|
RX-7 1st Gen Specific (1979-85) RX-7 1979-85 Discussion including performance modifications and technical support sections |
![]() |
|
Thread Tools | Display Modes |
![]() |
#1 |
Itchin' to Turbo
Join Date: Apr 2009
Location: Vancouver, WA
Posts: 33
Rep Power: 0 ![]() |
Missfire after drag racing, common?
So I finally took my stock 7 to the track (removed emissions and cat) and upon completing 9 passes on the way home and at idle I notice a light miss every so often.
Idle and cruise was rock solid before. Doesn't seem to hickup under acceleration. Is this common? I've got only 4000-5000 miles on a fresh tune up with the middle NGK plugs. I thought she was stronger too! Only mustered a 17.25 @ 79.20MPH in 80º weather. Thanks for any input. |
![]() |
![]() |
![]() |
#2 |
Non Member
Join Date: Jun 2008
Posts: 310
Rep Power: 18 ![]() |
Probably just got some deposits on the the plugs. Not really uncommon, as the plug heat range is designed to work better at cruise, or under hard acceleration. The "middle" range is a compromise between the 2 extremes. Works for both, but better suited for a more even mixture of the styles.
|
![]() |
![]() |
![]() |
#3 |
Itchin' to Turbo
Join Date: Apr 2009
Location: Vancouver, WA
Posts: 33
Rep Power: 0 ![]() |
Pulled all 4 plugs. They all looked the same. Bright orangey color on the ground straps, and the electrode's nice and clean.
Maybe the few runs w/o air filter plugged somethin in the carb then. I think I'll be getting a set of the colder plugs for racing. Definitely too hot a heat range for consistant 7K RPM. |
![]() |
![]() |
![]() |
#4 |
Itchin' to Turbo
Join Date: Apr 2009
Location: Vancouver, WA
Posts: 33
Rep Power: 0 ![]() |
Well I found the mixture screw was backed out a bit. Doesn't miss at idle anymore but still does a little bit at light light cruise.
|
![]() |
![]() |
![]() |
#5 |
Rotary since 1972
Join Date: Nov 2008
Location: Tucson
Posts: 231
Rep Power: 17 ![]() |
Try running some SI-1 through it. (Redline fuel injection cleaner, which is the only fuel cleaner that Mazda recommended other than their own. It will not detonate in a rotary like many other products)
Make sure all the wires, connections and cap and rotor (mazda only, non-mitsubishi will cause problems, cheap rotors have a tendency to wobble) are good. You do still have the metal spark container in the distributor. If it is missing you will have misfire issues. Good color on plugs for stock. Check your vacuum advance units. Factory setting for the screws - 1.5 top 2.5 bottom. If the throttle plate hasn't been played with and everything (includes all emission equipment) is working correctly it will start, idle, drive and ~0 the emissions. If emissions are high, anything above 75/100 hc or .5 co 1/4 turn out on the mix will make it drop to near zero. |
![]() |
![]() |
![]() |
Bookmarks |
|
|