The MegaSquirt Project has experienced explosive growth other the years, with hundreds of new MS installations occurring every week - a phenomenal success! MegaSquirt has been successfully used in all aspects of Internal Combustion engine applications including R&D, Industry, Race, and Research. The MS project has transformed itself from a simple R&D project into a full-featured mature engine control system. To reflect this the support structure has also changed to meet the needs of MegaSquirt Users.
Moving forward, the R&D forums for MegaSquirt project are in a read-only mode - no new forum posts are accepted.
However the forums will remain available for view, they still contain a wealth of information on how MegaSquirt works, how it is installed and used. Feel free to search the forums for information, facts, and overview.While the R&D forum traffic has slowed in recent years, this is not at all a reflection of Megasquirt users, which continue to grow year after year. What has changed is that the method of MegaSquirt support today has rapidly moved to Facebook, this is where the vast majority of interaction is happening now. For those not on Facebook the msextra forums is another place for product support. Finally, for product selection assistance, all of the MegaSquirt vendors are there to help you select a system, along with all of the required pieces to make it complete.
A forum for discussing applications and implementations of the MegaShift transmission controller code for the GPIO from B&G. This can control up to 8-speeds and 6 shift solenoids (plus a 16x9 table for controlling a PWM line pressure valve). It has manual and fully automatic modes (16x9 load x speed table), with under and over rev-limit protection, and full data logging of all inputs and outputs (among many other abilities). A TransStim to test your completed board is also available.
I got a chance to do some more digging over the weekend. I have confirmed that the transmission is not able to get into first gear. I did this by wiring up the transmission solenoids A and B to toggle switches. I turned them on/off as per sequence in each gear. I successfully have gears 2, 3, and 4 when shifting manually.
This leads me to believe there’s something internally wrong with the trans, either in the valve body or the bands/clutches. Solenoid A is used in both 1st and 4th gear. So by default, if I am getting 4th gear, then solenoid A is working. I know that the trans has shifted into 1st in the past, so maybe something has failed since, or a passageway is clogged. Either way, I can confirm the Megashift is not the culprit for my lack of 1st gear.
That said, I reviewed the solenoid outputs (SOLST) from a previous data log and it looks like the solenoid states align with the current gear. That is not necessarily something I am questioning. My still outstanding question, is why the Megashift does not seem to be shifting per shift table. And therefore, what factors are causing the shifts? I have attached my tune for reference to the previously uploaded datalog.
so not that I am a genius with this.... I am slowly learning this on my own. I looked at your current tune and one you posted a year or so ago. at least you are on the newest firmware. other than minor differences with your setup and mine I didn't notice anything out of the ordinary. I looked at all switch inputs and outputs. they are correct. one difference is on my tps by rpm table I have it bypassed for now while I dial things in. ie.... raw tps values carry across all rpm ranges. so for the 100% tps bin I have 100 in all rpm ranges. same for 75%,50% 25% etc. that puts the tpsxload dot on your shift table where it is. it had confused me when I was first doing this why my shifts were not where I expected them to be. I will adjust this table at some point but I have left it bypassed for awhile now while I work on other things. also when I built a second trans controller I was testing my outputs before I put load to it and my test lamp was telling me I was in 1st,2nd,3rd and 4th but I wasn't hearing it do the 1-2 shifts, up or down. and I have "paddle shifters" setup so I could command 1st or 2nd. well I put it on the ground for the heck of it and with weight on it I could hear 1-2 and 2-1 working. put it back on stands and could not hear it. so before you spend a million rebuilding your trans - as long as you know your outputs are working right I would drive it.... gently.
Thanks for the super quick response. I went back though my datalogs and noticed that my PC% control on this current tune was lower than when I knew I was in first gear on that previous tune. So I upped the table range to bring the bring up the PC% at lower throttle openings. I also noticed I had the PWM period set for the earlier trans, so I adjusted that. I am going to try again ‘on the bench’ and see if the increased line pressure and PWM period enables 1st.
I agree that there’s only so much you can do ‘on the bench’. I’ll probably take it for a spin soon, I am confident enough that everything is working to the point that it won’t leave me stranded. My issue is that I live on a hill, on a busy street, by a freeway on-ramp. So there are no ‘safe’ roads to test out a combo. When I leave my driveway I need to be damn confident that I can cruise the mile or so before the nearest empty side road. At least I can test for first right in my driveway.
I’ll also adjust the TPS/load table to be 1:1 on the TPS signal. I noticed the same thing on my datalog, where the load was significantly different from the raw TPS. I think the TPS/load table is a great tool to really refine the shifts, but definitely for testing purposes I’ll bypass it.
I would take 20 min and hook up manual shift buttons. I used a 3 position return to center toggle and a on/off switch for mine but anything will work. If you have any problems like a honkey vss signal you can shift thru gears to get you home.....
And it's fun as he'll too