Pre-Power Stroke Diesel (7.3L IDI & 6.9L) Diesel Topics Only

7.3 starts then dies

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Old 05-18-2010, 01:53 PM
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7.3 starts then dies

My 7.3 (1989 F350) is having issues, I tried cussing at it, kicking the tires, screaming and calling it all kinds of dirty names to no avail. So the symptoms are:

Key on, wait for glow plug light to turn off.<O
Light turns off, crank the engine over.<O
Fires within a few seconds but then stumbles and dies like it is starving for fuel.<O

Turn key off, then on again wait for glow plug light to turn off.<O
Light turns off, crank the engine over, and over, and over, and over, and over.<O

Turn key off, then on again wait for glow plug light to turn off.<O
Light turns off, hold go petal down, crank the engine over, and over, and over, and over, and over, <OWhite smoke starts coming out of tail pipe, still turning engine over, and over and over.<O
Engine fires and runs fine.<O
<O
After leaving it at work for 8 hours it fires like it is supposed to, but next day or if left for more than 10 hours, see above.

And yes, it has fuel (the correct type too). There is no fuel on the ground so I dont think it is a leak.

Any ideas? It is in need of a water pump soon (that is one thing that is leaking) but other than that it is servicable. Help me before I go and get my gun to put myself out of it's misery.
 
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Old 05-18-2010, 02:08 PM
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Sounds like theres air getting into the pressure lines... check into a return line kit would be all i can think of.
 
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Old 05-18-2010, 03:23 PM
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I was having the EXACT same problem.

Now, I wait till the voltage guage stops clicking ( cycling through the plugs? ) then it fires up fine. If I try to start it before the clicking stops it'll stumble and have the same symptoms as Black's truck.
 
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Old 05-18-2010, 04:12 PM
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Black, when it's sat long enough that it would do this, pop the fuel filter off and see if it is full to the top, or if it has drained down some. You may not have fuel leaking out, but you may have air leaking in, and letting the fuel drain back from the injectors and IP.

I suspect this is the major issue, and you will need to put a return line kit in it. (Generally called an injector installation kit at the parts places, with the copper washers only being used if you were to actually replace the injectors.)

Another thing to look for, if the rubber return lines between the injectors have the factory gray paint, they are original, and a good sign they should be replaced, along with the o-rings under the plastic caps.
 
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Old 05-18-2010, 07:13 PM
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was having the same problem.... well still am actually lol my return line kit is sitting on the floor next to me....

another thing to do while doing the return line kit is replace the fuel filter with this one

WIX 33617 - Fuel/Water Separator 1994 Ford F-250 | O'Reilly Auto Parts

that factory one will leak and was also causing my fuel to get air in it
 
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Old 05-18-2010, 09:04 PM
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The leaking return lines usually do not leak fuel out.

They let air leak in, breaking the vacuum that holds fuel up in the fuel system when the engine is not running.

So you start the engine on the fuel left in the IP, then suck in the air pocket from the fuel filter, and the engine runs out of fuel.

Now you have to crank the crap out of the starter, shortening the starter life considerably, to pump the air through the injection system before it has enough fuel to fire again.

When you only let it sit for a short amount of time, the air has not let all of the fuel drain back to the fuel tank, so the engine starts fine.
 
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Old 05-18-2010, 11:52 PM
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Speaking of the starter, crank for a maximum of 20 seconds and then wait two minutes before trying again. Otherwise, you'll be changing the starter along with the return lines...at least that's what happened to me.
 
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Old 05-19-2010, 12:22 AM
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I had the same problem. Check out https://www.ford-trucks.com/forums/9...fuel-pump.html for a possible solution.

Good luck!
 
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Old 09-20-2012, 02:05 PM
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Black, what did this turn out to be?
 
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