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N9438D

7400 fuel supply problem

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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!

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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?

Cooter

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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.

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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/

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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.

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It is an '06 model year truck.

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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.

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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.

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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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Check the glow plug relay. With a powerstroke engine, the voltage drops at least 3 volts, and if the relay is old the terminals inside get burnt amd the plugs dont heat enough to start it easily when its cold.

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Check the glow plug relay. With a powerstroke engine, the voltage drops at least 3 volts, and if the relay is old the terminals inside get burnt amd the plugs dont heat enough to start it easily when its cold.

Would this be the intake heater or does it have glow plugs also? The voltmeter on the dash shows a good 2V drop, but not 3 while operating.

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you have a DT466 correct? if so no glow plows you have a grid intake heater that thing should start right up even at 25 degree weather still sounds like a fuel problem . you need to hook it up to a lap top check your huei pressure needs min 300 psi to start .

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Could be a bad o-ring on an injector causing the fuel to leak off, could also be an injector, pretty safe bet to say you'll be pulling the injectors out and o-ringing them, these were bad for injectors and o-rings

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Could be a bad o-ring on an injector causing the fuel to leak off, could also be an injector, pretty safe bet to say you'll be pulling the injectors out and o-ringing them, these were bad for injectors and o-rings

We have internal injectors with a common fuel rail, actuated by oil pressure. Would these O-rings still be applicable to this type of engine?

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Okay, I will check into the O-rings issue. Thank you for the tip!

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Okay, we have a whole new animal with this problem now. The other day I was spreading a full load of urea on some pretty solid, flat bean stubble ground, and the truck lost power and almost died on me about 4 or 5 times within about 30 minutes or less. It also had a very hard time getting rolling from a stop with the bed pretty full. Once it got going, it seemed to run pretty well, except for the 4 or 5 times that it would all of a sudden just lose all power and come to a stop, idling at about 400 RPM with no ability to even accelerate with the transmission in neutral. The engine light would come on very often, even after I got some of the load spread.

Once the load got a bit lighter, the light would come on, but I could get it to go out for a minute or so by very quickly letting off the throttle, then to the floor. It definitely has a major problem, and I see it being one of those ghosts that sucks down a whole lot of money trying to chase it.

The next day I spread another load, half a load at one time, except it was on some hilly, freshly disked ground and the light didn't even come on. I would guess fuel pump, but it seems too inconsistent to be a pump. Could there be a computer going bad?

Any help is greatly appreciated.

Thank you,

Zac

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pull all 6 injectors only takes one to cause your problem if she don't start then sounds like huei pump gear loose on shaft.

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We finally took the truck to the shop and got it fixed. Turned out to be some sort of solenoid that had a glue bond that had come apart and was not operating all the time. It would vibrate back and forth and cause the erratic problem. The starting seems to be improved also. It is not perfect, but it starts much closer to normal and it's not going to ruin a starter anymore.

Thanks for all the tips!

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