air leaks in fuel line?

[gregory O]

first thing I do when there is a fuel prob. is remove the fuel cap and stuff a
rag in it.this will prove tank vent working or not.

then replace a section of supply to first filter hose with a clear plastic line
to watch the fuel cycle.

to me it sounds like a line that you touched while checking for more leaks came
apart in an interior ply and gets sucked closed when the pump draws head lift.

the issue proved the lines were weak. now screwing with the weak lines you may
have filled up the filters again. I dont replace fuel filters as often as
recommended but when they fail, you can bet that they will fail often untill the
source of the crap has cleared up.

I have, in a pinch, used plastic airline hose for fuel line and the performance
was so good I continue to use it in small diesel apps.

I would use the plastic line to bypass one filter then the other.



''Start by doing what's necessary, then what's possible, and suddenly you are
doing the impossible.
… – St. Francis of Assisi ''

Greg of Tim&Greg 94ptca
--- In WanderlodgeForum@yahoogroups.com, Greg Young wrote:
>
> We are in Fort Stockton TX at the Fort Stockton RV Park.  The owner is a
former Detroit Diesel mechanic and has been helping me diagnose and fix a
problem, but we are stymied...  I will try to explain the sequence of events:
>
> 86 PT40, DD 8V92 Silver
>
> Two of the small fuel lines (one the crossover from right block to left block,
the other the feed from the secondary filter to the right block) failed due to
abrasion against one another and started leaking.  We stopped in Fort Stockton
(having probably lost about 30 gals of diesel on the road and our tow car).  I
cobbled together a couple of new hoses and have replaced the ailing hoses.  I
took the opportunity to replace the primary and secondary fuel filters which
were both due.  Our friends at CCW had replaced the Racor filter with a Detroit
Diesel 382 filter, which uses a Donaldson P550467 cartridge.  Now, we are able
to fill the filter body and the main fuel line from the tank to the filter with
fuel (and the secondary filter too) to prime the engine, but after starting the
engine as soon as the fuel in the filters is depleted the engine stops.  I swear
I have not touched the main fuel lines!  It appears we are getting air
> into the fuel line, but we can't figure out where.   Any thoughts on
diagnosis?
>
> Remember that I'm not really a diesel mechanic.  I just play one on TV.
>
> No really, I don't know much about this stuff, but am picking up what I can.
>
> Thanks!
> Greg Young
> 1986 PT40
> Currently closing towards the end of a 5 month, 15,000 miles trip, having
survived transmission leaks, 2 weeks at Burning Man, oil leaks, almost
overheating, water temperatutre overheat switch failure, two flat tires on the
tow car... the list is long, and I'm proud that this is the first time I've had
to ask for help to the group.  (Though Curt took a call when the engine got
hot...)
>  Each time you judge yourself you break your heart.
> -Kirpal Venanji
>