Electrical issues

I just purchased a 1990 4.0 Aw4 cherokee

It has some starting problems. Each time I started it it was being jumped trying to start it on 2 different batteries it wouldn't start. While running If I turned anything on the voltage dropped below 12v. I took off the battery for a couple seconds and it ran fine. I drove it about half way home and it began sputtering. The more gas I gave it the more it sputtered and the RPM's dropped.
After getting it home I tried jumping it again and it wont start. It's not getting spark.

I was thinking a bad ground and maybe a CPS.

NEVER DISCONNECT THE BATTERY WHILE THE MOTOR IS RUNNING! Often that will blow out the electronics in the alternator.

So I've heard

Step #1 is getting a good charged battery into position. Clean and secure contact surfaces of connections at the battery, starter and grounds. If it won't crank with the key, use a screwdriver to jump current from the big wire on the starter to the small terminal on the starter. Make sure you are in park, as this bypasses safety features. You have to get it to crank before you can diagnose further.

That's the plan today.
I'm going to buy a CPS(could use a spare since I have 2 xjs now anyway), Cap and rotor + plug wires. Clean terminals and try grounding everything out with jumper cables to see if that helps.

I'll post up if the world ends or if it works
thanks

AIbandit said:

That's the plan today.
I'm going to buy a CPS(could use a spare since I have 2 xjs now anyway), Cap and rotor + plug wires. Clean terminals and try grounding everything out with jumper cables to see if that helps.

I'll post up if the world ends or if it works
thanks

Click to expand...

Your problem sounds like a battery/cables/alternator issue.

I wouldn't buy a CPS/CKP until you have the primary cause of your problem--lack of power--fixed. You might need that money for something else.

As you are starting with a vehicle you don't know, get a fully charged battery that has passed a load test installed. clean both ends of both cables, and measure the resistance of each cable. Should be near ZERO ohms. Renew your grounds at the dipstick tube, and renew the head to firewall ground--it is the sole OEM ground for the unibody.

Hopefully it should start now. Once started, measure the voltage between the battery terminals when running--should be 13.6~14.5 volts.

Fixed it.
Battery terminals had paint on the inside where the cable goes

Lucky me she's running great! and only cost 650$

Thanks guys.

AIbandit said:

Fixed it.
Battery terminals had paint on the inside where the cable goes

Lucky me she's running great! and only cost 650$

Thanks guys.

Click to expand...

Ok, you don't get off that easy--pictures and description of condition?