Skinny

I have tested several sensors and they seem to be good On the two wires the feed the primary side of the coil I have zero Voltage on the white wire and I do get the test light to light up on the green wire when I start to crank it over for about 2 to 3 sec , I tried a ECM from a junkyard same thing happens , can I run a new 12 V key on wire to replace the white wire. Or what would you recommend

CCKen

Do you have Sentry Key Immobilizer System in your Jeep?

Skinny

I don't think so . Can you tell me how to check on that ?

CCKen

With SKIS you will have a transponder key that shaped like the one in the pic. It is grey in color whereas the non-SKIS key is black and more square in shape.

Skinny

Thanks for the pic , no I don't have SKIS

CCKen

Here's the coil diagram. Note the wire colors and where they come from. Power to the coil will only come when the PCM sees the CPS signaling engine rotation then it powers the ASD relay, which will (among other circuits) power the coil. The coil driver in the PCM will trigger the ground to the coil when the Camshaft Position Sensor in the distributor tells the PCM which spark plug to fire.


Edit: Here's the coil test procedure:



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Always visually examine the coil for cracks.







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Cam, Crank, Coil diagram:



.

Skinny

Thank you very much I will do some more testing maybe it's the CPS after all I tested it for resistance and it was within the tolerance oh what you know how it goes thanks

Skinny

THANK YOU CCKEN For your explanation of how the ignition system works and the wiring diagrams the problem was indeed The CPS change it out last night and my jeep is now running !!!

CCKen

Good work, and thanks for the follow up.


Cheers

Jamie57

Gotta love it when there is a resolution to a thread!

Skinny

Now I have another problem I'm getting code po118 coolant temp sens circuit high voltage I changed the sensor and the thermostat,didn't help the temp gauge in the dash stays at the bottom 95% of the time and the motor is A little erratic and doesn't want to idel What do you recommend next

CCKen

P0118 is usually triggered by very high resistance in the ECT circuit; similar to removing the connector from the ECT sensor and turning the ignition switch to run.


First, you should remove the connector from the sensor and see if a pin is bent or broken off in the sensor. Then examine the pin cavities in the connector for corrosion or damage to the pin cavs. See if there's any signs of corrosion on the wires coming out of the connector (corrosion inside the connector).


If everything looks okay, plug the connector back in, run the engine to get the temp up, and while someone watches the coolant temp gauge wiggle the wiring coming off the ECT sensor to see if the temp indication changes.

The ECT sensor wires goes through the plastic wiring manifold then out the back and into the wire loom near the firewall. Verify the end of the fuel rail hasn't rubbed through the loom and in to the wires. Wiggle that loom and look for changes in the temp indication.


You should be able to clear that code by disconnecting the battery NEG post connector for around 5 minutes.

Skinny

Thanks I will go through these steps and keep ya posted, thanks for the help!

Skinny

I inspected the ECT for corrosion or a bent prong everything looked fine and I did and we will test it didn't seem to affect checked out the wires were they kind of lay on the fuel rail nothing was warn through the insulation, when I trace the wire colors to the PC and it looks like to me the number 4 and number 16 is that correct ? I haven't put a meter on it yet to see what type of voltage or resistance I was getting, The gauge did start working once during all of this then right back down to 100° or lower then I took her for a drive stop to the store when I came back out and start it went right up to 10 for a minute or two and then right back down when it's in park and Idling it will almost die but then it seems to catch it self , like its making a correction do you think it would have anything to do with CSP sensor I bought it from Oreilly it is BWD ?

Skinny

Any thoughts on the above questions??