Über855R Posted August 9, 2013 Report Share Posted August 9, 2013 In a nut shell. Car was running great. Parked it. Battery went dead. The battery was stored for some time and has needed replacing for a while. Jumped it, and the car started having very low vacuum ~3"Hg and very erratic AFR when cruising, running lean. Has anyone ever experienced similar issues due solely to an electrical problem? My first instinct is to look for a vacuum leak. But seeing as how it was all fine before the dead battery, it seems like low ignition power might be associated. Anyone have thoughts or similar experiences? Link to comment Share on other sites More sharing options...
Simply Volvo Posted August 9, 2013 Report Share Posted August 9, 2013 Maybe the ECU is relearning? Explains AFR but not vac. Link to comment Share on other sites More sharing options...
rmmagow Posted August 9, 2013 Report Share Posted August 9, 2013 I'd disconnect the new battery, tape the + and - cables together for 30 mins or so and hook everything back up. Clears the adaptives and lets the computer re-learn everything. Others chime in please, are you supposed to let the engine idle up to full temp when doing this? I sort of remember something about the idle air thing needing to re-learn. Link to comment Share on other sites More sharing options...
Simply Volvo Posted August 9, 2013 Report Share Posted August 9, 2013 I'd disconnect the new battery, tape the + and - cables together for 30 mins or so and hook everything back up. Clears the adaptives and lets the computer re-learn everything. Others chime in please, are you supposed to let the engine idle up to full temp when doing this? I sort of remember something about the idle air thing needing to re-learn. You should let the engine idle for about 5 minutes. Stay out if boost for the first 10 miles or so and then only boost to half boost a few times and then full boost a few times and it should relearn everything. Link to comment Share on other sites More sharing options...
Über855R Posted August 9, 2013 Author Report Share Posted August 9, 2013 Maybe the ECU is relearning? Explains AFR but not vac. I think this is it. Today, it started with a jump. (I Still need a battery) But the vacuum was normal 18-20"Hg and the AFR was normal. Boost normal. Weird Shiite. It seems like vacuum would be a mechanical function of engine idle, so not sure why electrical issues would affect it so obviously. Still, car seems to work perfect again. Has anybody had similar issues with electrical problems? Link to comment Share on other sites More sharing options...
Über855R Posted August 9, 2013 Author Report Share Posted August 9, 2013 Got a new battery, things seems fine. Really weird how the low power made vacuum read low. It just dawned on me that my Guages are electric so possibly the dead battery was under powering the Guages and not reading correctly. Possible however unlikely. Anyway, thanks for the ideas guys. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.