Just bought a 99 Cherokee in great shape with no rust and a 4.0 for $900. 145,000 miles. Want to fix up for a daily driver. Previous owner just stopped driving it after a small front end accident, and one day after 2 years sitting, couldn't get it started. It had bad gas, he drained the old gas, blew out all the lines, and basically got the fuel issues fixed. There is pressure at the rail now.

Now the issue is a lack of spark. He changed the crank position sensor, didn't seem to help. Then he gave up and sold it. So in I swoop to save the day. I already bought a cap and rotor, and the cam position pickup sensor or whatever it's called under the distributor cap. Haven't had a chance to install them yet. I was going to change them, and unplug and replug all harness connections a few times to make sure they don't have a poor connection. Any other ideas of things to try if these don't work? I am thinking the problem is corrosion of some sort since the car didn't break down, just sat for awhile. That's why I am changing anything that has a contact or things like that.

 

Start with cap, rotor, plugs & wires and see what happens from there.

 

With the key on, shouldn't there be 12 volts on one of the two coil wires? There isn't. And the auto parts store gave me the wrong damn cam position sensor.

 

this should help with you issueshttp://www.jeep4x4center.com/knowledge-base/index.htm

 

I may have found a clue as to why the autoparts store gave me the wrong sensor. Does the 4.0 versus the 4.0HO have different cam sensors? I read somewhere that they do. The style my car has is a plastic disc that is sandwiched between the cap and distributor body. The one the store gave me is a little thing that attaches with two little bolts. How can I tell for sure which engine I have?

 

oly show one kind for your yearhttp://www.autozone.com/autozone/par...mString=search

 

Well, the one you showed in your link is what mine looks like, it looks nothing like the one I got. So, I am up to 4 trips to the store to get one little part...........

 

have you ever checked to see if theres any codes b4 throwing more money at it??

 

I bought a 4.0 motor that sat for 10 or so years and installed it in my scrambler w/ a new harness from hotwireauto. I went to crank the motor and nothing. after a few hours, a scantool and a scope.. we figured the injectors were corroided shut and when the computer saw this it shut the driver controls off so it basicly was dead w/ no spark or fuel!!

 

No codes. And from what I have read, those pickup sensors go bad so often that having a spare is a good idea. I don't think $53 is "throwing money at it."

 

Did it not turn over, or turn over and not fire? Did you ever get it running?

 

the crank sensor has to do with spark the cam sensor has to do with injector pulse i would verify which is missing from the equation.

 

ive only pput one sensor on mine in 15 years and that was the crank sensor

 

Crank sensor is new, that was the last thing the previous owner did before he gave up.

 

Test your way to a solution.

Pull a plug. Keep it attached to the plug wire. Place the plug electrode near a good engine ground. Have a buddy crank the engine while you watch. You are looking for a strong, blue, snapping spark. Yellow/orange/white indicates a weak spark, which may not be strong enough to star the engine. Ignition coil is the primary suspect for a weak spark.

The above is the first thing I would do with a 99 no-start.

If you have good spark, try spraying some starting fluid or a splash of gas into the intake. If it starts and runs for a little bit, you have confirmed a fuel delivery problem.

A simple "noid light" purchased at your local parts store, will tell you if you have a pulse to your fuel injectors.