You'll need new O-rings.

 

Since you asked, it's an 8 channel oscilloscope that costs about 100 bucks (or there are ways to rent one). Anyway, you could test the performance of the CPS, CKS, injectors, and PCM (injector drivers). If you arbitrarily start replacing stuff, and the problem is the last shot of the parts cannon, you could end up dropping about 400 bucks.

Here's what a good injector looks like



and matching up CPS, CKS and one injector (the CKS is AFU cause the acquisition rate has been exceeded, but you get the idea):

 

Here's a good CPS/CKS. I can build a good CPS/CKS/injector pulse if you end up going this route and need an example:

 

Really good stuff, Dave!


I may have to pick up one of those.... Do you have a model number for me?

 

I got the 1008C, and added on a current clamp and an attenuator.

 

And to do injectors you need an attenuator. They're pretty cheap, and I suppose you could get 6 and look at all of the injectors at once. But one is fine, just go down the line.

A Cherokee injector waveform:

 

Update: I spliced in the new injector pigtails and now I have no more check engine lights! My engine is also no longer running like dog sh$t. The issue must have just been some bad connections between the old cracked plugs and the injectors. The bad news is that I still have a little bit of a rough idle that gets really rough if I give it a little gas right at 1k rpms (runs smooth anywhere after 1k). I'm not sure if this issue is related or just something else that happened to come up at the same time. Going to start checking for vacuum leaks now.

 

Good job!

 

I would keep checking for bad wires. Jeep XJ have dogsh!t for wiring and make 50yr old Lucas look like space age

 

Try disconnecting the injectors or plugs again to see if you can isolate it.

 

Or splice in an ODBII PCM and see if you can generate a Cylinder Misfire code.

 

^^^^^^^^^^^^^^^^^^^^^^^^^^^^ j/k

 

LOL yeah no thanks

 

Interesting that you mention an attenuator is needed for the Injectors, what is the maximum voltage of that spike ?

I'm sure there is others who would appreciate being schooled up a little

 

IDK I have the CH3 parameters there (which isn't running) I'll have to rerun it. Should be in the neighborhood of about 100 tho.