Compression test

[ackermanN]

Is there a way to do a compression test on the 5. 9L?

 

[JFaughn]

Just like gasser , except instead of removing the spark plugs , you remove the injectors .
The tools are different , that gauge has a higher pressure range , & you need an adapter to screw into the injector hole .
Why do you want to do that ?

 

[ackermanN]

Trying to determine where four quarts of oil goes every 500 miles.
No drips on ground, no undue bluish smoke. Runs pretty good.
Turbo works well, water temp at 200, oil pressure at a little over 40psi.
106000 miles. looking to isolate the problem. One suggested a broken ring so comp test would tell I thought. Injectors on my Harley just pop in and out, no screwing in or out. Was not sure if CTD was same or different in that regard. I guess common sense would suggest too high of compression would imply screwed in injectors. Too much to think about ... .

 

[Vaughn MacKenzie]

Compression test probably won't reveal condition of oil rings. If compression rings are tired you'd have quite a lot of blowby.

 

[ackermanN]

Vaughn, Where would the blowby manifest itself? I get little spots of oil on the tailgate but no major drips when parked.

 

[JFaughn]

An easy compression test , if everything els is OK , crack the injectors one at time , they should all make the same change in running , if any do not , thats a problem cylinder .
A leak down test is some els that should be done before any tear down .
Pressure wash , then look for fresh leak .
2 post ago it sounded like no leaks , then you mentioned tail gate ?
Have you checked you radiator , oil cooler may be blowing oil .
It is odd that you have a problem with an 05 , how many miles on it ?
More info to find out .

 

[ackermanN]

there are no obvious leaks as determined by drips on ground where
I regularly park. I understand that droplets on tailgate indicate a leak
from such as a main seal or so. Someone thought the oil could be coming from a bad turbo seal. have not had a chance to look in there. One other thought maybe a broken compression ring. Which got me here. I am the second owner. It was owned by a corporation in Phoenix, AZ and had 100, 141 miles on it when I got it. I needed an different tow vehicle as I was travelling from San Jose, CA to Chapel Hill, NC with a 26' toy hauler. I began to notice oil on the trailer and
the sides of the truck from just behind the front wheel wells. I had a dealer in Garner, NC look at it and they said the rear main seal was
bad. They replaced that and I thought that was it. Then after 500 miles
I checked the oil and it was down a gallon. I started watching closely after that and that is about the rate the oil is disappearing. Now trying to figure out the real problem.

 

[ackermanN]

Oh, and radiator is full and so is the reclaim bottle. Coolant looks
OK but it is not green. never overheats. stays right at 200 deg by
the temp gauge on the dash. The outfit runs great and I am very
pleased with it except for oil issue.

 

[WAckerman]

An easy compression test , if everything els is OK , crack the injectors one at time

I thought that cracking the injectors on a common rail was a pretty dangerous situation? Is that not the case?

 

[JFaughn]

Diesel , gas , mechanical , electrical injectors , its all the same , cutting fuel to one cylinder at a time .
I haven't had a chance to do that on a common rail yet , so do not have the procedure , but the idea is still the same , even with carbed gassers , but then its disabling the spark to each .
I got to the point of never figuring it was worth doing a compression test on a smooth running eng. , if its running smooth , it has to have good compression .
Pressure washing , drive a few miles at a time till you find a leak .
What I do is put a die in the crank case and use an ultra violate lite to see leak , the die lites up with the lite .

 

[JApol]

Vaughn, Where would the blowby manifest itself? I get little spots of oil on the tailgate but no major drips when parked.

The blowby tube on my 05 is just back from my fuel filter drain tube.

 

[JVolpe]

Vaughn, Where would the blowby manifest itself? I get little spots of oil on the tailgate but no major drips when parked.

While running open the oil filler cap and see if it is pumping out white plumes of smoke in conjuction with cylinder firing. As much oil as you are using the plumes should rival a steam train. Mine uses about a quart of oil around 1800 miles and you can see the blowby on mine.

 

[nickleinonen]

I thought that cracking the injectors on a common rail was a pretty dangerous situation? Is that not the case?

very dangerous. you need to be a fool to do this [gene pool can always use come chlorine]. . to do it properly, you need a rail cap fitting... remove a hp line and cap the rail, then start up and see what it does, move next and repeat. .



or remove the valve cover, disconnect a lead off the injector and start up. shut down and reconnect and remove another one off another injector. . repeat. .



you can get similar results by disconnecting the harness outside the engine. it will kill 2 cylinders on the 555 engines, the 600 engines i think have 3 cylinders off one harness connection

 

[BHolm]

That is a TON of oil loss. If it were leaking out anywhere, you would know it. Try dumping a gallon of oil on the garage floor, I bet it would cover the average garage. I would take a serious look at the turbo. That much oil almost has to be forced through the engine under pressure. To use that much due to blow-by would also be pretty obvious, try the oil cap removal trick too, see if it is puffing out that way.

 

[Johnstra]

Try what JVolpe said (and I said it earlier too). Remove the oil cap and see if you're getting crazy amounts of smoke/vapor out of the crankcase. That'll tell you if it's a turbo shaft seal, bad blowby possible due to a broken ring.

-john

 

[jelag]

Find some one with either a Sun Electric or Snap on, mac leak down tester

A leak down tester puts into the cylinder a calibrated amount of air when the engine is at rest with either the piston up or down... you measure in percentage the amount of air leaking and listen to where it leaks... standard leakage is 3-5% at TDC. . we measure air compressors if they come back for warranty consideration. (HD compressors, engine driven for air brakes)

The one we own is 30 years old and I used it for years to calibrate alcohol injectors on funny cars. .

It will show leaking valves, and issues with rings... .

Hope this helps...

 

[rbattelle]

BHolm's right - a gallon every 500 miles is a TON of oil. If it were burning it, you'd look like a freight train. If you're leaking it, it should be all over the truck.

However, your noting of oil on the tailgate is telling. There is NO reason for oil to be on the tailgate. But how in the world could a gallon of oil be leaking out and nothing dripped after shutdown?

If it were blasting out the tailpipe I'd expect a film of oil on the rear quarter panel.

Just to be sure - you're not checking the oil soon after shutdown, are you? Ideally, you should only check the oil level after the engine sits for quite awhile. Overnight is best.

Ryan

 

[ackermanN]

I did that last night an there was positive pressure in puffs as well

as vapors in puffs. Plus there is a lot of vapor coming from blowby tube.

So engine has a cylinder issue would be a fair diagnosis?

 

[ackermanN]

Also, I check my this way. I drive to work in the morning (40 miles or so)
so the engine is nice and warm) I park on a level spot. At lunch time I got out and check the oil. Sometimes it is mid afternoon when I do it. Also after
I add oil I check it and it shows up right away.

 

[JVolpe]

I did that last night an there was positive pressure in puffs as well

as vapors in puffs. Plus there is a lot of vapor coming from blowby tube.

So engine has a cylinder issue would be a fair diagnosis?

That would be a preliminary diagnosis. Leak down test would comfirm that.