NoOne

While trying to diagnose my 1221 code, no signal on front left wheel sensor, I've been reading about similar sets of problems relating to voltage.

What is normal voltage readings I should be seeing?

I have a 1 year old Optima Redtop, which I have heard are not the best.

I have the following:

Pioneer DEH6700 deck
Hifonics 440watt amp running 4 MB Quartz Speakers
Hifonics 600watt amp running a single 14" solobaric sub
Cap for those 2 subs
HID's(not sure of brand)
PIAA's
HUD
ASP Underdrive pulley
Autozone aftermarket Alternator about 8 months old
heads/cam
900rpm idle speed

The car pulls the code, and I've already ordered a replacement cable and wheel hub but I keep thinking it has something to do with the electrical system.

When I bought the car last week, it read 13.3.13.8 volts all the way home on the freeway.

Now it fluctuates between 12.2 - 13.3, even dipping down into the 11's at idle with the A/C and radio on.

The common part is, the code will set sitting at idle for periods, or after some city driving followed by shutting off the car and starting it again.

I had the Pioneer DEH7700 installed yesterday, the guy had the accessories on testing out the radio, the code set when he started the car, it then set again after 2 miles. Drove it on the freeway and it was fine.

I'm trying to come up with a set of situations where the problem happens and doesn't happen. It never was a problem coming back from TN but that was all freeway.

I've never had a problem on the way to work and back, all freeway.

I have had a problem around town, or driving to my other office, stop and go for 30 miles.

Each time it gets better once I pull over for a few minutes, let it sit, and then get right on the freeway.

I thought it might be a loose connector, but I went to the drag strip with it, 30 miles on the freeway, 3 passes, and 30 miles home, not a single problem, surely it would have come loose at that kind of constant acceleration.

Drove it 120 miles to dinner last night, all highway, no problems.

Last time it happened I was sitting in a parking stucture at work showing some people the car at idle for a long period, pulled out, pulled the code.

Electrical things cause strange problems. On my wife's turbo Miata a bad battery caused the aftermarket TEC III to command the fuel pump on and the injectors open, ALL THE TIME. You would turn on the key to accessory and it would flood the entire block, intercooler, turbo, etc with fuel. Fuel would start pouring out of the motor. We troubeshot that forever and just changed the battery one day, no more problems.

If ever there was a candidate car for a 42 volt system, this one is it

Any help would be greatly appreciated.

NoOne

Just an update. I originally wrote that this morning but CF was having problems posting.

I drove the car again this morning and turned the Sub down. The new radio has an option for Sub Volume and I turned it down to -2 from 0 where it was set.

Now I see almost constantly above 13 volts and when I start the car it dives down to 11 but comes back above 13, to 13.2 or so.

Before I was seeing below 13 with the sub turned up to its normal volume.

NoOne

Went to Autozone. They tested the Alternator and the Battery.

Both checked out fine, 13.55 volts on the alt and 2.2-2.4 amps at idle.

Battery also completed the check.

When I got back in the car the DIC showed 12.5 volts now instead of 13.2 which I left the house with. Shutting off the stereo brought it back upto 12.8.

Bad battery?

Larger Alternator?

Stock pulley?

JoeyG

Your charging system sounds fine. With the car in park/nuetral, the ac on, and the radio, there will be a voltage drop due to the excess load. As long as the charging system is at 11.5vdc or higher there shouldn't be any electrical problems (As long as the stereo isn't pulling the 11 to 13 to 11 to 13 swing shift). You might want to go ahead and upgrade the alternator to stater to battery wiring as well as engine grounds, to help better conduct the voltage in the car. With your stereo also a higher output alternator maybe a good option also.

Good luck with the wheel sensor replacement. Make sure the wires haven't rubbed bare on the A arm as mine had

NoOne

Another day and some more information.

Drove it in this morning and on cold start its almost always at 13.5-13.7 volts. As temps build it drops down to the 13.0-13.1 range and stays pretty consistent, on or off the gas, idle or driving, AC ON or OFF.

Today I went to drive it home from work, heat soaking outside at 96 degree's and very humid.

Start the car, 12.9 volts, won't budge. Turn on the AC drops to 12.6 volts regardless of the RPM or load.

Come to the first stop light, go to take off, again when there is load being pulled for spark, the DIC says 11.9 volts and the Service Traction Control System comes on.

I cleared the Reduced Power Mode while the car was running but the AH code was still set, but at least I could drive. I assumed if I left the AH code it would not set itself again and go into Reduced Power mode.

Several times on the way home it would drop to 11.2 volts when coming to a stop or leaving a stop.

With the air conditioning on it read 12.6 volts moving, 12.1 idling. Hit the gas to take off and it dropped down into the low 11's.

I am pretty sure its electrical now and not my wheel speed sensor or cable.

The temp seems to effect it and on the way home from picking it up its been a solid 13.9 all the way and slowly over a week and a half its peroformance has dropped.

The battery is less than a month old, but its a Optima so I'll get it replaced under warranty anyways.

I'm going to go with a 160 amp alternator, I hear this sets a code, is that all it does? I can just edit it out if thats the case.

I notice the lack of complaints from 01/02/03/04 owners in regards to electrical/AH problems compared to 98/99/00. GM didn't go from 110amp to 140amp for no reason at all.

Anyone have any other thoughts before I go get this new alternator or know the PCM part of it?

Also the strangest thing, now my exhaust pops pretty bad, before it would do it once in a while, but now it does it constantly, Corsa Indy w/ QTP Longtubes, no cats. I had a bad alternator on my 98 Z28(same unit) and had problems with it breaking up in the low rpm range, wonder if that is another sign of a electrical problem.

NoOne

This is driving me nuts.

Here is the latest set of numbers.

Start the car, nothing on, no radio, no AC, just running.

DIC reports 12.9 volts. Meter on battery says 13.55

AC ON DIC 12.6 volts. Meter on battery says 13.55

Stereo On(440watt/600watt/200watt) DIC says 12.3. Meter on battery says 13.55

PIAA's on DIC says 12.2. Meter on battery says 13.55

Rear Defrost on DIC says 11.5! Meter on Battery says 13.05

This was with the car sitting for 2-3 hours in the garage, still hot.

Anyplace I can read alternator draw?

Something is obviously wrong somewhere, like there is a drain somewhere else in the system.

Thanks

JoeyG

Thers at least 1/2 volt difference between what the DIC reads and what you'll measure at the battery. It's just drops from all the connections. For instance, on my 220Amp alt. I can measure 13.8 volts at the alt/battery, but on the DIC it'll read 13.0 flat

JoeyG

What size gauge wire engine and battery grounds?

NoOne

Joey,

I think, at least I hope, might have fixed it, but who knows...

It has a heavier gauge wire going right from the ALT to the battery for the stereo in addition to the one routing from the starter. All of the stereo stuff is done correctly as far as wire sizing. I don't know exactly but I had the guy who changed the head unit out over the weekend check it out and he said everything was done well and no corners cut.

I went back and read Bill's post about the grounds on the car. I pulled apart the driver side ground and it was a little dirty, but not too bad, cleaned it off with electric spray and scrubbed it clean.

Go over to the passenger side, the connector is I'd say about 1/8 to a 1/4 of the way out on one side. I pulled it apart, cleaned it, dirtier then the other and snapped it all the way back together and bolted it back down.

I went out and started the car, 12.9, hot, with a UD pulley.

Turned on the AC, Rear Defrost, Bottle Heater, PIAA's, stereo turned all the way up and drove it.

At times I went all the way down to 10.5 on the DIC, I had forgotten the bottle heater early to test, that is a huge draw, then I'd hit the purge which was good down to 10.3.

I lugged the motor, brought it down to 500rpm during launches, everything I could do to make it fail and it seemed to be fine through all of this.

Even opening and closing the cut outs, the only thing I didn't have on were the interior lights and the headlights since they are HID's and i heard they hardly draw anything once lit.

This was way lower in the voltage range that I was getting when I was getting the error.

Does anyone know where the wires from the passenger side ground under the coolant tank run? Is one of them for the BCM or TCS module?

Its even hot outside, so if it fails now I don't know what it could be unless its just a flaky alternator.

Battery is obviously fine.

I'll check the rest of the grounds when its not 100 outside.

How were you measuring the alt? I can wire something up so I can drive around and watch it if the problem is not fixed.

Thanks

JoeyG

measure it hood open, then I ran a FUSED lead from the alt, with the hood down but not closed and just verified the readings were staying constant. I had the laptop connected also to bouble check. Whats wierd is the HPTuners will show the same voltage as battery reading, but the DIC always displays 0.5-0.8vdc lower