DIY TCM Ideas

[robertisaar]

seeing how i'm using a run of the mill 1227730, that solves both the problems of a custom microcontroller setup not being able to deal with such events and the availability issue of the normal standalone controllers.

ECM to TCM.... had a couple of thoughts here:

one being an ALDL link(just have to setup ADX files that will allow regular communications between the two to happen without problems). this solves the issue of sharing sensors that aren't very happy about doing such a thing(mostly temp sensors), but it introduces the issue of making sure every ECM that might be connected to the TCM will be able to communicate in such a scheme. with well-understood applications, that's not a problem, but it's the oddball stuff that causes problems.

two being sharing sensors on a hardware level. i'll have to draw some of this out to see how much of an effect this will have on the temp sensors. those are really the only ones that will have problems.

three being a combination of the two.... only transmitting the temp sensors over the ALDL and sharing the sensors directly when possible. i THINK this will be the route i'll end up taking, but i may change my mind again.

four being the very elaborate method.... something similar to what RBob has done for the EBL in that it essentially sniffs on the ECM's address and data bus and updates some external RAM that the TCM will be capable of accessing. this has its own set of problems to overcome, including preventing the other processor from writing to the RAM while the TCM is reading from it. i have a few thoughts about that process already.



it's all a situation of compromises, i'm just trying to figure out which set will be the best to live with. i was playing with this yesterday and i've got about half of the total RAM eaten up already.

[brian89gp]

I'm a strong believer in KISS so my opinions for what they are worth are biased in that direction. ALDL link with parameters custom to nAst1 (for bidirectional) and leave the code open and well documented for people to adapt the TCM to other ECM's if they so wish.

You already have an ECM you need more room on and offloading to a TCM would meet the more room requirement, your ECM is meant to be somewhat universal and if it is going to be as awesome as you plan (and already is) then people will want to switch to it anyways, and people who use the TCM either need a TCM for an otherwise controlled engine or in combo with nAst1. If you make it so it can both read sensors and/or get the values over ALDL that was customized then you cover most of the use cases. Catering to the other special use cases is a lot of extra effort.

[robertisaar]

that does make sense... and would offload a LOT of work on my side.

i don't think the link would really need to be bidirectional even... there are only a couple of instances where the TCM would need to communicate with the ECM, the first thought that comes to mind is if the TCM is commanding max line pressure and still can't get clutch(or TCC) slip under control and needs spark advance reduced to keep the trans alive. i was planning on doing this with a discrete circuit(TCM grounds a circuit that the ECM monitors) that way you could use a LED or a buzzer or something that can be monitored while driving without logging.

[brian89gp]

The customized ALDL stream would also prevent a lot of those crazy things some people may try (and by proxy, time on your part trying to figure it out for them), because in reality most people will use it as a standalone TCM or use it as a TCM linked to a nAst1 ECM.

[robertisaar]

The customized ALDL stream would also prevent a lot of those crazy things some people may try (and by proxy, time on your part trying to figure it out for them), because in reality most people will use it as a standalone TCM or use it as a TCM linked to a nAst1 ECM.

perhaps i haven't thought about it long enough, but what kind of situations might arise?

also, since i have been trying to futureproof this for the most part, a little ALDL network between modules probably is the way to go.... especially if i completely jump the shark and split the ECM into 2 units.... one for mainly fuel control and the other for mainly spark control. the number of possibilities that would open up is HUGE.

[brian89gp]

perhaps i haven't thought about it long enough, but what kind of situations might arise?

Hooking it up to any random ECM to see if it will work, if the ALDL stream is similar enough the TCM might start recieving values that it thinks are one thing but are really something else. Probably wouldn't hurt anything aside from some erratic shifting but you never know. If you insert a key value or a special ALDL mode from the nAst1 side that the TCM checks for (and only operates if it see's) then you bypass this problem, and it is easy enough to replicate/program on other custom ECM sets such as code59.

ALDL would also be more reliable then sharing sensors and/or custom splitting hardware.

[robertisaar]

that's actually what i had planned on... keep the mode 0 messages intact and just add a mode above 10 to indicate a message meant for the TCM or for the ECM. the austrailian guys did this for at least one of their highly modded masks for NVRAM updates.

[brian89gp]

Got a link for that NVRAM stuff? That sounds pretty cool.

[robertisaar]

http://pcmhacking.net/forums/viewtopic.php?f=27&t=356&sid=fe792db5395b4ed31a1e291a32dc13de

[gar70614]

http://pcmhacking.net/forums/viewtop...1e291a32dc13de

Were you ever able to create a standalone tcm from a ecm? I have a 01 isuzu rodeo 3.2 it has a 4l30e trans wich is hardly enough in stock form and once I added lift and 33s its now begining to die, im going to be installing a 4l60e from a colorado with a 2.2 bellhousing, I can handle the mounting and even the wiring but the controlling is out of my league. Could I have 4l30e files removed and the 4l60e installed even though there shifted diffrenly? Do you have the ability to make me a standalone? I dont really want to spend the atleast 400 on a aftermarket controller if I could avoid it lol. Oh by the way the rodeo is controlled by a delco ecm. Thanks very much for your time.


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[robertisaar]

still working on it, especially weeding out good information from bad. the 4L60E is really easy to control compared to some of the other transmissions i have in my work list. some information i'm seeing shows the 4L30 as having an internal TCM, others don't show the same presence, so i don't know if it exists. if it does have one, i don't see it being easy to work around, since the PCM/ECM won't be very happy without it being present.

[gar70614]

I dont belive it does, ive had the pan off mine and theres nothing that appears to be a tcm, also its a 3speed trans with od bolted to the front of it so all the more I would doubt it being anything other than a possible od controllor or something, also still new to tapatalk so thought I was pming you not replying lol

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[robertisaar]

see what i mean about good info from bad?

there are a lot of confusing things to pop up on the less common units.