Let me get straight to the facts:
-About a week ago, I take Uncle Jesse to get an alignment. I notice while on my way, the speedometer and odometer have stopped. This didn't concern me as in cold weather the speedo would sometimes jump erratically and there would be a sort of grinding noise. I assumed it to be the speedo cable going bad. (88 XJ)

-The day after I got my alignment done, I noticed my voltmeter on the instrument cluster was showing a lower reading even though I had a normal reading of the battery on my multimeter.

-My right turn signal started blinking slower than the left

-Tonight we go for a gellato, on the way back I go to hit the gas, and I start sputtering a little bit, the trans starts shifting too early and too late, the instrument cluster starts to dim as do the headlights. The turn signals stopped working. These symptoms keep getting worse until finally I try and accelerate and the Old Boy just stopped. This all felt like a bad ground somewhere.

-I let the car sit for a few minutes while we were waiting for a tow, and I was able to start it again after the battery regained some steam, so it's not a bad battery. The alternator was just replaced with a brand new Bosch only a few months ago. Again it feels like a ground is bad somewhere.

-Could it be as simple as my instrument cluster ground causing all this? I'm gonna investigate tomorrow. Just wanted to get thinking tonight. Thanks in advance!

 

From Cruisr's website:
All the components listed below ground at the dipstick tube stud:
Distributor Sync Sensor, TCU main ground, TCU “Shift Point Logic”, Ignition Control Module, Fuel Injectors, ECU main ground (which other engine sensors ground through, including the Oxygen sensor, Knock Sensor, Cruise Control and Transmission Sync signal. All extremely important stuff.


Sounds about right. Will check it out tomorrow!

 

Upgrading battery cables is also suggested if not all ready done.

 

yes I already have heavy duty 5-90 cables.

Checked the dipstick grounds and no change in condition. Any other grounds that would effect my tcu and instrument cluster?

 

I had to run a ground off one of the GND screws on the back of my cluster. My cluster gauges would twitch and not work until I did this. I Have not had a problem since. But it seems like your alternator is not charging the battery voltage is dropping. This causes erratic things to happen until the motor dies.

 

Thanks. Yeah im just wondering if the alt/batt. Is bad or there is a bad ground sucking power off somewhere. Once i had a no start condition, turned out there was a crack in a plug wire and spark was arcing off onto my coolant overflow hose.

 

There is a ground inside on the left side kick panel, about the height of the lower dash. Cruiser has mentioned it before so it might be on his site. I think it is tied into cluster among other interior parts.

 

So I just did a reading on the battery. When it was just sitting there, it as about 11.25 volts. After I started it, it was charging at about 10.4 v and by the time I checked it a second time it was down to 10.04 v.

​​​​this leads me to suspect it is my alternator. I put the stethoscope up to the alt, and there was no audible sign of a mechanical defect. This is a little confusing in regards to my bad alt theory. The battery seems fine if it can start and run the vehicle.

should this even really be possible with a 3 month old new Bosch alternator?

what other conditions might cause it to charge like that? (Just trying to play devils advocate here) Could a bad ground cause such a draw on the alt as to inhibit its charging capability to such a degree?

 

Long answer, yup it sure can. Be sure your sure wires all good for a good reading. They can even intermittently charge before they die. Had that happen recently on wifes car, died while driving, dead battery no charging when I looked at it first. Testing other parts later, the damn thing was charging again.

12.6 should be a good battery resting voltage, any lower after a charge is signs of battery getting tired. I would give battery an overnight charge and see where its resting.

 

I thought 11+ wasn't bad considering the car died last night. It started one more time while waiting for the tow, but only after it sat a bit. Judging by the numbers today, it was probably charging at the same rate last night which definitely wouldn't give the battery a full charge. I'm gonna take it into an az to get it tested to be sure. I've got some time seeing as I'd have to warranty the alternator through rockauto anyway. Thanks!

 

I should have said, a fully charged battery 12.6 is normal with a good alternator charging. I would still throw it on a charger if you have one. draining down to 10v is not good for most starting type batteries in the long run.

 

Thanks, Os, I agree. I wouldnt be shocked if it were. A few nights ago I left it in reverse with the ebrake on. This drained the battery enough to keep it from starting until about an hour later when it regained its charge. The last time i killed a battery I left an inverter plugged into a lighter socket (not on but still drained the battery).

My other question is if the battery is bad would it also cause the low charging in the alternator? is it possible its just hitting a sort of wall in terms of charging because it is in poor condition?

 

Just got the battery back, its healthy. Gonna pull the alt and take it to them to be tested tomorrow.

 

New ain't what it used to be.............

 

and assembled in USA is now just fancy talk for "Made in China" lol:


pulled the alt. Im upping my bets on it's bad:
Some hard plastic appears to have melted and bubbled out. The positive post is also loose. It has a lifetime warranty so Im gonna try another new one.
Ive had three new alternators in the past 5 years. After my stock went out I got a reman off ebay that was good for 200 amps. That was the best one Ive gotten. Had it for a few years. I replaced that in Kamloops BC with a reman canadian wilson unit which lasted me approx. 15,000 miles. I replaced that one with this Bosch. Havent driven too much until lately because the rig has been having so much work done. My guess is it has much less than 1k miles. Good thing about this unit is it comes with a 24 month roadside assistance bonus and a lifetime guarantee.