Intermittent spark issue

[bobsxlch]

My 97 TJ, which has a 4.0 L 5 spd has an intermittent electrical issue. The jeep could be running perfectly fine, but then lose power and stall from not having spark, which I varified from the coil wire that goes to the cap with a grounded spark plug. I've tested the Crank and Cam sensor(after removing)by applying 5 volts and testing the output when introducing and removing a metal screwdriver, both tested good. The plugs, cap, rotor, wires and coil are all new... Any ideas or suggestions???

 

[Jerry Bransford]

Could be a bad ignition coil, could be a bad crankshaft position sensor. For either of those I'd try real hard to find a Mopar replacement and avoid store brands.

 

[bobsxlch]

Could be a bad ignition coil, could be a bad crankshaft position sensor. For either of those I'd try real hard to find a Mopar replacement and avoid store brands.

I had removed the sensors and tested them and the coil is new. Have you ever experienced an intermittent problem with these components? I hate just guessing and replacing components, I'd like to know or troubleshoot the root cause.

 

[Jerry Bransford]

I had removed the sensors and tested them and the coil is new. Have you ever experienced an intermittent problem with these components? I hate just guessing and replacing components, I'd like to know or troubleshoot the root cause.

The CPS can definitely still be intermittent even though it ohms out ok.

 

[bobsxlch]

The CPS can definitely still be intermittent even though it ohms out ok.

I'm gonna replace it but just for conversation sake I removed the sensor and tested it by putting 5 volts to the input wire and testing the output after flaging the pickup with a metal screwdriver. I thought this would be a more positive test. Anyhow, I'll let you know what I find. I HATE these types of problems, I'd rather see catastrophic failure of a component and know for certain. Thanks for the advice.

 

[bobsxlch]

The CPS can definitely still be intermittent even though it ohms out ok.

I replaced it and put over 15 miles on the jeep and didn't have any issues..... Time will tell if that was it but for right now, I'm happy.
THANKS!

 

[Jerry Bransford]

15 miles isn't much of a test but good luck on that being a permanent fix!!

 

[bobsxlch]

15 miles isn't much of a test but good luck on that being a permanent fix!!

You're right but before I replaced it, I couldn't go 1/2 block without having issues....

 

[Jerry Bransford]

You're right but before I replaced it, I couldn't go 1/2 block without having issues....

That's encouraging!