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F550 7.3 powerstroke trouble

shakeyjake36

Registered
I'm working on a 2000 F550, it has 7.3 powerstroke and it is driving me nuts. It will only start with the block heater plugged in. I have changed all the glow plugs, the solenoid and relay, the valve cover harness, and the ipc. it does not matter if tis 80 degrees outside , I still have to plug it in. ANY IDEAS????
 

Nick

Registered
Last Subscription Date
04/18/2014
Re: 7.3 powerstroke trouble

How many miles on the motor? How does it run when it finally starts? And how about when up to operating temp? Will it restart hot? Is it giving any codes? Did you by chance check the injector armature clearance whilst working on the glow plugs? Verified correct voltage at the GPR terminals and GPR operation?
 

Dan W.

Registered
Re: 7.3 powerstroke trouble

do you have a power programer installed, my programer one time shut off the glow plug cycle in the in the computer, i had to uninstall it and reinstall and has worked since then.
 

C-Wade7

Registered
Age
39
Re: 7.3 powerstroke trouble

Have had several do it in the past that had high mileage and it was an injector issue. We have a air check fixture to test them in but we almost always did all 8 if it was 300k. Usually 6-7 would fail bench testing.
 

s100

Registered
Here's a long shot. Years ago I bought my first Olds diesel and it would not start at cold start without a lot of cranking. Once it was started, it would restart just fine. (This was a big part of the reason the original owner sold me the car.) I changed the fuel filter and the world was a happy place. The non-OEM filter either did not have a check valve or if it did it was malfunctioning. Fuel would bleed back to the tank and the charge pump would have to refill the system each time. Since it took a while for the fuel to bleed back down, it would start easily for a while once it had been running. Understand this was not a plugged or restricted filter. When it was running it made good power and got plenty of fuel.

The Olds and the IH use a similar Stanadyne distributor pump. I don't know if the fuel filter is similar, too. With everything else you replaced on that thing maybe you'd consider replacing the fuel filter as well.

You don't say much about the symptoms, other than it starts when plugged-in. If you don't plug in and continue to crank, does it start eventually? Will it start with a snort of WD40? If it starts and you shut it off for a while, will it restart easily? How long must it be off before it won't start on its own? (Cold start, run for a minute or so, shut off.) When you crank, and it does not start, does it make white smoke from the exhaust? When you key-on, do the glow plugs pull the voltage down like they're supposed to?

It sounds from your post that you have done all the common sense things that should have solved the problem. That means the cause of the problem will likely be something that will have you saying, "Nah, it can't be anaything like that." Finding the cause of a problem like this won't happen by shotgunning parts. You need to get the service manual and go through the diagnostic tests and take data then compare them to the norm or the desired results in the manual.

And when you do find the problem, be sure to let us know what it was!
 

Mikey4026

Subscriber
Last Subscription Date
07/10/2019
Glowplug relay, does it have battery and control power to it?
Have you checked it?
Test the pass thru connectors in the valve cover gaskets, my guess is that they are the problem. They fooled me once.
You can by pass the solenoid (relay) to make sure the power actualy gets to the glowplugs, only do this test momentarily as you are connected and ready to test at each plug. I have seen the harness from the relay to the valve covers burn up, but not often.
If you have no control voltage to the relay, you have a wiring problem.
Those glow plugs are difficult to get to arent they!
Mike
 

shakeyjake36

Registered
The truck has 187k .it may not have been well maintained. After being plugged in the truck will start instantly( I doubt it has a fuel bleed). Once started it misses and blow some white smoke until it reaches temp. Once warm it runs perfect. It will start again no prob as long as the engine stays warm. This truck was buzz tested but I wasn't their so I don't know if the injectors sound muffed. It needed a injector o-ring but I didn't open the injector. The truck is chipped( it came that way, no idea what brand,all I know is it has 7 setting and does make a lot more power with softer shifts). With the key on,power is going the the glow plugs( test light at the plug). I really think it needs injectors but I really really don't want to spend $300 for new ones.
 

Nick

Registered
Last Subscription Date
04/18/2014
All a buzz test does is confirm the IDM, wiring and injector solenoids are working. Sounds like your injectors may be worn esp with an iffy maintenance history. I'd get in touch with Tim at Performance Injection Systems. His stock reman injectors run $1500. Or see what it would cost to check and rebuild your current ones.
 

bart price

Registered
I have seen all kinds of problems with these engines. I have had this problem with two trucks the computer may have a fault that says glow plugs are working. What happens is it won't shut them off and fries them you think they working butt they don't. Check a glow or two might be the problem. Let us know what you find Bart
 

Doug Tallman

Subscriber
Last Subscription Date
10/11/2019
Have you checked the air filter? I know it sounds stupid but I had one brought in with the complaint of hard start and having to cycle the glow plugs multiple times to get it running when cold. The air filter was plugged so tight you couldn't see any light through it. A new filter fixed it.
 
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