Weak Spark

[caseyrstewart]

Hi Everyone,

 

Was hoping to get some advice on a no start condition for my 4.0 87 Jeep Comanche. It died on me the other day while driving through a parking lot. Here's what has been done.

 

-CPS is only 3 months old and has been checked with a voltmeter (215 Ohms and 4 volts while cranking)

-Replaced the fuel pump relay

-Checked pump with fuel pressure gauge (pump is working)

-Recently replaced the entire distributor. Spark cables and plugs are a couple years old.

-Used in line spark plug checker (bulb lit up, but was VERY dim)

 

I'm having a hard time remembering how bright the spark plug bulb would normally light up under working conditions. It's hard to see during the day, but still I would expect it to be a little brighter. Is it possible that my engine is getting a weak spark? If so, what could be causing this? Thank you very much for your time!

[Zebvance]

replace your coil, plugs and wires and see if that helps at all.

[Pete M]

I had a weak spark in my 86 and it turned out to be corrosion on the input of the coil. 

[caseyrstewart]

I didn't think to take off the distributor cap because I just put a brand new one in 3 months ago. Lo and behold, my rotor snapped off completely. Pretty sure that'll do it. Looks like I'm cashing in on my O'Reilly's limited lifetime warranty. Thanks for your help, guys!

[cruiser54]

But why did it snap off?