: car computers,how long to reset?
I understand if you disconnect your battery some car computers need to be used for a while until they reset and your car runs better/cleaner. Does anyone know how long this generally takes? I have a car that has been laid for a year(didn't expect to be very long at the time but time marchs on,..) I DID put in gas stabilizer and a top oil but its running just a bit rough.Not bad but I'm concerned about it passing emissions inspection. Am I right in thinking it doesn't reset correctly by letting it idle in the yard? (catch 22 I'm not supposed to drive it w/o it being/passing inspection. But I think I'm supposed to drive it in order to make the computer work correctly.)
10-08-2002, 04:25 PM
When I was still involved in product development the general rule was "Disconnect the battery for an overnight period, then reconnect and drive around for at least 30 minutes in as variable conditions as can be found." The computer would reprogram itself during the drive and be as good as new.
10-08-2002, 04:48 PM
disconect the negitive terminal for a few minutes, it most cases if there truely is nothing wrong the puter will reset itself, if not in most cases when a car runs rough or idles bad its either a EGR valve or an O2 sensor, this is most cases, what kind of car we talking about.
10-08-2002, 05:05 PM
genrally, the puter resets after hitting operating temp of the engine twice.
10-08-2002, 07:40 PM
Whenever, I had a computer reset - I was able to get it stablized by simply running down the road, getting it to cruising speed, and back to idle for about 5 minutes. Basically, the computer needs to see idle, mid range, high speed and back - to set its operating parameters.
I have also heard of some cars, requiring them to get to the correct operating temperature once or twice - before being fully stable.
Bottom line - I don't belive that you will be reset, if you let the engine idle in the yard. It needs to get up to speed, so that the throttle sensor, the speed sensor, and the engine sensor can all interact and be properly calibrated.
10-09-2002, 04:17 AM
E-proms are pre-programmed to run the vehicle. The computer is set until manually changed. The only activity related to run time (for things like humidity, temperature, pressures, vacume and carbon and oxygen) is the sensory information. The computer runs its pre-programmed calculations based on the sensory combinations received while the engine is running.
It is more likely that if the engine is running rough after a long sit, it is due to old fuel and related problems, exhaust blockage (mice?), Injection ports fouled, fouled plugs and etc, etc...
10-09-2002, 05:09 AM
Once a vehicle's O2 sensors are heated up and switching good the computer takes over by adjusting the fuel injectors and IAC to keep a 14.7:1 ratio. After a computer reset and once the O2's are up to temp the computer will do readiness testing, a failed readiness test will fail your emmissions test. Check out www.obdii.com and look at driving cycles
The is an 88 Pont. Firebird 5.0L Not sure they had obdii codes then. I guess I will try to run it locally for a while getting it up to temp a few times. Another question it has 130K on it. Always used Mobile 1. Never burned ny oil but I noticed now after ideling for a while a bit of smoke that gets worse after reving it. I did this 3 times letting it get up to temp and then sutting it down for a few days. So in relation to getting the test. I drained it and put in a heavier Valoline high mileage oil that s said to "recondtion valve guides and seals ( put in the 20-50w) I drove it up the road a few times (only 2/10 of a mile each way AFTER it was at operating speed) and although it seemed to be as bad as ever when I started, however after driving it ,. it SEEMS to be much better (?) What do you think happened here,..the valve guides DID get conditioned by this oil, Or do you think the rings were stuck and got freed up? Can either happen?