Searching for vacuum leak on MY94
#1
Searching for vacuum leak on MY94
I have a mystery vacuum leak on my 1994 XJ6 daily driver.
I tried replacing a badly cracked crankcase breather hose but even after that I think the mystery vacuum leak is still there.
So I made a video about it to hopefully illustrate the problem
I hope the sound of the hissing noise is audible over the sound of the running engine.
I tried replacing a badly cracked crankcase breather hose but even after that I think the mystery vacuum leak is still there.
So I made a video about it to hopefully illustrate the problem
I hope the sound of the hissing noise is audible over the sound of the running engine.
#2
Pics of failed crankcase ventilation hose
Here are some photos of the failed crankcase ventilation hose that was probably original and only last 28 - 29 years before it cracked.
How original hose is located between the intake elbow and the crankcase vent hose leading to the port on the valve cover
See huge crack in the hose
Two ports that the hose fits between.
New hoses (bought a spare since the old one only lasted since 1994) obtained from ebay seller. These are not made out of rubber. Maybe silicone?
How original hose is located between the intake elbow and the crankcase vent hose leading to the port on the valve cover
See huge crack in the hose
Two ports that the hose fits between.
New hoses (bought a spare since the old one only lasted since 1994) obtained from ebay seller. These are not made out of rubber. Maybe silicone?
#3
Installed the replacement hose
New hose from ebay installed
Unfortunately I still had a vacuum leak after installing the hose. Somewhere around cylinder three or four on the intake manifold.
After spraying carb cleaner around various places and listening with a "hose stethoscope" I think there is a problem with the lower sealing o-ring on the bottom of number four injector.
So I guess I have to pull the fuel rail off and take a closer look at that o-ring.
New hose from ebay installed
Unfortunately I still had a vacuum leak after installing the hose. Somewhere around cylinder three or four on the intake manifold.
After spraying carb cleaner around various places and listening with a "hose stethoscope" I think there is a problem with the lower sealing o-ring on the bottom of number four injector.
So I guess I have to pull the fuel rail off and take a closer look at that o-ring.
Last edited by JensenHealey; 10-22-2023 at 06:56 PM.
#4
Solved vacuum leak problem, injector o-rings
Found the vacuum leak problem. Two of the lower injector o-rings were pretty torn up.
from cylinder four
from cylinder six
really torn up
When I went to put the fuel rail with the injectors all stuck into the cups on the fuel rail back into place, I carefully put some silicone grease on the lower o-rings before seating them into the holes on the intake.
This made the process of getting them properly seated WAY easier. I recall struggling with this before so I would recommend anyone do this if you have to pull your fuel rail for any reason.
If you don't have a tub of silicone grease like I do, you can buy little packets of the stuff at the autoparts store since I know O'Reilly's has them for keeping ignition wire boots lubricated.
from cylinder four
from cylinder six
really torn up
When I went to put the fuel rail with the injectors all stuck into the cups on the fuel rail back into place, I carefully put some silicone grease on the lower o-rings before seating them into the holes on the intake.
This made the process of getting them properly seated WAY easier. I recall struggling with this before so I would recommend anyone do this if you have to pull your fuel rail for any reason.
If you don't have a tub of silicone grease like I do, you can buy little packets of the stuff at the autoparts store since I know O'Reilly's has them for keeping ignition wire boots lubricated.
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