96’ 1hdft power problem

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May 26, 2014
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I’ve got a 1hdft in a 96’ it’s got 229,000km on it.
Been driving the MABDR the last two days at slower speeds and lower rpm’s.
Decided to jump over to the highway to make better time on my way home.
Upon acceleration I noticed that the cruiser had a sort of surging/ loss of power. It’s real subtle and only last briefly like a pulse. Feels like someone quickly taps the brakes.

Wondering if maybe I got some bad diesel? And I should just push the next 3hrs home. Or if it’s something more serious and I should look for a tow? Currently sitting at a auto parts store.
 
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Welp, I made it home.
Think it’s time to clean out the fuel system.
Found that when I primed the fuel filter I had little to no issues. Problem came back a little further down the road. I pulled over and pumped the primer again, prob about 70 pumps. Was able to drive the rest of the way home without issue. So I must be losing pressure in the system somewhere.
 
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could be a clogged air filter or fuel line getting in air. i would check the basics first

bad diesel is a possibility... are you getting any smoke?
 
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could be a clogged air filter or fuel line getting in air. i would check the basics first

bad diesel is a possibility... are you getting any smoke?
Some smoke around 3k rpm’s if I’m laying into it. But not a ton. I normally shift around 2-2.5k rpm’s and I don’t notice any smoke.
I was thinking a leak in the fuel line somewhere letting air in. Which is why I was able to prime the system, and somewhat resolve the issue. But I haven’t been able to locate any drips thus far.

Gonna go check the air cleaner, but last time I opened it up. It was pretty dang clean.

But thanks for your help
 
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Wilmington, North Carolina
I think I got some bad diesel a while back and had that same hesitation. Did the LiquiMoly treatment. Just rework the fuel pump supply & return lines to a bottle of LiquiMoly and run off that until almost empty. And I added a bottle to the fuel tank. Problem went away and hasn't returned.
But yeah, make sure of no air leaks.
 
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try some of this stuff it's supposed to be the strongest cleaner on the market. I've used it and it has saved me from bad diesel and fouled injectors.. its also good for your pump

DIESEL EXTREME
 
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I’ll order some now! Thanks
 
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I suspect air leak. That's the only reason your primer would be easy to push then firm up. The primer is at the high point of the fuel system so as to collect the air.
You mentioned you don't see any diesel drips. Bear in mind, this is a suction side air leak. The fuel lines between the fuel tank and the injection pump are under a vacuum, so they will not drip diesel out, but will pull in small air bubbles. Think like drinking soda from a straw that got bent and has tiny holes. That's what is going on.
 
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A0184274-D6A7-4DF2-90D2-2BDF3CC37ADB.jpeg


Sorry I couldn’t really get the camera to focus
inside any better. But I’m pretty sure that sediment wasn’t helping fuel flow at all, lol.

The suction side air leak, and being under vacuum makes sense. But wouldn’t I get a drip when the vehicle is turned off? And the system is no longer pulling a vacuum/ under pressure?

So far just sitting in my driveway after changing the filter the throttle seems much more responsive. Bout to run her into town and see how it does.
 
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Sorry I couldn’t really get the camera to focus
inside any better. But I’m pretty sure that sediment wasn’t helping fuel flow at all, lol.

The suction side air leak, and being under vacuum makes sense. But wouldn’t I get a drip when the vehicle is turned off? And the system is no longer pulling a vacuum/ under pressure?

So far just sitting in my driveway after changing the filter the throttle seems much more responsive. Bout to run her into town and see how it does.


The sediment is not good, and could be a good reason to look inside your fuel tank for rust, but that small amount of stuff is not affecting the flow of fuel with any significance. You could cut the filter open if you wanted to see how the actual filter media looks though.

No, when the engine is running, the lines between the fuel tank and IP are under a vacuum. When the engine it not running they are not. To push fuel out, you would need it to be under pressure, which it isn't.

Good luck, hopefully the fuel filter helps, but I still think if your primer has many pumps before firming up there's an air leak.
 
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The sediment is not good, and could be a good reason to look inside your fuel tank for rust, but that small amount of stuff is not affecting the flow of fuel with any significance. You could cut the filter open if you wanted to see how the actual filter media looks though.

No, when the engine is running, the lines between the fuel tank and IP are under a vacuum. When the engine it not running they are not. To push fuel out, you would need it to be under pressure, which it isn't.

Good luck, hopefully the fuel filter helps, but I still think if your primer has many pumps before firming up there's an air leak.
Yeah i think you’re right, I think that there’s got to be a leak somewhere. It doesn’t make sense why the primer would not get stiff without there being a leak.
Also think I’m gonna need to drop the tank and get it cleaned out. All that gunk is coming from somewhere.
 

mudgudgeon

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Very common to have a stumble, miss fire etc due to a small air leak in the fuel supply lines.
Often with no sign of a fuel leak.

I once had a filter vibrate loose on rough corrugated dirt roads. Engine died as the loose filter let it suck in a bit of air.

There's a chance you fixed your air leak by changing the filter. Could also be a cracked hose, loose hose clamp, cracked diaphragm in the primer pump.

Loads of threads here showing the same issue
 

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