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Backfire through Carb, Timing Issue?
https://slantsix.org/forum/viewtopic.php?t=58263		 Page 1 of 1
Author:  Slant6-M37 [ Tue Sep 01, 2015 11:30 am ]
Post subject:  Backfire through Carb, Timing Issue?
I recently added the GM HEI Conversion to my truck and now it backfires when under a load. In addition it is running very rich. Should the timing have been adjusted after doing this? I have not been able to find any info on the settings with the HEI conversion. I probably should also look at adjusting the carb but I don't know which to do first. Any help would be appreciated.
Author:  JBracey [ Tue Sep 01, 2015 3:36 pm ]
Post subject:  Distributor Wires
You might have your distributor wires backwards on the HEI module. I know when I did mine I had them reversed the first time. :)
Author:  Reed [ Tue Sep 01, 2015 3:37 pm ]
Post subject: 
Timing and carb setting should remain what they were before the swap. The only thing HEI does is provide a longer dwell period and a hotter spark. That's it.

I second the suggestion that you try switching the pickup wires going to the HEI unit.
Author:  Slant6-M37 [ Fri Sep 04, 2015 5:24 am ]
Post subject: 
Thanks for the responses, I'll check that out this weekend.
Author:  Slant6-M37 [ Wed Jan 06, 2016 7:15 am ]
Post subject: 
Thank you again for the suggestions on fixing this problem. I just got back to working on the truck and I found by back-tracking through everything the the back-firing was being caused by the #5 and #6 spark plug wires being in the wrong locations on the distributor.
Author:  64DartGT [ Wed Jan 06, 2016 8:23 pm ]
Post subject: 
Way to go, glad you figured it out!! :D
Author:  wjajr [ Thu Jan 07, 2016 5:58 am ]
Post subject: 
Quote:
caused by the #5 and #6 spark plug wires being in the wrong locations on the distributor.
You can't beat simple; no tools were abused in that repair.
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