87 4.0 xj
i have the fsm but i cant find the d%## value in all the manual

Cold compression test dry and wet. What are your tech opinion?

Cyl. Dry. Wet
1. 115. 120
2. 130. 135
3. 113. 115
4. 120. 125
5. 115. 120
6. 120. 125

 

From the '88 FSM (TUNE-UP - 6-CYL Section)

COMPRESSION SPECIFICATIONS TABLE
===============================================
Application Specification
Compression Ratio .................................. 9.2:1
Compression Pressure ....... 120-150 psi (8.4-10.5 kg/cm  )
Maximum Variation Between Cylinders .. 30 psi (2.1 kg/cm  )

 

Hi.. can you be so kind that share that 88 fsm link?
im using the 90s fsm. I didnt know a 88 exist

Hope is in pdf

 

Is this the 88 pdf? Can you confirm?

 

That looks more like a Haynes manual.

You can get the FSM here. Look in Download Options. grab the "PDF" (1 big PDF)
https://archive.org/details/jeepcher...88ocr1378pages

or go here for individual sections.

https://web.archive.org/web/20110706....com/tech.html

While here, grab the Parts Manual and the Renix Fuel Injection Manual.

 

Don't know anything specific about a renix , but those numbers look acceptable....they're not race motor numbers but you probably wouldn't know the difference if they were all matched at 125.... not any reason to pull a motor apart...run a can of marvels in the oil and gas for a couple of oil changes ...see if it breaks off some crud

 

amazing thx

 

Well these numbers are at cold crancking.. tomorrow i will do the hot test again. I thought thw rings were fried but as far i see at cold they are beginning to fáil.
the co relation between the 6 cylindecyline 120psi.. the bottom of the comp spec.
​​​​​the engine has a possible blown head gasket or warped head.. tomorrow i will do a.leak down test in hot.
i hope the water over flows when i apply 100psi to confirm 100% compression into water jacket..

fingers crossed.

 

Im amazed. Your reply was extremely helpful.
Im checking the renix mpi manual and simple wow thanks.. this was a good one

Just for curiosity? Why the parts catalog?

 

Complete the set. If you need a part and don't know what it's called, you can find it here. You can search for parts online using the OEM part number. You can also verify fitment by cross referencing the OEM part number to the aftermarket one. Rockauto often lists the OEM number in the description.

I often use HTTPS://MOPARPARTSGIANT.COM to look up part numbers but the online diagrams are not complete.

 

Cool. U are right.. i m gonna buy everything from rockauto

Is it true the cps has to be Mopar to avoid problems? Just as the o2 sensor?

 

i wont do that..
Cylindr leakndown test shows rings leak.
maybe for brokwn rings or wear.never knowd
If you have stuck rings.how would you know that?

I think ill have to change the gasket and hope for the best..
oh btw im think to grind the valve seat and make and improvmnt

 

BTW
your profile says you are in Peru. What is your elevation above sea level.. feet or meters?
The higher your elevation the lower numbers you will get when you measure compression.

 

i live in the coast. So no problem with that
leak down test shows wear or stuck rings