Vehicle info: 96 f350 crew cab dually. 7.3l engine. Dual fuel tanks. (However front tank has a hole in it pending welding.)


Let me start off by saying, while i am mechanically inclined, I am brand new to the diesel world and haven't learned all the trouble shooting yet. I bought this truck 6 days ago, and it ran great until Sunday. I was on the way back home when the engine started acting up. I began to loose power and the truck began to shake. It got progressively worse as I drove home to the point that i pulled into a parking long and called a budy to so if he had any suggestions. He said the symptoms described lack of fuel and that the cheapest and quickest prospective fix would be the fuel filter. Well, not only did that not fix the problem but now the truck wouldn't start. Things I noticed while changing the filter. The fuel bowl was only a quarter to a third full. Also the bleeder valve on the side of the bowl had no pressure behind it with the key on. Today, after learning that these trucks have suction issues with less than a quarter tank, I was near empty, I put 5 gallons in. As a result while it was turning over I got white smoke but no start. Personally I took this as an improvement over no start and no smoke.

So with the little knowledge of diesels I have, it seems to me that i have a fuel delivery issue. Are there any other pumps in the system other than the in tank lift pumps? What else could be wrong and is my logic, well, logical?


Thanks in advance for the help.

 

You have one fuel pump.

Its a mechaincal pump in the valley of the motor. It is driven off a lobe on the cam.

There is nothing in the tank, just a pick up.

You could have a bad fuel pump, you could have a plugged up tank pick up foot.

Rough running leads me to believe you ran it out of fuel, and it sucked up a bunch of air. An OBS is a bitch to get started again once run out of fuel. How much cranking have you done? Fill the fuel bowl with diesel?

 

The fuel lift pump is mechanical and sits behind the fuel filter on top of the motor, In addition to this pump there is a (HPOP) High Pressure Oil Pump that sits in front of the fuel filter on top of the motor. If your seeing white smoke wile cranking that indicates unburnt fuel and is common with an older 7.3 at cold start. There is a phew simple procedures you can do to start the diagnosis process.

1 Make sure the wait to start light illuminates when your turning the key, If it doesn't then you may have blown your #22 fuse check all fuses.

2 Does the tach move when the key is on and the truck is cranking? It should be If not start looking at the (CPS) Cam Positioning Sensor located in the front of the motor passenger side bye the water pump pulley. This is the most common problem Ive had with the 7.3

3 Check the oil level in your HPOP reservoir needs to be 1/2" to 1" below the filler plug.
The filler pug is located on top, drivers side and needs a T30 star socket to remove it.
Reservoir is located between the A/C compressor and the alternator in front of the motor on top.

4 Ive also had issues with my ICP sensor (Injector Control Pressure) located driver side top of head to the front of motor.

Starting here will get you going in the right direction, Ive just tackled a weird situation on my 7.3 as it was doing a similar thing. After driving say 10 to 15 miles it died and wouldn't start and after doing all the obvious steps it ended up being a bad socket at the CPS and after replacing with a good used one im up and running again!!

Another big important factor make sure you have good batteries the 7.3 needs about 900 rpm when cranking to start!! Very important!!

Good luck hope it helps.

 

Probably more cranking than I should have. I did fill the bowl.

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I'll check all those things in the am. I forgot to mention that I DID check all fuses and relays and they were all good.

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Quick update:
WTS light does come on, Tach moves when engine's turning over, HPOP reservoir appears to be at proper levels. What do i need to do to test the ICP sensor? Assuming it has sucked up a bunch of air, how do i remedy this problem?

 

ICP sensor is not your issue.

I can tell you if your fuel bowl is not getting fuel its a fuel issue.

You mentioned that you didnt get any fuel out of the drain valve when open? Open it and crank, you should see a good volume of fuel leaking out.

 

I did see a good volume of fuel come out. So i closed the valve and gave it to 20 second cranks over 15 minutes and what do ya know, it started. Took it for a test drive and it drove fine. So the question becomes what happened?

I've had the tank lower than it was on the highway, and i was driving cruise control on flat straight highway when it started acting up. Is there a mod i can do to keep the truck from loosing prime when the tank is below 1/4 tank? Thanks in advance for the help!

 

i have 1995 powerstroke changed injectors got check engin light after drove 10 miles loses power still runing mec. scand it replaced ipr cam sensor still same light off drive 10 miles light on loses power still runs not missing no power shut it off will not start back for about 10 min starts back light out like it has no trouble run great for 10 miles when trys to start no smoke as no fuel

 

Change your FPR return filter! Its sandwiched between the fuel bowl and FPR. or Try cracking open the fuel drain valve just a little, on the fuel bowl and see if the symptoms go away?

 

I have run my outta fuel a few times. All I do is crank a bit, press the air bleeder until fuel comes out. And repeat this a few times till it starts. Always works for me.