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nightly bleed down worse all of a sudden.

N

nealpellecchia

Active Member
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Location
Visalia, Ca.
Two years ago at this time of year, can it be seasonal?, I replaced the top hose from pump to return lines. I did this after replacing little hoses between pump and filter which didn't seem to help. also did the big o ring at the bottom of the fuel filter housing and the little one on the side. I'm worried that the head and rotor leak, if it's been leaking, is getting worse.

I have been able to use the truck because I put a toggle switch to the temperature switch so I could start it hot. Any ideas? Runs good once it's running but oh yeah the acceleration seems to pause a bit at low rpm. 1993 6.5 turbo HD automatic. 370,000 mi.
 
That clear tube from IP to return has a tendency to get hard over time and lets air in at the nipple, it wont hurt to replace it yearly.
Is that IP mechanical ??
If it is, then the leak could be a bad fuel hose between filter and the inlet at the back of the pump underneath the intake plenum
 
bison said:
That clear tube from IP to return has a tendency to get hard over time and lets air in at the nipple, it wont hurt to replace it yearly.
Is that IP mechanical ??
If it is, then the leak could be a bad fuel hose between filter and the inlet at the back of the pump underneath the intake plenum
Click to expand...

It is.. I did that hose and had to be careful not to over tighten the hose clamp at the pump or it will start to pop out of the groove. I'll replace the top hose. Wasn't it you who said to just leave the clamps off the top one?
 
bison said:
I just push it on,.i haven't yet found a clamp that works there.
Click to expand...

still a problem. ran better...very strong with new hose. then after 3 hrs. hard start. expect it to be bad in the morning. Fuel tank?...Put papers under fittings to find leak? How do you pressure test inj.pump with no place to hook one up on the pump?
 
you can't pressure test the IP.
sometimes they develop a leak at the trottle shaft (0 ring) can be either leak fuel when running or let air in after shut down.
Other place that can leak is at the bottom of IP at the mounting pad, there is a small orifice between 2 seals to prevent a leaking pump shaft seal passing fuel to the timing housing(not sure if a mechanical IP has it,..the DS4 does)

A leaking injector nozzle can cause bleed back as well including any return hose leak.
 
Make sure the OPS that controls the LP is working.

Hoses are still good?
O-rings are still good?

I know you replaced this fairly recently.
Sometimes, it is just the clamps.
 
Do the lift pump relay upgrade. Possibly instead of changing the OPS.

If the OPS is putting out any juice at all it will trigger the relay. Most times the OPS will still put out plenty of juice to trigger the relay, but will not run the pump.

If you need a new OPS, skip it and just do the relay upgrade. Do the relay upgrade regardless, to save your OPS - preventive maintenance, cheaper and easier than changing the OPS
 
You could pressure test it with a set up from Leroy off the ffm, using only Lp pressure with engine off. iirc there is a check valve in the Lp, maybe that went bad even if the pump part is working.
 
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