Engine and fuel?

Tiny
DSHJR
  • MEMBER
  • 1977 FORD TRUCK
  • V8
  • 2WD
  • MANUAL
  • 150,000 MILES
I have a 3208 V8 Diesel cat motor and a Ford l7000 series truck. When I go down the road with a load on it the idle grows high and won't go down until I push in the clutch and let it out quickly. I put a brand-new fuel filter in it and problem still there.
Saturday, May 31st, 2025 AT 11:39 PM

14 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,144 POSTS
Is this engine a turbo? If so, you can have a bad turbo that is leaking internally. I would remove the inlet or outlet to check the turbo endplay. Please go over this guide to see what I am talking about:

https://www.2carpros.com/articles/how-turbo-chargers-work

I would not drive the truck anymore until you find out, so you don't risk (engine runaway) This happens when the engine starts burning engine oil from the turbo. Please upload pictures or videos in your response.

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Sunday, June 1st, 2025 AT 10:32 AM
Tiny
DSHJR
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No it doesn't have a turbo. When the engine revs up high and won't stop until I put the clutch in and replace it quickly and then the engine will stop running like it's ran out of fuel. It won't start back up even if I prime it with the priming pump. The only way that it will start back up is if I put fuel down the intake and then it will run for a few miles and do the same thing all over again.
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Sunday, June 1st, 2025 AT 11:30 AM
Tiny
DSHJR
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Would you like a pic of the engine or the truck?
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Sunday, June 1st, 2025 AT 12:48 PM
Tiny
DSHJR
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Picture of the truck.
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Sunday, June 1st, 2025 AT 7:20 PM
Tiny
KEN L
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Okay, it sounds like the the fuel injector pump is going out. I need to say I am a automotive tech so I am a complete expert on larger trucks like this. I would look at the linkage for the throttle and make sure there are no fuel leaks.
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Monday, June 2nd, 2025 AT 11:26 AM
Tiny
DSHJR
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When I prime the fuel it does not keep the pressure for long it bleeds off quickly the and there is some fuel on top of the engine after I have tried to prime it a few times. When I bought the truck I noticed that there was a few bolts that were loose and tightened them up. But when I prime it I can hear something like it is bleeding off some where but I can't find where. When the engine RPM is high and won't go down when I let off the throttle or go back up step back on it. And when it is not moving down the road it will idle fine for a long time until I step on it and release it quick then the engine will run rough and die and won't start back up until I reprime it again I will try to make a short video on what I am talking about today.
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Monday, June 2nd, 2025 AT 12:36 PM
Tiny
DSHJR
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Here the video sometimes it doesn't start up that easy like it did in the video.
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Monday, June 2nd, 2025 AT 9:32 PM
Tiny
KEN L
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The fact that you need to prime it to get it started means the injection pump is going out or you have a hole or crack in the fuel line going to the fuel pump, I would check that first. Thanks for the video it helps.
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Tuesday, June 3rd, 2025 AT 10:53 AM
Tiny
DSHJR
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Okay, thank you for that information. I will check the lines and probably just get brand new ones to make sure that that's not the problem.
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Tuesday, June 3rd, 2025 AT 10:57 AM
Tiny
KEN L
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Yep good call.
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Tuesday, June 3rd, 2025 AT 11:09 AM
Tiny
DSHJR
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  • 11 POSTS
If changing the hoses or the lines don't work, then it'll probably be the ejector pump then, right?
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Tuesday, June 3rd, 2025 AT 11:12 AM
Tiny
DSHJR
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When I bought the truck I noticed on top by the ejector pump that some bolts release could that be the problem too I tightened them when I got it and it ran fine if they wiggled loose again would it make that problem happen the bolts that I tightened were underneath the intake where the air goes in.
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Tuesday, June 3rd, 2025 AT 11:13 AM
Tiny
KEN L
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Good find! Maybe it will need lock tight thread locker.
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Thursday, June 5th, 2025 AT 11:42 AM
Tiny
DSHJR
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Okay, I will put some on them.
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Thursday, June 5th, 2025 AT 11:49 AM

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