knightrider 0 Posted August 15, 2016 Engine has been fine last 20k or so miles. Left it for about 6 weeks, not driven. Battery was flat. Started and it now sort of pulses and hunts, very regular, when cold, kind of vrrooom, vrrooom, vrrooom. Stops once car is warmed to operating temp. Black smokes a bit when revved whilst cold. Seems to be running too rich. Any ideas what could be causing this. Sensor somewhere. I have a reasonable knowledge of cars and engines but do not know how VR6 cold enrichment works. Quote Share this post Link to post Share on other sites
robrado974 1 Posted August 16, 2016 Because of the battery being flat for a period of time the ECU needs to learn the engine again . If you do a search on it , you will find all the info . Quote Share this post Link to post Share on other sites
knightrider 0 Posted August 16, 2016 Thanks robrado974. Is that on here or more widely on google? Quote Share this post Link to post Share on other sites
robrado974 1 Posted August 16, 2016 Use the search on here . You will find what you need . Quote Share this post Link to post Share on other sites
Jim 1 Posted August 16, 2016 I would be surprised if this is the reason. During periods when not using my VR very much I always pull the battery, which can be off for weeks at a time. And when I reconnect it, it drives honestly the same as it does if I've left the battery connected between drives. Could be down to the coolant sensor for the ECU, though I'm not sure if that's in play right from cold - I think it is. Might be reading an incorrect value and not fuelling the car correctly - this would also explain the black smoke (possibly running rich?) Quote Share this post Link to post Share on other sites
