The jeep is a 95 4.0 auto and it was just parked at the house one night and the next day it wouldn't start. It turns over fine. I have fuel but no spark. The cap, rotor, and coil were already replaced without success. I also tried to start it in neutral and it was a no go. This is the daily driver and she's been down for a few days now. Thanks in advance!

 

1. Did you have this problem before you replaced cap, plugs, etc? (I take it from your post, the answer is yes, just making sure)

2. Did you get the firing order correct when you put everything back together?

3. Codes?

4. How did you verify you had fuel, but had no spark?

 

Yes had this problem before the parts were replaced. Thats why i replaced these couple of parts. They were old and due to be replaced anyway. Firing order is good. No codes. No spark.

 

You didn't answer the last one: how do you know you have fuel, but no spark?

I'm assuming when you say "no spark", you mean at the plug end...AFTER the cap?

Do you have spark from your coil?


Not trying to be difficult, just attempting to narrow down the problem...

 

Sorry no spark after the cap. None of the wires going to the plugs have spark.

 

Do you have spark OUT of the coil?

 

Could be the cam or crank sensor. Check for power and a pulsing ground at the primary plug on the ignition coil. If you have no power at the coil then you need to check the under hood fuse box for a blown fuse. If there is not a pulsing ground it will be either the crank sensor or cam sensor, might as well do them both.

 

Thats where I was going...

 

Do I use a test light to check for a pulsing ground at the primary plug? I went over all the fuses and the are in good shape.

 

A test light will work great, just clip onto the possitive side of the battery and probe the coil ground wire and then crank the engine over. The ground has to pulse. If the light stays lit or does not light at all it's time to replace the sensors.

 

Ok thanks a lot for the info. I'll try it tonight or tomorrow and let you know how I make out.

 

Any news? I was curious what you found.

 

Didn't have a chance to get back to work on it yet. Maybe tonight or tomorrow.

 

So I have no light what so ever when I test that coil harness. The sensor I need to replace is on the back d/s of the engine right?

 

I replaced the crank sensor and it fired right up. $58 for the sensor. Not to bad. Thanks for all the help guys. You got it up and running again.