7.3 question

guffey24

guffey24

Well-Known Member
Joined
Jun 7, 2006
Location
Hendersonville, NC
I bought a new tow rig

1997 ford f-350, 4 door crew cab, single wheel long bed, 226,000 miles, super clean truck, new transmisson, been driving it for about two weeks runs great UNTIL........

I drove it to Raleigh for a few days, on the way back I lost boost, didn't happen to look at the pyro gauge, not towing just driving

No crazy noises just a major loss of power, boost gauge goes to 10 then falls on its face back to zero

I then pull over for fuel, come to a stop at idle and it makes a loud noise like something is loose, give some fuel and it quietens down to no noise

Great oil pressure the rest of the way home, no overheating, tranny temps at 120-140

It used a good bit of oil, doesn't leak a drop, more smoke then normal

It does have a 5" exhaust, intake, and a ts performance chip


Turbo gone? What do I look for?

The noise at idle, would the turbo sound like this, it sounds like the motor is coming apart, until you give it fuel then it quits making noise at all

The chip was turned to the stock setting when this happened
 
What color is the smoke? Could have lost seals in turbo....using more oil causing it to smoke more. Noise can be bearing in turbo going bad from loss of oil. Give it fuel and sound decreases? More oil preasure / flow above idle maybe causing it to quiet. No power or boost can be related to turbo. Check exhaust pipe for oil. Take boots off turbo and check for oil. Check for play in the turbo shaft. Lots of play would mean bad bearings or wore out housing. Wouldnt think housing with that low of mileage. Hope this helps.

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Smoke is black

And yes sound goes away when you give it fuel, but at idle it is loud as hell

I will check it out this weekend, is it worth rebuilding or buying a new turbo, would this be a good time to upgrade the Garrett, even with stock injectors?
 
Check your map sensor hose as well. Mine come loose on my 01 and it wouldn't build no boost.
 
If its burning oil I would have thought that you would have blue like smoke. But then again if turbo is bad. There would be low airflow thus the 0 boost condition. The engine tune will be off. So it would be over fueling the motor. (This would be normal fueling if turbo was working) Poor gas mileage and black smoke. I don't know if it can defuel enough to compensate for loss of turbo. Depending on how much you want to spend...Craigslist usually has good condition 7.3 take off turbos with no shaft play for decent prices. If you want more power..bigger turbo and fuel system. Or just fix whats broke. All up to you :D

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Also check all intercooler/ turbo boots for oil and see if any came off. . To answer your last question I have seen some run bigger turbos with stock injectors. It works good for controlling egts when towing. But if you try to make good power from the turbo you will have to upgrade the fuel system. I'd rather have to much fuel than not enough!

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okay, installed a new turbo, all new o-rings, got everything buttoned up, fired it up, and still making a loud racket at idle, and will not build any boost unless its at 5000 rpm's

anybody got any ideas?

would a bad torque converter cause this no boost issue?, truck has power just doesn't have boost so its like the turbo is non existent
 
My buddy bought a 7.3 van and I thought it had boost or fuel problems when we test drove it cause it wouldn't pull a hill but at like 10mph, but the Trans was slipping, he had the Trans replaced and worked fine.

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I wish I had more insight but I would be tempted to install an new CPS from International or Ford. I just went through this with mine. It had all kinds of symptoms and issues and in the end it was a CPS.

Hope you get it straightened out soon.
 
tireburner1975 said:
My buddy bought a 7.3 van and I thought it had boost or fuel problems when we test drove it cause it wouldn't pull a hill but at like 10mph, but the Trans was slipping, he had the Trans replaced and worked fine.

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brand new built transmission that shifts nice and firm
 
Ah, brand new torque converter?

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frankenyoter said:
I wish I had more insight but I would be tempted to install an new CPS from International or Ford. I just went through this with mine. It had all kinds of symptoms and issues and in the end it was a CPS.

Hope you get it straightened out soon.
Click to expand...

you think this would cause the loud rattling noise at idle, almost like its out of time?

I can drive the truck a little at a time, and it has cutoff on me several times, I am going to pick one up from the Ford dealership this afternoon and see what happens
 
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The CPS tells the computer when to fire injectors. Had one go out on a 96. It had a random miss. Sometimes bad enough to shut the truck off. It did make a rattle / knocking sound when it missed. Sounded more like noisy valves on a gas engine when you shut it off and it keeps running.

However, there was no loss of power or boost so I doubt that's your problem. Good thing is it's a cheap fix if you wanted to swap it out just to check. At least then you would know or be able to rule it out.

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GREENCHEROKEE said:
The CPS tells the computer when to fire injectors. Had one go out on a 96. It had a random miss. Sometimes bad enough to shut the truck off. It did make a rattle / knocking sound when it missed. Sounded more like noisy valves on a gas engine when you shut it off and it keeps running.

However, there was no loss of power or boost so I doubt that's your problem. Good thing is it's a cheap fix if you wanted to swap it out just to check. At least then you would know or be able to rule it out.

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Thanks, going to replace it this afternoon, and recheck all my boost gauge fittings, any other ideas on the low to no boost
 
guffey24 said:
yeah, new torque converter also, I just hope the torque converter is still intact, crazy thing is, the noise goes away as soon as you give it fuel, truck runs great, just no boost
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Just what I have seen with that case, I wish I knew more about light diesels, just don't get many in to work on.

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GREENCHEROKEE said:
The CPS tells the computer when to fire injectors. Had one go out on a 96. It had a random miss. Sometimes bad enough to shut the truck off. It did make a rattle / knocking sound when it missed. Sounded more like noisy valves on a gas engine when you shut it off and it keeps running.

However, there was no loss of power or boost so I doubt that's your problem. Good thing is it's a cheap fix if you wanted to swap it out just to check. At least then you would know or be able to rule it out.

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Click to expand...


Mine sounded like crap. Almost like cylinders weren't hitting. I gave it some skinny pedal and it didn't do much. I agree loss of boost may not be attributed to a faulty CPS, but who knows. I can't stress the importance of getting the CPS from Ford or International. I installed two CPSs from box stores trying to get mine running properly and finally had it towed. Turns out it was the CPS.
 
frankenyoter said:
Mine sounded like crap. Almost like cylinders weren't hitting. I gave it some skinny pedal and it didn't do much. I agree loss of boost may not be attributed to a faulty CPS, but who knows. I can't stress the importance of getting the CPS from Ford or International. I installed two CPSs from box stores trying to get mine running properly and finally had it towed. Turns out it was the CPS.
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Just picked one up at the ford dealership, will let you know what happens later this afternoon
 
Had about the same problem your having on a 96 f-350..the truck run great for years
Until.....we installed a a ts 5 stage dial programer all went well for about a week then
One morning fired up the truck and it sounded like it was gonna come all to hell !!!!!

Truck would run extreamly rough as if were hitting on about 5 cylinders and
give it some fuel the rough idle would go away but still had no power at all
Turns out where the ts programer bolts in between the wiring harness and the firewall
It had a bad connection we took it out and it cleared up
 
Have you checked the bulkhead connector on the UVCH for melted pins/burnt wires???? With the truck running wiggle the connector and see if I changes anything.The inj's are elect and the wiring runs thru the valve cover gasket.Both of the PS's I've had,have had the harnesses,gaskets changed.My 96 so bad you could smell burnt plastic when you took the oil cap off.
 
MOE$ FAB said:
Had about the same problem your having on a 96 f-350..the truck run great for years
Until.....we installed a a ts 5 stage dial programer all went well for about a week then
One morning fired up the truck and it sounded like it was gonna come all to hell !!!!!

Truck would run extreamly rough as if were hitting on about 5 cylinders and
give it some fuel the rough idle would go away but still had no power at all
Turns out where the ts programer bolts in between the wiring harness and the firewall
It had a bad connection we took it out and it cleared up
Click to expand...

That is my next step, unplug the chip and see what happens
 
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