'94 Cherokee will not start

Factual Questions
1

Ok, car people, it’s my turn to ask.

My 1994 Jeep Cherokee (4.0 inline six, 4WD, automatic) will not crank. Nothing that I have tried seems to work.

-I have suspected charging problems. The in-dash voltmeter sometimes runs at 14V and sometimes slightly below that. Also, the starter has been slow to turn over at times.

-Several days ago, I had Autozone test the battery inside the car with their handheld tester; it checked out as ok, for what that’s worth.

-The starter relay inside the fuse box behind the battery clicks, and I have swapped relays with the two other relays that share a part number. They are now in their original positions.

-It did not start when I got a jump, though I didn’t wait very long before trying.

-I have not had any previous problems with the neutral switch. Also, I have tried starting in neutral and in park without success.

-The power windows will run up and down, and it looks like all other electrical systems work and don’t seem to lack power.

-The starter did not run when I jumped between terminals with a wrench, nor did the solenoid on the side of the starter click when I jumped between the hot and solenoid terminals. Running a jumper cable from the positive terminal to these terminals got me a few small sparks but the starter did not spin and the solenoid did not click.

-I also checked the ground connections by connecting jumper cables from the negative terminal to the air compressor and water pump–no luck here either.

-I pulled the battery and took it home. Using a small analog voltmeter, it showed 12V both before and after charging for three hours. Afterwards, I replaced the battery and tried again without success. After this, the in-dash voltmeter showed 10-11 volts (the hash mark between 9 and 14 volts.)

It may be the battery. I also suspect a bad ground internal to the starter since neither the solenoid nor the motor work when power is applied directly from the battery. All the same, I will probably replace the battery in the morning since it’s a few years old and pick up a starter just in case.

What do you think?

2

Charging issues and starting issues are different. Get the battery load tested. If it passes, then charge it, out of the vehicle. Once charged, reinstall it and see if the starter engages and turns the engine. If not, from what else you’ve listed, it is quite likely the starter or solenoid. Once you get the starter to crank the engine, you can move on to diagnosis of starting problems, and once it starts and runs, evaluate the charging system.

3

Yeah, there may be a charging problem since the voltmeter seems to have two voltages that it settles at. I’m suspecting that something went open in the starter, though I have no idea how the solenoid and the motor could both fail at the same time.

4

My bet’s on a bad starter. (It and the solenoid are usually married together and replaced as one lump.)

If moderatly high loads like the power windows work fine, the battery is probably OK. Do you need one now? Probably not. But, is it old enough that it might not last through the upcoming cold winter? Is it worth replacing on your schedule, rather than on its schedule? (which invariably is somewhere like the mall parking lot after the stores all closed on December 23, fifteen miles from home) I’ll leave it to you and your budget to decide, but if Bubbaville gets cold winters, or you have a high aversion to being stranded, it’s probably worth doing now. Oh, by the way, how’s your alternator?

ETA: No big surprise on the three different voltage readings as they were taken with three different meters. 14V while charging and 12 when not sounds normal.

Also, check the ground cable(s) and connection(s) to the frame and/or engine block. If it’s gone bad, power can’t get back to the battery, just the same as a bad supply cable will keep power from getting out of the battery.

5

The charging system should run about 13.9 volts or so give or take depending on the design of the system, move along here, nothing to see…

Am I correct in assuming that the starter did not crank, but the relay clicked?

did it crank, or just a click?

Which terminals did you jump with a wrench? the two big ones? No click from the solenoid when power is applied would tend to indicate a bad solenoid.

Huh?

Now I am confused. Your battery read exactly 12**.0** volts both before and after charging? Ah excuse me, but was the battery charger plugged in? I find it had to believe that any battery no matter how bad would read exactly the same both before and after 3 hours on a charger. I would expect a few tenths of a volt difference. Put the battery back on the charger and take a voltage reading before you start charging and then with the charger on. They should vary by about 1.2V If they are exactly the same, your charger is toast, or your battery is so dead, the charger won’t start. (Unlikely since the power windows work.)

I would do some accurate fault tracing, and replace the bad component. But hey that’s just me. Feel free to warm up your parts throwing arm. If you throw enough parts at it, I am sure it will get fixed.

::: OP reads reply::: OK smart ass what should I do?
Well first off get a digital multimeter, spend $10 at Harbor Freight.
Read the battery voltage to one hundredth of a volt. Write this down. If it is below 12.45 charge the battery.
Start the charger record the reading.
With the charger running, when the battery voltage is above 13.6V you may continue.
Put the battery in the car, and try to start it. does it start? does it crank? does it make any noise at all?
After several start attempts re measure the battery voltage, write this down.
Now comes the fun part. Set the meter to read voltage. Place the red lead on the battery positive, put the black lead on the large terminal on the solenoid that has the battery cable attached. Have someone crank the car. The reading will go from 0.0V then jump up and finally settle to a reading. Record the reading for the positive cable.
do the same test on the negative cable. Put the black lead on the center of the negative terminal of the battery and the red terminal on bare metal of the engine. (NOT a painted surface or plastic) Again have someone crank the car, and record the reading for the negative cable.
Post your results here.

6

Except for a deflection of 1-2V from day to day that doesn’t seem to change with RPM.

The relay (not the solenoid) clicks. I isolated bad contacts in the relay by swapping with other parts.

Both the two big ones and the big one that goes to the battery and the smaller solenoid terminal. No luck with either.

Using a jumper cable as a test lead, I applied direct voltage to the starter terminals. Nothing happened when power was applied to the terminal going directly to the motor (the big terminal NOT attached to the battery) OR the smaller terminal going to the solenoid.)

I would think that this would indicate an open ground, but the engine ground was later augmented by clamping jumper cables to the negative battery terminal and parts of the engine. Besides, even if the ground to the engine is bad there should be enough conductance through the chassis ground to at least click the solenoid.

I used an analog meter since I did not have a digital meter around. There may have been a voltage difference of less than a volt. The battery charger went to full charge immediately, but was short cycling and indicating a charged battery) within an hour.

Quite frankly, I didn’t take the meter back to the car because I was tired and just didn’t think about it, but hardwiring between the starter motor and the battery with a jumper cable should eliminate any problems with the switching.

:slight_smile: That’s ok. I’ve kicked myself enough over this one. It’s your turn.

Right. Check the voltage drops on the battery lead and the ground.

The battery read low on the dash when I got the truck this morning. I’ll post when I have any updates.

7

Fully charged battery = 12.6V Dead battery =12.0V. So yes the difference is less than a volt.

8

End of quest. The starter is faulty. Replace it.

For the edification of all: going back to when it wouldn’t crank even with jumper cables, and the relay could be heard to click, that’s the time to stop thinking about the battery and make the above test. And it even appears that the above type of test was related in post #1. A lot of unnecessary time and attention has been paid to the battery here, when the evidence suggested (and probably proved) that the problem was elsewhere.

9

Right on the money. One starter later, it is good as new, give or take a few hundred thousand miles.

What had me stuck was that the throwout woudn’t click AND the starter motor proper wouldn’t spin when I hit their respective terminals with current straight from the battery. I assumed that the solenoid was in parallel with the motor, but it seems that at least some of the field coil goes through the brushes, like this.