Power problem 03 V6 T4R, help!

[CFM]

So I decided to clear and paint the headlights on our V6 03 T4R yesterday, had the front bumper off obviously and the bulbs were laying freely. I had my fiance' pull it forward a little bit (it started to rain) and she forgot to turn the lights off, luckily I noticed within a few minutes and saw smoke. The high beam bulb burned about a inch in diameter hole in the battery. I figured well crap, I need a new battery obviously and we should be fine. Went and bought another new battery, installed it... and the car was idling low (around 500 RPM's) and when it was idling the headlights were dim, when I'd rev the vehicle the lights would get brighter. When I am driving, it drives fine until I come to a stop. Then it dies. I figured it was a faulty battery, nope... I'm thinking voltage regulator or alternator...

What could have happened? The vehicle ran perfect before this happened. I hope I was detailed enough to get some help! Thanks T4R!

-Coleton

 

[ebg18t]

Colton - are they any codes stored in the ecu?

 

[CFM]

I haven't checked as of yet, I live out of town but luckily I have my own towtruck so I am going to run it into town to check if any codes are there. No lights pop up but like you said maybe they're stored in the ECU somewhere. Is there any way for me to test if it's the voltage regulator or alternator?

 

[CFM]

I have a brand new battery and alternator.... it's still running the same... Very low idle, to the point where it is basically dying or does die. When I rev the truck the lights get brighter. All the same symptoms.... I'm at a loss here.... Anyone?

 

[DC runner]

I had this happen when I had my old battery replaced and for about a day or two after, I would notice odd idle. It went away.

I swear it has to do with the electric system re-calibrating after reattaching power.

Give it a day or two until real concern.

 

[preacher35]

I had this happen when I had my old battery replaced and for about a day or two after, I would notice odd idle. It went away.

I swear it has to do with the electric system re-calibrating after reattaching power.

Give it a day or two until real concern.

Yes, you are correct. When the battery is disconnected for longer than a couple of minutes, the ECU resets and must re-calibrate after the battery is reconnected. You might experience, rough idle, throttle hesitation, non-working automatic windows/moon roof, among other things. The rough idle should clear up within 40-50 miles of driving. Nothing to worry about.

 

[CFM]

Thank you guys very much.... I drove the vehicle around for about 20 miles, it was still doing the same thing. Then I continued to drive it around for another 10 or so miles and it was running fine. I drove it home and it seems perfectly normal. Wish I would've done this before putting in a new alternator! Oh well, atleast it's one less thing that will have to replaced down the road right...?

 

[BRossman]

Disconnect the negative battery cable, clean the throttle body and then reconnect the cable. You can cause the throttle motor to prematurely fail by not cleaning it. When power was disconnected the learned throttle position was lost. When power was reconnected the ECM reverted to a default throttle angle. The carbon build up in the throttle body caused the throttle plate to hang up causing the low rough idle. Trust me on this I deal with it every day at work.

 

[BlackWorksInc]

One more thing to note is that a lot of our Toyotas will revert to default values when the battery is disconnected for an extended period of time (this is basically because you hard reset the entire vehicle and clear the memory) So functions need to be relearned such as automatic window functions and idle.

I would try pulling the battery cables off for about 5-10 minutes, then reconnect them and let the vehicle idle with NO loads (i.e. no HVAC, no radio, no headlights, ect.) for about 5-10minutes. This will let the vehicle learn its idle again, but it will still feel/drive a bit rough as it needs to learn your driving style again (this can take upwards of 50-100miles), so don't be alarmed if it doesn't feel entirely the same as it did before. We do this a lot on the Corollas for the A0J recalls (where we replace the ECM) as well as when the ECM is reflashed or reset on most of our vehicles.