cp87xj

I have a 87 xj with 4 liter n manual trans it died yesterday and won't start now after dragging it a 1/2 mile thru the woods and into the shop I assumed it was the cps got on this morning n stuck it in still nothing. I have power to the disstriber thu the coil but no fire on the plugs. I'm still checking things but haven't found nothing else bad.

jakbob

Cps.

Parsnip

You say you aren't getting fire as in you pulled a plug and popped it onto the wire coming off the coil and grounded it, having a buddy turn the key so you could check to make sure your plugs were firing right?

cruiser54

TEST your way to a solution. start here:

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 to 3/8” from the stock 5/16”, 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 01-26-2013

cruiser54

And since it's an 87 and has this connector, which your CPS signal flows through, along with many other important ones, click on the link in my signature and go to post 2.

cp87xj

Cruiser 54 I found all ur renix tips last night after I put this up I'm in the process of going thru the list now. But I have power to the diss thru the coil wire but not to the plugs thru the distributer. I have got most all ground

cruiser54

Power as in spark through the coil wire?

You can't go wrong doing the tips recommended anyway. They'll prevent future headaches.

cp87xj

Cruiser 54 I found all ur renix tips last night after I post this I'm in the process of fixing all the grounds n cleaning all connections under the hood and gona check the cps n drill the holes on it like u said I'm cleaning grounds now

Bustedback

Did you ever pull the distributor cap off and check to see if the rotor is still in one piece? I have seen them come apart before.

cruiser54

Just drill the upper hole and test it first. Bustedback brings up a good point. That's where I was going with my question on spark at the coil wire.

cp87xj

Put new cap rotor plugs n wire on yesterday to

cruiser54

You still haven't answered our question about spark at the coil wire.

cp87xj

I don't have a buddy handy so I stuck the longest plug wire on the coil so I could c it but nothing happened when I turned on the key. I do have .5 to .6 v on the cps now

cp87xj

I've been over all the grounds under the hood. Took coil off cleaned the connection under it still no fire at the coil I have power going into the coil 12 v by a yellow wire on the 3 pin connectior and 5 v by a single yellow wire on other connectior is it supposed to have 12 v on it to I haven't found much of anything on the ignition in my repair manual

cp87xj

Does anybody know where to check the signal coming from the cps to the ecm going to the icm I think my computer took a crap but don't wanta buy one till I know for sure