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'99 & up 7.3L Power Stroke Engine and Drivetrain Discussion of the '99 & up 7.3L Power Stroke diesel engine and drivetrain in the 1999-Up Super Duty trucks and Excursions. No gas engine discussion allowed except on transmissions and drivetrain that pertain to all models. Please confine discussion of topics in this forum to those items that are specific to the 7.3L Power Stroke engine.

Thread: Have I finally worn my truck out? Reply to Thread
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  Topic Review (Newest First)
02-02-2019 03:55 PM
DonWarkentin I would get a timer and set it to turn on the block heater two hours before you want to start the truck. Also, I wouldn't wait too long to change the fan clutch. Mine let go and sent the fan into the radiator, destroying the radiator, fan, fan clutch, and water pump all at once. Expensive repair.
02-02-2019 12:20 AM
klhansen Compression numbers are right on the hairy edge of toast.


Ford's criteria is that the lowest has to be within 25% of the highest. Your lowest number is 24.7% lower than your highest number.
02-01-2019 11:04 PM
coslatrat
Quote:
Originally Posted by 79jasper View Post
Imo, that compression is piss poor.

Sent from my SM-N960U using Tapatalk
It is piss poor and it's what I've got... once the ol beast gets warmed up, it runs like a champ (for now). I'd like to take the truck to 500k before either replacing it, rebuilding the engine or a long block.
01-14-2019 03:44 PM
79jasper Imo, that compression is piss poor.

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01-14-2019 03:41 PM
coslatrat Harness was in good shape. Thanks
01-14-2019 03:17 PM
RT UVCH is the under valve cover harness - it connects the plug on the valve cover gasket to the injectors and glow plugs. It is a known point of failure, but the 99-01 models were more prone to losing the connection at the plug than the later models.
01-14-2019 03:08 PM
coslatrat
Out of the shop

The truck came out of the shop last Thursday - new LF hub assy, new injectors, new shoes for e-brake, new SSBC stainless steel vented (not drilled) rotors and pads, new spicer U-joints for the rear and a rear diff fluid change along with the Marinco mod (that puts the block heater plug in the bumper) and an empty checkbook.

Cylinder pressures aren't fatal but they aren't all that great either:

#1 - 241; #2 - 222; #3 - 234; #4 - 222; #5 - 220; #6 - 279; #7 - 237; #8 - 210

I still have a roar at 2250 rpm that's probably my fan clutch which has been locked up for a while and will get fixed next time there's money in the checking account. The roar is worst when cold and shakes the whole truck. The white paint is falling off too but it'll have to wait.

GP's and GPR were in good shape - what's a uvch 79jasper?

Thanks to all of you for your advice - truck turned 400,000 last Thursday!!!
12-07-2018 05:39 PM
bigb Count me as one of the people who finds it hard to believe that truck is worn out. If you could drive it to Tucson we have a very good and reputable independent shop here, or maybe do the work yourself if possible. Following along to see how this comes out and betting that there are many more years left in that truck.
12-07-2018 07:58 AM
79jasper I would for sure do gp's while in there, likely uvch as well.

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12-07-2018 01:26 AM
ArcticDriver
Quote:
Originally Posted by coslatrat View Post
Thanks to everyone for the replies.

I visited Rockin S last week and have ordered re-man stock injectors, stainless rotors and new pads along with a set of u joints - just waiting for the parts to come in... probably ought to replace the fan clutch while we're at it. Gotta do something, it took 15 minutes to start after leaving it unplugged all day Tuesday in zero temp.
Sounds like GPs & GPR would be a good investment...

Are they stainless rotors or “e-coated” rotors?
12-06-2018 11:30 AM
coslatrat
Update

Thanks to everyone for the replies.

I visited Rockin S last week and have ordered re-man stock injectors, stainless rotors and new pads along with a set of u joints - just waiting for the parts to come in... probably ought to replace the fan clutch while we're at it. Gotta do something, it took 15 minutes to start after leaving it unplugged all day Tuesday in zero temp.

Answering some questions, stealer didn't print out the compression #'s so the first thing we'll do is get real numbers for all cylinders and go from there.

I live W of Denver in the foothills and commute to one side of the EJMT or the other 4 or 5 days a week. The only trailers behind me have had boats attached (2 to 8k #'s).

Plan is to spend next summer in New England racing my sailboat so the truck has to last until then at least - hoping the repairs do the trick. I'll post the compression numbers when I get 'em.
11-11-2018 12:32 AM
klhansen
Quote:
Originally Posted by 79jasper View Post
You don't "have to." Its much easier/faster to remove it.
No need to remove the cab at all for a 7.3L. I think the cab removal thing started with the 6.0L or may be the 6.4L. I looked under the hood of a 6.4L when they were new and could barely see the engine for all the junk hung on it.

Here's where I got the adjustment for compression check at altitude: Compression Testing if anyone is interested.

I agree with rv6a that there may be something wrong with the injectors. They tend to last about 300-400k miles. Especially with cold oil, reduced armature clearance can cause the solenoid to not be able to open the injector pintle valve. There are shims available the might prolong the life of the injectors. Those can be installed without removing the injectors, just the valve covers and solenoids.
11-10-2018 05:04 PM
rv6a Wait a minute. Why does everyone think the engine is toasted? Gas expansion with heat comes to play here. At sea level a compression of 350 PSI divided by the heat of expansion from air (Aprox 1.4) divided by the atmospheric pressure gives us a compression ratio of 17:1. The 7.3L has a compression ratio of 17.5:1 so the numbers are close. Move this baby to 7500 feet ASL and the numbers 250/1.4/17.5=10.2 atmospheric so the numbers are again close. Consider the fact that on a standard day the atmospheric pressure at 7500 feet is around 11.1 psi.

So we plug in 11.1*17.5*1.4=271 PSI. So a 250 PSI compression check at 7500 may be a little low but I don't think the engine is toast. Something else may be amiss; ie. slow cranking speed, etc.

I think the problem may be worn injectors. He states the problem is reduced power when cold. I assume that it runs and has normal power once warmed up. I would not give up on this engine just now. Injectors could be at fault.
11-10-2018 12:21 PM
79jasper You don't "have to." Its much easier/faster to remove it.

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11-10-2018 09:47 AM
LMJD I'm from the pre-Powerstroke era, but a diesel is a diesel. Hard starting, cold or hot can be due to many causes other than claiming it's due to a worn out engine. Another thing to bear in mind, I don't know which year it started, but the later Powerstrokes require removing the entire cab assembly in order to do much more than check the oil or remove the alternator when it comes to working on the engine. When that info came out, I figured it was typical forum B.S. but if you check with reliable sources it's true. Or look under the hood of a new P.S.
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