No compression

[Therigwelder]

have a 93 ranger 2.3l that idles badly but when I give it gas it drives fine.Recently the check oil light has started coming on and I am adding a quart of oil every 3 days.the truck does not smoke at all.i decided to do a compression test. When I pulled the plugs they were all a light tan color, no burnt oil or wet plugs. I expected to have compression cause the plugs were in excellent condition. However I have no registrable compression The gauge reads zero on all 4 cylinders.just to double check my gauge I rented a tester from auto zone and it too registered zero.how does an engine even run with zero compression?i investigated further because I wanted to know where all the oil is going. There was some oil in the intake( I took it off to gain access to the spark plugs under it)I have oily soot in the tailpipe, lower rocker and back of bumper,I have no major oil leaks that would warrant the excess oil I am using,I have no oil in the coolant or vice versa. What is going on with this engine? How could I not be burning oil yet have oily soot at the tailpipe? Would a blown head gasket cause my no compression and oil usage?

 

[sheep herder]

It is impossible for a motor to run with zero compression.

 

[adsm08]

Engine can't run with less than 90 PSI compression.

Did you have the shrader valve installed in the spark plug adapter?

 

[Therigwelder]

I used a threaded adapter on the compression testers, firmly hand tight, all plugs removed, coils and fuel disabled. Both testers read zero. I don’t know why,I recently used my tester on another vehicle and it worked fine. So obviously I know I have at least the minimum compression for it to run and all cylinders are firing good according to the plugs. Everything on the engine has been replaced in the last year. I have no idea where the oil is going no major leaks no fouled plugs.this truck has always idled rough and with everything being replaced I assume that something is going on internally. Maybe the valves are bad. The truck has almost 400k on the original motor. I have another engine I plan to put in during my Christmas holiday but I would like to limp this engine along till then

 

[ThatOneGuy]

Just a guess but possibly bad exhaust valve guide seal, allowing oil to be sucked out exhaust manifold depositing an oily soot in tail pipe. Without getting hot enough to ignite the oil and smoke. But then it should burn in a functional catalytic converter. Making some smoke.

 

[RobbieD]

That's an 8 plug head. Did you pull them all?

 

[Therigwelder]

Just a guess but possibly bad exhaust valve guide seal, allowing oil to be sucked out exhaust manifold depositing an oily soot in tail pipe. Without getting hot enough to ignite the oil and smoke. But then it should burn in a functional catalytic converter. Making some smoke.

Catalyst was removed long ago,I might be bad valve stem
Seals

 

[Therigwelder]

That's an 8 plug head. Did you pull them all?

Yes

 

[RobbieD]

Yes

Only pull one side to do a compression test.

 

[Dirtman]

Well that solves that mystery...

 

[adsm08]

That's an 8 plug head. Did you pull them all?

Yes

Found the problem.

Put one plug back in each cylinder.

 

[sheep herder]

 

[Therigwelder]

Found the problem.

Put one plug back in each cylinder.

well I’ll be damned, it never dawned on me till you mentioned it. I am used to pulling all plugs before a compression test. I guess I wouldn’t have compression if it’s blowing out the other sidethank you, I will do a compression test in the morning. Boy do I feel like a dumbass overlooking that

 

[adsm08]

well I’ll be damned, it never dawned on me till you mentioned it. I am used to pulling all plugs before a compression test. I guess I wouldn’t have compression if it’s blowing out the other sidethank you, I will do a compression test in the morning. Boy do I feel like a dumbass overlooking that

Happens. About a month ago I put a transmission in a C-MAX and when I was done it would turn on but wouldn't go into "Run", engine wouldn't start, wouldn't move, and a few modules that had been working wouldn't talk to the scanner.

I forgot to reinstall the high-voltage service disconnect. Wouldn't have been so bad except I was fiddling with it while trying to figure out why the car wouldn't start.

 

[RobbieD]

Don't feel bad. Easy enough mistake to make if you're new to wrenching on the dual-plug 2.3L.

I'm still curious what you find with the compression test, since all of the plugs had a good "light tan color". Hope that you'll post the results.