PCV + Autotune + Heated Grips = Sputtering?

I have a fun electrical gremlin I need help troubleshooting:

Since I've installed my PCV + Autotune, I've got an issue with the bike sputtering randomly under both heavy and mild acceleration, and even steady throttle. I've tried different fuel maps, but they don't seem to affect the problem.

What *does* help the problem is when I turn my aftermarket heated grips off. When my grips are off, I get mild sputtering, but with my grips on, the sputtering increases. When I turn my grips to max heat, the sputtering gets even worse. Turning on the high-beam doesn't seem to affect the sputtering.

Other relevant electrical info:

- I also just installed an 8-cell AntiGravity lithium ion battery
- I have my grips, speedo healer, usb plug, and autotune all wired to a terminal block, which is attached to the battery with a relay on the + line preventing anything from getting power until the bike is turned on. (I think the relay trigger line is tapped into the rear light... not the brake light.)

What should I do next to continue troubleshooting the problem?

PS - bike is a 2008 wrx, stock fuel pump.

GoodShipT wrote:

I have a fun electrical gremlin I need help troubleshooting:

Since I've installed my PCV + Autotune, I've got an issue with the bike sputtering randomly under both heavy and mild acceleration, and even steady throttle. I've tried different fuel maps, but they don't seem to affect the problem.

What *does* help the problem is when I turn my aftermarket heated grips off. When my grips are off, I get mild sputtering, but with my grips on, the sputtering increases. When I turn my grips to max heat, the sputtering gets even worse. Turning on the high-beam doesn't seem to affect the sputtering.

Other relevant electrical info:

- I also just installed an 8-cell AntiGravity lithium ion battery
- I have my grips, speedo healer, usb plug, and autotune all wired to a terminal block, which is attached to the battery with a relay on the + line preventing anything from getting power until the bike is turned on. (I think the relay trigger line is tapped into the rear light... not the brake light.)

What should I do next to continue troubleshooting the problem?

PS - bike is a 2008 wrx, stock fuel pump.

I'm no expert but if this is all running off the battery and from what I understand the Lithium ion batteries need a special charger so won't all this strain be on the battery and not on the charging circuit of the bike.

I haven't had the need to mess with my electrical system yet and still have the stock battey. Just a thought does it do it with the stock battey or was it dead?

I just switched in the old Pb battery and is shows the same symptom - lots of sputtering and power loss with heated grips switched on and turned to high, mild sputtering with heated grips off.

I'm at a loss about what do next... based on some threads I've read, it could be something to do with how everything is grounded?  I had always assumed that grounding everything to (-) on the battery was the best way to ground on a bike...

Also, the Antigravity Li batteries are design to charge off the bike's system just like a traditional Pb battery... just don't charge it off the bike with a charger designed for Pb batteries.

Ok well let's start again I guess and leave the battery out for now.

What mods do you have and which map are you running?

What we probably need to do is get your bike running well with auto tune turned off. Then enable it. Then work on the heated grips issue.

I don't have auto tune but I have the PCV. I'm sure you can run it with a non auto tune map and wire up a switch so you can turn auto tune on and enable it in the second map position with its own map. So you can try different things.

Maybe it's TPS related. I didn't have to calibrate mine but it is mentioned on the PCV paperwork. Also there are threads about it. Just a thought never had any real issues with mine.

Engine Mods:
Ultimate Air Box (stock air filter currently)
AIS removal
EXUP removal
FMF Q4 + Powerbomb
PCV w. ignition + autotune

Electrical mods:
Oxford heated grips
Weather-proofed 2A USB plug
DRD Speedo-healer
DIY relay + terminal block

I've tried running the 006 Leo Vince map from Dynojet, x3n05's map, and a zero'd map (zeros in fuel, autotune, and ignition tables). Same sputtering issue with all the maps I've tried.

My next instinct is to remove the PCV all together, just to confirm that it's an electrical + PCV problem, and not an electrical problem independent of the PCV.

I've also emailed Dynojet to see what they'd recommend I troubleshoot next... hopefully they'll have some good advice.

Maybe worth looking at the TPS.

Here is a link to someone else's post with how to measure it. It won't hurt to check but going back to stock and removing the PCV is not a bad idea either.

https://wr250rforum.forumotion.com/t5568-throttle-on-off-at-idle

Update for posterity / other people having a similar issue: I solved this by changing where my heated grips connect to (-) negative.

Originally both (+) and (-) for the heated grips was attached to a terminal block (as well as the PCV, Autotune, etc.), that was then attached to the battery via a relay, etc. After chaining the (-) on the heated grips to go directly to the negative on the battery, the sputtering problem has gone away.

I'm sure someone withe more electrical knowledge could tell you why this worked, but I did this on a hunch, not because I have any good electrical wisdom.

GoodShipT wrote:

Update for posterity / other people having a similar issue: I solved this by changing where my heated grips connect to (-) negative.

Originally both (+) and (-) for the heated grips was attached to a terminal block (as well as the PCV, Autotune, etc.), that was then attached to the battery via a relay, etc. After chaining the (-) on the heated grips to go directly to the negative on the battery, the sputtering problem has gone away.

I'm sure someone withe more electrical knowledge could tell you why this worked, but I did this on a hunch, not because I have any good electrical wisdom.

Interesting...

Assuming that your stator is good and holding voltage it almost sounds like you were creating noise in the electrical system with the heated grips which may have been playing havoc with the PCV or fuel system.

But usually when I use a terminal block I run the ground terminal right to the battery anyways so I am not sure why that would make a different... unless your negative terminal connection on the battery was loose or dirty. If that was the case then I could see how that would create a sputtering issue.