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Weird stutter after vtec engages then below vtec engagement

Posted: Sat May 27, 2017 2:14 am
by TheOhKcivic
So i have a 95 civic coupe with a k20z1 6spd trans. It has skunk2 IM and skunk2 70mm tb, rdx 410cc injectors and a header. Ktuner end user. Blah blah blah. Im running the 3rd map. So now what happens is ill drive the car no problem ill go hit vtec go to 7k or so rpm then slow down but below the vtec engagement still giving it gas but just cruising it will sputter and jerk for a sec then just stop and run normal. Ive tried different maps but no change. It feels like something is catching for a second like vtec or something. Kind of feels like when you run a b series low on oil and hit vtec and it engages on and off rapidly. Any ideas? Plus im looking for a map thats better suited for my setup if anyone has one

Re: Weird stutter after vtec engages then below vtec engagem

Posted: Sat May 27, 2017 4:17 pm
by KTuner
Sure sounds like VTEC transition, but not sure how you're stuttering if you're so light throttle that your RPM is decreasing. You can adjust the engage disengage RPM so they're further apart if you're catching VTEC engagement again.

Re: Weird stutter after vtec engages then below vtec engagem

Posted: Fri Jun 09, 2017 6:58 am
by TheOhKcivic
Its not that im slowing down but light throttle i actually moved the engagement points closer and it seems to have rectified that issue.
Next question is I am running k20z1 map 3 with 410cc rdx injectors and when vtec engages my a/f shoots to 8. Should i reinstall the oem rsx 310 injectors or what?

Re: Weird stutter after vtec engages then below vtec engagem

Posted: Fri Jun 09, 2017 12:57 pm
by KTuner
If you go rich on transition, simply tune the fuel maps appropriately or go to a tuner who can.

Re: Weird stutter after vtec engages then below vtec engagem

Posted: Thu Jun 15, 2017 9:50 pm
by TheOhKcivic
Thank you

Re: Weird stutter after vtec engages then below vtec engagem

Posted: Thu Jun 15, 2017 10:24 pm
by KTuner
No problem. Also make sure you've setup the injector sizing and battery offsets correctly.

Re: Weird stutter after vtec engages then below vtec engagem

Posted: Wed Jun 21, 2017 8:48 am
by TheOhKcivic
how would I go about doing that?

Re: Weird stutter after vtec engages then below vtec engagem

Posted: Wed Jun 21, 2017 3:23 pm
by KTuner
Both of these options are listed in Main Parameters.

Re: Weird stutter after vtec engages then below vtec engagem

Posted: Wed Jun 13, 2018 3:51 am
by TheOhKcivic
I think Tim from xact has been talking to you but here's my current problem

I have 2 civics one is k20z1 6spd as listed above then I have another one with a k20z3.

The z1 is stuttering at high rpms. Apparently the cam timing ignition timing etc is wigging out. So tried a different vtc oil control solenoid etc but nothing's fixed it. So today I loaded up my tune for the z3 into the ecu then took that car for a drive same issues as the z1 car happened in the z3 car. So I drove the z3 car with the original z3 ecu for months no issues including up until I swapped ecu's but when I swapped the original z3 ecu I was running back in those problems from the z1 ecu persisted. Any idea what could of causes the ecu to damage a sensor or something on the engine without throwing any codes?

Re: Weird stutter after vtec engages then below vtec engagem

Posted: Wed Jun 13, 2018 7:22 pm
by KTuner
The ECU didn't damage a sensor, as everything reads appropriately at all other times during the logs I saw.

As I pointed out to the tuner TPS and MAP both go to a value one would only see when off the throttle when your blip occurs. Perhaps start there.