Howdy All.

I've got a '99 F250 Super Duty XLT with the 7.3L Powerstroke motor. I just rolled it over to 101,000 miles and the truck is in great shape.

My issue is the turbo failed to work twice when I've started it up. I waited a couple of minutes and tried it again and it fired right up. Both times, the vehicle sat over night. Any body have any clue for a newbie like me where to start? There was a sucking sound, but not the 'whistle' you hear from the turbo when it's engaged.

I just picked it up this week and it will be going to the dealership for a complete inspection this weekend. I'd just like to know what direction to point the mechanic to in order to help keep the diagnostic charges reasonable. Thanks.....

Chris

Wow,

I guess I'll find a chat room where they're still breathing. Had high hopes for this forum, oh well................

Sorry, I'm moving. My diesel guy is on vacation. We're hoping you had all the answers.

Sidewinder,
I'm a little confused when you say it didn't work when you started the engine up. You won't hear the turbo spool up when the engine is at idle, only when under a load. As far as the sucking sound, check all the connections netween the air intake and the turbo, between the intercooler connections and the pipes, and between the pipes and the heads. They have a way of working loose at times and could definately cause a noise like that. Are there any issues with power? On a stock engine, the turbo whine isn't really loud like it is on a modified engine. Check those things and let me know.
Jake

Jake,

I just bought the truck 2 weeks ago. It's my first diesel truck so I'm blindly feeling my way around. I've read a number of the articles here on your site (great by the way)and tried to puzzle this one out on my own, but didn't find anything similiar on any other forums.

It has happened one more time since my original post. The common thread in all 3 instances was the truck sat for at least 8 hours. Upon start up, the truck had almost no power at all. It crept forward at 3-5 miles an hour. I revved the engine the first time this happened and that was when I didn't hear the turbo. I have not revved the motor while experiencing it since. Not knowing what it is, I did not want to damage the engine. The first time, I barely made it back up my driveway which has a slight incline. I let it set for 3-4 minutes and it fired right up and had full power while driving.

Since it seems to be hit or miss, when I had the truck checked out by my mechanic (not at dealership) prior to buying it, it was not apparent. It got a clean bill of health and then it started this 3 days latter. I bought the truck for use on our horse ranch and haven't towed anything with it yet. I ran a check through Carfax prior to buying, but it had no info after the truck left Utah in 2002. I'm in southern CA.

The Ford dealrship was booked solid this last weekend so I had to make an appointment for the upcoming weekend. I am only driving the truck to work, about 15 miles a day total, until I get an idea of what is wrong.

Mine is an automatic. My father has the exact same truck in the standard cab with manual trans. I've driven his for years and never heard/experienced a problem like this. We are going to be moving to Montrose Colorado next month and would like to make sure I have no issues while pulling the horses. Thanks again guys.

Chris

OK,
It happened again last night when I went to leave work. The truck had little very power and there was a definite sucking noise when power was applied. I turned the truck off, waited 4 minutes and it worked perfectly on start up. What stumps me is after checking all the connections you mentioned, I still get what sounds like vacuum leak when this occurs. A tear in the hoses or a loose fitting wouldn't go away and then come back I would assume.

Thanks,

Chris

It kind of sounds like maybe the Exhaust Backpressure valve may be sticking. This is a little butterfly type device that is mountedon the exhaust side of the turbo housing and it's main function is to restrict exhaust flow when the engine is cold so that it will warm up quicker. When engaged, some trucks almost sound like a jet engine from the exhaust. It's supposed to automatically de-activate when the accelerator is depressed and I have seen them hang up a few times. IF it keeps up, one thing you can try is to unplug it. Beneath the intake side of the turbo there is a two wire connector, disconnect this and it takes the EBP out of the system. Try it for a few days and see what happens. If that cures it you can do one of two things, run without it if it starts and runs fine, or you'll have to replace the valve itself or the turbo pedestal where the actuator is mounted. The actuator isn't sold seperately and the pedestal assembly is pretty pricy.
Let us know what you find!

We have this problem occasionally with the 444E engines in our school buses. This is basically the same engine as the 7.3L Ford. The plate which is supposed to be actuated to divert the exhaust to help the engine warm up is sticking. The mechanism is part of the turbo pedestal and our cost to replace is $210. Unplugging the actuator works, but I have been told by several in the industry it may cause replacement of the engine in about a year. Does anyone have any information whether this is true? The problem goes away after a few miles of driving when the engine warms up. You will also notice very black smoke from the exhaust when the engine is cold and when it warms up the engine takes off and the noise and smoke stop. McWheels

Thx for the replies guys. It has been in the 20's in our part of CA the last few nights and the hissing was very pronounced yesterday morning when I started the truck up. After 10 minutes on the road, it stopped. I will have it looked at right away and let you know, but I think your right.

So has your problem cleared up since the weather has warmed up?? The hissing noise definately sounds like the backpressure valve working like it should to help warm the engine. Let us know!

I have a 95 250 7.3L turbo diesel.When it starts up it runs fine, but after about three to five minutes then engine stops running.I get no type of check engine light or anything. Sometimes while I am driving it will feel like a bad miss, and as I turn a corner it just quits. I replace the glow plug relay today per a mech suggestion no help. All lights are still on after engine shutdown.It always starts right back up.Happens no matter what tank is selected.

Kenny... I would check the easy things first. Fuel filter, lift pump operation, kinked hoses, tank breather. Then go to the expensive stuff.
Good luck to you.

Recently changed oil and fuel filter hoping it would fix this problem, put fuel filter gasket in wrong the first time, fuel pressure seems good, their are days when the truck runs great with no problems, this just started happening a few months ago.I am trying to get a shop manual for my F-250 so I know where everything is and how to test it.

quote:

Originally posted by Hosspuller:
Kenny... I would check the easy things first. Fuel filter, lift pump operation, kinked hoses, tank breather. Then go to the expensive stuff.
Good luck to you.

Just as a thought. I have heard of many people having crankshaft position sensors go bad. It will produce many of the problems you described.

Talked to a mech at our vehicle maintenance section at work and he said to replace the camshaft position sensor, the glow plug relay wasn't cheap, I wish I could figure out a way to test it before I replaced it, it's even more expensive. I feel like I am working on an airplane.

This message has been edited. Last edited by: Kenny,