See it runs, now it doesn't? - Page 2 - JeepForum.com

Reply
 
LinkBack Thread Tools
post #16 of 24 Old 08-18-2011, 11:49 AM Thread Starter
stenyeart
Registered User
1990 YJ Wrangler 
 
Join Date: Sep 2007
Location: Lewiston
Posts: 195
I undertand that.

Here is the problem, no ground to sensors. I know this because I can check the 5 volt supply with a body ground, but not with the sensor ground in the connectors. Wiring from sensors to PCM is good. Ground supply for computer is good.

My question is, does the computer always supply the sensors with ground or does it control the ground. If it is controlled, what triggers the computer to supply ground?

stenyeart is offline  
Sponsored Links
Advertisement
 
post #17 of 24 Old 08-18-2011, 02:08 PM
Que89YJ
Web Wheeler
1989 YJ Wrangler 
 
Join Date: Apr 2008
Location: Detroit
Posts: 22,187
Pm sent call me
Que89YJ is online now  
post #18 of 24 Old 08-19-2011, 10:52 AM Thread Starter
stenyeart
Registered User
1990 YJ Wrangler 
 
Join Date: Sep 2007
Location: Lewiston
Posts: 195
After much help from Que89YJ and a few days with a DVM glued to my hand, it runs.

I ended up putting a jumper from ground to the sensor ground. This provided the ECT, TPS and IAT sensors with the ground it was missing.

I then disconnected the battery to clear the codes.

When I tried to start it, I was getting the following codes:
12 - Battery disconnected
11 - Cam or Crank Sensor
55 - End of Message

I have aleady replaced the crank sensor, so I backprobed the Cam sensor, it tested good.
At this point I decided that I was going to do the same to the Crank sensor to check for signal.

The ignition was in the on position, when I grabbed the connector for the Crank sensor, the fuel pump primed. I noticed that I could get it to cycle on if I moved the wires around. Had the wife crank the jeep while I wiggled the wires and she fired right up (the jeep, not the wife).

Once again, big thanks to Que89YJ for all the help.
stenyeart is offline  
post #19 of 24 Old 08-19-2011, 10:59 AM
dtn8tr
Registered User
1997 TJ Wrangler 
 
Join Date: Mar 2010
Location: Waconia
Posts: 1,331
Nice job...you too Que! It seems that most of the more frequent issues boil down to the crank or cam sensor.

1997 TJ, 5" IRO front with 4.5" HD IRO WJ rear, 35x12.5x15 Mickey Thompson MTZ, JKS disconnects
dtn8tr is offline  
post #20 of 24 Old 08-19-2011, 12:00 PM
Que89YJ
Web Wheeler
1989 YJ Wrangler 
 
Join Date: Apr 2008
Location: Detroit
Posts: 22,187
This is the info on the VSS you need:

VSS is the vehicle speed sensor. You have a cable that goes to the cluster but the newer 4.0L need the speed output. The later models 92-95 had a electronic cluster that receives the speed from the ECU. The 87-90 were all cable driven. The 91 YJ had a combo along with the list post on the link.
Here is a list on a post of all the vehicles that use the combo sensors that should work:
http://www.jeepforum.com/forum/f12/91-vss-any-other-vehicles-have-1095229/

Here is a links for you to read through:
http://www.jeepforum.com/forum/f12/4-0-swap-vss-connection-963222/
Que89YJ is online now  
post #21 of 24 Old 08-19-2011, 12:51 PM
Que89YJ
Web Wheeler
1989 YJ Wrangler 
 
Join Date: Apr 2008
Location: Detroit
Posts: 22,187
Que89YJ is online now  
post #22 of 24 Old 08-19-2011, 01:59 PM
oldtime_ironman
Web Wheeler
1991 YJ Wrangler 
 
Join Date: Dec 2010
Location: 14304 Niagara Falls
Posts: 2,537
Way to go guys! Ya did it!
oldtime_ironman is offline  
post #23 of 24 Old 08-19-2011, 09:31 PM
johnny27030
Registered User
1991 YJ Wrangler 
 
Join Date: Aug 2011
Location: Mt Airy
Posts: 138
Not sure about a jeep but I know on some of the later model vehicles the oil pressure switch controls the fuel pump after that initial 3 second prime. It made to shut the engine off in a crash if the engine looses oil pressure. Like I said not sure if it applies to this model Jeep or not, but if so ide check that oil pressure switch\sensor!
johnny27030 is offline  
post #24 of 24 Old 08-19-2011, 09:33 PM
johnny27030
Registered User
1991 YJ Wrangler 
 
Join Date: Aug 2011
Location: Mt Airy
Posts: 138
nevermind. Didnt see the second page of replies
johnny27030 is offline  
Reply

Tags
cps , sensor , starting problem

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Jeep Forums Replies Last Post
Runs like on 3 cyl, help if you can. a8ball YJ Wrangler Technical Forum 6 09-16-2010 07:53 AM
Engine runs rough intermittently, runs rich... Cactus737 TJ Wrangler Technical Forum 7 04-22-2010 08:40 PM
Runs Rich and Runs Rough madjeep1 YJ Wrangler Technical Forum 1 01-04-2010 11:27 AM
2.5 runs but not well labman1 YJ Wrangler Technical Forum 10 09-14-2009 04:14 AM
Cold=Runs Like Crap, Warm=Runs Good - Help! CheapSunglasses YJ Wrangler Technical Forum 9 11-24-2008 10:56 PM

Posting Rules  
You may post new threads
You may 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 On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome