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

93 7.3idi starts but won't stay running.

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Old 03-10-2014, 06:20 AM
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93 7.3idi starts but won't stay running.

Just bought a 7.3idi ran great for about 3 weeks now it's hard to start and won't stay running.
 
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Old 03-10-2014, 05:14 PM
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Figured out part of the problem. There was air in the fuel system. Bled it now need to find the leak. Does anyone have any suggestions or tricks?
 
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Old 03-10-2014, 06:46 PM
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Replace everything made of rubber in the fuel system. I am really getting sick of hearing of how much air intrusion causes our engines to have constant starting problems, mine included. There has got to be a better way. I am just going to install an E-pump and let it prime for a few seconds before starting. Air intrusion has been a constant thorn in my side since i bought my first IDI ford truck 8 years ago. I believe it is because of something in the new ULSDiesel that we get is corrosive to the rubber in our fuel system. the plastic caps that come in the return line kits will cut the o rings on your injectors so if you dont push them on perfectly they will still leak air into the system
 
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Old 03-10-2014, 07:05 PM
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Originally Posted by IDI guy
There has got to be a better way.
you ain't lying.




FACET® DURA-LIFT® Solid State High Performance Heavy Duty Diesel Electric Fuel Pump for Thermo King and Carrier Trucks.Carrier Transicold #30-01108-02SV
Installed In Engine Bay w/5a inline fuse & 30a relay off the battery w/FSS line to trigger pump w/turn of the key w/Mr.Gasket Fuel Pump Block Off Plate #5422

main specs to look for:

Voltage: 12 Volt
Minimum Shut Off Pressure: 9.0 PSI
Maximum Shut Off Pressure: 11.5 PSI
Gallon Per Hour Flow: 33

example:
http://shop.aftermark.net/shop/dura-...ift_Fuel_Pump/
 
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Old 03-10-2014, 07:53 PM
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Thanks. What else can I do to make the motor better and run forever?
 
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Old 03-10-2014, 11:25 PM
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Warning, warning, To much fuel pressure to inlet of Ip May cause erratic operation of the governor and or the timing advance inside the Ip. The Idi consumes approx. 7 oz of fuel in one minuet at cruse speed, there is no need. for hi pressure hi flow pumps, and I do not recommend doing away with the return line from the filter head as it removes air bubbles from sloshing of the tank when driving. perhaps 4x that at full trohttle thats 14 gallons a hour, all most any e pump will be fine, cept them mr gasket junk.
 
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Old 03-10-2014, 11:28 PM
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Originally Posted by speedwrench72
Warning, warning, To much fuel pressure to inlet of Ip May cause erratic operation of the governor and or the timing advance inside the Ip. The Idi consumes approx. 7 oz of fuel in one minuet at cruse speed, there is no need. for hi pressure hi flow pumps, and I do not recommend doing away with the return line from the filter head as it removes air bubbles from sloshing of the tank when driving. perhaps 4x that at full trohttle thats 14 gallons a hour, all most any e pump will be fine, cept them mr gasket junk.

That's this one, no bueno:


 
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Old 03-11-2014, 05:34 AM
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So just a standard e pump nothing high flow. Got it.
 
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Old 03-11-2014, 08:52 AM
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Originally Posted by jkinghorn6.0
So just a standard e pump nothing high flow. Got it.
actually, no. a standard e pump is what you do not want to use.
the facet duralift pump is what you want to use.
 
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Old 03-11-2014, 04:08 PM
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Ok. Can I use it injunction with the manual pump or run it directly
 
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Old 03-11-2014, 04:53 PM
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you can use it before the mechanical pump but if the diaphragm in the mechanical pump rips it will fill the crankcase with fuel

i prefer bypassing the lift pump and just using the E-pump
 
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Old 03-11-2014, 07:57 PM
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Ok that's good info. Thanks
 
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Old 03-11-2014, 08:23 PM
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I read an article explaining the problem:
There is supposed to be a check-valve in the filter head. This is what is failing(ULSD? Time?), and that means air is sucked into the filter:
Ford diesel 6.9 7.3 IDI

On 7.3 engine the filter return orifice contains a check valve. This check valve is usually a rubber flap inside the fitting, and if this fails air is drawn into the filter as the fuel cools and contracts. This can be detected by removing the fitting and trying to blow through it from the hose barb end. If you are able to blow through it from this direction, it needs to be replaced. Seal the threads on the orifice with Loctite 515 Gasket Eliminator or PST. There are two different flapper valve orifices--3/16" and 1/4"--and the correct one needs to be used with the coresponding hose size or leaks may occur. Starting in 92 a 1/4" filter orifice was introduced without a flapper valve using a spring and plastic check ball. The spring-and-ball and flapper orifices are not interchangable; they have different headers. Also, the correct size return lines hose needs to be matched to the injector caps and the proper clamps used--not worm-gear, this will distort the hose; either OEM spring clamps or fuel injection system screw-and-band type.
http://www.intellidog.com/dieselmann/filter.jpg


Note that I just added an outside checkvalve myself, and it totally solved my own air intrusion problem... Even with one of the return lines open to the air!
 
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Old 03-12-2014, 07:05 AM
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eliminating the line with the check valve going to the #1 injector was a TSB issued by ford back in 89 or 90 to solve the issue of air intrusion.
 
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Old 03-12-2014, 09:31 AM
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Ifrythings took one of these valves apart and posted pics here:

https://www.ford-trucks.com/forums/1...l#post13225262

Good info!
 

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