August 17, 200718 yr Interesting .... My shop says my altenator is putting out the proper voltage/current using their new fangled shiney digital tester. My slightly dirty big metal box with the two humongus battery terminal connectors says otherwise. They had to put in a new battery under warrenty because the battery wouldnt hold a charge anymore. They tried to explain that my wiring was suspect. I disagreed. Blu has had Two aftermarket altenators on him (from differnt shops) , and both seemed to put out too low for my tastes (and man am i pissed). Now that my back is starting to let me do things again (but man do i pay for it the next day) I looked into a OE altenator. 61.00 plus core of 50.00 wow my last one cost 223.00 Oddly thats the same price as an imprezza altenator. SO i called 1st subaru an ordered an altenator. I told John what I have been going through. He said he has had several customers in the same situation, they got frustrated and went with OE (thinking the cost be damned) and it solved there problem. These are subaru rebuilt altenators, so I ordered one. If this solves the problem, the moral of the story would be not only can OE be cheaper, but better. Thought I would share. nipper
August 17, 200718 yr Hm..interesting nipper. Let us know if the OEM works out better. I've been noticing in '00obw the voltage is usually around 13.3V, but when stopped at idle with a/c on and foot on brake it starts dipping...12.8V, 12.7V, etc. Have seen it get down to 11.6V at long stop lights or stop/go traffic....not sure if this is an oem alternator or not.
August 17, 200718 yr Author Hm..interesting nipper. Let us know if the OEM works out better. I've been noticing in '00obw the voltage is usually around 13.3V, but when stopped at idle with a/c on and foot on brake it starts dipping...12.8V, 12.7V, etc. Have seen it get down to 11.6V at long stop lights or stop/go traffic....not sure if this is an oem alternator or not. mine is 13.1, and too me thats too low. I've gone down as low as 11.9 at lights too nipper
August 17, 200718 yr You might want to try upgrading the wiring for the alternator and battery to make the best of both. In car audio circles its called the "big 3". Run additional large gauge wire from 1. the battery negative terminal to the chassis 2. the alternator positive to battery positive (fuse this one) 3. engine ground to chassis. The biggest help for sound systems seems to come from the battery to chassis connection. But you might benefit from the 2 others since that is how the neg. and pos. of the alternator get to the battery. Alternator casing is "negative" and bolts to the engine which is grounded to the chassis. Doing this certainly wouldn't hurt. By the way, lots of newer Subie owners see high 13's voltage stock.
August 17, 200718 yr The Subaru diagram says if at idle with the headlights on, the voltage is between 12.5V and 15.5V then it's OK. But 12.5V does seem low; isn't a fully charged battery like 12.8V? I've been thinking about putting in some 8 ga. additional ground wire, to the AT, block, body, then battery. I did check with a voltmeter to confirm what my gauge was reading, and checked the voltage drop from the alt to the battery, and the battery ground to body, block, etc., while I had every accessory turned on, but didn't see anything over .1-.2V drop.
August 17, 200718 yr You might want to try upgrading the wiring for the alternator and battery to make the best of both. In car audio circles its called the "big 3". Run additional large gauge wire from 1. the battery negative terminal to the chassis 2. the alternator positive to battery positive (fuse this one) 3. engine ground to chassis. The biggest help for sound systems seems to come from the battery to chassis connection. But you might benefit from the 2 others since that is how the neg. and pos. of the alternator get to the battery. Alternator casing is "negative" and bolts to the engine which is grounded to the chassis. Doing this certainly wouldn't hurt. By the way, lots of newer Subie owners see high 13's voltage stock. Very sound advice. What kind of condition are all your battery cables and grounds. I've also seen cases where a "grounding system", which connects various engine points and the chassis of the car together, can help stabilize voltage through the system.
August 17, 200718 yr Are there any overdrive pulleys available for these alts? Though the stock alt pulley is pretty small already so not sure it's feasible to use anything smaller.
August 17, 200718 yr My lower back bothers me on that type of work. Now, I use a chair foot rest. I kneal on the foot rest, doing that saves my back.
August 17, 200718 yr Author I added a ground right to the alt and it made no difference. Even at 2000rpm with everything on the alt is undercharging using a tradational load tester. I may replace the battery cables this weekend, other then that nothing else I can think of. nipper
August 17, 200718 yr Nipper, Have you checked the AC voltage at the battery while the engine is running at around 2,000 RPM? If there is more than one tenth of a volt then some of the diodes are not working.
August 17, 200718 yr Author Yup, that it does. Thats why I ordered the replacmenet, as it actually was a little lower then at idle. nipper
August 17, 200718 yr It sounds like the shop needs to improve their new fangled shiney digital tester.
August 17, 200718 yr Author It sounds like the shop needs to improve their new fangled shiney digital tester. I wonder if they ever calibrate it. This is the second time i've gotten burned by a new fangled digital shiney tester. Some times too much information is a bad thing. nipper
August 22, 200718 yr Author I think I know why they keep missing the problem. I stayed in NJ overnight, and it got down to 58 degrees. I started blu up and he was putting out 13.2 volts (still a little low but the highest i've seen in a while). 295 was a 500 foot drive to the on ramp. As the car wrmed up, I noticed the voltage dropped. Eventually It went down to its 12.5-12.8 where its been sitting. As the Alt heats up it looses output. I am planning on chainging the battery cables, and am wating for the Alt from Subaru. The reason my shop kept missing it was because they were testing it cold. nipper
August 22, 200718 yr That makes sense Nipper. A diode could be breaking down I suppose or there may be a bad connection inside heating up.
August 23, 200718 yr I am starting to notice this as well. After it warms up now my voltage is at 12.7v again when my lights are on. Did I read what you said correctly? $61 for a NEW OEM alternator?
August 23, 200718 yr Author I am starting to notice this as well. After it warms up now my voltage is at 12.7v again when my lights are on. Did I read what you said correctly? $61 for a NEW OEM alternator? Subaru rebuilt unit. Yeah i couldnt beleive the price either, but thats what they said on the phone, so i said gimmie.... https://www.1stsubaruparts.com/ Jamies site has it too, just i dont have her link handy. nipper
August 23, 200718 yr Ok well if it works out for you. I guess I will be buying one. I like having my interior lights and exterior at the same brightness all the time :-p
August 31, 200718 yr Author Problem fixed. The new 61.00 alt is putting out 13.9 volts. I checked the numbers, it seems whoever is supplying my mechanic is selling imprezza altenators as a one size fits all. Now its time to start a war. nipper
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