2003 F350 Compression Readings

ETS · December 15, 2011

Truck is late 2003 6.0. 134K miles. Dead miss #6, Blows smoke rings from oil fill tube, Blue smoke from tail pipe at idle. Has very little contribution from #6. Also has #8 misses. Codes as follows, P0278 #6, P0603 Due to programer, P0132B Turbo Boost Control A, Found small exaust leak before turbo. It is sluggish off the line. Question is: What should compression be?? Running test this morning. Also has weird hiss from top of engine. It comes and goes in cycles like every minute or so it is more noticeable. Sounds like maybe intake valve issue? I am going to pull valve cover and look for high pressure leaks also. Oil is not overfull. Also has 5" exaust and K&N Filter {Very Dirty}. Looks like teardown time.

ETS · December 15, 2011

Hey guys, Had some time to get a little deeper into this, Does programer alter MAP readings? This truck is stuck on 19 all the time. Switched sensors with same results. Also has anyone seen a scanner cause engine to stall when you change screens? Truck has edge tuner. As example, If you change from drivability to turbo it will stall. Using solus scanner. Never had one do that before! All readings are constant until engine starts to stall. Just like key is off. SYNC yes, FICM readings are constant and OK. Sets cam and crank codes also. Only does it with scanner plugged in. Another thing Fuel Pressure at WOT drops to 45. Too Low?

lmorris · December 15, 2011

Depending on where you are and the condition of your compression tester 350 PSI is usually a good bench mark for compression. If you have the stream train effect, as I like to call it, from the oil filler you can guarantee the engine is dusted. The cycling hissing noise is the VGT cycling. All 2003 MY's do this, its for VGT calibration because they no longer use the EBP as a turbo input.

ETS · December 15, 2011

lmorris, What is stream train effect? And how do you check for it? Thanks in advance, Mike

lmorris · December 16, 2011

Meant steam train, sorry. You know puff puff puff out the oil fill pipe like the smoke stack on a steam train. The puffing is caused by poor sealing piston rings and pushes all the compression into the crankcase on the compression stroke.

Keith Browning · December 16, 2011

Trains are fun to play with but I think I would rather perform a crankcase pressure test when verifying the condition of an expensive diesel engine. Posted Image

ETS · December 16, 2011

Ran compression test on left side, #6 105 PSI, Rest 350-375. Put shop air to cylinder and got enough air from exaust side to spin turbo. But no autible pressure from crank case. Definately exaust valve. Santa came early here. Going to try out new bore scope through glow plug hole and get a look at cylinder bore. I agree Mr. Browning I will reassemble enough to do test if bore is not toast.

lmorris · December 16, 2011

Trains are fun to play with but I think I would rather perform a crankcase pressure test when verifying the condition of an expensive diesel engine.

I should have worded that better. When you get that from the filler pipe you are better off going after base engine before injector and HPOP issues. Sorry for any mis-understanding.

ETS · December 16, 2011

Out of luck, Can't see much with scope. Piston is washed clean with raw fuel. I have read here crank case pressure gauge is easily made. Use old fuel pump test gauge? Block off vent and oil fill, Check pressure through dipstick tube? What is maximum pressure allowed? I have seen it discussed here but thread search didn't come up with anything. Will test still be accurate with bad head? Thanks in advance; Mike

Keith Browning · December 16, 2011

Originally Posted By: Keith Browning

Trains are fun to play with but I think I would rather perform a crankcase pressure test when verifying the condition of an expensive diesel engine.

I should have worded that better. When you get that from the filler pipe you are better off going after base engine before injector and HPOP issues. Sorry for any mis-understanding.

No mis-understaning here. I have seen the train-like puffing of smoke and gasses from the oil fill pipe!

lmorris · December 16, 2011

It almost seems you have more than one issue here. If the exhaust valve is burnt and dropping compression then crankcase pressure should be low and you wouldn't get the smoke rings from the filler pipe. I have only used inches of water to measure crankcase pressure, not PSI. anything over 4" with Ford supplied tools is high. But a stuck or bent valve won't raise crankcase pressure. If you are losing that much compression past a valve you should be hearing a popping from the exhaust or intake when its running. Did you verify TDC on the compression stroke before doing the air leak test?

ETS · December 16, 2011

Yes TDC Was verified. I am sure there is no pressure on rockers holding valve open. And yes there is popping through exaust louder at idle. Everytime that cylinder fires. Guess I will look into a gauge through tool dealer. We are an independent truck shop so any special tools come out of my pocket and into my tool box. Customer has denied teardown says it is going to scrapper. Happy Holidays!

lmorris · December 17, 2011

At least you got some experience for the next one that comes in. Buying a good magnahelic gauge with the proper adapters is a good way to go if you see a lot of these.

Bruce Amacker · December 17, 2011

I have read here crank case pressure gauge is easily made. Use old fuel pump test gauge? Block off vent and oil fill, Check pressure through dipstick tube?

If you do this, it will break the gauge or blow the fluid out of the tube. You must provide a calibrated orifice for the gasses to escape.

What is maximum pressure allowed? I have seen it discussed here but thread search didn't come up with anything. Will test still be accurate with bad head? Thanks in advance; Mike

This should explain it using factory tool 303-758, or making a homemade version:

Note that when using a homemade water manometer, the measurement is the difference between the two fluid levels, not how much one leg moves. So if the left leg lowers by 3", your pressure is 6" of water. This is easily misread.

I know several guys on this forum prefer to use the crankcase pressure test over a conventional compression test, but I'll warn you that I've tested known good engines in class that failed the test. Don't rely on a single test to condemn an engine, use common sense and verify your results using other tests.

Good Luck, and Merry Christmas!

:grin:

Mbl35 · December 19, 2011

Bruce, the home made water manometer fits well into my curent tool budget. Is an adapter needed and what diameter hose?

Bruce Amacker · December 19, 2011

You'll have to make the tubular adapter shown above with the .298" orifice in it. It does not matter what size vinyl tube you use as the principles of physics take over and 6" of water pressure is 6" of water pressure, whether it's in a 1/8" tube or a 1/2" tube (or any other size).

Good Luck!

Posted Image

ETS · December 19, 2011

Bruce, Thanks for the illustration. I have enough pieces around to make this easily. I will be contacting you for training material soon. 33 year Master Tech. 7 years with Ford/Linc. Merc. Dealers 79 to 85. Only doing diesel for about 1 year. It's a whole different world. This site has been a huge help. Lots of great people here!!

Merry Christmas To Everyone, & Happy New Year