1984 6.2L will not start ,have some interesting clues

My 1984 jimmy started idling wired and then died. I then changed the fuel filter base from a standyne base to and aftermarket fuel base with a screw on filter/separator because I knew I had a problem there because of diesel slowly leaking from the back of it. bled out the injectors and still will not start. I also installed new glow plugs because I had planned to and this was the best time. Will not start. What I’ve noticed is that the fuel cap has a huge amount of pressure on it when I try to take it off. I mean like I have to use a large channel lock pliers to get it of. I know this can’t be right so this I think is a clue . the injection pump was change about 3 years ago but has just been driven around the property an not had any real miles put on it so it is fairly new. Any help or thoughts?

First, replace the fuel cap. If it's holding any notable pressure or vacuum, the vent has failed, and can cause a number of issues, including what you are experiencing now. They are consumable, and inexpensive. Make sure to replace it with a "Diesel Fuel Only" cap, as they vent differently than gasser caps. It is also likely that it is still air-locked after the filter change. It can take quite a bit of cranking to process all that air. You can expedite priming by pressurizing the fuel tank with low pressure shop air (~5 PSI, use your old fuel cap and adapt an air fitting or use an air nozzle in a new hole in the old cap). Apply the low pressure air and bleed at the filter until all the air is gone. Verify fuel lift pump operation and keep the batteries at full charge. Limit cranking cycles to less than 30 seconds with a few minutes between to allow starter cooling.

I suspect the fuel injection pump is airlocked.

1- Make sure you have plenty of clean diesel fuel in the fuel tank.
2- Make sure you bleed the fuel filter to remove all air.
3- Plug in the engine block heater for at least 4 hours. This normally allows a 6.2/6.5 to start even without glow plugs.
4- Dribble 2 tablespoons of diesel fuel into the intake manifold. Try to get some in at least a few of the intake runner. Some will make its way into a few cylinders.
5- Crank in no more than 20-30 second intervals with a 3 minute cool-down between cranking cycles. Engine should begin to fire on the raw diesel fuel. Repeat steps 4 & 5 till you begin to get the engine to run (even if roughly). If the engine still refuses to fire, you may have some type of mechanical failure (timing issue).

Starting fluid can cause engine damage unless it's used correctly. Best not to use it...


Jim

Sounds like you have too much air in your fuel system after you replaced the old leaking Square Box crap fuel filter and housing. And because of it, it won’t start because of all the air. More Powers method is a good way to get it running. Might have to jump start the batteries from another vehicle while doing all that cranking. My recommendation is to prime your fuel system somehow.

To solve my air in fuel line issues after replacing fuel filters, I bought and tried a few different primers. Here are a few pictures of some primers/pumps I used and that worked.

This primer/Pump is installed in the Fuel Filter Housing. It’s Ava online or you can buy it from me. It has helped a lot!

https://hosting.photobucket.com/imag...r/001(38).HEIC

This Primer/Pump is installed somewhere in your fuel line. This one is my favorite and I’ll be using this one again with my FM100 Fuel Filter Housing.

https://hosting.photobucket.com/imag...r/001(37).HEIC

Also before priming air out, it helps to crack the injector lines to get air out.

Since you have a bad fuel filler cap, I would crack the injector lines and use this method to not only get the air out of your lines, but to also check for fuel leaks.

https://www.thedieselpageforums.com/...em-A-Tutorial!


Having a primer/pump has saved me a lot of time and hassle. It reduced cranking time and you do not have to pour fuel in your intake which will get dirty faster. Oh yea, I also recommend installing a small fuel pressure gauge after the fuel filter outlet. It’s a great way to monitor when your fuel filter is ready to be replaced and monitor your mechanical fuel pump. The needle will normally bounce up and down between 5-7 psi when everything is working.

https://hosting.photobucket.com/imag...tetler/001.jpg

Good luck and please keep us updated!

The add on pump is a great idea. I don't know if this is the right way to do things, BUT, when I change filters I make sure I fill them with diesel after which I try and start it. If it fails to start I'm sure there is air in the,system. I get someone to spray WD40 into the intake while I crank it. You can keep it running on WD40 until the air is gone and it runs on its own. It doesn't take hardly any WD40 so don't get carried away. You can also do this if you run out of fuel, it will start right up. Reason for WD40 is because of the glow plugs, ether will more than likely destroy your engine.
RudyJ

If you have access to an air compressor with a good regulator, you can dial-down the regulator to somewhere between 5 and 10-psi, Stuff the air hose nozzle into the fuel filler neck on the fuel tank (wrapped with an oil-soaked rag, to provide a seal of sorts), then apply the air. This small amount of air pressure will allow you to fully prime all of the fuel lines and fuel filter, ensuring that an air leak in the fuel system isn't causing this no-start. The procedure I mentioned earlier can then be used to help move any remaining air out of the fuel injection pump, fuel injector lines and injectors.

Thank you all who replied . This is an awesome site. I finally got it started. The final piece of the puzzle was the return check valve. Broke it out and then she fired right up. I really like the idea of a pump on the fuel housing so I’m going to do this. You guys are awesome!!!!!