I promise....I did a few searches on this and didn't find anything that matched up with my scenario....so don't flame me!

I don't drive my car that often (although, it may be much more frequently with gas prices the way they are.....I parked the Nissan Titan today to drive the Vette).....

In any event.....I recall the last time I drove the vette I was getting about 27 mpgs on the DIC from a full tank of gas on the way home from work....parked it in the garage and that was it....that was about 2 weeks ago.

Today, I get in the car and the MPG reading was 0.0 Is this normal? Or is something up??

 

Was your reading the Average or the Instant MPG? Sitting still, th Instant reading will be 0.0.

 

Average for sure....I watched it all the way to work this morning and by the time I got to work it was back up to over 24 mpg...but it took awhile to get there.

 

Also, I've noticed that if I change the view on the heads up display to where it is showing the fuel level, for example.....when I turn the car off and then get back in, it sort of resets itself and goes back to the oil level (or temp, not sure which one it is exactly).

 

Did you hit the reset button by mistake?

 

No, I wish it were that simple.....I've noticed this on a couple of other occasions but thought I was going crazy.

 

Maybe I'll go down during lunch and start it up and see if it reset again....

 

I noticed the same thing on mine when it sat for extended periods through the winters. Perhaps your battery is dropping below a certain charge level for the computer to retain its temporary level and it's loosing those settings - at least that was my thought. I bought a BatteryTender for those long periods when I would drive the Vette for a while and that seemed to take care of the issue.

Now that I'm driving the Vette regularly again, the issue hasn't returned so that's the best explanation I can come up with.

Anyone else?

 

It's caused by a low battery, the computer starts to go to default settings. The system knows that there is low voltage and begins to take items out of memory to save voltage. If you get in the car and you see that the mileage is on the DIC this is a sure sign of a low battery, if you had it set for another reading. For an extended time of non use (7 or more days) you should use a battery maintainer. This will extend the life of your battery. Bill

 

My 98 does the same thing when sitting idle for more than a week or so.I think because battery voltage drops below a preset threshold.

 

So is this an indication that my battery is kaput and I need a new one or will getting some sort of battery maintainer extend the life of the battery?

Thanks for eveyones help!

 

Okay....went to lunch and started the car up....went right back to an average of 0.0.

Forgot to mention that I do have an Optima Red Top....not sure that it matters at this point though.

 

Okay guys, sorry to re-hash this one, but still having some weird issues.....

I went and got the battery checked and was told it is totally fine. Then about two days after that, "Check ABS" and "Check Active Handling Sys" popped up on the dash. Turned the car off, and then back on, and the message went away.

I'm also still having the same issue with the Avg. MPG resetting back to zero "almost" every time I turn the car off.

Do you think any of these things could be related? Could I have a bigger issue goinig on (electrical)? I'm dreading bringing it into the dealer but might have to at this point.....

 

When the batteries start to drop into the 11.5v to 12.0v range, which will still check fine on a battery tester, these cars start to demonstrate weird behaviors. You said you have an Optima, but you didn't say how old it is.

I keep my Optima on a CTEK charger when I know I'm not going to be driving the car for more than a few days. Summer time is especially hard on batteries. Combine the high ambient temperatures, with high underhood temperatures, a marginal battery will fail in a short time.

Heat is much harder on a battery than cold. When I used to live in the midwest, I routinely got five years of battery life - now that I live in the Desert Southwest - if I get two years out of a battery.....doesn't matter if its an Optima, or a traditional cell lead acid battery - even those batteries that claim to be "Heat Busters" or whatever, I'm feeling very lucky.

These cars with their multiple processors produce a fairly substantial continuous drain on the battery - and the heat only exacerbates the condition.

So my guess is that your battery is discharging and is causing your problems. And then your occasional driving is not fully recharging the battery. Get yourself a battery maintainer like the CTEK available from Chip or a Battery Tender.....don't use a traditional trickle charger - it will cause sulfation of the battery.

 

Thank you for the reply BlackSedan!

The battery would be three years old in december....I know b/c I went to the same place that I purchased it to have it checked and was told that it had a three year warranty, which expires in Dec.

Do you thinki it would be safest to go ahead and get a new battery and then start the habbit of using a maintainer or tender?

 

You're welcome! And, yes - I would get a new battery and get into the habit of using the battery maintainer if you're not going to be driving the car daily.

 

Awesome, thanks again....

I don't frequent the forum near as much as I used to....is there a supporting vendor that you could recommend getting the maintainer from?

 

Just my 2 cents, but the battery does not sound like the problem based on the description. If the car cranks over fine you have more than enough battery power to retain all memory, and why would only the MPG memory be affected, i.e. what about radio memory, etc. A load test on the battery will tell if it is unable to hold a charge. Also, your AH/TC warnings are probably unrelated but you should pull the DIC codes to pinpoint the cause of the warnings.

As for your MPG average issue, the cluster pulls fuel consumption data from the PCM module. First I would recommend you pull the DIC codes and see if there are any related to fuel data. According to the service manual, the average MPG is calculated by the IPC based on the fuel consumption data sent from the PCM and the distance traveled from the odometer. Maybe the data is not being read correctly by the IPC or there's a fault in the IPC itself. A scan tool may be required to verify the data and see where the problem is.

 

I recommend Chip at C.C.A - here's a link to his site for the CTEK charger....click here!

You can purchase a Battery Tender which is less expensive, but I honestly think the CTEK is the best one, and Chip is the best vendor for it.

 

That's what it sure sounds like to me. Using a battery tender between drives should help.