john.monteith79

I know there are lots of threads on this topic and I have searched most of them, which is how I got the idea to replace the stuff I have replaced but now I have hit a wall and dont know what else to do.

I have a 1990 Cherokee Pioneer 4.0. For a while now it has been stalling on me and I would have some trouble starting it back up. Now it wont start at all. I've replaced plugs, wires, distributor, distributor cap, rotor, coil, ignitor, and now the crank position sensor. Still no spark.

Please please please con someone help?
Im starting to drive myself crazy.
Thanks

caged

it could be, but unlikely, the pick up coil a.k.a. camshaft sensor.
on our renix, it's in the distributor. but you'll have to pull the dizzy to get to it.

another cheap possibility is the ceramic ballast resistor on the drivers inner fender.

cruiser54

Inside the dizzy on our Renix Jeeps is a sync generator, not a pickup coil or cam sensor. It controls ONLY the sequential firing of the injectors and if unplugged or defective will not keep the Jeep from running. This is unlike the 91 and later models where the sensor inside the dizzy is defective, the Jeep will not run.

Even though the CPS has been replaced, they are many times defective out of the box. The problem is their signal is too weak to trigger the eCU. At this point it is best to verify the CPS output using the following instructions before proceeding.

Renix CPS Testing and Adjusting
　
　
Renix CPSs have to put out a strong enough signal to the ECU so that it will provide spark.
Most tests for the CPS suggest checking it for an ohms value. This is unreliable and can cause some wasted time and aggravation in your diagnosis of a no-start issue as the CPS will test good when in fact it is bad.
The problem with the ohms test is you can have the correct amount of resistance through the CPS but it isn’t generating enough voltage to trigger the ECU to provide spark.
Unplug the harness connector from the CPS. Using your voltmeter set on AC volts and probing both wires in the connector going to the CPS, crank the engine over. It won’t start with the CPS disconnected.
You should get a reading of .5 AC volts.
If you are down in the .35 AC volts range or lower on your meter reading, you can have intermittent crank/no-start conditions from your Renix Jeep. Some NEW CPSs (from the big box parts stores) have registered only .2 AC volts while reading the proper resistance!! That’s a definite no-start condition. Best to buy your CPS from Napa or the dealer.
Sometimes on a manual transmission equipped Renix Jeep there is an accumulation of debris on the tip of the CPS. It’s worn off clutch material and since the CPS is a magnet, the metal sticks to the tip of the CPS causing a reduced voltage signal. You MAY get by with cleaning the tip of the CPS off.
A little trick for increasing the output of your CPS is to drill out the upper mounting hole, or slot it so the CPS bracket rests on the bell housing when pushed down. Then, when mounting it, hold the CPS down as close to the flywheel as you can while tightening the bolts.

　
　
Revised 07-30-2012

john.monteith79

Im not getting any spark from the ignition coil. Could it still be the pickup coil??

123456bmx

Follow the crank position sensor wire to the connector,and blow into it like a nintendo 64.renix's are picky about clean connectors.Clean as many connections as possible.

F1Addict

It could be a failure in any of the components you've mentioned but diagnosing these things is a process that starts with your CPS so test it following Cruiser's instructions and let us know what you find, we'll go from there.

BearMBD

Lately I have a problem with the neutral safety switch. The jeep was acting as if it was not getting spark. If you move the gear shift to any other position and back to park it it starts. Not saying that is your problem just something easy to consider

cruiser54

There's a difference. There is "no crank" like you got with the bad NSS, and there's "crank-no start" like the OP's problem where the engine spins over but does not start.

cruiser54

Read the first part of Post #3.

atom89xjlmt

Try changing the ignition switch that is boltedto the column. I was having similar issuses about a week ago and found out the switch was arching out inside of the housing.

F1Addict

This is the first I've ever heard of an ignition switch causing a crank-no-start situation. Again, test your CPS according to Cruiser's instructions in post #3. I'll keep writing that until it gets done :P

atom89xjlmt

Yeah I was having the same issues about a month ago and you and cruiser helped me alot. I changed all the stuff you guys said and work for amonth and then it actef up on me again. It died four times on my way home and then wouldnt start again. So i started looking at other places and decided to check the ignition switch out and noticed it was arching out inside and also the plug was starting to melt were the connection is.

cruiser54

Here's a pic of the ignition switch when it "arcs out" but we still need to get a CPS reading in the OP's case.

john.monteith79

I will test out the CPS and blow into the plug on Wednesday. I had to work today and have to work tomorrow. Thanks for the ideas and I will let you know what happens.

Thanks

john.monteith79

Tested the CPS today and it looks good. Also blew into the connection and plugged it back in. Still no start. Any other suggestions? I losing my mind.