I have a '92 12 valve that has me puzzled...It stalled on me one day a week or so ago. It turned over as if it was not getting fuel so I guessed the lift pump was shot. I replaced it but no difference to my problem. I then changed the filter - not a waste of time but no difference. Then it decided it wanted to start! So I was happy until it quit again. This time not wanting to idle either before it died. I cracked the injectors and it will shoot fuel to the hood but it will not start. I gather from this it is getting fuel. I tried the timing and it is fine. Once again when I tried to start it yesterday, it started up fine -at a touch of the key like it normally does and then even idled for about an hour before I used it. After using it for three hours it would not idle and quit. I tried to re-start right away but it just spins as if there was no fuel in her. I know the pre-heat is not working properly but I am stumped as to why it will not start after running for 4 hours. I checked the resistance on the intake manifold sensor and it has none.....Does anyone have a suggestion for me? Would it have anything to do with the PCM? Thanks for any suggestions.

 

Fuel pressure test ?
How cold is it where you are ? Where are you ?
I never replace a part without a test , showing that that part is needed .

 

I am in British COlumbia -Canada - It was -20C yesterday when it started at a touch of the key. It was plugged in of course. I have not done a pressure test yet as the problem seems to come and go without doing anything to it????

 

I've had exactly the same problem you are having and i'm in Kentucky. I did everything you did except the fuel pump change and timing and it does the same thing. One minute it will start great and the next minute it rolls over and coughs then idles hard then runs fine. All I can think is that its bad diesel or water in your lines that just decided to make problems. Maybe you can get it started again and then put new fuel in it with additives. Or drain the tank and just start over.

 

As a mechanic , I was saying that with a diesel , the 1st. sign of engine running problems , you should do a fuel pressure test .
I am not as familiar with the 1st gen as my 2nd , so a list of possibilities may get you to just start replacing things , testing is what should be used to replace parts .
Guessing what to test is where your at now , symptoms tell you what tests to use .
Being that your temps are where there at , is also a guessing point as to what to look for , gelling fuel , is a possibility also , using a glass container to drain some fuel out of the filter , to see if there is anything in the fuel that shouldn't be , then leaving outside to see if it clouds / gels .

 

If it were water or poor fuel would it run normally when it does decide to start? If I keep the throttle lock out a bit it will run normally other than idle higher than it should be. I have no explanation at to why it starts some attempts and just spins like crazy others??? Thanks for posting your experience too - I can drain the tank easy enough and it does not cist anything to do it!

 

Just thought of something else to look at , is the fuel shutoff system , the solenoid - is the rubber boot missing / broken [ dirt can cause issues ] , then the relay that runs it , then the ignition switch , all of those can make intermittent problems .
Use a test light to check all of those .

 

If your questioning the RPM , tell us where its at ?
Should be 850 RPMs , with auto trans in gear , AC on , sense you mentioned the idle up cable .

 

I really don't know what water does to the performance, all I know is since there is no spark, fuel quality is very important in diesels. You could be sucking up water and fuel and maybe sometimes there is more water than fuel being injected into the engine.

 

I would look into some electrical issues on the shut down solenoid on the pump. Quick test would be to take a jumper wire directly from the solenoid to the battery.

 

Mine has started doing that, and I've found that the shut off soleniod connection seems to be bad. If I take it off, then push it back on it starts right up and runs normal until the next time it happens. Goint to do the ring terminal mod this week to fix it permenantly

 

sure sounds like the shutoff solenoid.

 

this happened to me also. i replaced my fuel filter and primed the heck out of it and crack the fuel lines and turned it over until the air was out. she fired up after about 25 mintues of cranking on it.

 

I thought of the shut off solenoid and tested that too. It appears to be in good working order...when it is turning over it does eject fuel from the lines if they are cracked. It is the older type in the injector pump so the boot does not exist. If it was water in the fuel woudl it run until I shut it off and not start again?
I have a 5-speed tranny and there is no tach in the truck so I am not sure what RPMs it is at but I do know that when I started it yesterday it idled at what I would say a normal RPM and after three hours or so it would not idle on it's own at all. It seems to fix itself for a short period of time somehow or I am hitting a wire or something without knowing it. I will drain some fuel and see if it gels tonight. I have another Fuel Shut off that I can swap from another truck - I will try that tonight as well. Thanks again for all the ideas. I live 200 miles from a major centre and it can be a task to get to places if she is not running 100%.

 

If that connector on the shutoff solenoid is loose it can cause all kinds of intermittent troubles. Replace it with a ring terminal before you go chasing other possibilities.