woohoo7676

I have a 2005 S2000, have had it for around 10 years. I recently had a KPro chip installed with a street tune (only other mods are Berk HFC and K&N FIPK) - when I got the car back, it would be really jerky when going on and off the throttle, even if I just touched the gas or let off the gas extremely lightly. It feels like the car is rocking back and forth somewhat violently.

I took it to a tuner to get a dyno tune done a few days ago, since I thought it might be the tune or chip settings - they were able to smooth it out some, but it still happened. However, the temp was in the 70's-80's for the past couple days when this was happening. Today it was around 30-40 degrees, and the jerkiness was *much* better this morning, still a bit present but manageable. It was still good even when the engine got up to temp.

Any ideas of what this could be? The tuner said that it could be the motor/trans/diff mounts, TPS sensor, or I might need to swap in an RSX Type S wideband o2 sensor. I've looked at a few related threads, but wanted to get an opinion before I spent money on new parts, thanks

flanders

Post your calibration and a datalog with the jerkiness happening and me or someone else can take a look.
Which version of kpro do you got? The RSX wideband solution is really not recommended.
I think some users here did get it working on the older kpro versions but on the v4 it's much easier to use an aftermarket sensor instead.

woohoo7676

Thanks, will post a calibration/datalog when I get home tonight.

I have a KPro v4 - I've also heard about some issues with using an RSX wideband so definitely would like to avoid that if I could.

jaymz

I had issues with my car jerking and not being able to drive along slowly without surging. Almost made my wife sick lol.
Turned out my throttle position sensor was out of wack. I used a multimeter and set the voltages and solved my problem.

flanders

Yes it's possible your tuner forgot to calibrate the TPS.
It's very easy to do in kmanager, no need to use a multimeter.

woohoo7676

I'll definitely check the throttle position voltages out, thanks for the suggestion!

flanders - I went to go hook up my computer today (first time) and I guess the USB cable was not hooked in already - tried finagling it in, but I guess you have to hook it up before you mount the ECU because the clearance is so tight? Anyways, I will def get you those logs, just might be a bit longer til I get the time to deal with getting the ECU out and back in sorry about that!

flanders

Yeah it's super tight up there, I got my USB cable mounted permanently so it's easy to connect anytime I want to check something.
No need to be sorry

RolanTHUNDER

How does KPro stack up to stand alone EMS or piggyback units?

flanders

It's the best of both worlds.

RolanTHUNDER

Interesting