86 pup diesel no start

The place to discuss problems and routine maintenance questions and tips. This is for topics that are specifically diesel-related.
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Isuzu vehicle(s): 1985 Isuzu pup 2.23 diesel motor

86 pup diesel no start

Postby Jimmyjoebob » Sat Jul 21, 2018 7:38 pm

I bought this truck a few years ago. It’s never missed a beat. But it sat for several months. Battery was dead I put a new one in it. If I put fuel in intake it run for a second. I have tried bleeding the injectors. I have far more knowledge of gas engines. My alldata does cover the pump or any tech data on it. I don’t even know what the parts are. Any advice would help. Thank you in advance.

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Re: 86 pup diesel no start

Postby puttputtinpup » Sun Jul 22, 2018 5:04 am

You will find 2 steel lines up against the firewall coming from the tank. One line goes to the fuel filter. The other is a return line from the injection pump back to the tank.
Try this to purge any air from the inj pump and lines.
Remove the return line from the pump to steel line at the firewall. Temporarily replaxe it with a piece of clear line of the same size so you can verify when bubbles are gone.
*Take the fuel cap off and grab a rag, wrap it around an air hose blow gun.
*turn on the key to energize the fuel cutoff solenoid in top of the pump. This will open up the passage of fuel through the pump.
*Have a helper watch the clear return line for you (unless you have a long enough piece to loop up out of the hood so you can see it).
*THIS IS IMPORTANT! Use the rag to somewhat seal off around the filler neck with the air nozzle pointing into the tank. What you wanna do is GENTLY WITH SMALL BURSTS OF AIR pressurize the tank so fuel will be pushed through the lines into the fuel filter, the inj pump, and back out the return line. Too much pressure at once will blow your fuel lines off or damage something.
*You could also use a vacuum brake bleeder attached to the return port on the pump to pull fuel through. This brake bleeder is also great for bleeding Pup brakes. See my review in the Tool Review section of the forum.

*Once you see a good flow of fuel coming through the return line, put your air hose down, turn off key, turn back on the restart the glow sequence and try to fire it off. It may take a +two tries til fuel gets to the injectors.
Assuming your glow plug system is working, it should fire off.
*One other way of bleeding if you dont have a compressor is attach a boat motor primer bulb to the temporary clear return line. You may need adapters.

If this helps, you should buy all new rubber fuel lines and clamps to ensure no air can enter the system.