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Ok.,I recently purchased a 1990 c4 70,000 original miles,garage kept cleeean! But battery was done! After a quick charge to move the car,I decided to stop and have the oil changed,went good,feeling better,but the battery died! Then next start,proceded down road,car started missing and sputtering,so o turned around and just got home when it cut caroff..next start the car will not idle hardly by itself but no codes on computer? Talked to original owner who said"if battery dies car runs crappy for out 20 miles?????? Ok whats the secret on this issue.,.
have the battery load tested and make sure it is fully charged. testing the alt would not be a bad idea. make sure battery connections are good on both ends.
Last edited by antfarmer2; Dec 15, 2015 at 11:48 AM.
Any time you disconnect the battery, the computer has to re-learn the settings. The previous owner is correct.. Also you will have to reset the clock and the radio settings...
Any time you disconnect the battery, the computer has to re-learn the settings. The previous owner is correct.. Also you will have to reset the clock and the radio settings...
Drive the car at different speeds, do some acceleration like easy on the gas, medium throttle, and WOT. Can't hurt to do some downshifting, even driving at different speeds without a lot of shifting.
Not sure if a full 20 minutes is needed but definitely 10-15 minutes.
As far as the battery, it would be a good idea to have a load test done on the battery. Don't go to the chain auto parts stores. Take the car to a reputable shop and have the entire charging system tested. You may have a good battery but a bad alternator.
Any time you disconnect the battery, the computer has to re-learn the settings. The previous owner is correct.. Also you will have to reset the clock and the radio settings...
Clock and radio, sure. re-learn, IDK. It might not be at the finest but unless something is further out, why wouldn't the ECM be able to use stock programming with minor tweaks? My car might not be perfect after the battery is removed but to say it runs crappy, I can't say I ever had that. All my other cars have had batteries removed and they never ran crappy. In fact, it is hard to notice.
Clock and radio, sure. re-learn, IDK. It might not be at the finest but unless something is further out, why wouldn't the ECM be able to use stock programming with minor tweaks? My car might not be perfect after the battery is removed but to say it runs crappy, I can't say I ever had that. All my other cars have had batteries removed and they never ran crappy. In fact, it is hard to notice.
I've had the battery out of mine more than once.
And when the battery is installed again, you don't really notice any difference in the way it runs.
I've had the battery out of mine more than once.
And when the battery is installed again, you don't really notice any difference in the way it runs.
I would think that the only way it can happen is if the car needs to have the system "learn" because it has been set so far out that it is pretty close to the edge of what it can "learn". In which case, you removed all the adaptation by removing the battery. Other than that, the programming should be pretty close. Close enough you can't tell the difference, I would think
Sounds like you have issues aside from the battery. I've never had a car run "rough" after a simple battery change. Might be time for a tune up and overall evaluation of the car.
From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
The ECM needs to "relearn". This means some time and a few miles are necessary after dropping power off the ECM.
Yes it may run rough or behave differently at first startup after reconnecting the battery.
Not to worry.. Chive On!
Positive battery post.
Last edited by JrRifleCoach; Dec 15, 2015 at 10:22 PM.
It is my experiance that these cars run the best when the batt, is fully charged and the charging sys. is keeping the running voltage of the car at approx. 13.2 volts. Good luck!
It would be a good idea to check what the voltage is when the car is running badly. IF the voltage is down in the sub 11.5 volt range - you have a charging issue, and it's possible that the low voltage is bothering the PCM.
Anytime you deeply discharge a battery - you hurt it. If the battery is old, and deeply discharged, there is a good chance the damage is terminal. Trying to charge such a really dead battery CAN hurt the charging system - so IMHO - Step 1 is to test the battery, and unless it tests out like new - I'd probably replace it. Step two - with the new or known good battery in the car - start it and after a minute or two of running - check the voltage. As Red91 said - over 13 Volts is the right answer here. Not seeing that - you probably have a charging system problem.
Dead Battery Reset?
Drive the car at different speeds, do some acceleration like easy on the gas, medium throttle, and WOT. Can't hurt to do some downshifting, even driving at different speeds without a lot of shifting.
