Jabo

I have a 89 xj that Ive put plugs plug wires dis.cap and rotor button on trying to get rid of a skip (miss) Its not doing it all the time its doing it spuratically.It reminds me of a sensor going out Are there any way to pull codes out of the ecm to see what is going bad that needs to be replaced.

BlueXJ

'89 is a Renix thus no stored codes. You can check the cam position sensor in the dizzy. It is not hard to check but if it needs to be replaced the dizzy has to be removed. I just explained that proceedure on here a week or so ago. But will try to outline it again. I have that stored on my 'puter.
Stator Test Procedure
Sync Pulse (Stator) Test: Do NOT disconnect your "distributor" to do this test! Backprobe the connectors by inserting the voltmeter's probes into the connector where the wires enter the connector from the distributor or harness! You'll have to make sure that you have good contact but it's not hard to do... the connector MUST remain connected to do these tests!

RENIX TEST PROCEDURE
1-Insert + voltmeter lead into BLUE wire at distributor connector.
2-Insert negative - lead into Gray W/trace wire at dist connector.
3-Set voltmeter to 15vac, turn key on & should show approximately 5.0volts.
4-If there is no voltage present - double check the backprobed leads to ensure good contact.
5-If there is STILL no voltage present; the Factory Service Manual says you need to "Perform vehicle test using DRB II tester. I don't have one. You don't either.
6-At this point, If you DO have voltage then remove / disconnect the ECU (computer).
7-Check continuity between the Blue wire and C-16 at the ECU. - If no continuity: repair harness wire.
8-Check continuity between Gray W/trace and pin C-5 at the ECU. - If no continuity: repair harness wire.
9-Check continuity between Black wire and "ground". - If no continuity: repair harness wire.
8-While observing analog voltmeter (That's one with a needle, folks! Your average digital meter won't show this...) crank engine & voltmeter needle should fluctuate back & forth while engine is cranking over. This confirms stator in distributor is 'pulsing' correctly and sending signal out for ECU.
10-If there is no sync pulse you will have to replace the stator by removing and dissassembling the "distributor" following the service manual procedure. * - Helpful Hint: Before pulling your distributor... "bump" the engine until the rotor is pointing straight forward and aligned with the side of the engine. That way you'll know where the rotor needs to end up pointing after reassembly.


WARNING!: The term CPS is most often used to describe the CRANKshaft position sensor! Be SURE to ask for the correct sensor! Both the crank and cam position sensors work together feeding the ECU (computer) information on the engine timing to fire the injectors and maintain engine timing. In the case of the Jeep 4.0L engine: the CAMshaft position sensor is also called the 'sync pulse generator' (or stator) and can be found in the "distributor" while the CRANKshaft position sensor is located on the transmission bellhousing.

Jabo

thx blue

BlueXJ

Hope that helps you solve your miss/skip Jabo.

xj4life2

You might also try this link , alot of good info there :
http://www.lunghd.com/Tech_Articles/...iagnostics.htm
Sounds like a o2 sensor gettin' jiggy

Jabo

Drove it home Yesterday and made it about 10 mi.from the house ,It went to popping out the throttle body so I'm thinking that the cam pos. sensor went out in the dis.After I got it home tryed to get it to start to pull into the garage it wouldn't start all it would do it back fire threw the throttle body

BlueXJ

Jabo you might consider looking at the timing chain too. That may be so worn as to cause a loss of timing especially when warm.

Jabo

Thanks every one. After replacing things that were evidently starting with the dis. moving on to the C.P.S and then to the timing set finally had to pull the valve cover to find the problem who would ever thought that a lifter would go out while driving down the rood not letting the exhaust valve to open .Thanks again every one.

BlueXJ

Would have thought that would have been more constant not just worse when hot. Anyway glad you found it and got your Jeep running right again.