89 Navistar 7.3 idi----Learner Question

[hrsitton]

Reading in a Stanadyne service bulletin. They begin discussing the solenoids on page 11 as ETR and ETSO, energized to run, and energized to shut off.

The DB2 is an ETR which sort of makes it clear that an engine using this solenoid should NOT start even if it runs with the top on since the solenoid is required to ETR.

Nice pictures too.

https://www.stanadyne.com/dealerportal/ssi/english/Training/99687 Part 1.pdf

 

[hrsitton]

From Page 7 & 8:

Quote: "Energized-Run (ETR).

De-energizing the shut-down coil allows the spring to release the shut-off arm.
The lower end of the arm moves the governor linkage hook, rotating the metering valve to the closed position and cutting off the fuel, as shown in Figure 5-71B" End Quote

http://seabeemagazine.navylive.dodl...50A-Construction-Mechanic-Advanced-Part-3.pdf
.

 

[Thewespaul]

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[hrsitton]

.........then it is apparently fitted with an Energize To Shut Off (ETSO) and not an Energize To Start (ETR) as my truck is fitted with.

If it were an ETR solenoid, the ETR solenoid would need to be in place to "R" run.

When the ETR is de-energized, it is a spring that closes the fuel.

But what do I know actually? Nothing much. I'm just regurgitating what Stanadyne indicates in their own service bulletins.

I also read that leaving the ignition on could damage the solenoid on the ETR setup as the coil is always energized while the engine is running and relies on the return fuel for cooling. With the engine shut down the coil can over heat. Again, not from me but rather from Stanadyne.

I took a screen shot from Stanadyne's service bulletins showing the two types. The look a little similar at first glance but much different operation of course.

https://photos.google.com/photo/AF1QipPL3gq-HhNnm0JnIuKS6XJl0D1rt_wyQkn7RLrp

 

[Thewespaul]

You’re overthinking it, the coil is energized to move the metering valve linkage open but when it is denergized it holds pressure on the linkage holding the metering valve shut. Without the top cover installed, you can manually move the linkage to open or close the metering valve, but if the top cover is not installed correctly then the linkage will not have full travel to close the metering valve, and will be held in a wide open throttle position, with no way to shut fuel flow since the arm on the fss blocks the linkage from moving. Keep in mind stanadyne puts all kinds of different fuel shut off solenoids on different pump applications, so not all of the information may be pertinent to your application.

 

[Agnem]

Think of it this way... when the solenoid is energized, it is kept "out of the way" of everything that is in there. In other words, the same physical result of not having the top cover installed. When the power is off, the spring puts the lever in such a position to force the metering valve closed. It sounds to me like this engine sat for quite a while, and the pump is all glued together. I'd be willing to bet if that's the case, that it neither pumps fuel to the return, nor puts any to the pistons. You can overcome the later, by spraying some 2+2 in around the metering valve, and hoping it softens up until you can move it. The pump vanes and plungers are another matter. It's time for a rebuilt pump.

 

[hrsitton]

@Thewespaul

Well, your not the first to suggest me overthinking things and likely not the last, and I may well be overthinking but my standard defense is that it is almost always better to overthink than underthink.

Anyhow, did go to town and picked up some Seafoam. Loosened the IP inlet pipe to drain and then filled from the top with Seafoam. Not sure that was a good idea as that was past the filter. But I did. May not matter.

Also filled under where the cover goes. May not do a thing but I needed to grab at any straw available.

Somehow I got in my head that the shut off needle/plunger/whatever it consists of needed a bit of force. Then I realized the float valve in a carburetor shuts off a bit of pressure with very little force.

Then I read what Agnem said and that made sense.

Glad you guys are patient enough to put up with a hard-headed old duffer.

@Agnem

Where is the metering valve? I'd be glad to spray whatever had a chance of opening things up. But, yeah, I realize that an IP may be in the offing. But I want to be sure first.

Meanwhile, I've been noticing the brand new Facet Duralift 5-7 PSI has been dropping in PSI after a period of time. Brand new batteries but brought another and sat right at the lift pump and connected with large gauge wire. Same thing.

I installed a brand new filter and the meter is downstream from the filter so tomorrow I'll relocate the meter right on top of the pump just to make sure before I call the supplier.

If the pump is bad, it'll be a few days before I have any more info. If it's not the pump, I'll order another filter. The new one had been stored for around 5 years but it was in plastic.

Thanks a million.

Harold

 

[Thewespaul]

Harold, nothin wrong with overthinking anything. Just wanted to point it out to help you stay on track with the issues at hand, like Mel said it’s beginning to sound like that pumps shot, here’s the location of the metering valve circled in red

You must be registered for see images attach

 

[hrsitton]

Ok, thanks. Looks like the Seafoam will be soaking that area while the fuel supply issue gets sorted.

I searched for 2+2 solvent and came up empty.

 

[hrsitton]

Brief update: The pressure gauge was relocated to the top of the pump and still shows decreasing pressure after a minute or two running. The intermittent nature of the pressure reading has me wondering if there is a problem with the pickup line. There is a large clear filter housing on the bottom of the pump with no air. And none at the Schrader on the filter.

Before going forward more, a pickup line will be ran into a 5 gallon can of diesel to determine for certain where the fluctuating pressure and pumped volume lies.

At the moment, the rain has caused flooding in the normally dry wash I live across and may not be able to get to town for a day or two.

Will post again when more info available.

 

[Clb]

Sounds like a shop day (rained in) I wonder how the e pump could fluctuate more than a small amount due to the open return that keeps it running??? Hmmm

one of these guys mel,wes,justin...
made mention once the ip has a internal pump capable of self feeding enough fuel to do the job (just not well) but your no flow issue reads more fubared ip....
thats all I got.
Cb

 

[Thewespaul]

It could just be the e pump straining since it’s being deadheaded and fighting itself. Most e pumps have a internal bypass valve that really only works in a dead head scenario like this. When the pressure on the inlet side becomes too great the valve will open and it will bleed fuel back to the inlet of the pump. That’s likely what’s going on when you see the pressure changing, it’s just the valve cycling on and off. Once the engine is running it shouldn’t be an issue.

These db2s have a babe style transfer pump in the cone of the pump, on a lot of ag applications where the tank is mounted above the engine there’s no lift pump because the gravity feed is sufficient to feed the transfer pump which bumps pressure up to 75-95 psi depending on advance settings

 

[Clb]

Wes is it a typo ??? During a dead head "outlet" returns to the inlet or bowl ...

 

[Thewespaul]

Nope, the inlet of the e pump is under suction from the pump, the outlet going to the injection pump is under pressure when the engine isn’t turning, so it’s a dead head, when the pressure going to the injection pump overcomes the bypass setting, it bleeds pressure back to the inlet of the e pump. All this happens internally to the e pump, sorry if I worded that in a confusing way. Lots of pumps everywhere

 

[hrsitton]

@Clb Yeah, I remember from 4-5 years ago when the mechanical was going out and I was blowing white smoke, (thought it was water at first), I was reading up on the net and read that the IP can do some of the work of the lift pump but can become overworked and die an early death. I READ THAT ON THE INTERNET!
.....................................................................................................................

Well, I made it across the wash to town and back.

The plot has thickened considerably.

With the pickup line in a 5 gallon can of diesel, the pump was working so furiously that the needle on the gauge was flipping between 4 and 6 PSI. For a long time.

So the gauge was relocated at the filter return.

After the air was bled, the pump held about 4.3 for a long long time without any variation. Just sat there like it was stuck, which it was not. Good volume coming out the filter return.

Soooooooooooo................

I think I have a clue what caused my mechanical to go out. Then I put on a cheapie $40-$50 Facet. Got 4 PSI all was fine. Then more problems developed where I now sit. Got loose for about a $60 Facet that had a higher PSI and lift spec. Could not get 4 PSI consistently.

Did some more reading recently, here I think, and went with the recommendation for a commercial Facet Duralift that could lift 10 feet for refer trucks.

Got my 4 PSI at first. Good and steady. I'd turn the pump on, see 4 PSI then forget it while I tried starting the truck. Then I discovered the PSI was dropping, sometimes to zero. Nope. No air.

I believe I have an intermittent blockage in the tank pickup. There's only about 10 gallons or so in it but it's a steel saddle tank so it's heavy, but it's gonna need to come off to be certain.

The pickup is in the center of the tank with the return at the front. So when the pump is running, there is a circulation........like yall didn't already know this.

But if there is a plastic baggie or two or three, they would drift toward the pickup, especially when the fuel is low.

So that's what I'm betting I'll find.

Sorry for the long winded post, I'm decompressing.