April 21, 201212 yr Author comment_387775 Ok! I check my alternator and its a 12v 60a alternator! I believe it's a 280z or 280zx alternator? The previous owner Bridges the connector where it suppose to plug into the voltage regulator! He jump two wire for the light and one wire on the connector back down. I don't know if that's right? I don't see any wire coming back from the alternator to the battery! The only wire that's connect to the battery is the big red wire from battery positive terminal to the starter motor. Any one have the charging system diagram to convert external to internal voltage regulator for 1971 240z? Link to comment https://www.classiczcars.com/forums/topic/42965-car-stumble-and-backfire-when-accelerated/?&page=2#findComment-387775 Share on other sites More sharing options...
April 21, 201212 yr comment_387780 It sounds like a PO did a swap for a later model alternator. Here is a link to the alternator swap for a 240Z: http://www.zhome.com/ZCMnL/tech/280Alt.html. Link to comment https://www.classiczcars.com/forums/topic/42965-car-stumble-and-backfire-when-accelerated/?&page=2#findComment-387780 Share on other sites More sharing options...
April 21, 201212 yr Author comment_387824 Thanks! I'll try that converting! Link to comment https://www.classiczcars.com/forums/topic/42965-car-stumble-and-backfire-when-accelerated/?&page=2#findComment-387824 Share on other sites More sharing options...
April 22, 201212 yr Author comment_387931 OK! I have fix the issue! It was the alternator! The previous owner wire it wrong and it did't charge my battery so the car was only running on battery with nothing charging it. With that issue! My MSD ignition set didn't have enough juice to run properly. Thanks to all ya help! Now if anyone can tell me where's the idle screw for the Mikunis? so i can do my timing or can i just have someone rev it to 3000rpm? Link to comment https://www.classiczcars.com/forums/topic/42965-car-stumble-and-backfire-when-accelerated/?&page=2#findComment-387931 Share on other sites More sharing options...
April 22, 201212 yr comment_387932 Now if anyone can tell me where's the idle screw for the Mikunis? so i can do my timing or can i just have someone rev it to 3000rpm?Have somebody hold your RPM's at 3000. If you are running triples you really need to get a wideband to know where you are. Lots of recent posts on this topic. Link to comment https://www.classiczcars.com/forums/topic/42965-car-stumble-and-backfire-when-accelerated/?&page=2#findComment-387932 Share on other sites More sharing options...
April 22, 201212 yr Author comment_387945 Thanks for the info! but i would like to adjust my idle, it's setting at 1200-1300 rpm. Any one help! Edited April 22, 201212 yr by Cali71z Link to comment https://www.classiczcars.com/forums/topic/42965-car-stumble-and-backfire-when-accelerated/?&page=2#findComment-387945 Share on other sites More sharing options...
April 25, 201212 yr Author comment_388196 OK! i adjust my timing at 3000 rpm with 35 degree and at idle it's showing 20-22 degree is that right? I think i did it right? Anyone help? Link to comment https://www.classiczcars.com/forums/topic/42965-car-stumble-and-backfire-when-accelerated/?&page=2#findComment-388196 Share on other sites More sharing options...
April 25, 201212 yr comment_388213 If the idle speed is still to high the base timing will seem too high because it is still advanced some. Did you get the idle speed lowered properly? Link to comment https://www.classiczcars.com/forums/topic/42965-car-stumble-and-backfire-when-accelerated/?&page=2#findComment-388213 Share on other sites More sharing options...
April 25, 201212 yr Author comment_388216 Thanks! I forgot to check the idle speed! yup i believe it set around 1200-1300! I still couldn't figure out how to adjust the idle! Any help well be appreciate! But i'll do more read and hope i figure it out some day! Link to comment https://www.classiczcars.com/forums/topic/42965-car-stumble-and-backfire-when-accelerated/?&page=2#findComment-388216 Share on other sites More sharing options...
April 26, 201212 yr comment_388408 Odds are your carbs each have an idle speed screw that adjusts each carb independently of each other. You will need to resync the carbs carefully. Which from the sounds of it you may not know how to do. You need to find an article on setting mikuni carbs up for the first time and do that. It will require patience and a flowmeter. Link to comment https://www.classiczcars.com/forums/topic/42965-car-stumble-and-backfire-when-accelerated/?&page=2#findComment-388408 Share on other sites More sharing options...
April 28, 201212 yr Author comment_388593 Thanks! I have been reading and have fix my issue! Car is running strong now! Link to comment https://www.classiczcars.com/forums/topic/42965-car-stumble-and-backfire-when-accelerated/?&page=2#findComment-388593 Share on other sites More sharing options...
April 28, 201212 yr comment_388612 Thanks! I have been reading and have fix my issue! Car is running strong now!How did you fix it, it would be nice to know. Link to comment https://www.classiczcars.com/forums/topic/42965-car-stumble-and-backfire-when-accelerated/?&page=2#findComment-388612 Share on other sites More sharing options...
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