View Full Version : Mild flat spot, 1500-1800 rpm...
38Blackfin
Mon, April 25th, 2011, 03:36 PM
New Gryphon 5000 miles ago, 87 Perf custom tune, 2008 SCrew 5.4, Gotts, Mag SISO, stock cats and y-pipe, 100,000 miles.
New plugs, fuel filter, everything else original, throwing no codes. Did the BG clean thing for the injectors, MAF, TB about 10,000 miles ago.
3 things:
Flat spot 15-1800 rpm, right after a shift typically, push a little harder, drives through it.
Smells lean at start-up. Most 50+ yo's will know what I'm talking about:cheesy smile:
Slight knock at hot start, sounds like spark knock.
Other than that runs great, 17-18 mpg average.
thanks!
Randy
Jackpine
Tue, April 26th, 2011, 08:51 PM
New Gryphon 5000 miles ago, 87 Perf custom tune, 2008 SCrew 5.4, Gotts, Mag SISO, stock cats and y-pipe, 100,000 miles.
New plugs, fuel filter, everything else original, throwing no codes. Did the BG clean thing for the injectors, MAF, TB about 10,000 miles ago.
3 things:
Flat spot 15-1800 rpm, right after a shift typically, push a little harder, drives through it.
Smells lean at start-up. Most 50+ yo's will know what I'm talking about:cheesy smile:
Slight knock at hot start, sounds like spark knock.
Other than that runs great, 17-18 mpg average.
thanks!
Randy
Great mileage! I get 15.1-15.5. I don't have your "flat spot". I wonder if the Torque Converter is locking up too soon? Have you monitored that? And if it is, you can adjust the part throttle lock/unlock points in the Custom Options.
I also don't have the spark knock at hot start or the "lean smell". I doubt this is a significant worry, since it is a fairly momentary condition.
Did Bill try to write you a tune to maximize economy?
I really only worry about spark knock under load, or at cruise.
- Jack
38Blackfin
Tue, April 26th, 2011, 10:30 PM
Great mileage! I get 15.1-15.5. I don't have your "flat spot". I wonder if the Torque Converter is locking up too soon? Have you monitored that? And if it is, you can adjust the part throttle lock/unlock points in the Custom Options.
I also don't have the spark knock at hot start or the "lean smell". I doubt this is a significant worry, since it is a fairly momentary condition.
Did Bill try to write you a tune to maximize economy?
I really only worry about spark knock under load, or at cruise.
- Jack
Mine's 2wd, and 60%+ of my miles are highway.
Bill wrote me an 87 tow and an 87 performance, happy with both. I'm not getting any pinging underway. I'm about 2000 miles into a Mag SISO, so I'm hearing a lot more than I used to.
I don't run my Gryphon plugged in, so I don't have any numbers. When I searched, CHT came up as a way to monitor lean-ness. Anything else to look for?
Thanks, JnJ!
Randy
Jackpine
Tue, April 26th, 2011, 11:10 PM
Mine's 2wd, and 60%+ of my miles are highway.
Bill wrote me an 87 tow and an 87 performance, happy with both. I'm not getting any pinging underway. I'm about 2000 miles into a Mag SISO, so I'm hearing a lot more than I used to.
I don't run my Gryphon plugged in, so I don't have any numbers. When I searched, CHT came up as a way to monitor lean-ness. Anything else to look for?
Thanks, JnJ!
Randy
Yes, DO use the Gryphon to monitor the CHT. Mine is anywhere between 200-225, depending on temperature and load (I tow). I can't think of anything else other than looking at the plugs themselves for a lean running condition. No pinging underway sounds good to me.
If detonation was causing the PCM to pull timing, I think your gas mileage would be in the toilet.
- Jack
38Blackfin
Fri, April 29th, 2011, 12:59 PM
Thanks, Jack!!
Randy