Miss at Idle--Problem Found
Thread Starter
Instructor
Joined: Aug 2014
Posts: 128
Likes: 20
From: Panama City FL
Miss at Idle--Problem Found
(2013 GS ) I replaced plugs and wires this morning with factory AC Delco parts. All wires checked out fine reading in the 783K ohm range, the new wires read approx. the same. All plugs removed easily and looked the same tan color. All plugs were gapped properly in the .038--.040 range except for numbers 3 & 5. These two had the center electrode nearly worn away which made the gaps be in .070 range. Not sure of the explanation for this but it certainly idles well now and runs out smoothly down the road.
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,108
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
I had lost the iridium tips on 7 of 8 plugs. Under light load it was not noticeable up to about 3/4 throttle. At WOT it killed at least .06 off my 60' time and maybe twice that on the 1/4 mile ET. There's something about a huge plug gap that these engines don't like. 
Last edited by HOXXOH; Sep 24, 2016 at 12:45 PM.
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,108
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
It not totally unusual for the iridium tip to break off. I don't know for sure what causes it, but I heard high temps and/or running lean could do it. According to my wideband and exhaust tips lean is not my problem, but the Phoenix heat in rush hour traffic might be.
Safety Car
Joined: Aug 2005
Posts: 4,279
Likes: 82
From: North Strand, NMB, SC; Retired x 2 (US Army: 70-90 AD) (US Army: 91-16 DAC); yea, I'm old.
Three inches from the ☀️ in rush hour, what do your coolant temps look like?
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,108
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
Factors include, 4000 stall converter, trans cooler and Vararam blocking airflow, pavement temps exceeding 120.
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Safety Car
Joined: Aug 2005
Posts: 4,279
Likes: 82
From: North Strand, NMB, SC; Retired x 2 (US Army: 70-90 AD) (US Army: 91-16 DAC); yea, I'm old.
In stop 'n go traffic on a warm day (100-109) where 20 mph is considered fast, I'll get to 230+ in 10 minutes. If it's hot (110-119) the time is less. When/if it hits 240, the AC goes off and the heater goes on with max fan. If it doesn't drop at that point, I bail out and find a place to park. I've seen 245 too many times to count.
Factors include, 4000 stall converter, trans cooler and Vararam blocking airflow, pavement temps exceeding 120.
Factors include, 4000 stall converter, trans cooler and Vararam blocking airflow, pavement temps exceeding 120.
Melting Slicks
Joined: Aug 2016
Posts: 2,448
Likes: 160
From: JARRELL TEXAS
If you have plug wire failure I have a solution.
Magnum Plug wires... Solid Stainless Steel core wire (0 Ohms), RF choke (no radio or electronic interference), Marine grade boots & HD silicone cover.
Magnum Plug wires... Solid Stainless Steel core wire (0 Ohms), RF choke (no radio or electronic interference), Marine grade boots & HD silicone cover.
