical reference library section on here?
 
WarWagon said:
You have a plugged tank sock or kinked hose. I had the same issue and the tank cap being loose did help, but wasn't the problem. Diesel will boil under a vacuum and you will be purging 'air' that is evaporated diesel as the IP can pull enough suction to find an air leak or boil diesel.

I suggest the following cure to eliminate the tank sock.

Get a Walbro FRB-5 from http://leroydiesel.com/
It has a built in strainer on the bottom of the pump.
Drop the tank. Replace the pickup assy if rusted. Throw away the tank sock and DO NOT REPLACE IT! Unless you enjoy dropping the tank.
Replace the lift pump with the fittings and the Walbro pump.
Excess tank suction would be "normal" or a bad fuel cap. I ALWAYS get a hiss when I open the tank caps and I have a new one.

Depending on what is plugging the sock you may want to run some biocide in the diesel or replace the tank if the silver lining is flaking off.

I assume you have tested your lift pump and OPS per the technical reference library section on here?
Click to expand...

OPS ? The lift pump is 2yrs old and passed. O pressure switch?
 
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