Hi folks this is my first post, Just bought a 4.0 manual 2006 TJ. The jeep has had it''s original engine replaced from a desert rally TJ, but previous owner is not sure of any mods to the engine.
I have been measuring the vacuum on this engine and record vacuum at 17.8 to 18.1 inhg. I am using a vacuum gauge connected to the vacuum line on the brake booster vaccum hose and used the hvac vent controls port. From this I suspected piston rings worn, so did a compression test.
These are my compression readings,
1 155ps
2 165psi
3 155psi
4 167psi
5 163psi
6 160psi
Readings are above the factory spec of 150psi max, but within the variation range between cylinders. Is my engine modified from factory. The vacuum should be above 20-22 inhg right?
What do these engine measurements indicate.
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- Vehicle Year: 2006
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Re: What do these engine measurements indicate.
Was your throttle body propped open when you ran the test? Hot or cold motor?
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Re: What do these engine measurements indicate.
Throttle fully open, cold engine
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Re: What do these engine measurements indicate.
Elevation ? That does play a bit in numbers.
Assuming relative sea level there is likely a small cam in it. "From the Factory" is meaningless without knowing what "Factory" your talking about. An engine setup for JeepSpeed would likely have been cammed a little to boost power, yes.
If you have good oil pressure and no abnormal noise than run till it doesn't have oil anymore or starts making expensive noises.
Assuming relative sea level there is likely a small cam in it. "From the Factory" is meaningless without knowing what "Factory" your talking about. An engine setup for JeepSpeed would likely have been cammed a little to boost power, yes.
If you have good oil pressure and no abnormal noise than run till it doesn't have oil anymore or starts making expensive noises.
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