Crank No Start

[kcdigiacomo]

I have 1991 7.3L that will crank and not start. You can smell the fuel burning and smoke coming from tailpipe. I just replaced the fuel filter thinking that may have been the cause. The glow plugs are working as I have tested and bypassed the relay with push button. Where do I go next without throwing parts at it?

 

[goatwrangler]

How's you air filter ? Compression ? air+fuel+compression= running diesel engine

Have you crack your lines at your injectors to make sure you are getting fuel to the injectors and trying to bleed the air out of the system.
How are you batteries and connections? Does it seem to be turning over slower then normal? Have you had your batteries tested?

With someone cranking your engine over depress the shrader valve on the filter head and see if you are getting good fuel pressure from the lift pump through the filter. When you changed your filter did you fill it up with diesel or ATF or just throw an empty filter on it ?

 

[kcdigiacomo]

I did fill it up as much as I could and then just tapped the ignition hoping to fill it the rest of the way and get the air out. It started and ran seemingly better after doing so but it sat overnight and now when I tried this morning would not start just crank. You could smell burning diesel and white smoke was coming from the tailpipe but just would not start so I am stumped.

If I have air getting into the system how do I find the leak to fix it?

How do I get the air out permanently?

 

[goatwrangler]

You have a leak somewhere in the return system. It is most likely your return lines/o-rings between the injectors. After the truck wouldnt start this morning did you check your fuel filter again? Im guessing it is no longer full from air getting in the system and draining the fuel back to the tank. Pull your fuel filter off and fill it back up and bleed the system of air. If you have a battery charger hook it up while youre cranking and remember for every 30 seconds of cranking let the starter cool off for at least two minutes. This is a very common problem that many if not all IDI owners have combatted.

 

[kcdigiacomo]

How do I locate and fix this leak?

The Schrader value is what on the filter housing? I am not much in the way of mechanic lingo.

 

[79jasper]

Schrader is the valve stem looking feller on the filter head.
If it's the return caps, you need new orings at minimum, new caps would be best.
Typ4 and Agnem sell good kits that come with everything you need.
Check the rubber fuel loop down by the lift pump.

Sent from my SM-G900R4 using Tapatalk

 

[goatwrangler]

Thx Jasper. Also what Ive done in the past to figure out if my leak was between the tank and lift pump or between the lift pump to the injectors is disconnect the supply line from the lift pump and submerge a hose in a 5 gallon can of diesel fuel, run it off that and let it sit for a few hours to see if the fuel filter drains back.

 

[kcdigiacomo]

Well I thank each and everyone for your replies and have figured that I now have another issue. I did crack all the injectors on the drivers side and fuel came out. Also I believe that I did not put one of my plugs in very snuggly and saw that fuel was bubbling out, not good so I pulled it. Good news is that yes fuel is getting to them also. What I have no found is that I have been putting a constant 6v to the glow pugs and have fried them out because now none of them work or test.
My best guess and talking it over with a friend of mine that is a mechanic but does not do diesels is that the relay is stuck allowing the voltage to remain constant at 6v which has in turn ruined each and every one.
I checked to see if my relay bypass worked and I get 12v on the glow plug outlets from the harness when button is depressed.