How do Iset my timing on my Jeep? - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Grand Cherokee & Commander Forums > ZJ Grand Cherokee Forum > How do Iset my timing on my Jeep?

Component speaker deal for your dash - NalinMFGIntroducing MONSTALINER™ UV Permanent DIY Roll On Bed LineSteering and more from Ruffstuff!

Reply
Unread 08-31-2007, 01:36 PM   #1
02Lightning
Registered User
1995 ZJ 
 
Join Date: Dec 2005
Location: Dayton, OH.
Posts: 553
How do Iset my timing on my Jeep?

I know how to set it but is there something you disconnect to set base timing?

__________________
1995 Jeep Grand Cherokee Limited 4.0L NP249 Transfer Case, 42RE, 206,000 miles
02Lightning is offline   Reply With Quote
Unread 08-31-2007, 02:27 PM   #2
rm2001wj
Web Wheeler
 
rm2001wj's Avatar
2001 WJ 
 
Join Date: Aug 2005
Location: Memphis, TN
Posts: 3,083
I'm pretty sure that the "base" timing is programmed into the PCM and there is nothing much you can do about it. The PCM adjusts the timing, as needed, based on various sensor inputs and its programming. Timing adjustments different from those produced by the PCM can be made by intercepting the CPS signals, making changes, and then sending them on to the PCM. Also it's possible to intercept the PCM signal going to the coil and then add a delay.

What are you thinking about doing?
__________________
2001 WJ Limited with Quadra-Drive, Kenne Bell Supercharger, 3-inch Kolak exhaust, Stillen rotors (F/R) and MM pads, Addco sway bars (F/R).

Last edited by rm2001wj; 08-31-2007 at 02:38 PM..
rm2001wj is offline   Reply With Quote
Unread 09-01-2007, 03:32 PM   #3
02Lightning
Registered User
1995 ZJ 
 
Join Date: Dec 2005
Location: Dayton, OH.
Posts: 553
Make sure my base timing is set. I know on a 88 mustang I use to have you would pull a plug to get base timing. I know on early 90's GM cars you had to jump a plug under the dash. I want to put a timing light on my jeep and see where base timing is and adjust it if needed. I'm about 95% sure you can change your base timing on a jeep. All you have to do is move the distributor, I just want to be sure I'm looking at base timing with no advance and I need to know how to eliminate the advance before I mess with it.
__________________
1995 Jeep Grand Cherokee Limited 4.0L NP249 Transfer Case, 42RE, 206,000 miles
02Lightning is offline   Reply With Quote
Unread 09-01-2007, 03:43 PM   #4
UltimatE
Resident Audio Guru
 
UltimatE's Avatar
1994 YJ Wrangler 
 
Join Date: Sep 2004
Location: Worcester, Mass
Posts: 7,035
Putting a timing light on your engine will tell you where your timing stands as it is right now. Compare that to what the manual says should be the correct timing for your engine.
__________________
-Matt

White '94 YJ Sport
Black '98 ZJ Laredo - 45x60 Surco Rack - 2" Budget Boost, Addco Front Swaybar

Project (s)Low - A build log.
UltimatE is offline   Reply With Quote
Unread 09-01-2007, 04:40 PM   #5
rm2001wj
Web Wheeler
 
rm2001wj's Avatar
2001 WJ 
 
Join Date: Aug 2005
Location: Memphis, TN
Posts: 3,083
The camshaft position sensor is in the distributor and its signal is used for timing the injector pulses. If you try to move the distributor from its factory position the injector timing gets messed up. Also, the cam position sensor is used to tell the PCM which cylinder is #1. As I mentioned earlier, the crankshaft position sensor is used for ignition timing. It's possible to ream out the bolts holes and move it a little for a minor timing adjustment. Usually the CPS is so hard to get to that hardly anyone would try that.

Still, let us know if you have any success.
rm2001wj is offline   Reply With Quote
Unread 09-01-2007, 06:33 PM   #6
02Lightning
Registered User
1995 ZJ 
 
Join Date: Dec 2005
Location: Dayton, OH.
Posts: 553
Quote:
Originally Posted by rm2001wj
The camshaft position sensor is in the distributor and its signal is used for timing the injector pulses. If you try to move the distributor from its factory position the injector timing gets messed up. Also, the cam position sensor is used to tell the PCM which cylinder is #1. As I mentioned earlier, the crankshaft position sensor is used for ignition timing. It's possible to ream out the bolts holes and move it a little for a minor timing adjustment. Usually the CPS is so hard to get to that hardly anyone would try that.

Still, let us know if you have any success.
Maybe I stand corrected, sounds like I can't move the distributor like old school cars then?
__________________
1995 Jeep Grand Cherokee Limited 4.0L NP249 Transfer Case, 42RE, 206,000 miles
02Lightning is offline   Reply With Quote
Unread 09-01-2007, 06:35 PM   #7
greasefingers
Registered User
1994 ZJ 
 
Join Date: Sep 2003
Location: Northern VA, USA, NJ
Posts: 8,237
Correct the distributor does not rotate
__________________
Cheers Steve

94 Black Laredo 4-Liter with QuadraTrac (42RE trans & NP249 TC) 200,000 + miles purchased new

88 Cherokee 2-door with 5speed manual 139K miles(deceased) purchased new
greasefingers is offline   Reply With Quote
Reply
Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.