3b-t lost power; ideas? (1 Viewer)

[nuclearbeef]

3b with axt manifold and volvo garrett turbo.

began loosing power at highway cruise and quickly (in a mile or 2) became undriveable. (I wasn't driving, so that's about as much info as I have for when it started having problems)
It will idle, although rough. Maybe only on 3 cyl.
Mashing the pedal in neutral, the engine will rev up to about 1800 or 2000 rpm then die as if fuel was cut.
If you let off the pedal, it will return to a rough idle and not die.
I can barely move it around the yard, no power at all.
All temps and pressures are normal. All fluid levels normal.

I bought this truck with the 3b installed, and I know little about diesels in genera,l or the 3b in particular, but I am handy with a wrench.

Where should I begin my investigations?

JW

 

[gerg]

Fuel filter is where I'd start.

 

[essar5]

Fuel filter is where I'd start.

Solid place to start looking. These are much like a gas engine if you are used to those but you can rule out a spark issue, leaving you with fuel and air as likely suspects. Your situation sounds like it isn't getting enough fuel at load and the fact that it started getting worse immediately points to a possible clogged filter.

 

[RufusTheDufus]

Did this problem happen recently when it was unseasonably cold in TN?

I wonder if they use winter diesel there or if it's warm weather diesel? The problems would go away when it warms up.

I've had problems with fuel filters plugging up from running a B25+ biodiesel mix when the temps dropped below freezing.

But I agree that it's likely just a clogged fuel filter.

 

[nuclearbeef]

It was not too cold when it happened. Certainly above freezing when I moved it around the back yard before the ice hit.

I'll try to get a filter today.

Fuel problem explains the dying under load; rough idle…I guess we'll see.

Can only be three things, right? Fuel, air, or spark (compression). I'll definitely go down the road of easy stuff first.
Fuel: Clogged fuel filter or fuel pick-up.
Air: Collapsing intake hose.
Spark: Let's hope I don't make it this far down the list. (hole in piston).

Thanks for the suggestions. I'll report back.

It's got a spin-on fuel filter that the Auto-Zones don't carry. I'll check the NAPA or the truck stops next.

JW

 

[RufusTheDufus]

There's a NAPA gold that will fit. Check the part number FAQ here in the diesel forum. It's in there.

 

[gerg]

It's not going to be air or compression. No compression=no start. No air= burns dirty.

 

[nuclearbeef]

Looks like a new fuel filter fixed the problem!
95% better. Still an occasional stumble which I will chalk up to air working itself out of the system.
I only got the chance to take it around the block at lunch time. I assume a longer drive will cure the problem.

I don't know if my hand priming pump was working. Never got any fuel out of the bleed nipple. Never felt much resistance in the hand pump. I gave up after awhile and just cranked it. Cranked for about 10 seconds and started right up. Ran rough maybe for 30 seconds then idled smooth. (or at least as smooth as a 3b can idle.)

Thanks for the quick and helpful suggestions.

JW

 

[gerg]

The stumbling is the air purging the system. Fuel should come out of the nipple for sure (top of the filter housing) or there is still air in the filter. Always good to fill the filter, but I asume you did that. These systems are pretty low on the complication scale and it will eventually totally prime, but always good to hand pump and purge the filter, then crack the nut on each injector and let the fuel barf all over the place to clear each injector line. I rev it up a bit and stuff a rag on it as its a very messy job. I think the nuts a 14mm or a 17. Anyhow it's the one that connects the line to the top of each injector. Lots of wd40 and don't force them hard as they can stick and you can end up twisting your injector line. I always watch the line closely and work it back and forth till it's totally unbound. Never seize after is always wise. Better to learn its sticky and rusty in the garage than on the side of the trail. Good to know how to do this sequence as its what you do if you ever run it out of fuel, or run it low and use your fuel filter to clean your tank.

 

[nuclearbeef]

See, it's people like you (most people on MUD) that make me comfortable buying an engine that was never sold in the US. I bet there's not another 3b within 300 miles of Memphis, much less a capable shop to take it to.

I'll crack the injector lines next. I've performed that operation on a cummins 6cyl power unit. (multiple times)

 

[gerg]

Hey that's cool man. We appreciate it. Just happy to help.

 

[roma042987]

hey hey im less than 300 miles from you and there are plenty running around the Nashville area glad to hear you got it figured out.

 

[MrMoMo]

Should probably drain the sedementer while you are at it....

 

[nuclearbeef]

Well, I spoke too soon. I can drive around the block about twice after cracking the injectors, then it looses power, idles rough, and finally dies. I'm pretty sure I'm being starved for fuel.
After it dies, if I try to use the hand pump to get the air out of the bleeder on top of the filter, I can't get it to pump any fuel out.
When I raise the plunger, it feels like I'm fighting a vacuum. (like drawing back a syringe with your finger over the needle end)
The plunger will snap back down when I let go of it.
I assume this is not normal operation. I should feel resistance as if I'm moving fluid, right?

So:
1) pick up in tank plugged
2) fuel line blocked
3) tank vent plugged (just thought of this one, I'll try opening the fuel cap)

There is not an electric lift pump is there?
It has a 40 gallon long range tank in place of the original.

Been too rainy to investigate further. Will get to work on it when it dries out and I have time.

 

[nuclearbeef]

I had a Racor in my FJ55 after I did the diesel swap. The nice plastic bowl, that is so nice to allow you to see what's going on, got a hairline crack in it and I was chasing air locks. Finally I removed it and went to an OEM filter on the frame rail just like the factory. Since then, no more air locks. The other benefit with the OEM separator is that the dash light works. The Racor uses a capacitance or resistance measurement of the water/diesel mix while OEM is a simple float switch.

In this original engine bay photo you can see the Racor next to the brake master cylinder (behind the hood support).

Here is the factory sedimenter mounted on the frame rail. It works much better in my opinion.

After a quick search for sedementer, I found this post from Charles. (I bought Charles' pig)

I think my next trouble-shooting step will be here. Do I just replace it? I don't have a dash light on. Anyone know the part number to keep me from having to crawl under the pig in the mud?

Thanks in advance.

JW

 

[MrMoMo]

Sounds to me like you have a blockage, or a plugged vent if you can't even lift the primer pump. As reference to the power of the lift pump - I've seen a tank (not OEM) implode from the suction of the pump when the tank had no vent.

So, I would say - remove the tank cap first then see if you can lift the primer pump. If yes, you have a blocked vent line.

Are the temps still below freezing? If so, then maybe you have a section of the fuel line, or the sedimenter frozen if there is water in your fuel. The sedimenter has a drain on the bottom of it, so if you can warm it up then drain the water out you might clear the blockage.

If the sedimenter is in the factory location (this comment based on a BJ60), it should be on the inside of the passenger side frame rail, just ahead of the rear wheel. Looks like a metal can (about the size of a can of beans) with a fuel line going into it, one coming out, and some wires in the top. The wires may be un-plugged which would then prevent the light on the dash from coming on.

 

[MrMoMo]

Like this;

 

[nuclearbeef]

Emptied sedimenter. No water, some small rust flakes… Didn't fix the problem.

Disconnected fuel line running back to the tank at the sedimenter. Fuel barely dripped out, so I hooked up the air hose to the fuel line and shot 80 psi back up toward the tank. I could hear bubbles, but the fuel line would hold pressure for 10 or 15 seconds after cutting off the air.
Removed air hose, no fuel siphoning out of the line. Pressurized the fuel tank slightly until fuel came out the end of the line.
As soon as I removed my hand from the filler neck, releasing the pressure in the tank, the fuel stopped coming out the line.
Reconnected fuel line and it ran good for quite a bit longer, but then returned to the same old tricks.

Next step: drop the tank.

 

[nuclearbeef]

I have a long-range tank. Don't know who built it.
It has four vent hoses, a filler and a vent for the filler on the driver's side.
On the passenger's side it has two tubes exiting the top of the tank; one hooked to the fuel line, the other capped.

Is the capped one another pick-up?
Can I switch the fuel line to the capped one?
Why would a tank be built with two pick-ups; for an occasion such as mine?

 

[ERNRAM]

what was the final fix?