Got a 99 F250 truck, 300k, runs and drives good but smokes white out the exhaust. And also I can feel rythmic puffing thru oil filler neck.

So, I got HF diesel compression gauge, few fittings and made an adapter for glow plug hole threads.

I could not get a straight shot at the threads without removi by rocker arm tho, so I removed arm on #2, screwed adapter in, reinstalled arm and turned over motor......reading 0. I tried three times. 0. Moved over to #4, same procedure, same result. 0.

I switched compression gauge from 0-1000 to regular 0-300 to see if it was a bad gauge, same result. Gauge didn't move at all. On either #2 or #4.

Started raining had to close the hood up, didn't test further tonight.

Hmmm....not sure what's going on. Unlikely both cylinders have hole in a piston to show 0.

I'll test more cylinders tomorrow, just trying to get some input if I am crazy or don't know what I'm doing or what.....tnx!

 

Should not need to undo rockers. You need to re think your adaptor. My kit had one for a powerstroke. Motor must be at running temp. You don't crank it to test, you run it. Engine running. A lot of guys make an adaptor out of an old glow plug. Can you see compression getting past your adaptor out the glow plug hole? Might be loose? Does you gauge have a dump valve that is open, or a button your holding down by mistake? If you have two dead cylinders, your going to notice it running. You should notice one out at idle easily. Bad miss. White smoke is usually un burnt fuel. All said. If those cylinders have no compression, you can test by unplugging those injectors one at a time to see if the motor changes sounds. If no change in sound, then the cylinder is dead, and smoke will decrease unplugged. But if it stumbles, then it was firing plugged in, meaning it at least has some compression.

 

Thanks for the reply

I built adapter from grease hose whip and 10x1 boss, however that one would not screw in at all, with rocker arm on or off (?). So rigged another setup to get it in there. It installs nice and tight.

All videos I saw on YT show test while engine is not running. I have 42pin connector unplugged for this.

Since I am turning the key, I can't see or feel what's going on under the valve cover. I am also not holding pressure release schrader valve either. I tested with two gauges, one is good known 300psi gauge that holds pressure. 1000psi gauge is new and unknown

Before this test #1 #5 & #8 didn't pass buzz. I was testing #2 & #4 holes.

 

I'd fix that buzz test fail - it has nothing to do with compression. You can click the UVCH link in my signature for more info on that.

Speaking of links, you can click this one for help with your HF tool: [LINK]

Compression test - there is a running test and a cranking test. I have a pre-2002 vehicle, so I have the starter relay on the passenger fender to crank the engine without starting. I assume you've pulled the fuel pump and PCM/IDM fuses so the engine won't run off without you?

Here is a cranking test after I blew up my HF conglomeration and bought an OTC adapter and gauge (different world there, but a bit pricey for just one purpose):

 

Thanks. I didn't pull any fuses, but 42pin plug is disconnected so no power to uvch area where I'm working. I'll fix buzz after I determine health of the bottom end.

I have tested compression many times on many engines, gas and diesel, never seen 0 reading on a running motor....and on two cylinders to boot

Truck is 99, I'll look for my remote starter button and crank it while being able to look and feel around the heads

 

I found this a couple years ago on a website forum. I can't speak to its accuracy. Use at your own risk.


I can't imagine you have a good seal. You should be seeing something I would think even with holes in the Pistons. And to have two? Would it even run?


-------------


COMPRESSION TESTING, 7.3 DIT

Pressure reading:

A common test of an engine’s ability to compress the air-fuel mixture is an engine compression test. A pressure gauge is connected in place of the spark plug. The engine is then cranked to create a pressure reading. A compression test is a good way to check the engine’s ability to create pressure. The gauge reads the positive pressure created by the cylinder.

Tools: Compression Tester Gauge 0-1000 PSIG, A Diesel Glow Plug adapter - Ford Navistar 7.3L Power Stroke DIT 99.5 - 03 MY: Tool source #8276 Manufacturers #: MVA5621Also known as: #MITMVA5621 #MTY-MVA5621 to name a few sources.

Supplies: You may wish to replace the GP's since you'll be there. Use OEM Only. Too many problems with others.

NOTE: Ford does not provide a cranking pressure specification, only an acceptable range.

Process:

1. Charge Batteries and keep the Charger on the Batteries throughout testing.

2. Remove Valve Covers to expose the Glow Plugs. Remove electrical connectors at each GP.

3. Remove all eight GP's. This will take about 90% of the strain on Batteries and Cylinders. Some may require carburetor cleaner or similar carbon deposit solvent. Use just the amount needed. It evaporates fast.

4. Remove Fuse #30 (30amp) in the under dash panel. This will disable the starting of the engine while still allowing
cranking.

5. Install Adaptor and Compression Gauge.

6. Crank the engine 5-7 revolutions.

7. Record the pressure and move to the next GP Hole. I like to do 1,3,5,7,2,4,6,8.

8. Refer to the Compression Pressure Limit Chart.

9. If one or more cylinders reads low, squirt approximately one tablespoon of clean engine oil meeting Ford specification
ESE-M2C153-E on top of the pistons in the low-reading cylinders. Repeat the compression pressure check on these cylinders.

TEST RESULTS:

The indicated compression pressures are considered within specification if the lowest reading cylinder is within 75 percent
of the highest reading.


INTERPRETING COMPRESSION READINGS

1. If compression improves considerably, piston rings are faulty.

2. If compression does not improve, valves are sticking or seating improperly.

3. If two adjacent cylinders indicate low compression pressures and squirting oil on each piston does not increase compression, the head gasket may be leaking between cylinders. Engine oil or coolant in cylinders could result from this condition.

NOTE: Use the Compression Pressure Limit Chart when checking cylinder compression so that the lowest reading is within 75
percent of the highest reading.

4. Reassemble in reverse order.

LEAK DOWN TESTING:

An engine leak down test is a compression test in reverse. Instead of measuring the engine’s ability to create pressure, compressed air is introduced into the cylinder. One gauge on the tester measures the pressure of the air entering the cylinder and the other measures the percentage of the air escaping (or leaking) from the cylinder. The loss percentage will indicate the condition of the cylinder and overall condition of the engine.

Tools: Leak Down Test Gauge Set 0-100 PSIG, A Diesel Glow Plug Adapter - Ford Navistar 7.3L Power Stroke DIT 99.5 - 03 MY: Tool source #8276 Manufacturers #: MVA5621Also known as: #MITMVA5621 #MTY-MVA5621 to name a few sources. You will need a compressed air source, a leak down gauge kit, spark plug socket, basic hand tools, vehicle service manual and a notepad to record results.

1. Remove Valve Covers to expose the Glow Plugs. Remove electrical connectors at each GP.

2. Remove the Glow Plug on the Suspected Cylinder Ensure the cylinder being tested is at Top-Dead-Center (TDC).

NOTE: TDC: Before sending air into the engine, the cylinder being tested must be placed at Top Dead Center (TDC). The piston must be at the top of its travel. The intake and exhaust valves must be closed. When the air is compressed into the cylinder, the leak down tester will measure any loss of air escaping past valves or piston rings. If the cylinder is not at TDC, air escaping past an open valve will give a false reading.

3. Insert the Diesel Glow Plug Adapter

4. Apply air and record the result.

Reading results:

No engine will have perfect sealing with 0 percent loss. Five to 10 percent loss indicates an engine in great to good running order. An engine between 10 and 20 percent can still run OK, but it’ll be time to keep an eye (or ear) on things. Above 20 percent loss and it may be time for a teardown and rebuild. Thirty percent? Major problems. The percent of leakage should also be consistent across the cylinders. Any great differences indicate a problem in that cylinder.

Hearing:

Beyond getting an overall picture of engine condition, the engine leak down test is an excellent way to pinpoint where problems are before tearing down the engine. Listening for where the air is escaping by ear can isolate the problem.

Intake valve: Air whistling out of the intake, indicates a leak at the intake valve.

Exhaust valve: Air heard hissing out of the tailpipe, turbocharger or exhaust manifold means an exhaust valve leak.

Piston rings: Whistling or hissing out of the PCV valve, oil filler cap hole or dipstick tube means the air is pushing past the rings. Suspect ring or cylinder wall wear.

Head gasket: Air bubbles in engine coolant seen at the radiator filler cap could mean air escaping into the coolant past the head gasket.

Cracked cylinder head: Bubbles in coolant or coolant being pushed up out of the radiator neck can also indicate cracks in the cylinder head or cylinder walls.

 

Wouldn't You have a lack of or 0 compression if You had Your rockers off or loose.

 

If the rockers were loose or off, the valves would be closed so no loss of compression, even if you were @ TDC on an exhaust stroke if the rockers were completely off.

 

I got it working, and results are not good. As I suspected engine seems dusted. Cold results

1 185 fails buzz
2 300
3 160
4 200
5 0 fails buzz
6 300
7 85
8 300 fails buzz

I tested each couple of times and results are same. Odd thing is it runs good, 75mph cruise on the highway, just smokes white at idle (clears up or not visible at speed over 30).

 

I took them off to install adapter, then put thme back on to test

 

Do all the tests you posted. What were the readings with the table spoon of oil in the bad ones?

 

It would seem to me that if, the Rockers were off, the valves would remain closed. Unless I'm missing something here.

 

Perform a Running Compression Test and see how quickly the cylinders recover and how high they actually get.

 

Compare your readings using the attached chart. Well, I would have posted the Navistar Compression Relation Chart but it would not allow me.


EDIT: I just can't help but think something is not accurate here. Looking at the numbers the Relative Compression Test should have been all over the place. Especially with #5 and #7. Ray Charles should have been able to see that without Glasses.


I would get someone to help me and re do them both cold and hot.


As for adding oil, that's really not necessary for a Diesel due to the amount of compression made. Or, in your can not made.


I know it takes time, but another Relative Compression Test, Cold/Hot/Running would be on the order. The numbers above are all over the place. Unless by Dusted you mean someone put pebbles through the intake. What does the Turbo Impeller Look Like and what type of filter is or was being used?

 

I have a very similar issue with my truck except with cylinder 1. looking at your test results you have a problem with the head or the gasket. keep all your GPs out and put some air in. better yet take off the rockers to close all the valves and then do it. you should see some air coming out somewhere. ill bet you end up with air in the cooling system seeing as you're burning coolant