power draw at night
06-30-07, 02:23 PM
#1
power draw at night
I just noticed an interesting power draw in my DD. It's an 89 GTU. I just finished replacing the transmission then this problem started. if i'm cruising on the freeway and I tap the brakes, the radio shuts off and the lights dim. I also noticied that the voltmeter would get all jumpy.
I'm almost thinking of ripping out the alt and having it tested.
Any ideas?
I'm almost thinking of ripping out the alt and having it tested.
Any ideas?
06-30-07, 06:41 PM
#6
It sounds like your electrical system isn't able to put out enough juice anymore.
Well, I just had to pull my alt so...
Disconnect the battery terminals.
Get an ohmmeter and measure the resistance across the terminals. You can also use a test light or measure the current. If you get anything, start pulling fuses until the short disappears. Check the name of the fuse that got rid of the drain, that's where your short is. The BTN fuse is connected to the fuses inside the car. So if that fixes the short, put it back in and check the internal fuses.
Check the belt tension on your alternator (see below). If it's too loose then your alternator won't put out enough juice, which might be your problem.
Next remove your battery (w/ wrench) and alternator (w/ wrench, sometimes a mallet too). Take them into an auto store and have them test both (free). They will also recharge your battery for you, if it's still good. Installing the alternator requires a wrench, sometimes a hammer (for the spacer, if it's real tight), and a prybar/crowbar to tighten the belt. Long part of belt should deflect 1/2" (give or take) when you press the center with your finger. Otherwise the belt is too tight or too lose.
I've had two remanufactured alternators go on me in a row. So I brought it into a mechanic. He said it's b/c remans suck, I just got unlucky with them twice in a row, and to go new. Next alt will be new. Only $200, compared to $90-$120 plus $40 core charge for a reman. I'm waiting until monday on that. So we'll see if that works. The mechanic said RX-7's have really simple charging systems: battery, alt and 3 wires. So it's either the alt or a short circuit that keeps appearing and disappearing. Mechanic said he didn't think it was a temporary short though, just seemed like a small possibility to me.
Well, I just had to pull my alt so...
Disconnect the battery terminals.
Get an ohmmeter and measure the resistance across the terminals. You can also use a test light or measure the current. If you get anything, start pulling fuses until the short disappears. Check the name of the fuse that got rid of the drain, that's where your short is. The BTN fuse is connected to the fuses inside the car. So if that fixes the short, put it back in and check the internal fuses.
Check the belt tension on your alternator (see below). If it's too loose then your alternator won't put out enough juice, which might be your problem.
Next remove your battery (w/ wrench) and alternator (w/ wrench, sometimes a mallet too). Take them into an auto store and have them test both (free). They will also recharge your battery for you, if it's still good. Installing the alternator requires a wrench, sometimes a hammer (for the spacer, if it's real tight), and a prybar/crowbar to tighten the belt. Long part of belt should deflect 1/2" (give or take) when you press the center with your finger. Otherwise the belt is too tight or too lose.
I've had two remanufactured alternators go on me in a row. So I brought it into a mechanic. He said it's b/c remans suck, I just got unlucky with them twice in a row, and to go new. Next alt will be new. Only $200, compared to $90-$120 plus $40 core charge for a reman. I'm waiting until monday on that. So we'll see if that works. The mechanic said RX-7's have really simple charging systems: battery, alt and 3 wires. So it's either the alt or a short circuit that keeps appearing and disappearing. Mechanic said he didn't think it was a temporary short though, just seemed like a small possibility to me.
Last edited by ericgrau; 06-30-07 at 06:52 PM.
07-01-07, 02:48 AM
#7
Yea...That's pretty much what I was going to do tomorrow. My multimeter and all of my tools were in my TII which was sitting at a friends house 30 miles away and I just didn't want to deal with the GTU today, lol.
In the mornin, i'll test everything and hope that it's just the alt. I don't want to be chasing electrical gremlins no matter how simple the charging system is.
In the mornin, i'll test everything and hope that it's just the alt. I don't want to be chasing electrical gremlins no matter how simple the charging system is.
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07-01-07, 03:05 AM
#8
use a multimeter and set it to read voltage. Get the car running and check put the positive probe onto the +post on the alt, then ground the black probe to the car. The voltage reading should be between 14 and 15 volts. If not then your alt is dead.
Or bring it to kragen or similar place and have them check it out
Or bring it to kragen or similar place and have them check it out
07-01-07, 07:14 AM
#9
new to the rotary world
i have kinda the same problem with my 7 but not that drastic just dims when i have lights on and i hit the brakes or i turn on the hearter it drops about 1 or 1/2 vol. i tend to notice it more when i hit the rear defroster????
07-01-07, 03:08 PM
#13
An AMMETER is used to measure current. Most El Cheapo models of multimeters can only handle about a few Amps max, amps being the draw on the car.
What you do:
Disconnect the positive cable, then connect one lead to the battery terminal (positive), and the other lead to the cable (positive). Make sure the car is off and in the configuration you leave it at night (doors closed, any alarms you may have set, etc..)
Then take the reading.. You should be in the milliamps range MAX. If you are reading anything in the single digits (one amp or more), you have a DEFINATE power drain.
Then you start pulling fuses till the power drain disappears...
What you do:
Disconnect the positive cable, then connect one lead to the battery terminal (positive), and the other lead to the cable (positive). Make sure the car is off and in the configuration you leave it at night (doors closed, any alarms you may have set, etc..)
Then take the reading.. You should be in the milliamps range MAX. If you are reading anything in the single digits (one amp or more), you have a DEFINATE power drain.
Then you start pulling fuses till the power drain disappears...
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