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will it suck air ??????Help Help

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Old May 20, 2010 | 07:31 PM
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idahoturbo94's Avatar
idahoturbo94
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will it suck air ??????Help Help

I just redid all the return lines on my 7.3idi turbo. It is still a hard start but it used to start right up the rest of the day unless i let it set for more than 3 hours. But know it cranks and cranks even after a 20 mile drive. I found 1 leaking fuel cap in back that is still seeping a little. I was wondering if I tore a oring on the injector when i was reasimbling would it suck air and cause an imediate hard start even after it is warm???? Runs great once it turns on. ??????
 
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Old May 20, 2010 | 07:38 PM
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Any time you move the caps it could break the seal (especially if old). Which probably did happen. Remember that air will seep into the fuel system but fuel will not ooze out because fuel is thicker than air. Keep looking! You'll get it! Also a bad fuel pump on the engine could leak fuel back to the tank.
 
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Old May 20, 2010 | 07:48 PM
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idahoturbo94's Avatar
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I see what you mean I think since the pump is cheap i am going to put new fuel pump on engine and Pull that Cap and look at orings and see what i messed up, there is a little bit of diesel seeping out from under cap i just dont know why it just wont fire up right after i shut it off and it used to before i changed rreturn lines????
 
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Old May 20, 2010 | 08:24 PM
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Some of the replacement caps are lacking on quality control.

If you did tear an O ring, yes you could have fuel leaking out and an imediate restart could be hard since it will let in a lot of air fast.

Fuel leaking out while running, it's leaking air in bad when the engine is off.

Also inspect the cap for cracks carefully, while the cap is off the O rings are not putting pressure out on the cap.
When the O rings are over the injectors and the cap is over them, they are putting pressure out on the cap.
 
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Old May 20, 2010 | 10:19 PM
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Visit......Ford diesel 6.9 7.3 IDI there is much info there..... find the air in the system and clear line test..... use a verticle pigtail in the clear line so as to see which way the air is coming/going.

There are rubber seals under the line nut at the filter header from lift pump and both ends of the line from filter header to IP. there is an IDI parts page with #s on the above link.
 
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Old May 20, 2010 | 10:48 PM
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Ensure the caps are fully seated.
Did you use a liberal coat of Vaseline on the o-rings.

The filter head is another known air leaky location.

Should pull the filter after a time frame that it usually does it to see if it's full or not, if it isn't you either didn't get the return lines sealed, the filter head is leaking or the IP is leaking.

[edit]

The seals for the fuel line from filter to IP are 5/16" Vibra-Loc - McMaster-Carr Item 50385K83

[/edit]

-Enjoy
fh : )_~
 
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