E67 to T87/T87A TCM interface needed

Bosch Motronic etc ECUs and PCMs
Horshack
Posts: 9
Joined: Sat Jul 04, 2020 1:43 pm

E67 to T87/T87A TCM interface needed

Post by Horshack »

As the post says, looking to interface the two. Opened a new thread to avoid polluting another one.
Tazzi wrote:
Horshack wrote:
Tazzi wrote:Yeah I dont think thats what those files are for.

If the TCM and ECM do not have compatible operating systems, then its not going to play nicely.

Would need to make a middle man module to translate the information to/from both TCM and ECM to make them play nicely with one another.
Assuming that is responding to my post. Supposedly they can speak to each other, but I only have the word of a harness maker on that, not a computer dude. Can't see why they wouldn't be able to, as the Gen 4 and Gen 5 both speak to the 6 speed. Presumably, if the Gen 5 can speak to both the 6 speed and the 8 speed, something between them must be similar enough that the Gen 4 can be made to speak to the 8 speed. But before I go any further, should I keep posting on this thread or start a new one? That post I quoted before made it look like this would be the place.
Probably best in its own thread.

But the best analogy I have to explain this, is imagine having two identical Laptops. One has windows XP, and the other running windows 10.
They both technically use windows and can run programs, but doesnt mean they have the same capabilities or run the same software.

ECUs a similar. The ECU operating system needs to be compatible with the TCM operating system otherwise it will not understand whats going on. I see that regularly here where there is a mismatch between OS's and there will be an actual fault code indicating missing TCM data from the ECM.

As far as Im aware, there was no factory setup between a E67 and T87. Both will be from Global A vehicles, but I believe the E67 still requires a custom touch.
Do you have it fitted already or trying to work out if it works first?
I'm trying to verify it will work before buying it. I am getting to the point where I have to make a decision for a project. Either I go with a lightly supported Gen5 engine and use an 8 or 10 speed transmission, or go with a heavily supported Gen4 engine and a 6 speed. Best outcome would be the LS3 and the 8/10 speed. I have an engine builder who can either modify a stock Gen5 block to make a 408cid engine, or can build a Dart block as a 427. The Dart block will handle the power much better, as can the 8/10 speed transmissions.

I already know that both the E67 and the E92 can speak to the 6 speed transmission. I have an early 2015 Tahoe with the 6 speed and an L83. Later model 2015s and 2016s came with the 8 speed. Since the TCMs run the transmissions and just use CAN data from the ECM to decide when to shift, I can't see it being too difficult to make them speak to each other unless there was a language change. GM putting both behind the 2015 Gen5 tends to rule that out though as I can't see GM changing languages for just 1/2 a year's run they used to use up their last 6 speeds.

If anyone were able to read the inputs for the T43 and the T87/T87A and see if they are looking for the same stuff, then perhaps it's just as easy as repinning a connector. Unfortunately I don't have the skills to determine this, nor have I ever been able to make sense of it. Reading the originating post, I could kind of follow along with the goals, but the computer stuff, right over my head.

If anyone could come up with a standalone controller for these guys, there would be a lot of money in it. I'd certainly be a customer, and I'd be buying several as my hobby is old car restoration. However, I just can't see using 4 speeds anymore and the 6 speed is quickly going to go away since they came out with the 8 and now 10 speed just a few years apart. Even the 8 speed is going to be a unicorn in a few more years. A standalone controller would need to be something that could read whatever sensors are needed as standard sensors, then convert it into something the transmission could read. If I understood computer programming, believe me, I'd already either be working hard at it, or would have something on the market.
In-Tech
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Re: E67 to T87/T87A TCM interface needed

Post by In-Tech »

I'm slowly looking into it as time allows. If I play too much, the lights start flickering :thumbdown: I've been gathering parts for testing. 8L90, plenty of different ecm's, tcm's for bench testing. I'm fairly certain the e67 can talk to the t43 but I've never tested it. Like you mentioned, the trick would be e38,e67,e78 talking to a t87 8spd. Earlier controllers were tps/mph based, now there's that plus all the load calculations in the ecm that drastically affect the trans behavior.
Horshack
Posts: 9
Joined: Sat Jul 04, 2020 1:43 pm

Re: E67 to T87/T87A TCM interface needed

Post by Horshack »

The E67 definitely talks to the T43, as the E67 was used on the 4th gen stuff that the 6L80E/6L90E used. My hope here is that since the E92 (Gen 5) spoke to both the T43 and the T87, and it's highly unlikely that GM did custom programming for a half-year run, that the Gen4 and Gen5 ECMs and TCMs used the same inputs and outputs between them. It's likely that even though the Gen4 and Gen5 are different, they only actually need to exchange stuff like throttle position, RPM and VSS readings between the ECM and TCM.
In-Tech
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Re: E67 to T87/T87A TCM interface needed

Post by In-Tech »

My plan is to rig my engine run stand so I can hang a transmission on it too. Then I can test these scenarios. The case of that 8 spd is pretty large and I don't have a donor vehicle/frame off resto at the moment to try it in so the run stand will be the fastest for me. Too many irons in the fire right now :thumbup:
Horshack
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Re: E67 to T87/T87A TCM interface needed

Post by Horshack »

Good deal. After my request, I hate to say this but I no longer need this interface. My goal was an 8 speed behind an LS3 engine, and I have found one.

soundgermanautomotive.com

This isn't for a GM 8 speed though, it's for a ZF 8HP90 transmission. I'll have to build an adapter to connect my LS3 to the ZF transmission, but this controller only needs an RPM signal, a TPS signal and a Dodge Charger shifter to operate the transmission as a 100 percent standalone unit. I hope you are successful in finding a solution to the 8 speed and 10 speed transmissions though, I think anyone who can come up with a working interface will be able to start a thriving hot rod business with one and might even be able to sell out to one of the bog boys for a small mint. I'd even suggest buying one of the controllers these guys make to see how they do things, because really I don't see the GM transmission needing much more to run. I'm sure GM has fudged up the program to the point that the trans needs stuff from the virtual VE table and the torque maps to run the shifting, but in reality all you'd need to do is figure out how to make the transmission shift correctly, then write a program that decides that if the TPS is here and the RPM is there, then the trans needs to be in this gear, if the TPS suddenly goes here and RPM is there then the transmission needs to shift to that gear. And, as the GM 8L transmissions allow you to shift directly between gears (8 to 4 instead of 8 to 7 to 6 to 5 to 4) the control program would need to be able to take that into account as well. And, it would need an actual gear selector input, like the ZF needs the Charger shifter for. Likely a Camaro shifter would work for this, and would probably be able to incorporate a tap shifter.

I plan to keep watching this thread, and may even contribute if I think I can help, but unless there's a working product by the time I'm ready to buy my engine and transmission I'll be using the ZF transmission. They run behind Hellcats and Demons, so they'll handle my planned power output easily.
EdNobodee
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Re: E67 to T87/T87A TCM interface needed

Post by EdNobodee »

Hello,

Long time lurker, few time poster. I am currently working on a device for the 6L series to interface with the P01/P59 pcms. I could possibly work out something for the 8 speeds as well. lemme know if you are still looking or have found another option.

Ed
In-Tech
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Re: E67 to T87/T87A TCM interface needed

Post by In-Tech »

Hiya Ed,
The struggle is adding the load based stuff. I'm all ears if you have an idea of how to do. Are you Ed from OK :silent: ?
EdNobodee
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Re: E67 to T87/T87A TCM interface needed

Post by EdNobodee »

Ed from OK, that is a name I have not heard in quite some time.... :-)

I am working through the engine load/torque stuff currently. Once I procure a couple of suitable test ecms/tcms I can begin work on those specific devices.

Ed

edit: I am working through the torque stuff regarding e38's and t43's
In-Tech
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Location: California

Re: E67 to T87/T87A TCM interface needed

Post by In-Tech »

EdNobodee wrote:Ed from OK, that is a name I have not heard in quite some time.... :-)

I am working through the engine load/torque stuff currently. Once I procure a couple of suitable test ecms/tcms I can begin work on those specific devices.

Ed

edit: I am working through the torque stuff regarding e38's and t43's
Not sure if you're the Ed, lol. That was a long time ago back in the majordomo days at Ohio State but either way HELLO :thumbup:

It does seem the T87 likes to be on the end of a bus and does need a termination resistor to get happy with some communication interfaces. I have a couple if you need anything and also for anyone listening, I have a great bud that works for a nationwide junkyard in the US that gets me anything I want :mrgreen:
EdNobodee
Posts: 6
Joined: Sun May 31, 2020 8:31 am
cars: 1972 Buick Skylark 350c 2bbl, 2001 Camaro 3800 Auto, 1990 Chevy Stepside 5.7L Auto, 1980 Honda CB400T Night Hawk ||

Re: E67 to T87/T87A TCM interface needed

Post by EdNobodee »

Sorry to dissappoint but I am not majordomo Ed LOL.

I too have ready, open access to such salvage resources, ain't life grand. :-)

The TCM and ECM relationship is somewhat different from the other devices on the bus. The two are typically the terminating ends for each other as evidenced by the terminating resistors, while other devices on the bus are not much different than the scan tools we plug in to the DLC.


One issue that may arise will be the Global A device ID. I am still reading on the matter so bear with me and my assumptions and assertions on the subject. It is to "prevent" module swapping. One way around it may be to program the ECM as a manual trans equipped chassis and just poll the ECM for the requisite data for the TCM as has been done for other swaps.

Mind you, these are ramblings after only 1 cup of coffee so as the fog clears, I may amend my comments lol

Ed
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