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7400 fuel supply problem

hard starting

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#1 Zac Weidner

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Posted 22 January 2012 - 06:24 PM

Hello,
We purchased a used 7400 SFA International truck last year. It has a DT466 engine in it. If it sits more than a few days, it acts like it isn't getting fuel. It takes several tries of cranking for 30 or more seconds each time to get it to start. Sometimes it will act like it wants to run while cranking, but dies as soon as the starter is let off.
It seems like it is getting worse every time it sets for very long.
Is this a common problem, or is it going to be expensive?

Thanks!

#2 1954cooter

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Posted 22 January 2012 - 09:46 PM

How much fuel do you have in the tank?If the fuel pick-up is located on top of tank and if its down on fuel and if theres a cracked fuel pick-up pipe it'll cause the fuel to run back into tank and let air into fuel system when engine is shut off.Does it work ok once its running?

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#3 Zac Weidner

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Posted 23 January 2012 - 06:00 AM

The tank is full now and it doesn't seem to make any difference. Once it starts, it runs great. Also, when we are using it almost every day in the fall and spring, it has no trouble starting. It only acts up when it sits for a few days.

#4 Owen Aaland

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Posted 25 January 2012 - 04:28 AM

You probably need to replace the rubber seals under the fitting nuts on the fuel lines. Once they get old they can allow air leaks but since they are on the suction side rather than the pressure side they will not leak fuel/

#5 Zac Weidner

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Posted 03 March 2012 - 09:12 AM

After doing some more experimenting on this subject over this past week, I've decided that it's not a fuel supply problem. I think it is something in the engine, like glow plugs. I can take the fuel line off and pressurize it with no results either better or worse.
However, if I plug the truck in overnight, it starts fairly well.

When it is not plugged in and about 70 degrees ambient, I have to crank it about 4 or 5 times at 30 second intervals to barely get it running, then it runs very sickly and slowly gets going up to normal idle speed. The intake heater works, because the voltmeter drops down about a volt while the "Wait To Start" light is on, then back up to normal battery voltage when it goes out.

I don't want to have a truck that is this start, but I'm also not wanting to spend big dollars chasing ghosts.

Any help is greatly appreciated.

#6 ontsandfarmer

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Posted 03 March 2012 - 01:52 PM

what year is your 7400 ZAC

#7 Zac Weidner

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Posted 03 March 2012 - 06:11 PM

It is an '06 model year truck.

#8 ontsandfarmer

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Posted 03 March 2012 - 07:22 PM

i would replace the fuel lift pump and check valve on the back of the cyl head check with your navistar dealer i think there was an update on lift pump.

#9 Zac Weidner

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Posted 06 March 2012 - 08:38 PM

I have ordered a lift pump. It was the cheapest part that the service department could think of as a possible fault, so I will see in a few days if that is it. Sounds like the lift pump is also the only part that I can put on myself without taking it to a service center for them to tinker around on my dollar.

#10 Zac Weidner

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Posted 09 March 2012 - 05:38 PM

Got a new lift pump installed with no improvements. Same old problem. It does start pretty well when it's warm (70 or above), so it's still puzzling me.

Any other ideas?



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