I have swapped out my Andrews 37s for 26s.

The issue I am having is that bike is hard to start when cold, but after warm up it runs great...have done some auto tunes.

I tried to use the same map as the 37s which fired up and idled fine, but with the 26s does not start up well when cold.

I have moved my IAC home, but I am not really sure which direction is doing what...been anywhere from 51 to 81!

Any info I find says to fire up and run IAC auto...that is great and fine, but what if bike has to be blipped to keep running or stalls when doing IAC auto?

Will the auto tune eventually fix the rough start when cold or do I need to keep tweaking the settings untill it starts on my own?

Love the Thundermax but frustrating to get it set up at starts.

I had the same issue when I first did the big bore and the 37 cams.

Did a big bore and Andrews 26s on my brother's and it fired right up and runs great...haven't even done an auto tune for his yet.

 

Try increasing cranking fuel 1 to 2 milliseconds.. What map are you using.. You can increase cranking timing a degree and see if that helps.. Make sure you don't get kickback tho..

Add. You can also increase "Initial fuel pulse"

 

How's your battery? Mine starts rough sometimes when cold also, think it's because mine went dead over the winter when I was an idiot and didnt have it on a trickle charger. If i'm riding it regularly or out & about, it starts just fine. If not, I have a rough time as well. I think it's just a battery issue.

Also, you can run IAC auto any time, not just after installing a new map. Put your bike on a charger overnight, then give it a shot in the morning. I bet you won't have a problem starting or running IAC Auto.

And curious, what base map did you load?

 

One other question: have you updated the firmware in your t-max? Very easy to do in the software as long as you have an internet connection.

 

Battery is new...also, I usually hook up a battery charger (real charger, not trickle charger) to it when I am messing with the settings for a while. I do know that the Tmax is very sensitive to a weak battery and will have issues.

Firmware is the updated version.

Basemap is #745.

I did alter the timing VS temp map since I had some pinging at full throttle. That has disappeared, but maybe I need to go back and bump up the timing where it was at the lower temps.

I will try the fuel settings next..if I remember right, when I initially set up the map after putting the big bore and 37 cams in, I did alter those settings. I need to maybe pull up that old map and see what I did...it has been a while.

On a couple week stretch of working night shift and finding time to mess with it is rough right now.

Thanks for the suggestions..will let you know how it works out!

 

Dang....well I'm close to being out of ideas if all that stuff checks out. What does it say in the t-max software when you go to Tools>Auto Tune Points Analyzer?

 

At this point I would do a data collection run and send it to Zippers with an explanation of the problem. They usually respond quickly.

 

FWIW,, Best to sent the stuff directly to Thundermax / Thunderheart.. Zippers has given the tech support back to Thundermax which really closes the loop on support.. The latest release will collect all the parameters and send the info to them.. I don't think you have to be under warranty to do this.. The tech support group will review the files and make suggestions. If they are stumped they'll walk over to the next office and bug the engineers..

 

I think the cranking fuel setting is a good idea. I read up on that over the weekend and adjusted mine & it started way easier this morning. It was set at 6.5 and I raised to 8. It's on the "Basic Settings" tab, really easy to find and adjust.

 

I think the cam is the issue here. The Andrews 26 is designed for stock compression. According to your sig you are running a 10.25:1 compression ratio when it should be somewhere between 9 - 9.5:1.

Your intake valve closing is to early for that much squeeze.