PDA

View Full Version : lawn mower idle with heater on



muddeprived
09-29-2015, 06:39 PM
1999 TJ SE 2.5 manual 99,800 miles NO AC
tuneup two months ago

I used my heater today to defrost the window since it was raining and its fogs up instantly. As soon as I turned it on the jeep starts idling like a lawn mower, pretty rough. No CEL, no goofy rpms, or anything else out of ordinary except for the rough idle. It calms back down as soon as I turn off the heater. What could cause the jeep to idle like this when the heater is on?

oros35
09-30-2015, 11:02 AM
Alternator not putting out enough to keep up with the draw of the heater, drawing voltage down screwing with the computer?

muddeprived
09-30-2015, 11:31 AM
Wouldn't that trigger a CEL?

oros35
09-30-2015, 11:45 AM
Might not.