Re: M998 HMMWV accelerator problem

From: mblair1@home.net
Date: Sun Jan 02 2000 - 23:51:01 PST


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Well, it looks like my engine problems live in the injection pump.
Grumble. I temporarily installed a couple lengths of clear vinyl
tubing at the fuel filter outlet and at the fuel injection pump return
port, and also tee'd in a pressure meter. The fuel pressure looks
good, at about 7 PSI at idle and about 5 PSI with the engine revving
(4 PSI is the minimum, according to the TM), and there's no air in the
supply line. There is air in the fuel pump return line, so it looks
like I have one or more bad seals in the injection pump. There isn't a
steady stream of air, but every now and then another burpfull of
bubbles goes through the return line. I let the engine run for a long
time, revved it up and down, jumped on the truck, etc. to make sure
that I shook out all of the air that got in when I messed with the
fuel lines, and I'm sure that air is getting into the pump somehow.
The cold advance solenoid connection was a bit loose, so I pulled off
the top cover and tightened it up, but that didn't make much of an
improvement. Maybe some of the pump's seals went bad while the truck
was sitting outside for a year waiting for me to buy it!

I didn't have the time or energy to pull the pump out tonight, so I'll
do that next weekend. I also want to hose the crud off the engine
before I start removing the intake manifold. In the mean time, I
pulled out the shift lever box to take it home, clean it and lubricate
it. It was full of sand (really, the boots at the bottom were full of
the stuff!), and completely dry, so it's very hard to get the truck
into neutral without overshooting into drive or reverse, because the
lever sticks on the neutral start switch. A good cleaning and some
grease should fix that right up. The rubber boot didn't survive being
removed, so hopefully I can get a replacement shipped to me by Friday.
The wiring on the neutral start switch is a bit messed up, so I might
replace it if it's not too expensive (otherwise I'll try to fix the
wiring).

Now, why the heck did they have to go and use a mixture of inch and
metric bolts in the engine? The truck mostly uses inch hardware, but
so far I've found that the injector tube flare nuts and the intake
manifold bolts are metric. Thpppt!

Thanks for all of the help y'all have given me. I'll keep you posted
on my progress with the truck. I'm crossing my fingers that the
injection pump rebuild will be the only major repair necessary to get
the truck road-worthy...

--
Mark J. Blair, KE6MYK <mblair1@home.net>
PGP 2.6.2 public key available from http://pgp.ai.mit.edu/
Web page: http://www.qsl.net/ke6myk/
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