BearsLexus

Here's the deal-

In October, I had to replace my battery as it died on me while out at a haunted house. Everything's been fine on that front up until about 2 weeks ago. Battery light came on and I had a ****ty 3 mile drive home (very low power). As I had just put in a new battery about 5-6 months ago, I thought maybe it was the terrible cold and my extremely short drives every where I go (I rarely drive farther than 4 miles for ANY given starting of the car. I charged the battery overnight, went to work the next day and everything was hunky dory.
2 week pass and again the car is acting up... battery light, CEL, low power, weird shifting. I charge the battery overnight again, but this time the problem persists. I go up to Auto Zone and buy a volt meter and read my CELs.
Voltage at battery with car turned off - 12.6V
Voltage at battery with car at idle - 13.4V

This looks right to me.

CELs - I have had some of these before, and I have looked them up and understand what they say. My problem is I don't know what to do to fix this. I changed my OCVs about a year and a half ago (see my DIY for this!)
I am also aware that the last 3 are indicative of O2 sensors being bad. Really, the big issue here is the electrical system that seems to be causing problems.
P0300
P0302
P0304
P0306
P0172 - I've had this one and P1150 intermittently for quite some time.
P1150
P1155 - this is new

Any Ideas anyone?? Need to get this fixed so I can go to work so I can afford to keep fixing my RX.

salimshah

Battery light you refer to, comes on when the battery is not being charged. This could be a charging issue, but my guess is your engine rpm is falling low and that is causing the light to come on.

When you have that many codes, I would suggest that you clear them out and then get a read on the first onset of CEL.

How are the air cleaner, MAF, vacuum hoses and exhaust leaks etc.

Salim

BearsLexus

yes, the idle is being low, though not every moment.
Air cleaner - I've had a K&N which I clean and re-oil 3-4 times per year
MAF sensor - I clean with MAF Sensor cleaner at every oil change (about every 4K miles)
Vacuum hoses - I've changed everyone which I can reach
Exhaust - no leaks - had one a few months ago- fixed it.

I did clear the codes after reading them, but the car runs so badly right now, that driving is a worry... I'll take it for a few laps around the block to try to get a new code to pop.

salimshah

just my 2c

Filters like k&N which require oiling can create a problem as the MAF gets coated with oil. Freer flowing intake is nice, but it can impact the metering built in [although there is compensation based on pressure difference ... vac line to the air-box].

lets not hijack the thread.

If you can clean your maf and go back to dry air filter till things go back to normal. <= just eliminating a variable. Again do it if it is convenient.

If you hold the rpm to about 750 with throttle, does your battery light go away?

While servicing/repairs, were any ground wires disconnected? Your oil control valve issue may have been bad ground too.


Salim

BearsLexus

Drove around the block... I am still having a significant lack of power (and quiet engine) which will then, if I really get on the gas, suddenly run like it should, but as soon as I slow down, say to turn, the super weak power is back. Eg. half throttle, the acceleration feels like it is literally only running on 3 cylinders... the revs go up but I am only creeping along gaining maybe 3 mph per second... takes me like 10 seconds to hit 30 mph... but if I am up over 3000 RPM (guessing) and I increase throttle (say 3/4 throttle or more) it's like everything kicks in and all cylinders are firing.
Really what it kind of makes me think of is that the clutch is engaged a little so I am getting some but not most of the power, but then suddenly the clutch disengages and I suddenly have full power.

Ok, so as Baetke had suggested in a previous misfire post I made in December, it may be an OCV that's gone bad, I am starting to think that this may be the issue... I am now having hard brakes in addition to the other symptoms. I did get a CEL and when I checked it it was only for the Air/Fuel mix ones again (0172, 1150, 1155), and no misfire codes, but the car was still running like I described above.

BearsLexus

Ok, ordered in 2 new VVT Solenoids to my O'Reilly... they'll be in around 6:30. I'll replace the one from the front bank again - hopefully this will be a solution to my issue. If it does solve the problem, what I really want to know is what's causing the problem in the first place... this would be the second one I've replaced in 1.5 years.

2KHarrier

Dumb question, but where's the engine temp in all this? Is the car running abnormally cool? My T-stat was stuck open, which made the car run cool, which in turn raised havoc with a number of sensors and the VVT solenoid operation as well...
After a quick (and surprisingly painless) swap of the T-stat, all systems were back to normal. I did change the front bank VVT solenoid, because I too was getting the P0300, 0302, 0304, etc codes...

BearsLexus

Not sure what the temp is during this issue, but I've not noticed the temp as higher or lower than the approx. middle of the gauge.

BearsLexus

No, I do most of my own repairs and changes, etc. with the exception of big work like having the engine rebuilt a few years ago and the transmission rebuilt a little less than a year ago. (This thing is a money pit and a constant source of worry and stress)
Ground wires, nope... I only just started having this issue about a week ago... the Air filter was the first thing I did, and I do maintain it regularly, as well as cleaning the MAF sensor probably 2x as often as I maintain the air filter. I also clean out my IACV at every oil change, since I had issues with that once, too...
As for the battery light, no it doesn't go away when driving at least until about 2k+ rpm. Like I mentioned earlier though, I am reading something like 13.4 volts at idle.

I am presently changing out the front VVT Solenoid (OCV) and changing my oil (and cleaning MAF, IACV). Just needed to come in to check the DIY I made on the subject!

I'll let everyone know how things are running, once I'm done and go for the test drive.

Bear

BearsLexus

Ok... finished up changing my front VVT Solenoid, changed the oil, etc. I cleared my DTCs and went for a little drive... the car runs better again, though the battery light still is on at idle... when I start moving from a stop sign, the light goes off, though if I allow the RPM to drop under 1000, the light pops back on, and will not go away until about 3k rpm or so - unless I come to a stop and start moving again.
I used my test drive to go up to O'Reilly where they came out and tested my system - battery good, starter drawing proper amps, etc... but they said that my reg/rec has a bad diode. Well, now I know.
The fellow said that my model has a separate reg./rec. from the alternator, which is a relief, since a reg rec is much easier to swap out than the whole alternator... so now I'm going to find that little bastard and fix it!

BearsLexus

Salim,

In a past Post from several years ago, I read you saying, "Voltage regulators are things of the past (when we used to have generators) .. now with alternators the regulators are not needed ..the alternator as a unit self regulates by the field coil." ( https://www.clublexus.com/forums/rx-...lectrical.html )
I was just told today that the 2000 RX300 does, in fact, have one. I have attached a picture of the one of which I was shown a picture.
Was I told incorrectly what the issue with my electrical system is and shown a false picture?
- just trying to figure out the truth of my issue!

carguy07

I don't know if this is your issue, but yes this alternator does have a replaceable voltage regulator and that is basicly what it looks like. The rectifier is a separate part too. They are not cheap.

salimshah

Help me remember the context .... I grew up with dynamo [the precursor] of alternator and they needed a stand alone regulator with relays ... and they have gone. Now we have solid state rectifiers and regulators which are housed inside the alternator. This is much more efficient and long lasting setup [no more commutators that need servicing] and most of all electrical noise is now much reduced. In an alternator theoretically the only things that can wear out are the brushes, slip rings and the bearings. The solid state stuff is practically good for a lifetime (unless there was a massive short).

First thing I would do is try to hold rpm around 500 -750 and see if the 'battery light' goes away. If it does you need not look further into the charging system.

If you still want better and complete testing, take the alternator off and take it to an auto shop. They have a jig and can test the alternator for you.

Sorry if my past post(s) have mislead you. The principle of generating the voltage is ,,, a conductor is moved through a magnetic field. The rate of change of magnetic field is proportional to the voltage .. so if the rotor spins at higher rpm, you will get higher voltage, so some regulation is needed

Salim
[more info can be obtained from looking up dynamo. generators and regulators].
Also a regulator will cut down the voltage at higher rpm and has no capacity to create more voltage at idle. When your regulator fails to regulate, generally you boil your battery.The other scenario is the regulator fails to produce any voltage.

When the Rectifier diodes go bad, your battery gets drained out ir it fails to charge up.

BearsLexus

Thank you Salim You certainly didn't mislead me, I was just looking up info on the voltage regulator here and found that post, and got a little confused.
As for testing things, I went up to O'Reilly and they put some kind of charging system testing box on the car and it said that the voltage regulator has a bad diode and wasn't putting high enough voltage to the battery.
The battery light goes out over 1000 RPM, but comes back on under.
I'll be replacing my Voltage regulator ASAP, cuz I sure as heck don't want to be buying a new battery, too!
Thanks for everyone's help!

BearsLexus

So, it really didn't hit me until the drive in to work today, Salim, you had mentioned holding the rpm at 500 to 750 rpm and see if the battery light goes away... when my car is all warmed up this is about the rpm range that it idles at. Is this incorrect?? Now I'm worried again!

lol... anyway, I was able to get in to work today and that is a relief, at least!