Troopie Fuel Problems (2)

Submitted: Friday, Jun 04, 2004 at 13:42
ThreadID: 13455 Views:1525 Replies:4 FollowUps:0
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Thanks to all for your comments and suggestions (Post 13384) - I think I'll just have to go over everything one more time, even though at the moment it's running perfectly! I hate intermittent problems - wish it would stop dead once and for all then maybe could find something!

If the problem was algae, I assume this would be visible as muddy/sludgy fuel?

Does anyone know if there is a pressure relief valve inside the fuel pump/injector assembly which allows excess fuel to bleed back to the tank ? I am thinking that if there is, and it sticks open sometimes, this could cause the symptoms of no fuel but without a visible leak.

Rob
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Reply By: Wayne (NSW) - Friday, Jun 04, 2004 at 14:54

Friday, Jun 04, 2004 at 14:54
Rob,
On most fuel pumps there is a return line for fuel that is not used. I am not aware of any valve, I think it comes out of the pump after the pump has taken what it needs. At idel it would return more than if the vehicle was going hard up a hill.
You could have picked up a bad batch of fuel which has now cleared. There are some products that will help stop the build up of algae, I have not used them my-self and would not comment on them. The only thing I can think of in the future is to buy fuel from the big fuel company owned outlets and to get out more so that the fuel does not sit in the tank for too long.

Wayne
AnswerID: 61688

Reply By: Richard Kovac - Friday, Jun 04, 2004 at 14:59

Friday, Jun 04, 2004 at 14:59
Rob
yes there is a regulator valve fitted to the RH side of the pump (from drivers seat) this is not a check valve and should not be the problem, when it opens its feeding back to the inlet of the feed pump also if it is opening before if sould you should have a lack of power.

The fuel system on the 1HZ engine has the feed (lift) pump built in to the main injector pump so evey thing up stream from the pump will be at a neative pressure (when the engine is running), fuel is not sucked into a pump it is pushed in by atmospheric pressure so check all fuel lines, breathers, and filters etc. if the pump cannot get fuel to fill the void it creates then the pump will cavitate and will not prime the plungers, or the air pressure will enter the system (note: some things in the system act as a check valves eg. lip seals, filter o rings and will alow air in but not fuel to leak out)

I would also be checking the fuel cut of solenoid. I had a problem with a Grader with a Cummins engine fitted to it which would shut down when it wonted too one time on a pit ramp and the operator had to use a dump truck (head on) to pull up (no brakes or hydraulics) many people had worked on it and could not fine any problem. A lot of parts were replaced It turned out to be a wire runing to the fuel cutoff solenoid the wire had broken at the crimp but under the plastic cover and would pull apart some times.
In the end a cheap 12 v test light found it (when testing across the conection the glob was duller), try using a meter to check resistance across any joins or try hooking up a LED across the solenoid and having it in the cab when the problem happens check to see if the LED is on (you may wont to check with a auto sparky first)

Regards Richard Kovac
AnswerID: 61690

Reply By: mijochka - Saturday, Jun 05, 2004 at 13:32

Saturday, Jun 05, 2004 at 13:32
Rob.
Not sure that algae neccessarily presents as sludgy fuel. In my case it was present as particles adhering to walls of tank which only caused havock when a piece dislodged and found it's way to the gauze filter on the pickup. I know my mechanic removed both tanks, flushed them with I'm not sure what and the problem was resolved. My understanding is that algae forms when diesel is stored for a longish period and even minute amounts of moisture (condensation?) are present.
Mick.
AnswerID: 61824

Reply By: Davoe - Saturday, Jun 05, 2004 at 18:25

Saturday, Jun 05, 2004 at 18:25
I have seen problems (often) with the duel tank solonoids eg take from one tank return to another not working etc look there first
AnswerID: 61861

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