At 10:57 20/05/02 -0700, you wrote:
>
>Here's another question for all you diesel experts:
>
>Isuzu NPR 3.8l turbo diesel cab over moving truck, 140k+ miles, 2 years
>of reliable service for me. Even in the dead of winter, between racing
>seasons when it only gets driven once a month, it always starts right
>up, thanks to two giant batteries.
>
>Maybe 6 weeks ago, I parked it on a funny slope for a few weeks.
>When I went to start it, I could tell it was cranking slower than
>normal, and didn't start. About 5 minutes with my 110v battery
>charger/jump starter and it started right up. I did a few errands,
>shutting off and restarting the engine, no problems. Then I parked it
>for almost a month, and tried to start it again yesterday.
>
>Same slow cranking, so I put the same charger on, but this time it still
>didn't start. Left the charger on for a few hours, still no start.
>Lifted the cab to look for any obvious dangling wires/hoses, didn't see
>anything. Pulled out the air filter, and maybe a cup or two of water
>ran out. (It's an ordinary paper element, not an oilbath style. The
>air intake snorkel cap looks good to me, but we sure do get our share of
>rain out here.)
>
>Lowered the cab, left the air filter out completely, sucker started
>right up. Put the air filter back in, unhooked the charger, drove
>around the block. It ran great, but when I pulled the key out, the
>engine kept running. When I turn the key from off to on, the dash
>lights come on, indicating the key switch is still working. I had to
>pull a fuel line off between the tank and the water trap/filter to get
>the engine to stop.
>
>It can't be a coincidence that it wouldn't start, and then wouldn't
>stop, since it's never had either problem before. Could there be some
>kind of fuel valve that was stuck shut at first, then stuck open? How
>is a diesel engine supposed to shut off? All the standard ways of
>stopping a gas engine involve parts that aren't on a diesel. The wiring
>is pretty well routed and zip tied so I don't think anything could get
>pinched by rasing/lowering the cab.
>
>For some odd reason, there's no Isuzu NPR enthusiasts mailing list, so I
>have to ask here. I think I know my way around a gas engine just fine,
>but all I know about diesels is to put that other kind of fuel in there,
>and that they sound and smell funny.
>
>keithka
>
Hi Keith,
I don't pretend to be a diesel expert but with our fuel prices we have
plenty of them over here in the UK.
Perhaps the root of the problem lies in that funny slope which could have
encouraged the rain to follow unusual pathways. If there was a cup of water
in the air filter there's a good chance the element was restricted, hence
the engine ran when the element was removed. As others have mentioned the
modern diesels have solenoid valve fuel cutoffs. Some rain could have
tracked into the terminals and fouled things up. The cutoff is usually on
the injection pump. Look for some wires around there and clean the terminals.
Another thing to check is the preheater plugs in the inlet manifold.
Sometimes these go bad and cause hard starting, particularly in cold weather.
Good luck,
Nick Brearley
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