Greetings (With A Question)!

ForCom5

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'02 Proteg5 / base
(hi)

Pleasure to come across the forum!

I just got my '02 Protege5 from a dealer. 140K Miles, new transmission. I did a brake job and replaced all but the brake calipers, replaced a gasket and an engine harmonizer, and also replaced a timing belt. Fun! (and thankfully just within the initial repair budget) (nana)

Now here's where my knowledge takes a nosedive. I'm driving along and after some days of ownership, whenever I hit about 2.5-3 RPM, my load goes way up, AC gets louder, lights get brighter, and it doesn't stop until a downshift occurs.

Fun facts: Battery and alternator "check out" according to Advanced AutoParts (skeptical), buuuuut the battery is bigger than what is needed for the vehicle; it literally punches into the air intake hose.

Now then, should I be looking into getting a new battery, replacing the alternator (which is loving placed in a location that is hard to work with), or replace both? And while I'm at it, should I overhaul my electrical wiring?

If it means anything, the car has been in South Florida forever and has seen no time up North.


Of course, any input/snide remarks are welcome. Being very new to cars I'd very much like to learn how to care for and repair my first car.
 
I have a preference for Interstate batteries, but this vehicle can use 2 batteries. It says the standard OEM is a 310, but it will also accept a 520 CCA. I have noticed with these vehicles if your lights are on and the window is already all the way up, if you pull up on the window switch the headlights will briefly become dimmer with the standard 310 battery.

Have you checked your EGR valve?
 
The alternator is controlled by the ECU.

There is a separate wire running from the ECU to the alternator that turns the output up and down.

There may be some sort of communication issue?? (or bad connection on that wire)

Or your ECU is wonky and needs a reset. ( disconnect the battery for 10 minutes and turn on the interior light.)

You might want to consider "The Big 3" which is an additional grounding method for the car.

Check all your grounds as well...including battery connections.
 
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Get yourself a digital multimeter (Harbor Freight has them for under 5 bucks, or free with a coupon) and check the voltage at the battery with the engine running. You'll use the DMM a bunch, so buying a good one is a good investment.

The voltage should be between 13.5 and 14.4 volts.. Any less or more than that and you have a charging issue.

Alternators make more current at high RPMs. What you're seeing might be normal.
 
The alternator is controlled by the ECU.

There is a separate wire running from the ECU to the alternator that turns the output up and down.

There may be some sort of communication issue?? (or bad connection on that wire)

Or your ECU is wonky and needs a reset. ( disconnect the battery for 10 minutes and turn on the interior light.)

You might want to consider "The Big 3" which is an additional grounding method for the car.

Check all your grounds as well...including battery connections.

Get yourself a digital multimeter (Harbor Freight has them for under 5 bucks, or free with a coupon) and check the voltage at the battery with the engine running. You'll use the DMM a bunch, so buying a good one is a good investment.

The voltage should be between 13.5 and 14.4 volts.. Any less or more than that and you have a charging issue.

Alternators make more current at high RPMs. What you're seeing might be normal.

+1 for both of these.
 
+1 for both of these.

I'll be sure to get that multimeter! Then, do a reset of the ECU with the instructions, and check my wiring (notably the grounds).

Thanks for the continued assistance! I'll be sure to post my results as soon as I can perform the functions! (wiggle)
 
Alrighty...here's where we are.

Swapped out both battery terminals for a...semi-shiny new one. While doing so, I did the ECU reset. Both things were ineffective. Given that the battery reads just fine (13.7 volts), and an alternator check reads similar, I think it is safe to presume that the Voltage Regulator is moot, which in turn means that the ECU is also less than proper. Thankfully, it is apparently an easy fix - albeit according to this forum - a bloody and expensive fix.

It seems as though a pair of Mechanix Gloves and a new a new ECU are in the future! ...Now, where does one get an ECU? ...(google)

You all have been more than helpful, and I can't wait until I can contribute more to the community (rather than just ask questions)! (rei)
 
Alrighty...here's where we are.

Swapped out both battery terminals for a...semi-shiny new one. While doing so, I did the ECU reset. Both things were ineffective. Given that the battery reads just fine (13.7 volts), and an alternator check reads similar, I think it is safe to presume that the Voltage Regulator is moot, which in turn means that the ECU is also less than proper. Thankfully, it is apparently an easy fix - albeit according to this forum - a bloody and expensive fix.

It seems as though a pair of Mechanix Gloves and a new a new ECU are in the future! ...Now, where does one get an ECU? ...(google)

You all have been more than helpful, and I can't wait until I can contribute more to the community (rather than just ask questions)! (rei)

Did you try turning on as much electronics in your car as you can and then checking the battery voltage while the car was running?

Try revving the car while checking the voltage.
 
Try revving the car while checking the voltage.

^^ What he said... Try to get a voltage reading while everything gets bright.

Chances are it's just your alternator and not your ECU.

Check the connection on that control wire...
 
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Alternators make more current at high RPMs. What you're seeing might be normal.

^^ What he said... there may be nothing wrong... It may be just fussy or something that doesn't matter...

Unless your voltage is hitting 17 volts ... then there's something wrong...

(I had one do that.. It went up to 17.3 volts when the regulator went... luckily it didn't blow anything up...)
 
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... I think it is safe to presume that the Voltage Regulator is moot, which in turn means that the ECU is also less than proper... a new a new ECU are in the future! ...

I went through 4 alternators before i found one that agreed with my car... others have had the same problem... Your ECU is almost certainly OK.
 
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By the way,... if replacing your alternator is in your future,...

Apparently the best way to remove it from the engine bay is to partially (but not all the way) remove the half shaft from the transmission which gives you just enough room to drop it out the bottom...
 
Found this too...

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I had a similar issues in my WRX with lights, and electronics and it was the alternator. While it happened though it never damaged anything. It was just kind of an annoyance. Welcome to the forums by the way.
 
Did you try turning on as much electronics in your car as you can and then checking the battery voltage while the car was running?

Try revving the car while checking the voltage.

Interior lights, hi-beams, cargo light, A/C. Hell, I even ran all four windows at the same time as well. Battery reads fine. :/
 
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^^ What he said... Try to get a voltage reading while everything gets bright.

Chances are it's just your alternator and not your ECU.

Check the connection on that control wire...

Check the control wire, got it.

^^ What he said... there may be nothing wrong... It may be just fussy or something that doesn't matter...

Unless your voltage is hitting 17 volts ... then there's something wrong...

(I had one do that.. It went up to 17.3 volts when the regulator went... luckily it didn't blow anything up...)

I'll be sure to note the voltage while running.

I went through 4 alternators before i found one that agreed with my car... others have had the same problem... Your ECU is almost certainly OK.

That makes me hopeful.

By the way,... if replacing your alternator is in your future,...

Apparently the best way to remove it from the engine bay is to partially (but not all the way) remove the half shaft from the transmission which gives you just enough room to drop it out the bottom...

I needed this! I read it was possible, although I never really got much instruction on the matter. I'll be sure to be with my auto tech friend when I attempt this.


Interesting, also noted.

...

Just got an hours cut at my job...so more time to look at my new mode of transportation! :D I'll be sure to check in as progress is made.
 
Got a re-manufactured Denso Alternator as a gift from a friend. Slapping it in on Monday! I'll update when it's done. (mj)
 
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