"edb" wrote:

Hi Team,
until I can post pix again, fuel leakage past the Inj Pump Plungers still can be be minimal at the troughs in a worn Inj. Pump plunger and barrel--P & B.
Wear takes place by dirty fuel eroding the plunger at the helix and the barrel bore at the fuel bypass port.
There is a a possibility of excess leakage if the entire length of the bore and plunger are scored at a land that helps stop this occurring.

In the stop position, transfer pump pressure fuel can be seen as spurts as the plunger rises, due to restriction of the trapped fuel above the plunger exiting the bypass port and so creates a visible spurt when the injection line is loose or removed from the Inj. pump P & B Assembly.

Wasted half an hour trying to find where I posted pix in the past many times over from a Service Manual explaining all this clearly.

Cheers,
Eddie B.

Eddie, I appreciate the time you have spent looking for pictures. That's awesome of you. #rule303

I hadn't thought of the wear in the helix and port. I'm definitely pulling the injectors.

hello ,one more thing to remember - www.acmoc.org/bb/showthread.php?17155-d2-starting-problems

"Whitedog" wrote:

It moves all the way forward and back.

Edit: Watching Squatch install the pumps on 5J1113, after everything was installed, he moved the rack forward and backwards and it appeared to be spring loaded back through the governor spring. I don't recall it springing back, but I'm not sure this is relevant to not starting. I think it's worth popping off the pump cover again and pulling the governor cover.

You and Eddie have it right. The governor flyweights are on the front of this engine and act to move the rack forward as the rpm increases. The governor spring is in the rear compartment behind the fuel pump housing and when it’s stretched it pulls a lever that moves rack to the rear, increasing rpm by opposing the flyweights up front which are trying to slow the engine down.

The shutdown stop allows you to feel where low idle is and then push the throttle lever more to compress the shutdown stop plunger into its socket and further remove tension from the governor spring allowing the flyweights to pull rack forward to a fuel shutoff position.

The rack will NOT be locked in a shutoff position as we are used to on the later engines with the over center detent that’s built into the adjustable low idle stop. On the D3400, the shutdown is dynamic, the governor spring must be so slack that the flyweights are almost completely unopposed and can keep the rack forward even as the engine is stopping or at least is slowing below a minimum rpm where it can not recover if fuel isn’t completely shut off.

I also think it would be worth it to check base fuel pressure. 1/8 NPT 90 degree fitting to get into the fuel housing, then a 30 PSI Gage and some hose should do it. BTW, the Gage that's on it if NFG, which is why I need to install one.

Sounding more like a fur ball every day....

As our Expert on here, Mr Edb keeps reminding me when trying to fix a problem, "Mike, always return a machine to original specification before attempting major repair" and I've found that excellent advice over the years.

These old Cats have been abused by a whole congo line of misfits, bar flies and donut dunkers over the years, thrashed, beaten, poorly serviced if at all, yet we get surprised when that 80 year old tractor doesn't run as it should, it's a miracle we get so many saved from the scrappers, it's all about time and money, you need plenty of both.

Mike, I certainly agree with the factory spec thing. When working on cars and trucks, troubleshooting is so much easier when everything is stock.

I found out yesterday that he's not the only one wanting to get this running. He wants to use it out on his place and he has been borrowing another guy's new Bobcat and he had already broke things on it. So there's that.

The fuel pressure in the tower is very important and if the fuel pressure gauge on the machine isn't working then definitely hook up a working gauge, the pressure is not super high, I think it's less than 10 pounds, but it must be there.

You will see a 1,000 old threads here from people asking why their old Cat won't start and low fuel tower pressure is often the cause, there is a one way valve where the fuel line from the tank enters the tower and the spring that holds that valve usually get's tired and needs re-stretching or replacing, or the little one way valve itself get's crud stuck in it preventing pressure from building. Definitely investigate that area.

I've found a old Cat will run with low fuel tower pressure, but it usually will not start too easily, or will not start at all.

Sounds like your buddy is a hard man on machines, he sounds like my neighbor, 3rd generation farmer but doesn't even own a grease gun, bottle of oil or a set of tools, he runs his tractor out of fuel regularly yet can't remember how to bleed the system. Mechanics love old fleas like him, because the repair bills always have a lot of zero's!!

"Mike wrote:

The fuel pressure in the tower is very important and if the fuel pressure gauge on the machine isn't working then definitely hook up a working gauge, the pressure is not super high, I think it's less than 10 pounds, but it must be there.

You will see a 1,000 old threads here from people asking why their old Cat won't start and low fuel tower pressure is often the cause, there is a one way valve where the fuel line from the tank enters the tower and the spring that holds that valve usually get's tired and needs re-stretching or replacing, or the little one way valve itself get's crud stuck in it preventing pressure from building. Definitely investigate that area.

I've found a old Cat will run with low fuel tower pressure, but it usually will not start too easily, or will not start at all.

Sounds like your buddy is a hard man on machines, he sounds like my neighbor, 3rd generation farmer but doesn't even own a grease gun, bottle of oil or a set of tools, he runs his tractor out of fuel regularly yet can't remember how to bleed the system. Mechanics love old fleas like him, because the repair bills always have a lot of zero's!!

Good info, Mike. I thought I had a 90 degree fitting to hook in, but alas, I'm off to the parts store for more parts.

I removed all of the high pressure lines and when cranking they squirted evenly, but it just occurred to me as I am typing this, that I should have moved the fuel lever to see if the quantity of fuel would change. Or maybe it wouldn't because the flyweights should be trying to hold the rack at Max fuel.

So she struggled to get to 10PSI. Like it took a full minute to get there. TPump is off and I'll go though it.