89 7.3l IDI fuel problem

[Kirinov]

So i was doing a full flush yesterday with a new radiator. Drove it all day for about 5 miles between about 8 flushes. No issues at all. Started, drove, idled everything fine. Finished up was going to take it from one last long drive to mixed the antifreeze and all up. She started for about 5-10 seconds then just died like she has no fuel. I checked the filter, has good pressure past it, cracked the injector lines to bleed them and got nothing, when i took the lines off the injectors, it just dribbles out if not at all. No pressure what so ever.

My question is this: is this a sign of a sudden dead Injection Pump that had been slowly going bad or something else.

I’ve read up both here and other places never really got a straight answer, that or i missed it completely. It does white smoke pretty good on start after sitting for a few days. Once it warms up it’s fine. It just threw me do to it just running fine, no starting problems or anything all day. After the first 5-6 sec cranking after sitting it would start right up everytime after. Then this evening, after running easy all day, just nothing. I’ve had the truck about 1.5 years now. Slowly been replacing parts on it. Like the radiator for instance, nothing more than the fuel filter and the return lines in the fuel category. She has either 125-225k on her, don’t know which, leaning towards 225k since it still has the old 10k odometer.

 

[franklin2]

Have you been messing around the injectors before it happened? All you have to do is bump one of the small lines around the injectors, and it can break the seal on the o-rings and let air in. Once the air goes in, the fuel runs down the return back to the tank. Then you are left with air, even though you had fuel at the filter.

Try pushing all that air out with a lot of cranking. If you start getting a lot of smoke out of the tailpipe, then hit the glowplugs and it should take off.

 

[Kirinov]

No, nothing more than the occasional bleed after a filter change. I have tried that unfortunately. I’ve tightened all the lines, no air or it seems. I’ve cranked on it off and on to the point where it needed a charge including earlier today. Fuel is getting to the IP but no pressure to the injectors. Unless i’m missing something completely it seems my problem starts right there. I’m mechanicly inclined but no mechanic so i very well could be.

 

[gandalf]

You give the mileage as either 125k or 225k. The 125k is about when you might start expecting to need a new IP, though some people have had them last much longer. An important question, at this point is whether the IP currently on the engine is the original, or is it a replacement. If it's original I wouldn't be surprised that it has problems.

When you crank the engine as you have been, crank it for only 15-20 seconds, then let it cool for a couple minutes. If you crank continuously for too long you'll burn the starter.

 

[Kirinov]

Yeah, i’ve not been killing the starter. Just troubleshooting alot. I’ve quit for a while till i have a better understanding. I don’t know if it is or not. Is does look newer but without going out in the rain at the moment i can’t tell ya.
I’m wondering if it’s the fuel cut off solenoid. It’ll click when I unplug it but almost never upon reconnecting. Few times not upon disconnecting.

 

[gandalf]

...
I’m wondering if it’s the fuel cut off solenoid. It’ll click when I unplug it but almost never upon reconnecting. Few times not upon disconnecting.

The lack of consistency with the fuel cutoff solenoid sounds a bit troubling. That could be the solenoid itself, or it could be the wire supplying power to the solenoid.

Try pulling the wire off the cutoff solenoid (it's the forward connection on top of the IP), and running a temporary jumper from the positive post on the battery to the solenoid. Just hold one end against the positive post, and touch the solenoid, touch it and pull it away. Do that over and over. If the click is absolutely consistent then suspect the wire coming from the harness. If the jumper is inconsistent then it's probably the solenoid.

 

[Kirinov]

Well, I replaced the cut off solenoid and after help from the Excursion’s alternator and periodic starting And a new fuel filter for the preventative ocd side of me. I got it to bleed out and she coughed to life and ran like you couldn’t stop her. Idled fine and steady for a good 20-30 minutes, drove well. Started and stopped with no issues as if it never happened. I miraculously didn’t kill my starter in the process. I do believe a new IP and injectors in the not to distant future will be the next big project after i get my air bags and compressor on. I don’t believe it about to lay down anytime soon but considering i just don’t know how many miles it has on it, i’m just going to put it on the list of importance. The oddest part if she doesn’t do the old motor trying to catch and cough. When it catches she runs and doesn’t stop. I guess that solenoid just randomly had enough.

 

[Kirinov]

Try pulling the wire off the cutoff solenoid (it's the forward connection on top of the IP), and running a temporary jumper from the positive post on the battery to the solenoid. Just hold one end against the positive post, and touch the solenoid, touch it and pull it away. Do that over and over. If the click is absolutely consistent then suspect the wire coming from the harness. If the jumper is inconsistent then it's probably the solenoid.

This is exactly what led me to the fix btw. The old one just wasn’t consistent when a straight jumper applied. Thank you for the advice sir. I’m glad i found that before dropping $600 on a IP I didn’t need just yet.