NAXJA Forums -::- North American XJ Association  

Go Back   NAXJA Forums -::- North American XJ Association > NAXJA Unibody Jeep Technical Forums > Jeep Cherokee XJ (1984 - 2001) > OEM Tech Discussion
HOME Member FAQ Sponsor Info Rules Bylaws E-Mail

OEM Tech Discussion Forum for OEM (Original Equipment) or stock XJs and MJs.

Reply
 
Thread Tools Display Modes
  #1  
Old January 26th, 2005, 14:44
LuckysHunter LuckysHunter is offline
On a Time Out
 
Join Date: Jan 2005
Location: Phoenix, AZ
Posts: 1
Crankshaft Position Sensor on '88

What kind of voltage and resistance should be coming out of this? Also, when replacing the flexplate, there's a spacer/washer type thing; does that go on the engine side or the tranny side of the flexplate?
Reply With Quote
  #2  
Old January 26th, 2005, 14:50
XJade XJade is offline
NAXJA Forum User
 
Join Date: Oct 2003
Location: 87XJ_4L-Automatic, Arizona
Posts: 248
Re: Crankshaft Position Sensor on '88

For the CPS part of the question:

http://www.naxja.org/forum/showthread.php?t=45376
Reply With Quote
  #3  
Old January 26th, 2005, 14:58
XJade XJade is offline
NAXJA Forum User
 
Join Date: Oct 2003
Location: 87XJ_4L-Automatic, Arizona
Posts: 248
Re: Crankshaft Position Sensor on '88

I got the following from a website about sensor diagnostics before the site became a dead link. Good thing I saved it to my harddrive for future reference.

Test#1 - Get a volt/ohm meter and set it to read 0 - 500 ohms. Unplug the cps and measure across the CPS leads, the CPS should measure aprox. 275 +/- ohms. If it's off by much, replace it.

Test#2 - You'll need a friend to help ya with this one.
Set your volt/ohm meter to read 0 - 5 AC volts or the closest AC Volts scale your meter has to this range. Measure across the CPS leads for voltage generated as your friend cranks the engine. (The engine can't fire up without the CPS connected but watch for moving parts just the same!) The meter should show .5 - .8 VAC when cranking. (That's between 1/2 and 1 volt AC.) If it's below .5vac, replace it.
Reply With Quote
  #4  
Old January 27th, 2005, 06:59
Eagle's Avatar
Eagle Eagle is offline
Lifetime NAXJA Member
 
Join Date: May 2002
Location: Terra Firma
Posts: 10,019
Re: Crankshaft Position Sensor on '88

The reinforcing ring goes on the transmission side of the flexplate.
__________________
Eagle - Lifetime Member

Owner/Driver/Enabler of "The Fleet"
Self-appointed President-for-Life of the World MJ Preservation Society
Reply With Quote
  #5  
Old January 27th, 2005, 10:15
old_man's Avatar
old_man old_man is offline
NAXJA Member
 
Join Date: May 2003
Location: Loveland, Colorado
Posts: 15,835
Re: Crankshaft Position Sensor on '88

Also be careful to get the right flex plate. The Renix and HO engines use a different flexplate. They both will fit but the pattern of notches on the sensor ring are different and they are not interchangable.
__________________
Tom Houston - Former Colorado Chapter President, current Treasurer , Terminal Adrenaline Junkie, and Rocket Scientist
Loveland, Colorado My teardrop build
You're just jealous because the voices don't talk to you.
Reply With Quote
  #6  
Old February 1st, 2005, 08:46
Don Becker Don Becker is offline
NAXJA Forum User
 
Join Date: Apr 2003
Location: Beaverton, Oregon
Posts: 194
Re: Crankshaft Position Sensor on '88

[/QUOTE]Test#1 - Get a volt/ohm meter and set it to read 0 - 500 ohms. Unplug the cps and measure across the CPS leads, the CPS should measure aprox. 275 +/- ohms. If it's off by much, replace it.

Test#2 - You'll need a friend to help ya with this one.
Set your volt/ohm meter to read 0 - 5 AC volts or the closest AC Volts scale your meter has to this range. Measure across the CPS leads for voltage generated as your friend cranks the engine. (The engine can't fire up without the CPS connected but watch for moving parts just the same!) The meter should show .5 - .8 VAC when cranking. (That's between 1/2 and 1 volt AC.) If it's below .5vac, replace it.[/QUOTE]

I tried this on my '88XJ Limited last night. The engine runs fine otherwise but has this annoying momentary cut-out . . . it'll idle at just under 1000 rpm for a varied period of time and then, basically, just die, momentarily (severe drop in rpm) . . . most of the time, it then continues running. it never fails to start and ahs no "high-rev." When this condition was at its worst, I did the disconnect/wiggle-the-connection-around/re-connect at the CPS plug and it got noticeably better but did not entirely "cure" the problem. The CPS in there is a high altitude CPS and probably has less than 6000 miles on it. The engine ran fine for some, say, 5800 of those miles before this problem arose. There is no wire contact with the manifold, etc.

When I ran the test above, I got no resistence at all with test #1 and no voltage at all with test #2 ...................... yet, the engine runs?????

Don
Reply With Quote
  #7  
Old February 2nd, 2005, 07:11
Don Becker Don Becker is offline
NAXJA Forum User
 
Join Date: Apr 2003
Location: Beaverton, Oregon
Posts: 194
Re: Crankshaft Position Sensor on '88

'Anyone got an idea or two for me? Thanks! Don
Reply With Quote
  #8  
Old February 2nd, 2005, 13:17
XJXJ's Avatar
XJXJ XJXJ is offline
NAXJA Forum User
 
Join Date: Jan 2005
Location: SW_USA
Posts: 360
Re: Crankshaft Position Sensor on '88

When I ran the test above, I got no resistence at all with test #1 and no voltage at all with test #2 ...................... yet, the engine runs?????

'Don't think your test is/was accurate. The engine will not run without CPS signal. To see for yourself, with the engine running, unplug the CPS connector.

Are you experienced with a DVM/meter? There's gotta be 200-300 ohms across the CPS. The signal voltage test is hit/miss because of potential loading of the meter. But, the ohm test should at least be in the accepted range. That connector isn't very good IMO. I finally just hardwired the damn thing into the harness and my CPS troubles have gone away.

My Renix sometimes "hunts" for idle. To prevent the engine from dying in traffic when it does, adjust the throttle plate for a minimum hot idle speed of around 600 RPM with IAC fully closed. After that, adjust the TPS to account for the new TPS idle position reference.

There are a couple of ways to force IAC closed -

1) Engine running, pull small vacuum hose like the EGR, engine speed will climb and then should try to fall back down to normal in a few moments. This lets you know the ECU/IAC is working. Next, pull the brake vacuum hose and once idle doesn't reduce anymore it's pretty safe to assume the IAC is fully closed. Unplug the IAC, reconnect vac hoses and adjust throttle butterfly for around 600 RPM hot.

2) the other method is to pull the IAC off the TB and gently pull the pintle out far enough to seal-off the port. Re-install and leave it unplugged while you do the throttle plate adjustment for base hot idle.

Perform the regular TPS adjustment and you should be good with the idle speed dipping while Renix decides what it wants to do next. Explore your CPS measurement procedure because I don't think you are getting the results you should be getting.

Last edited by XJXJ; February 2nd, 2005 at 13:20. Reason: Tidy it up...
Reply With Quote
  #9  
Old February 2nd, 2005, 16:43
Don Becker Don Becker is offline
NAXJA Forum User
 
Join Date: Apr 2003
Location: Beaverton, Oregon
Posts: 194
Re: Crankshaft Position Sensor on '88

No, I'm not that experienced w/testing resistance. I'll try to get back to that XJ, and do some of the checking you suggest, this weekend. I appreciate the help! Don
Reply With Quote
  #10  
Old February 3rd, 2005, 13:49
Greg Smith Greg Smith is offline
Jeep addict
 
Join Date: Mar 2003
Location: Spotsylvania, Virginia
Posts: 212
Re: Crankshaft Position Sensor on '88

Here is some info I have posted in the past:

If on a crank but no start the unplug and replug of the cps wire harness connector gets you going you may just have a wire harness connector going bad and may not need to replace the cps sensor. Here is how to test: hook volt meter to both wires from cps sensor w. harness unplugged. Set the range on meter to less than one volt. Crank engine and if cps generates .5 to .8 or more volts it is ok and your connectors need tightening or replacing. I got my parts for a couple of $ at pepboy but advanceauto.com also has them. They were made my Dorman under the Motormite Conductite tech grad name # 85303, 85304 and 85305. There are about 5 pieces in each box. You can also get a small tool set that helps on the install number 85360. I fixed my 89 this way a couple of months ago when I got tired of unplugging and replugging the connector every few weeks. My cps was only 1 yr old so the engine side harness connector part was worn out. I replaced both the female and male side internals of the connectors and it not only starts every time but the idle was also improved.

Greg
Reply With Quote
  #11  
Old April 11th, 2006, 11:05
The Federation The Federation is offline
NAXJA Forum User
 
Join Date: Apr 2006
Location: Palatka, Fla
Posts: 33
Re: Crankshaft Position Sensor on '88

Another CPS issue here but same thought. I read on Autozone that you can check the opposite side of the connector and from mid pin to one side you should have 5 volts the other side should be zero. On the zero side with the engine cranking over the zero side should flucuate between 5 and 0. Has anyone ever heard of this? if so here is a follow up question I tried this test and I get the 5 volts on on both side of center pin with no flucation during cranking , any ideas?
By the way mine is a 98 xj
Reply With Quote
  #12  
Old April 11th, 2006, 14:20
theMJ6000 theMJ6000 is offline
NAXJA Forum User
 
Join Date: Apr 2004
Location: Wisconsin
Posts: 23
Re: Crankshaft Position Sensor on '88

Did you resolve the issue? I have been trying to narrow down the same symptoms you are experiencing on my '88, although, sometimes mine dies at idle and it seems to happen for the first few minutes of startup and is less troublesome when the engine is hot. I would love to replace all of my sensors and vaccuum hoses to fix this issue, but why do they cost so much?
I do have a link for you which has info on all of the sensors. http://www.lunghd.com/Tech_Articles/...iagnostics.htm
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Camshaft position sensor help! Phil OEM Tech Discussion 8 October 12th, 2007 18:04
Throttle position sensor for 4.0 non high output joe88xj For Sale: Private Party Only. XJ ITEMS ONLY 9 January 24th, 2005 17:28
how do I find and dry out my throttle position sensor on 90 xj lapaul OEM Tech Discussion 5 December 22nd, 2004 08:10
CPS (Crankcase Position Sensor) - HELP! XJ-wrecks OEM Tech Discussion 13 September 15th, 2004 12:52
231 X-fer Case position switch Aloha365 Modified Tech Discussion 4 January 4th, 2004 09:26


All times are GMT -7. The time now is 04:44.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
NAXJA and NAXJA logo's Copyright NAXJA. All content/images Copyright NAXJA 1999-2014