Mounting bracket? Can you give me more details or a picture of where it is? Sry I'm a noob, what side of the front of the engine? Near the AC compressor or?
Low voltage
- Thread starter HiTech6
- Start date
Superrmario
Member
- Joined
- Nov 6, 2013
Earl.. If you don't mind, I would like to ask a question.
Had field issues with my alternator that you helped me resolve in a past post a few weeks back. Now I am starting to see low voltage at higher RPM's I haven't got to the ignition switch yet, but I have tested the following:
Resistance from the negative battery terminal to the block is .5ohm roughly. I also tested the ground strap on the firewall that is bolted to the intake manifold with .5-.7ohm Its likes to bounce around. Negative terminal to the body is all over the place (I'm probing on fender bolts). ranges from 1ohm to 15ohms. Back of alt to a ground is 14.4v running. Back of alt to neg battery terminal is the same as well as the orange wire to the ECM. Should I ground the block to the chassis and see how that works?
Superrmario
Member
- Joined
- Nov 6, 2013
Thx Earl. If you may, where should I look at the resistance issues? Sounds stupid I know, but I am not too electrically inclined in vehicles
Since we are on the topic I was running through my grounds the other day and getting messed up readings. I blamed the meter and bought a new one that was actually worth more than a few bucks and was still getting occasional garbage ohm measurements. This prompted me to think about how a digital multimeter actually reads resistance. While I don't claim to be an expert my understanding is that the meter applies a small voltage across the leads in order to measure the resistance. This made me think that if the battery is still hooked up and there is any amount of voltage going to ground then the measurement could be off. Later on, I stumbled across this from our repair manual.
After disconnecting the battery completely my grounds all fell in line and produced repeatable results.
After disconnecting the battery completely my grounds all fell in line and produced repeatable results.
I was referring to the paragraph that talks about measuring resistance with a digital multimeter.
I have a volts gauge but I have no idea where the previous owner attached it to. I don't see any wires plugged directly into the fuse box. Here is my situation. With all accessories running- bright lights, A/C, rear defroster, stereo, GPS plugged into cig. lighter, the volts gauge showed 11.5 volts. I checked the volts at back of alternator and it was 12.5. Should I be worried? With all accessories off, volts at alternator was 14.1 while gauge reads around 13.
Previous owner must have replaced the ignition switch on the column because I can't turn the key to the ACC position. He must have gotten the rod in wrong. I think I'll go ahead and replace the switch and see if that makes a difference. But what I don't understand is, if the alternator and battery show decent voltage, am I chasing a problem that doesn't exist? Or does it sound like the three year old alternator is bad? The headlights are bright even with the accessories running, if that means anything.
I used my cheapo Harbor Freight voltmeter and also went from memory. I could have been off by .1 volts. I'll check it again and report back. The BWD ignition switch is only $14 at Oreilly's but I know it is a pain to install as I did it once on my other car.
I wouldn't worry too much about being off by 0.1V or anything as you can overcharge a battery some as well. The main thing is that in one load scenario your alternator is putting out the same voltage as a fully charged battery and that is worth looking into or you will at the least be staring at your voltmeter everywhere you go instead of enjoying your ride.
I would at a minimum disconnect the battery and clean the terminals, clean the alternator lug terminals and check the grounds. Your alternator is charging when you have a low load at idle but doesn't keep up when you do have a high load at idle. It isn't bad necessarily, but it isn't ideal if that makes sense.
You may also want to consider taking the alternator and battery out and have them checked while cleaning up the cables.
You may also want to consider taking the alternator and battery out and have them checked while cleaning up the cables.
What do the volts look like at cruise? I would be less concerned if these were just idle numbers.
Varies based upon the alternator. The volts under boost and the drop between what you see at the alt vs the battery are the primary concerns. 1 whole volt difference is quite a bit.
I'll check the volts at cruise and get back with you. My volts guage kind of shows a range from like 12 - 14. At cruise on hwy it is on or a just little above 12. With brights on it dropped below 12
I'll plug in my scan tool and get a more accurate number. BUT from reading thru this thread it seems the voltage can get lost in the ignition switch, is that correct? So it might be a good idea to replace the switch as the car has over 200k miles?
