I've got a 2001 with 235,000 miles. I bought it at 195,000 miles from a diesel shop that had "rebuilt" the engine, whatever that means. For the last six months or so it's been smoking at start up and burning oil. 3 months ago I replaced the injector rings and glow plugs. While I was in there I noticed that the head bolts were loose. I retorqued them to spec. The symptoms have continued so I did a compression test over the weekend. Here are the numbers:

1 – 275
3 – 200
5 – 325
7 – 300
2 – 350
4 – 300
6 – 350
8 - 325

I swapped injectors 1 to 5 and 3 to 7, to see if that was the problem. Compression improved a bit, but I think mainly because oil got in the cylinders and sealed them.

Next I'm going to pull the injectors on the passenger side and try torquing the head bolts again. I don't think that will fix the low compression.

I assume my next step is to get a leak down test to pinpoint where the leak is. Does that sound reasonable? Anyone worked with shops that will come out to do leak tests? Or do I have to put everything back together and drive the truck to a shop?

Brian

 

Seek out "TUGLY" in this forum. He has a leak down chart that will save you bookoo.

Denny (check his sig line on his posts. It may be in there)

 

even a few km with improperly torqued head bolts could've screwed your head gaskets. i think you'll need to pull the heads no matter what. sorry.

 

if you had a loose head bolt, your gasket is toast and needs to be replaced


Diesels don't burn oil like a gasser, it will burn most types of oil as fuel unless you have low compression, worn out turbo or worn out injectors


pull the heads off and see where the leaks are
replace the head gaskets and then do a compression test again, maybe you will be fine after

 

Questions:

Other than Oil Burning at start up, does it continue or reoccur at start-up when warm?

How much Oil every 1,000 miles?

Have you inspected the Turbo for Wear?


Is there a "Skip" when cranking? Or, is it smooth and uniform?

How is it running?

Idling?

Any Coolant in Oil / Oil in Coolant?

Coolant spewing from DGAS Bottle?

Have you performed a KOEO Cylinder Contribution Test?

Have you performed a Running Compression Test? Watched Exhaust Valve Movement and compare to other Cylinders? What were the Peak Numbers?

 

Those #'s are low for a "rebuilt" engine and if your head bolts are loose that head gasket is toast have the machine shop go over the heads and resurface them just to be on the safe side. and when you do a compression check make sure you remove all glow plugs from that bank if not you will have compression jumping to the other cylinder giving wrong readings.

 

"Questions:"

"Other than Oil Burning at start up, does it continue or reoccur at start-up when warm?"

No. Start-up when warm, or in hot weather, does not produce smoke.

"How much Oil every 1,000 miles?"

I haven't paid really close attention, but I would guess at least a gallon.

"Have you inspected the Turbo for Wear?"

Yes. The vanes look fine and there is no back and forth movement, and very limited side to side.

"Is there a "Skip" when cranking? Or, is it smooth and uniform?"

Nothing unusual when cranking, except for missing/worn teeth on the flexplate that causes the starter to spin occasionally

"How is it running?"

Well...there is also, unrelated I think, an issue with the IDM and/or wiring. I've performed the 3 IDM tests described by DTech and others. Several injector circuits ohmed very high in the first test, and both circuits in test 2 were way high. I tested all injector solenoids on the bench and they came in around 2.6 and both ucv harnesses look fine on the bench, though I'll retest in the truck.

Aside from the IDM issues, when it's cold the truck often lacks power until warmed up. I thought this might be due to worn poppet valves, but all injectors sound strong and even during the buzz test. Could the lack of power be especially low compression while cold?

"Idling?" Fine

"Any Coolant in Oil / Oil in Coolant?" No, which makes me cautious to quickly conclude that the head gaskets must be shot.

"Coolant spewing from DGAS Bottle?" No

"Have you performed a KOEO Cylinder Contribution Test?" Yes, but I forgot to record the results and the injector harness is now removed. I don't think they were unusual.

"Have you performed a Running Compression Test? Watched Exhaust Valve Movement and compare to other Cylinders? What were the Peak Numbers?"

No. I've never heard of this test. Do you have an example, maybe video, of what to look for with the exhaust valves? What peak pressures should be?

The other thing maybe worth mentioning is that there is a lot pressure at the oil cap and a lot of oil in the intake.

 

Pressure at the oil cap - that's rings... or at least one oblong cylinder not addressed by the "rebuilders".

Injector solenoids are best tested from the 42-pin connector (link in my signature) or the IDM if the IDM is out. You describe a bad UVCH.

Cautionary tale - there are mechanics out there that know very little about the 7.3L, and they completely miss the mark when troubleshooting it. I have also run into very unscrupulous people who "piggyback" on the reputation and popularity of the 7.3L. They will tell you the engine came out of a wrecked vehicle with low miles, or say they rebuilt the engine - when all they did was reman the heads and hope for the best on the bottom.

Doing the heads in the truck is not worth the hassle - there's a high probability the gasket will suffer damage while trying to get that anvil in place for the first bolt.

You are on the mark with that leak-down test. As for the procedure, I'll bypass the drama in my thread and [LINK] you to the moral of the story.

 

Thanks, Tugly. I've seen your post on the 42-pin connector. Once I've got this compression issue resolved, I plan to test the wiring, working back from the uvch, to the 42-pin, and then the IDM plug. Of course, I'll reinstall the uvch and wiggle the plugs it as I test, looking for shorts.

I can't imagine pulling the heads with the engine in the truck. Even if it is possible, it would be a major PIA and likely to damage the gaskets, as you say.

I bought a new torque wrench last night, my 10-year-old one gave up the ghost recently. I pulled the passenger-side injectors before work this morning. I hope to re-torque the head bolts tomorrow. This weekend I'll try the running compression test pirschwagon suggests.

I'm going to call a couple of mobile diesel mechanics to see if they can do leak down tests and how much they charge. If it's close to the price of the tester in your link, I'll probably have them come out and do it.

I was suspicious when I bought the truck that the "rebuilder" took the time to address the bottom end. I hope I don't have to pull the engine for a rebuild, but I'm not opposed to doing it. But if the compression numbers aren't too bad, I might live with low compression for a while.

 

Finally had a chance to do a running compression test. DieselTechRon has a good video on it:
The good cylinder he tested showed over 600psi. The best I saw was 520. I only tested the passenger side, since it's the worst, and I'm pretty sure my numbers for #7 are low. The engine might not have been completely warmed up and I only left the tester on for a few seconds. The other cylinders I let the engine run a good minute before taking a reading. Here they are:

Cylinder Cold Compression Running Comp
1 300 460
3 250 340
5 350 520
7 390 410

I'm pretty sure this means something's wrong with the cylinders. Looks like I'll be pulling the engine this spring. I'll probably take it for rebuilding to L&R, as detailed in this article: Ford 7.3L Resurrection?A ?To The Bones? Engine Rebuild

I think a rebuild will be cheaper than buying a reman. Does that sound reasonable?

 

rebuild on your own can be cheaper if you have the time and knowledge but some of the machining does add up fast

 

Rebuilding your own is not a cheap venture, so don't look to save thousands of dollars there. Time is my enemy, and I estimate It'll be one year of prep work before I swap the engine. Your calendar may say something different.

In the meantime... "Stinky" is quakin' in his boots with the snot box of another truck in the garage - so he chose now to be on his best behavior (after I already have my money into parts). Stupid truck motor.

 

Assuming my injectors, turbo and hpop are good and can be reused:

L&R Machining quoted me $4950 for a long-block rebuild.
Domestic Diesel quoted $5200 for a reman and $2000 labor to pull and reinstall.

I guess one question is whether my time is worth about $2000. I'm inclined to pull it myself; I can refresh the trans while I'm at it.

Anything else I should consider?

 

Where in California are you?

 

riverside 92506