I pulled my carpet to do floor pans and now i have no spark when trying to start. Its an 87 comanche with a 4.0. Really need help quick

 

First thing I'd do after checking for any plugs or wires you might have bumped in the process.

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

 

"Do floorpans".

Did you cut through some wires? Unplug or jostle something?

 

We just checked the cps and coil. Both tested fine. Checked everything under the dash and it all looks ok.

 

Did you replace the floors yet?

 

We just checked the cps and coil. Both tested fine. Checked everything under the dash and it all looks ok.

 

Sorry. Posted twice i guess. Im a newb haha. yes the floors are done

 

Come to think of it... I never disconnected the battery when i was welding. What are the chances i fried something?

 

HOW did you test the CPS?

Got spark yet?

 

I tested the cps by using the steps described above. And no i dont have spark yet. I think i narrowed it down to the coil pack though

 

Zzzzzzzzzzzzzttttttttttttttt!

 

I had a 90 Cherokee, that I pulled in my driveway, and would not start. I checked everything including coil, and it came back good. Well I was at my whits end. Finally bought a new coil, and that's what it was, even though it checked good. Another thing is the icm below the coil, but coil is cheaper to replace. I've only seen one icm go bad since I have been into jeeps.

 

I don't like the sound of that. Not that I have the experience to say much, but just curious, where did you ground the welder?

 

See post #11. Electricity takes the path of least resistance. In this case, could have been the coil pack.

 

Im guna replace the coil first and see if that solves anything. I have power all the way up to it. So thats what I'm going start with.

When i was doing the floor pans, i grounded to the seat mounting studs.

Lesson learned. This lesson is guna cost me though.

Thanks for the help guys!