Could low voltage cause rough idle?
Thread Starter
Instructor
Joined: Jul 2001
Posts: 146
Likes: 0
From: Hermitage, TN
Could low voltage cause rough idle?
Since I put my alternator pulley on, the voltage runs from 12.5 to about 11.8 with the air conditioning or headlights on. I pulled all the plugs this evening and they had some carbon build up. How many volts do I need for my ignition to perform optimally? Thanks for the help. :cheers:
Melting Slicks
Joined: Jun 2001
Posts: 2,525
Likes: 1
From: Sarasota, FL
Re: Could low voltage cause rough idle? (SLOWBUSA)
Voltage sure sounds low, but I don't know at what levels it begins to effect ignition. If you still have the old parts, put 'em back on and see what happens.
Melting Slicks
Joined: Jun 2001
Posts: 2,525
Likes: 1
From: Sarasota, FL
Re: Could low voltage cause rough idle? (SLOWBUSA)
I am putting the original pulley back on tomorrow. :yesnod:
Good Luck
:cheers:
Instructor
Joined: Sep 2000
Posts: 188
Likes: 0
From: Fort Collins, CO USA
Re: Could low voltage cause rough idle? (BobMachus)
A fully charged battery should read 12.6 v. When running it should be about 2 volts above that. At your readings (if accurate) you will just barely stay even or most likely it will be constantly discharging.
Low voltage doesn't only affect the ignition, it can affect the whole powertrain management. All computer sensors and acutators plus computer controled transmission can be affected.
Even an underdrive pulley should keep the battery charged. Check to make sure the alternator wasn't damaged in the pulley change or that all the connections are good. It sounds like you might have done it in when working on it.
Good luck. bf
Low voltage doesn't only affect the ignition, it can affect the whole powertrain management. All computer sensors and acutators plus computer controled transmission can be affected.
Even an underdrive pulley should keep the battery charged. Check to make sure the alternator wasn't damaged in the pulley change or that all the connections are good. It sounds like you might have done it in when working on it.
Good luck. bf
Melting Slicks
Joined: Apr 2001
Posts: 2,117
Likes: 222
From: Ca.
Re: Could low voltage cause rough idle? (SLOWBUSA)
Ditto to above, plus; In your programming you have a table for inj. pulse width vs voltage. It increases the inj. pulse width with lower voltage to compensate for it; you may need to adjust that if its making it run too rich with the lower voltage.
