Beastmaster Report post Posted February 23, 2014 I have a 1973 GMC motor coach with an Oldsmobile 455 with Howell fuel injection. Does anyone have any experience resetting the warm idle speed?Mine idles warm at a bit over 1000RPM.The Beast Master Share this post Link to post Share on other sites
dickandlois Report post Posted February 23, 2014 Beast Master, Welcome to the FMCA Forum! The first item that comes to mind regarding your idle speed being high is a vacuum leak! A leak will increase the idle speed about 300 RPM, if its a substantial leak. That being the case and the heat around the engine area, I would suggest replacing ALL the vacuum Lines if they have not been changed. Post the status of the lines and if they have been replace for the forum. That gives all a good starting point. Also, have you look over this website, it may also prove helpful: http://gmcmotorhome.info/howell.html Only running on one cup of coffee! Remember to check to vacuum advance of the distributor. Do you have a hand operated vacuum pump? A defective vacuum actuator will have a direct effect on idle speed. Rich. A direct link to the Vacuum system information. http://gmcmotorhome.info/howell.html#VACUUM Share this post Link to post Share on other sites
wildebill308 Report post Posted February 25, 2014 I don't know if this will help but most of the throttle body injections work much the same. http://www.gmcmidwestclassics.org/Web%20pages/Tuning%20the%20TBI.pdf http://en.wikipedia.org/wiki/User:Jayrabe/GMCMH-EFI http://gmcmotorhome.info/list.html Bill Share this post Link to post Share on other sites
