valve cover pcv valve?
Thread Starter
Seasoned Member
Joined: Jul 2010
Posts: 381
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From: Portland, OR
Year: 89
Model: Cherokee
Engine: 4.0 L
Hi guys! I just got my second ever xj today. Its an 89 cherokee pioneer with 130k and a nice poo/bronze/gold color. Ive named it The golden heap! It was 650 dollars and has numerous problems. First off i thought it had a death wobble but it was just a bad tire so i put the studded slightly smaller spare on...lol Good enough for now!
Biggest problem is the idle changes while running. Enough to nearly stall out. The first thing i noticed is the pcv on top of the valve cover is missing and hte hose is just mangled. Would that cause this issue other than spraying oil all over the engine? If so can someone find the part on autozone for me?
Biggest problem is the idle changes while running. Enough to nearly stall out. The first thing i noticed is the pcv on top of the valve cover is missing and hte hose is just mangled. Would that cause this issue other than spraying oil all over the engine? If so can someone find the part on autozone for me?
CF Veteran
Joined: Aug 2011
Posts: 10,489
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From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
On these they call the deal that provides Positive Crankcase Ventilation a CCV valve. (go figure) It goes on the rear of the valve cover, then the tube to the intake manifold sucks on it. The large front tube needs to be free to vent to the air cleaner.
If you scroll down from the link in my signature there are some Napa part #'s for that stuff in there somewhere. (on top is a link to Cruisers info on your geep, it's in there also) You might want to clean your IAT and TB..
Does it cycle every 20-30 sec? (slow down, almost die, surge, then repeat?) That would be a dead 02 sensor.
If you scroll down from the link in my signature there are some Napa part #'s for that stuff in there somewhere. (on top is a link to Cruisers info on your geep, it's in there also) You might want to clean your IAT and TB..
Does it cycle every 20-30 sec? (slow down, almost die, surge, then repeat?) That would be a dead 02 sensor.
Herp Derp Jerp

Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
Everything you need to know about your new Jeep, and how to fix a lot of the problems: https://www.cherokeeforum.com/f51/cruiser54s-mostly-renix-tips-153657/
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From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Renix Vacuum Harnesses
The vacuum harness that attaches to the front of the valve cover and includes the grommet/fitting, and is called the front harness, is Napa part number BK 715-1367
The vacuum harness that is closest to the air cleaner, EGR etc, and is called the rear harness, is Napa part number BK-715-1366.
The tube from the rear of the valve cover to the intake manifold is part number 715-1365.
The grommet alone for the rear is a 42088 Dorman.
Revised 09-11-2012
The vacuum harness that attaches to the front of the valve cover and includes the grommet/fitting, and is called the front harness, is Napa part number BK 715-1367
The vacuum harness that is closest to the air cleaner, EGR etc, and is called the rear harness, is Napa part number BK-715-1366.
The tube from the rear of the valve cover to the intake manifold is part number 715-1365.
The grommet alone for the rear is a 42088 Dorman.
Revised 09-11-2012
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 24
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
OK, I edited the info in my sig;
Renix Vacuum Harnesses/CCV stuff.
The vacuum harness that attaches to the front of the valve cover and includes the grommet/fitting is Napa part number BK 715-1367
The vacuum harness that is closest to the air cleaner, EGR etc, and is called the rear harness, is Napa part number BK-715-1366.
The tube from the rear of the valve cover to the intake manifold is part number 715-1365.
The grommet alone for the rear is a 42088 Dorman
Renix Vacuum Harnesses/CCV stuff.
The vacuum harness that attaches to the front of the valve cover and includes the grommet/fitting is Napa part number BK 715-1367
The vacuum harness that is closest to the air cleaner, EGR etc, and is called the rear harness, is Napa part number BK-715-1366.
The tube from the rear of the valve cover to the intake manifold is part number 715-1365.
The grommet alone for the rear is a 42088 Dorman
Thread Starter
Seasoned Member
Joined: Jul 2010
Posts: 381
Likes: 0
From: Portland, OR
Year: 89
Model: Cherokee
Engine: 4.0 L
On these they call the deal that provides Positive Crankcase Ventilation a CCV valve. (go figure) It goes on the rear of the valve cover, then the tube to the intake manifold sucks on it. The large front tube needs to be free to vent to the air cleaner.
If you scroll down from the link in my signature there are some Napa part #'s for that stuff in there somewhere. (on top is a link to Cruisers info on your geep, it's in there also) You might want to clean your IAT and TB..
Does it cycle every 20-30 sec? (slow down, almost die, surge, then repeat?) That would be a dead 02 sensor.
If you scroll down from the link in my signature there are some Napa part #'s for that stuff in there somewhere. (on top is a link to Cruisers info on your geep, it's in there also) You might want to clean your IAT and TB..
Does it cycle every 20-30 sec? (slow down, almost die, surge, then repeat?) That would be a dead 02 sensor.
Thanks for the suggestion. Tomorrow is pick n pull day at the junk yard. Just trying to come up with parts list.
It does seem like that is the issue where it cycles through idling. High and low.
Its also heaitng oddly. While driving the temperature went up nearly to redline. At a stoplight the temperature dropped. I was told there is a coolant leak from the water pump but i didnt see anything and i think its got straight water in it at the moment.
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Herp Derp Jerp

Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
The elbows on top of the valve cover are just empty elbows, no PCV valves at all. You won't find any CCV fittings at the JY worth pulling. They will explode in your hand when you try to remove them as the plastic becomes brittle with years of heat cycling.
Is your temp accurate? XJs made prior to 1997 have a separate sensor that drives the dash gauge and it notoriously goes out. It's installed at the rear of the block. You need something like an IR thermometer pointed at the thermostat housing to find the real temperature.
Straight water in Oregon?! You wanna keep driving that thing?? :O
Is your temp accurate? XJs made prior to 1997 have a separate sensor that drives the dash gauge and it notoriously goes out. It's installed at the rear of the block. You need something like an IR thermometer pointed at the thermostat housing to find the real temperature.
Straight water in Oregon?! You wanna keep driving that thing?? :O
Thread Starter
Seasoned Member
Joined: Jul 2010
Posts: 381
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From: Portland, OR
Year: 89
Model: Cherokee
Engine: 4.0 L
Those nappa part numbers arent pulling up anything for me.
This is what i found for vaccum harness though.
http://www.napaonline.com/Catalog/Ca...367_0390168068
http://www.napaonline.com/Catalog/Ca...366_0390168066
Annoying that you have to buy the whole darn thing but if one of my vaccum lines is this jacked up they are all probably due for replacement. Should i get both of these?
This is what i found for vaccum harness though.
http://www.napaonline.com/Catalog/Ca...367_0390168068
http://www.napaonline.com/Catalog/Ca...366_0390168066
Annoying that you have to buy the whole darn thing but if one of my vaccum lines is this jacked up they are all probably due for replacement. Should i get both of these?
Thread Starter
Seasoned Member
Joined: Jul 2010
Posts: 381
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From: Portland, OR
Year: 89
Model: Cherokee
Engine: 4.0 L
Lol im in portland. We dont get below freezing too often. But part of my plan is a good flush system. Is this radiator system much different from a 92? I didnt realize i was getting a renix era one and im trying to understand the differences.
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 24
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
Well...the CCV valve belongs on the rear, and the front was just an "L". That front will make a mess if it's not routed right. A free 1/2 inch tube to the air cleaner.
You want a 50/50 mix of coolant asap. The best way to drain it is to remove the E-fan with it's two little screws and pull the lower hose. The water pump has a "weep hole" where it will leak when the seal goes. Might be intermittent at first.....
Check out Cruisers stuff, check your sensor ground resistance and clean things up, (grounds). You can endlessly chase your own tail if that isn't handled.
You might save the 02 stuff for after you handle more imitate stuff. Your mileage will suck in the meantime. Idle cycleing every 20-30 secs?
It may or may not be tough to find that fitting that is not brittle and just breaks.
One more thing;
There is a brittle little tube. It comes out of a rubber plug, low on the engine side of the throttle body. It runs back to the firewall, then up to your MAP sensor sort of high up there near center on the firewall. CRUCIAL!! The MAP will tell the ECU to dump fuel with less/no vacuum. Any crack or blockage and it will be pig-rich.
You want a 50/50 mix of coolant asap. The best way to drain it is to remove the E-fan with it's two little screws and pull the lower hose. The water pump has a "weep hole" where it will leak when the seal goes. Might be intermittent at first.....
Check out Cruisers stuff, check your sensor ground resistance and clean things up, (grounds). You can endlessly chase your own tail if that isn't handled.
You might save the 02 stuff for after you handle more imitate stuff. Your mileage will suck in the meantime. Idle cycleing every 20-30 secs?
It may or may not be tough to find that fitting that is not brittle and just breaks.
One more thing;
There is a brittle little tube. It comes out of a rubber plug, low on the engine side of the throttle body. It runs back to the firewall, then up to your MAP sensor sort of high up there near center on the firewall. CRUCIAL!! The MAP will tell the ECU to dump fuel with less/no vacuum. Any crack or blockage and it will be pig-rich.
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 24
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
Thread Starter
Seasoned Member
Joined: Jul 2010
Posts: 381
Likes: 0
From: Portland, OR
Year: 89
Model: Cherokee
Engine: 4.0 L
I wish you guys were in oregon =P Well first step is im gonna go to my grandpas and try to find my manual. Gonna get an ignition cylinder and some door lock cylinders because the jeep can be started without a key... Junk yard grabs ive got so far will be rear right hand bumper cover and tail light cover and drivers seat belt buckle.
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 24
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
Renix cooling system is a "closed" system. That is an expansion bottle, should be left 1/2 empty so the air can compress.
Thread Starter
Seasoned Member
Joined: Jul 2010
Posts: 381
Likes: 0
From: Portland, OR
Year: 89
Model: Cherokee
Engine: 4.0 L
So can i cut the heater hose and put a T in there and hook a garden hose up and back flush out through that lower radiator hose? There is no radiator cap then?


