7.3 idi cranks but no start

[Dustin Kim]

Alright so story time!

I bought a used 1992 F-350 7.3 idi non-turbo. Drove it for a few months with no issues. Finally decided that an oil change/fuel filter change was needed. Changed the oil and fuel filter. I added 3/4 diesel fuel into the fuel filter and actually drove fine for a day. Came back home the next morning and realized that I should change the tank from the rear to the front tank since the fuel level was reading fairly low. My rear tank does tell me how much fuel I have but the front does not. Front will send fuel just reads full all the time which is why I run off the rear tank and keep the front full. Well I started it the next morning, which turned on just fine but then I went approximately 3 miles down the road and the truck just decided to die like there was no fuel. Got it towed back home and have had it sit.

I got extra diesel fuel and filled it to just under 3/4 full to the rear tank since I know at least the rear tank fuel sending unit works and moved the fuel selector valve back to rear.

I initially pushed the shradder valve and had air come out so I pulled the filter off, filled entirely with fuel and placed it back on. Now while cranking, a steady stream of fuel does come out of the valve.

Pulled the air cleaner off since that would eliminate one of the three things needed to start.

I then went to the injector pump. Injector pump fuel shut off gets 12v while the truck has power and you can hear the solenoid click when the plug is touched. Cracked the injectors and cranked to make sure I got fuel coming out of the tops of them. I have fuel coming out of 6/8 of them. I can't get the #1 open and haven't got any fuel out of #8. I tried the room temp water on the IP but still just cranked no start.

I have been cranking a lot so I pulled the batteries and had them tested. they are 850 cca batteries from March 2019. One was at 530 cca and the other was at 650 cca. I trickle charged them full. Before I put them back in I checked the shrader valve again to see if I had any air back in it and it had a full stream of diesel fuel coming out so assumably no air in the fuel filter and no air leak since the last time I tried which had been a couple weeks. I put the batteries back in, waited for glow plugs to warm and tried to crank but again no start.

I feel the only other thing that I may be missing is the starter is not strong enough to make the compression to start? I believe having fuel to 6/8 injectors should be enough to at least get it going. I don't think its an air issue but I may be wrong. But theres fuel definitely coming out of the injectors when cracked.

Any thoughts before I start throwing a load of money at this thing? Thanks guys!

 

[Christian9112]

hows your glowplugs? Is it so cold out that you can see your breath?
I think you do have air in your fuel. combine that with bad glowplugs, slow cranking starter from the batteries and you could have a no start

 

[Dustin Kim]

Recently its been about 50 degrees during the day and around 25 at night. When I wait for the "wait to start" light to go away, I can hear the glow plug relay clicking several times but I will go and check each individual glow plug.

 

[matthew mcelhaney]

Not 100 percent positive on how the selector valve functions but if it is a solenoid type valve as I think it would be, it may be stuck causing a complete blockage. That could explain why you made it 3 miles after flipping the switch and had air in the system. I would pull the Fuel line off and see if you have any flow from the tank.

 

[quickster]

if your starter isn't spinning fast enough, the motor will not start. If you have a charger with a high setting or assist like an Associated, have it on while trying to start. Passenger side battery.

 

[Dustin Kim]

Ok I will also try that as well. I figured since I haven't lost prime at the fuel filter I have fuel coming from the tanks and through the fuel selector valve.

 

[quickster]

sounds like you're getting fuel. you need compression now.

 

[Dustin Kim]

if your starter isn't spinning fast enough, the motor will not start. If you have a charger with a high setting or assist like an Associated, have it on while trying to start. Passenger side battery.

Gotcha. After recharging the batteries, the starter sounds like it used to when it started after the first couple cranks. I definitely cannot count the amount of times it cranks when it does so I assume it is ok?

 

[matthew mcelhaney]

Not 100 percent positive on how the selector valve functions but if it is a solenoid type valve as I think it would be, it may be stuck causing a complete blockage. That could explain why you made it 3 miles after flipping the switch and had air in the system. I would pull the Fuel line off and see if you have any flow from the tank.

I suppose I should have read the entire post rather than skimming and I would have seen the continuous flow of fuel part ha.

 

[IDIBRONCO]

I suppose I should have read the entire post rather than skimming and I would have seen the continuous flow of fuel part ha.

There could still be air pockets in the injector pump and there's almost certainly air in #1 and #8 since one won't open and the other has no fuel coming out. Don't worry about those two. The other that do have fuel will be enough to get your engine started. If all else fails, plug your truck in for a couple of hours. It's still not a bad idea to check your glow plugs though. If your glow plugs are good, and since your batteries are charged up, your engine should start now. It will run rough and smoke until all of the air is worked out, but it will run.

 

[Dustin Kim]

There could still be air pockets in the injector pump and there's almost certainly air in #1 and #8 since one won't open and the other has no fuel coming out. Don't worry about those two. The other that do have fuel will be enough to get your engine started. If all else fails, plug your truck in for a couple of hours. It's still not a bad idea to check your glow plugs though. If your glow plugs are good, and since your batteries are charged up, your engine should start now. It will run rough and smoke until all of the air is worked out, but it will run.

Definitely going to try all these things soon. Just got to find some time now to try it all haha

 

[IDIBRONCO]

Just got to find some time now to try it all haha

Good thing it only takes a few seconds to plug it in.

 

[Dustin Kim]

Well thanks to everyone’s advice she’s running again! Installed new motor craft glow plugs all around, new injector o-rings, new return fuel lines, and what I believe actually got it running again? New powermaster 9050 starter. I guess the old original starter sounded good to my ears but it wasn’t compressing fast enough. So thanks again to everyone for their input it definitely made my brain work!