And yet another no start 6.9 thread...

[Rattlenbang]

Hey all, I've done a lot of reading on the subject but I think my lack of experience with this rig is showing. Ive worked on a lot of 4 cylinder diesels but not a V8. Background is that I bought a nice '86 project motorhome cheap, primarily because it had a rare diesel engine. It was a non-runner. Talking to the PO, and I have no reason to doubt him, it was working fine for them though they rarely used it, they parked it, it sat for a couple of years, he started it ran if for a bit then it died and wouldn't restart. tried adding more fuel, and his mechanic told him probably a problem with the fuel pump or related system, and he just left it. He had several projects on the go, and just sold it as-is.

I had it towed home and went through all the possibilities recommended: checked the FSS, made sure the fuel filter was full, replaced the fuel filter (had to remove that with a chisel and 5lb sledge), seemingly good pressure to the filter, fuel coming out the injection pump to the return lines, so fuel is making it's way through the system. Crank 15 secs rest 2 min, crank, rest, crank rest. New batteries and it spins really well. Maybe 20 cycles of cranking and resting. Injection lines are open but still nothing coming out.

I read about running seafoam through, so I pulled the filter (with the chisel) and added a can to the new filter and installed it. Went to crank, and fuel showed up at the injectors at the first turn. Now I know seafoam is supposed to be good but its mere presence in the filter is unlikely to immediately start fuel flowing, and I put this down to coincidence. I tightened the injectors and she started right up, ran really well. I drove it around my storage yard and then parked it, facing uphill on a moderate slope and left it idling for about an hour when it started to overheat (I suspect thermostat).

Next day of course, no start. Assuming the injector pump and fuel pump is now proven okay, I'm assuming the return fuel line system is leaking air and it's losing prime.
Try to bleed again. Crank rest, crank, rest, crank rest. I must be at 25 cycles, and no start. I appear to have fuel at maybe 5 injectors, but the rest remain dry, unlike the previous attempt when they all started squirting at same time. I've closed off the ones that seem to have fuel, but no start. There's grey smoke coming out of the exhaust. Do I keep cranking this thing or am I missing something? I haven't checked the GPs since it started last time. The FSS still has power, still click, still have lots fuel running through the IP. How many cylinders have to have fuel for it to start?

Any advice appreciated. Hate to burn out this starter.

 

[chillman88]

There's grey smoke coming out of the exhaust.

Sounds like you have fuel if it's smoking. Check your glow plugs.

Do you have the factory water separator filter plugged in? Lots of people have had issues with them leaking air into the lines.

 

[Rattlenbang]

No water separator on this rig... Gp are the only thing I think I haven't checked, because I did it get it started that first time.

 

[Selahdoor]

How much fuel is in the tank that you have selected?

Try running a line from the fuel pump input, straight into a 5 gallon can of fuel.

 

[Rattlenbang]

How much fuel is in the tank that you have selected?

Try running a line from the fuel pump input, straight into a 5 gallon can of fuel.

Ive got 3/4 of a tank, but fuel pressure to the IJ pump seems good.

 

[aggiediesel01]

Here is the Diagnostic Manual for the '94 IDI. It's not completely helpful without the rest of the ford manual set but the way to diagnose is basically the same for all the IDI engines. See if there's something in here that helps.

 

[Rattlenbang]

Here is the Diagnostic Manual for the '94 IDI. It's not completely helpful without the rest of the ford manual set but the way to diagnose is basically the same for all the IDI engines. See if there's something in here that helps.

That's very useful, thanks. Interestingly the only possibility they have for no fuel at injectors is faulty FSS and the advance solenoid. I didn't know that the advance solenoid was required to have 12v when starting and I'll have to check it out. Lots of good info on testing glow plug circuits and air intrusion into the fuel system.

 

[gandalf]

No water separator on this rig... Gp are the only thing I think I haven't checked, because I did it get it started that first time.

I see possibilities of several problems, with about equal chance on each. One bet would be a leakback air intrusion. The temporary fuel supply will help determine that. If you can place the temp fuel higher than the fuel filter. My other bet would be the glow plugs. Have you tested them? They pretty much all have to work for an easy start.

You say that it fired right up when you filled the filter with Seafoam? I don't know whether Seafoam is combustible, but I've got to assume that it is. If that is the case I'll bet it has a lower combustible temp than does diesel. These engines must spin at a good rate to heat the cylinders and have the diesel pop off. If it does not spin fast enough it won't heat enough, and fail to fire. If it's not spinning fast enough it's either that the batteries aren't strong enough, or the starter itself is failing.

Just for S&G's charge the batteries fully, and run a jumper from another vehicle while you try to start. That will insure that the starter is getting plenty of power.

Report back.

 

[Rattlenbang]

This is where it's gotten complicated, and more so than the other threads I've read where the solution was straightforward. I have to assume batteries and starter are good because on the first time when I bled the system and got it started, once I saw fuel at injectors I closed them off and it fired right up. It does spin quite fast and hasn't changed.

I don't want the seafoam to be a red herring. As soon as I put it in the filter, the next crank fuel showed at the injectors, I closed them off and it started, long before the seafoam got to the pump. It had nothing to do with it starting. it ran for an hour after that at idle, so there could be some seafoam still in there; even at idle I have to imagine the motor used up all the diesel in the injection pump and burned away some of the seafoam. Since I was advised to run a can through the pump, and many others have done so, the engine must be able to run on the stuff. The reason it's not running is that I'm not getting fuel to all the injectors after so much cranking. If and when I do I'm certain it will start, as it did before.

I suppose I could install a bit of clear hose on the output of the IP to see if any air bubbles are there. If so I could work my way back to find the source of air intrusion.

 

[gandalf]

...
I suppose I could install a bit of clear hose on the output of the IP to see if any air bubbles are there. If so I could work my way back to find the source of air intrusion.

Here's a picture, just to give you a visual of what that might look like. This is on my '92 engine, 7.3 NA.

I don't think you've said what year engine you're dealing with, though I think you did specify 6.9.

You must be registered for see images attach

 

[Scotty4]

Here's a picture, just to give you a visual of what that might look like. This is on my '92 engine, 7.3 NA.

I don't think you've said what year engine you're dealing with, though I think you did specify 6.9.

You must be registered for see images attach

‘86 motorhome.

 

[Rattlenbang]

Just took another look and checked the glowplugs. 2 were burned out and one had been accidentally disconnected. All three were on lines that eventually showed fuel while cranking.

What I'm thinking happened is that the air leak allowed the high pressure lines to drain but not all to the same amount. So after a lot of cranking at least 5 were showing fuel at the injectors while 3 were still dry. But since 3 glowplugs of those 5 weren't working, it wouldn't fire up. My hope is that once I get those plugs changed I'll be able to get it started so that the remaining lines will finish bleeding out and I'll be able to tighten them off as well.

It's just strange that with my first bleeding session it started right away, though the glow plugs might have failed since then with all the cycling on and off.

 

[Selahdoor]

One of the reasons many of us have converted to manual glow plug circuits.

At a time like this, you are really cycling those things a lot.

They are just mini electric heater elements. And as with all electric heating elements, they have a finite life span. A finite number of cycles are available.,. The more you use them, especially when they aren't needed again, the shorter they will be around.

 

[riphip]

One of the reasons many of us have converted to manual glow plug circuits.

At a time like this, you are really cycling those things a lot.

They are just mini electric heater elements. And as with all electric heating elements, they have a finite life span. A finite number of cycles are available.,. The more you use them, especially when they aren't needed again, the shorter they will be around.

And why we chose to go to electric fuel pumps (proven dependable ones).
If this vehicle sits a lot, could be gathering moisture in the tank(s). Parking on a hill, nose up, may also have pickup strainer deteriorated. Sucking air somewhere.

 

[bbjordan]

Just because the glow plugs test ok does not mean they are working. The GP controller could be bad, or the solenoid could be bad. You are getting smoke out the tail pipe, so that's a good thing. You could try disconnecting the GP relay and giving it a shot of starting fluid. If it fires right up, it means you have a problem with the Glow Plug system.

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