Jellybean Posted December 4, 2016 Share Posted December 4, 2016 Car: BPU with 264 cams , NGK BKR7EIX Gapped to 0.8 from 1.1 Took the car out for a spin since mapping last week , Intermittent Getting a pop slow speed dropping a gear outside the power band First time from from 3rd at 2.5k rpm drop gear to 2nd 2K rpm , while on the brakes , going into a bend ,pop on gear change Second time slowing for a ramp 3rd to 2nd , from low RPM to Low RPM , Third time , slowing for traffic lights pop on gear change On WOT drop gear within the power band no Misfire , car pulls good Bit of a strange one! Link to comment Share on other sites More sharing options...
ibby Posted December 4, 2016 Share Posted December 4, 2016 Spark plugs ? Link to comment Share on other sites More sharing options...
Jellybean Posted December 4, 2016 Author Share Posted December 4, 2016 Spark plugs ? /QUOTE] They are only about 900KM old , and OEM coilpacks are in 2 months , 100 miles on them Removed the plugs while on the dyno , looked good but had some arching reason for 0.8 gapping from 1.1 Link to comment Share on other sites More sharing options...
ibby Posted December 4, 2016 Share Posted December 4, 2016 Maybe just dampness ? Link to comment Share on other sites More sharing options...
Nic Posted December 4, 2016 Share Posted December 4, 2016 (edited) A pop/burble from the exhaust when you come off the throttle on overrun is quite normal on a BPU car. Edited December 4, 2016 by Nic (see edit history) Link to comment Share on other sites More sharing options...
mellonman Posted December 4, 2016 Share Posted December 4, 2016 As nic says its as you lift off , if you have a afr gauge you will see the afr go rich for a second after lift off , I expect the longer duration cams will enhance the affect. Link to comment Share on other sites More sharing options...
Jellybean Posted December 4, 2016 Author Share Posted December 4, 2016 A pop/burble from the exhaust when you come off the throttle on overrun is quite normal on a BPU car. Was thinking that but would you consider 2K-2.5K cruising at 50KM overrun? Would expect it if I was on WOT dropping a gear Link to comment Share on other sites More sharing options...
Jellybean Posted December 4, 2016 Author Share Posted December 4, 2016 As nic says its as you lift off , if you have a afr gauge you will see the afr go rich for a second after lift off , I expect the longer duration cams will enhance the affect. Thanks Will check the Logs on the ECU Link to comment Share on other sites More sharing options...
Chris Wilson Posted December 6, 2016 Share Posted December 6, 2016 Pops on throttle lift are often indicative of a small air leak somewhere towards the front of the exhaust Link to comment Share on other sites More sharing options...
Jellybean Posted December 7, 2016 Author Share Posted December 7, 2016 Thanks Chris I have provision for two wideband connections on the exhaust towards the front, maybe it is loose or gone , it was in use recently Link to comment Share on other sites More sharing options...
Wez Posted December 7, 2016 Share Posted December 7, 2016 Check your map in the vac area, maybe your mapper added some fuel there to give this affect, its often requested as can be fun in tunnels etc Link to comment Share on other sites More sharing options...
Jellybean Posted December 7, 2016 Author Share Posted December 7, 2016 Will do! Thanks Wez Link to comment Share on other sites More sharing options...
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in
Sign In Now