What is this for???? - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > YJ Jeep Wrangler Forum > YJ Tech Forum

Join Wrangler Forum Today


Like Tree4Likes
  • 1 Post By Luckymac
  • 2 Post By MoabCarl
  • 1 Post By Luckymac
Reply
 
Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 12-10-2019, 07:27 PM
Thread Starter
  #1
Newb
 
Join Date: May 2019
Posts: 13
What is this for????

I found this unplugged and I do not what it is for. It is located on the passenger side at the rear of the motor. It is a 4.2.

Thanks in advance.

Attached Thumbnails
Click image for larger version

Name:	7D738319-0924-4FF9-8966-295D8BFBE89C.jpg
Views:	20
Size:	211.6 KB
ID:	4189689  
Barberm is offline   Quote
Old 12-10-2019, 07:48 PM   #2
Jeeper
 
8thtimer's Avatar
 
Join Date: Oct 2019
Location: White mountains of AZ
Posts: 239
Looks like the oil pressure sending unit.

8thtimer is offline   Quote
Old 12-10-2019, 07:56 PM
Thread Starter
  #3
Newb
 
Join Date: May 2019
Posts: 13
Quote:
Originally Posted by 8thtimer View Post
Looks like the oil pressure sending unit.
My oil pressure gauge is working great though,
Barberm is offline   Quote
Sponsored Links
Advertisement
 
Old 12-10-2019, 09:02 PM   #4
Jeeper
 
Rudys88's Avatar
 
Join Date: Mar 2014
Location: Denton, Texas
Posts: 52
I believe its the oil pressure switch. Different than the sending unit.
__________________
____________________________________________
'88 Wrangler 4.2L with famous BA-10 trans, 31" Kelly Safari's, 2" body lift, Carter/Crown BBD.

But a constitution of government once changed from freedom can never be restored. Liberty, once lost, is lost forever.John Adams
Rudys88 is offline   Quote
Old 12-10-2019, 09:13 PM   #5
Jeeper
 
Gottagofast's Avatar
 
Join Date: May 2017
Posts: 8,447
You can actually see the oil pressure sender in that pic too....

EDIT.... oops, I coulda sworn you said 4.0....
Luckymac got ya....
__________________
I come in peace.... I mean you no harm
Currently in the stable: ... 97 tj 4.0 5 speed stock....04 tj 4.0 auto 4" and 33's... 98 tj roller for future build... 94 yj sahara 4.5" RE and 33's... 92 yj sbc 3/4 ton axles and 38's... Cj5,7,yj,xj,ex mud dragster project

TJ dash speakers that actually rock! Kicker sub and amp in center console
Gottagofast is offline   Quote
Old 12-11-2019, 12:21 AM   #6
Moderator

WF Lifetime Member
WF Supporting Member
::WF Moderator::
 
Luckymac's Avatar
 
Join Date: Jan 2014
Location: SouthEast of Denver
Posts: 9,547
It's an electric choke switch. It closes with oil pressure (per the 1988 Factory Service Manual for carburetor circuits.

If your jeep starts and runs well, disregard it.

Good Luck, L.M.
Barberm likes this.
__________________
"Wrangler....It's not just a vehicle, It's a lifestyle".
.................................................. ........................
1987 YJ-4.2L-Standard Shift- Re-manufactured Carter Carb-2" body Lift-31X10.5X15 BFG KOs-190K Miles No back seat.
HEI distributor with computer and all related relays and wiring removed.
12K Badlands winch with dual batteries.
Warn front bumper. Matching imitation Warn bumper on the rear.
Luckymac is online now   Quote
Old 12-11-2019, 10:37 AM
Thread Starter
  #7
Newb
 
Join Date: May 2019
Posts: 13
Quote:
Originally Posted by Luckymac View Post
It's an electric choke switch. It closes with oil pressure (per the 1988 Factory Service Manual for carburetor circuits.

If your jeep starts and runs well, disregard it.

Good Luck, L.M.
You are awesome.

It runs well, but is a bitch to start. When I get home in a few weeks Ill hook it up and see if it makes a difference.

Thank you
Barberm is offline   Quote
Old 12-11-2019, 11:18 AM   #8
Jeeper
 
MoabCarl's Avatar
 
Join Date: Jan 2019
Location: Metro Detroit MI
Posts: 691
It is the self destruct switch. Do not plug it in!
Barberm and OldBarn like this.
__________________

Red Rock 4-Wheelers EJS Trail Gunner
2001 TJ 4.0 Auto
2007 JKU LS3, PR60s, too much to list....
2012 JKUR bone stock
2018 Tacoma TRD Off-Road
MoabCarl is offline   Quote
Old 12-11-2019, 04:42 PM   #9
Moderator

WF Lifetime Member
WF Supporting Member
::WF Moderator::
 
Luckymac's Avatar
 
Join Date: Jan 2014
Location: SouthEast of Denver
Posts: 9,547
Find a post by Got it at last. In his signature there's a free link to several Factory Service manuals and a couple Factory Parts Manuals.
Open that link and click on the manual that you need.
In the 4.2 engine section of the FSM, you'll find the carburetor section and there will be instructions on how to set the choke.

Your fuel filter should be mounted with the smaller outlet to the fuel return line on top, at 12 o'clock.

If your Jeep starts up easily once it's been running, but has to crank for several seconds or more after it's sat for a couple days, you can add a one way valve as shown in the pics.
The pic shows a plastic one way valve, but the metal ones seem to last longer. Google "gasoline one way valve".

Pic 1- is the wrong way to mount the filter (overflow to 6 o'clock, and no one way valve.

pics 2&3 show the correct mounting position.

Good Luck, L.M.
Attached Thumbnails
Click image for larger version

Name:	DSCF0081.jpg
Views:	8
Size:	238.4 KB
ID:	4189931   Click image for larger version

Name:	DSCF0625.jpg
Views:	8
Size:	235.5 KB
ID:	4189933  

Click image for larger version

Name:	DSCF0624.jpg
Views:	8
Size:	230.2 KB
ID:	4189935  
Barberm likes this.
__________________
"Wrangler....It's not just a vehicle, It's a lifestyle".
.................................................. ........................
1987 YJ-4.2L-Standard Shift- Re-manufactured Carter Carb-2" body Lift-31X10.5X15 BFG KOs-190K Miles No back seat.
HEI distributor with computer and all related relays and wiring removed.
12K Badlands winch with dual batteries.
Warn front bumper. Matching imitation Warn bumper on the rear.
Luckymac is online now   Quote
Old 12-12-2019, 12:27 AM
Thread Starter
  #10
Newb
 
Join Date: May 2019
Posts: 13
Quote:
Originally Posted by Luckymac View Post
Find a post by Got it at last. In his signature there's a free link to several Factory Service manuals and a couple Factory Parts Manuals.
Open that link and click on the manual that you need.
In the 4.2 engine section of the FSM, you'll find the carburetor section and there will be instructions on how to set the choke.

Your fuel filter should be mounted with the smaller outlet to the fuel return line on top, at 12 o'clock.

If your Jeep starts up easily once it's been running, but has to crank for several seconds or more after it's sat for a couple days, you can add a one way valve as shown in the pics.
The pic shows a plastic one way valve, but the metal ones seem to last longer. Google "gasoline one way valve".

Pic 1- is the wrong way to mount the filter (overflow to 6 o'clock, and no one way valve.

pics 2&3 show the correct mounting position.

Good Luck, L.M.

That is exactly my problem. Thank you very much for the info. When I get home this is the first thing Ill be doing.
Barberm is offline   Quote
Old 12-12-2019, 01:11 AM   #11
Jeeper
 
Gottagofast's Avatar
 
Join Date: May 2017
Posts: 8,447
Seems to me that the check valve should be on the inlet side of the filter not the return line...
__________________
I come in peace.... I mean you no harm
Currently in the stable: ... 97 tj 4.0 5 speed stock....04 tj 4.0 auto 4" and 33's... 98 tj roller for future build... 94 yj sahara 4.5" RE and 33's... 92 yj sbc 3/4 ton axles and 38's... Cj5,7,yj,xj,ex mud dragster project

TJ dash speakers that actually rock! Kicker sub and amp in center console
Gottagofast is offline   Quote
Old 12-12-2019, 02:27 AM   #12
Moderator

WF Lifetime Member
WF Supporting Member
::WF Moderator::
 
Luckymac's Avatar
 
Join Date: Jan 2014
Location: SouthEast of Denver
Posts: 9,547
A couple or few years ago another poster discovered in the FSM that there's supposed to be a check valve in the fuel return line where the rubber hose connects to the metal line that runs back to the fuel tank.
Through the course of years, when the fuel filter gets changed, the tiny check valve gets discarded along with the old rubber hose.
The check valve is no longer available.

The other poster speculated that with the check valve missing, the fuel in the fuel bowl gets sucked back into the tank over the course of a couple days. With an empty fuel bowl,it takes a few seconds of cranking to fill the bowl and get fuel into the cylinders.

The aftermarket check valve (one way valve) is normally closed. It takes a certain amount of pressure from the feed side or vacuum from the tank side to open the valve.
I'm guessing that any vacuum caused by cooling gasoline or whatever reason isn't enough to overcome the normally closed valve.
When I first installed a plastic valve, it cured my "hard start after two days". The plastic check valve worked fine for a few months and then quit.
I bought a pack of metal check valves, but they don't appear to have a strong enough check valve spring to resist the vacuum generated in the tank.

When the other poster (I don't remember his name) discovered this, there were several threads with titles like "Hard start after two days".
With 4.2s becoming scarce there are fewer and fewer threads with questions about carbs and related problems.

Good Luck, L.M.

__________________
"Wrangler....It's not just a vehicle, It's a lifestyle".
.................................................. ........................
1987 YJ-4.2L-Standard Shift- Re-manufactured Carter Carb-2" body Lift-31X10.5X15 BFG KOs-190K Miles No back seat.
HEI distributor with computer and all related relays and wiring removed.
12K Badlands winch with dual batteries.
Warn front bumper. Matching imitation Warn bumper on the rear.
Luckymac is online now   Quote
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off






All times are GMT -5. The time now is 09:50 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.1
User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.

Jeep, Wrangler, Liberty, Wagoneer, Cherokee, Gladiator, Mopar and Grand Cherokee are copyrighted and trademarked to FCA US LLC.
Wranglerforum.com is not in any way associated with FCA US LLC.