83stariontravis Posted January 26, 2015 Report Share Posted January 26, 2015 I am running a 4 pin HEI ignitor for ignition and a brand new stock replacement coil. Wondering if the HEI requires a different spec coil. At full throttle I get a very slight studder that goes away if I back off a little bit. 16g turbo at 10lbs of boost. Runs great otherwise. AFR gauge shows full rich during the studdering. I am running the NGK 7031 plugs that are recommended. Maybe I need a different heat range? Going to pull plugs now to inspect. 4 pin HEI ignitor install discussed here:http://www.starquestclub.com/forum/index.php?showtopic=140828&st=20&hl=knock#entry1459419 Link to comment Share on other sites More sharing options...
scott87star Posted January 27, 2015 Report Share Posted January 27, 2015 The HEI ignitor has a set dwell obviously optimized for an HEI coil, I've never measured the dwell so I have no idea what it may be. It can't be too far away for the optimum of a stock 12V coil but that only applies when you're running stockish boost levels. I guess I'd be interested in the plug read. Link to comment Share on other sites More sharing options...
JohnnyWadd Posted January 27, 2015 Report Share Posted January 27, 2015 Regap plugs smaller and do a test run ? Link to comment Share on other sites More sharing options...
83stariontravis Posted January 27, 2015 Author Report Share Posted January 27, 2015 I figured someone would say that. Ill try that today. Plugs look rich so i put in a hacked stock maf. Problem still there but afr looks better. Heat range looks as good as it can get and i see no evidence of detonation. Link to comment Share on other sites More sharing options...
JohnnyWadd Posted January 28, 2015 Report Share Posted January 28, 2015 I think its a spark issue with what you are saying about AFR and no detonation. Maybe check coil and plug wires with a multimeter too. If going to a smaller gap fixes it the issue I would upgrade the coil. Link to comment Share on other sites More sharing options...
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