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1989 Navistar 7.3L, Tried All I Know To Try

4K views 13 replies 6 participants last post by  haroldsitton 
#1 ·
I know this is a Ford list but hope it's ok to ask about my Navistar 7.3L.

Been sitting for about two years. Has always started right away.

Not starting now. Not hitting or in any way even trying to start. Battery is up and whirling the engine. I keep my efforts at 15 seconds or less.

Using a clear fuel line it appeared my Gold Flo had stopped working for some reason. I think now it may have had a vacume leak.

At any rate there's a Posi-Flo in place now with a 50 inch wet lift and rated at 5-7 PSI. Meter reads 3 PSI at the filter entrance. No water in bottom of filter. Disconnected filter exit to IP and a lot of fuel coming out.

I have a clear line running from the filter to the left bank fuel return. Lot of fuel running.

The fuel return for the right bank comes out of the IP. No fuel coming out there. With engine stopped or engine cranking.

Checked the fuel solenoid at the IP for the clicking sound. Getting good clicks. Only about 10 volts show getting to it so I've use a jumper to it from the starter solenoid just to make certain it's getting enough juice to work. Still nothing coming out of the IP to the right return.

About a month ago I wondered if I had a glow plug problem. Ran out the test from this forum on the module behind the breather. Power to all that was supposed to have power. Checked resistance on the glow plugs. Some were a bit low but not enough to stop it from even hitting.

I have tried squirting WD40 while shorting out the starter solenoid. With the key on. And also tried with the IP fuel switch jumpered. No difference at all.

Would it even try to hit if no fuel was getting through to the injectors?

Oh yeah, I cracked the connection to the top of a couple of injectors. No fuel coming out when cranking. I even completely removed the pipe from the top of one and no fuel.

Ok, so what could have happened while sitting for two years to cause what appears to be no fuel getting to the injectors? Have I been sabotaged? Or what?

Thanks, Harold
 
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#3 ·
Put your complete truck in your signature.

The 7.3 Navistar engine has been built from 87 to 2004. From 87 to 94 it is an IDI, from 95 to 2003 it is a PSD computer controlled engine.

I take it you have a 7.3 IDI. There is no electronics that control that engine. There is no CPS.

I have no idea why your post was moved to General Diesel, it should have stayed in the 7.3 IDI forum.

Please refer to the engine as drivers side or pass side, there is no question on which side your referring to then. You said "right side" which is probably "LEFT" drivers side.

Now to your Problem.

WD40 is not a engine starter, it no longer has Propane as a propellant, you have to use Ether or Engine Starter. Using Ether, just a quick spritz of one second after the glow plug cycle has finished.

Three PSI at the inlet of the filter is low, output may be to low. Replace your filter, after two years it probably has deteriorated.

It takes a lot of cranking to fill the injector to IP lines, do like your doing cranking, but keep a battery charger on so it keeps the batteries up.
 
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#7 ·
I have no idea why your post was moved to General Diesel, it should have stayed in the 7.3 IDI forum.
Because the 7.3 IDI section is a sub-section of the "Ford Diesels" section, and this isn't a Ford.

Restating the left/right bypass. Appears to be plenty of fuel coming from the filter to the drivers side return line which I do have a clear line on. The passengers side return line comes from the top of the IP. I removed the hose and there is no fuel coming out while cranking.

I read on another post somewhere that that no fuel out of the IP return clearly indicated a fuel supply problem. That points back to my suspected vacuum/air leak and low pressure.
Sounds like you're on the right track. IIRC, that passenger-side return line should have fuel going FROM the return path on the cylinder head TO the filter head. What you're seeing tells me there's no return fuel coming from the injectors. 'Course, this could indicate an IP problem. You said you did check the FSS, and at least can hear it clicking, right?

Can you elaborate on what fuel pump you have? The Ford folks here won't be familiar with it. Is it an electric pump? Is the mechanical pump still in play? Hmm, maybe it's an initial supply problem, a restriction in the supply from the tank(s). Maybe you could try running a supply line to the pump from a jerry-can.

That extra fitting is a ferrule used for setting timing. On trucks it's usually on injector #1 and on vans it's on #4. Makes me think the engine may have been transplanted.
True about the FORD trucks and vans. The OP hasn't elaborated on what this vehicle is.
 
#5 ·
@Trucker87The reason the post was moved may have been that I referred to the engine as a 7.3L rather than a 7.3 IDI.

Thanks about the WD40. Solves that question.

I'm getting air out of my Shrader. Read somewhere there should be absolutely none after purging. That's sort of what I thought.

So I must have a vacuum leak below the pump somewhere. That would explain why pressure before the filter is only 3PSI when the new pump is rated 5-7 PSI.

When I go to town again, (i'm 50 miles from the nearest parts store), I'm going to get some clear line to test for air coming out of the pump and also fittings to move the pressure gauge to the down side out of the filter.

The filter only has a couple thousand miles on it but I have a new one to install.

Restating the left/right bypass. Appears to be plenty of fuel coming from the filter to the drivers side return line which I do have a clear line on. The passengers side return line comes from the top of the IP. I removed the hose and there is no fuel coming out while cranking.

I read on another post somewhere that that no fuel out of the IP return clearly indicated a fuel supply problem. That points back to my suspected vacuum/air leak and low pressure.

Question: One of the injectors, second from the front on drivers side, has an extra fitting between the injector top and the line connector. Wondering what that is and what it's for.

@Trucker87[MENTION] [MENTION]JESSE 1 ; Thanks for the replies and help so far.
 
#6 ·
That extra fitting is a ferrule used for setting timing. On trucks it's usually on injector #1 and on vans it's on #4. Makes me think the engine may have been transplanted.
 
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#8 · (Edited)
I'm getting air out of my Shrader. Read somewhere there should be absolutely none after purging. That's sort of what I thought.
Air out of the Schrader valve indicates your still sucking air in somewhere in the tank to lift pump, it will never start that way.

If you added an electric lift pump, you have to bypass the engine mechanical pump. If you don't, it's possible to rupture the diaphragm in the mechanical pump.

You don't indicate what year you have. The older IDI's are prone to have the in tank pickup deteriorate, the fuel then cannot be picked up, or very little without sucking air in, this will happen with a 1/4 tank or less. THE PICKUP IS COMMONLY KNOWN AS A SHOWER HEAD. damn caps button, sorry.

EDIT: I see it's an 89 now. Yup your tank pickup has fallen off or deteriorated. Both tanks have them.

This indicates for a Powerstroke, but there the same from 83 to present.
http://www.ebay.com/itm/DIESEL-FUEL...ash=item3acc223f51:g:xJEAAOSwARZXiON9&vxp=mtr
 
#9 · (Edited)
Please refer to the engine as drivers side or pass side, there is no question on which side your referring to then. You said "right side" which is probably "LEFT" drivers side.
FYI, whether it's a car, truck, or tractor, whether your standing on your head, facing the radiator, or on the rear bumper, in the truck and auto world the right engine/trans/differential side is ALWAYS the passenger side and the left engine side is ALWAYS the driver's side. (Excluding England of course)
 
#12 ·
Oh for Chris sake, just brilliant. Some people just don't know that. DRIVERS OR PASSENGERS SIDE (Pass) is positive.

A solution to his problem would be more fitting.
 
#11 · (Edited)
@madpogue I'm still here.

@chuckster57 Yup, you're right. The fitting is on #1. I bought the truck directly from U-Haul. It had been a service truck for the 10 years before I bought it about 8 years ago. Has the original engine except U-Haul put in short blocks if the compression was at some variation but no engine swap for certain.

@Trucker87 Pump is a Facet 60302 POSI-FLO. Mechanical pump is bypassed. Had a Facet Gold-Flo on that I thought had died. Probably still good. Fuel is below 1/4 tank. Only one tank on the U-Hauls. When I can get to town I'll pick up enough hose to run straight into the tank and also some clear hose to use to watch for air.

Sound like I'll be pulling my tank from what you've said.

But the good news is it's hopefully not the IP. And the truck is probably gonna run.

Thanks everybody!
 
#14 ·
@Trucker87

Update:

Finally got clear hose from the pump up to the filter. Also clear from the filter to driver's side return, and clear from the IP to passenger's side return.

Had a small air leak at the vacuum side of the new pump. My bad.

Fixed. No air out the shrader. But only 3.5 PSI on my gauge going into the filter. The driver's side bypass is out a tiny port on the filter so clamped that hose shut and PSI came up to 4.5.

Pump is a Facet Posi-Flo 60302, 5-7 PSI, 12 inch dry lift, 50 inch wet lift, check valve, 32 GPH

I have a dry lift of close to 12 inches, maybe a little more, and then 24 inches up to the filter. If the rated minimum of 5 PSI is at the pump, then 24 inches would drop it to 4 PSI. Plus the loss to the return would drop it more.

So anyhow, I made three cranks at 15 seconds each. There was some fuel in the IP return before cranking. The line is sloping up a little and the fuel did not go any higher during the three cranks.

Soooo, the Posi-Flo 60303 is 7-10 PSI with about the same specs. 40 GPH.

I almost bought that one but I had read that too high a pressure would change the timing.

Only $36 plus shipping so I think I'll order that unless someone has a suggestion of what else to try first.

Thanks, Harold
 
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