LS1 with PCS TCM-2650 and 6L80 - stuck in 1st, poor 4 -5 change and more!

Hello!

I've got a Commodore VX SS, with a fresh rebuilt lightly modded LS1 (RHS As Cast 205cc heads, 220/224 575" 112LSA Elgin cam, JE pistons) mated to a 2007 VXR8 6L80e, with the PCS TCM-2650 as the go-between.

The main issues I am having are as follows;

Transmission often sticks in 1st gear, sometimes in 2nd. The fix is either to take it from D to N and let the idle settle, then place it back in D (50/50 chance of it working afterwards), or a touch of brakes might get it to change into 2nd, 3rd etc.

The changes from 1 to 2 to 3 to 4 are all generally ok, but 4th to 5th is a flare and a dump into 5th. On a light throttle around town, it will mostly change up then down to 4th again. The PCS gear indicator plugged into the OBD port (and the readout on the laptop when connected to the PCS software) shows the transmission as flicking between 4 and 5 and also 5 and 6 at higher speeds.

The trans is getting and transmitting all its speed readings, but I haven't got the dashboard speedo reading properly as yet.

I unfortunately do not have access to HPT at the moment, but have attached a recent transmission log and the trans tune as it was originally. The one tuner I have visited so far found that the transmission is rapidly switching between normal and pattern a, even though I have no mode switches connected. He made both patterns the same, so that the trans would see no differences, but it didn't make that much difference. No obvious earthing issues either..... The harness is all new, but the gearbox is of course a total unknown.

Attachment 123037

Jim at Zero Gravity is being really helpful, so I have the option to send him the TCM-2650 for testing. I'm wondering if I should send the TEHCM from the trans too....

Thanks in advance for any help and advice!

Attachment 123038

Can you post up a manual for the TCM-2650. I can't find one.

Just to get started, make sure that trans tune is the correct STOCK tune for that transmission matching the OS from the vehicle it came from.

Also, check the wiring diagram notes about unused inputs. It may say that you need to connect them to ground or positive if not being used.

Thanks hjtrbo, the trans tune I attached was the unmodified tune from the VXR8 the trans came out of. I have no reason to believe that the tune does not match the OS from that car, but I know assumptions are a bad thing!

https://www.powertraincontrolsolutio...ockdiagram.pdf

The above is the wiring diagram for the TCM-2650, as supplied with my kit. The only adjustment I have made is with swapping pin 41 to pin 17, to try to make the speedo work. I am doing the same conversion as Tre-Cool and he did this, amongst other things.

I would need to scan the Zero Gravity installation manual to get more information for you, unless the block diagram is sufficient?

Thanks again for taking the time to look at this for me.

The pdf for the TCM-2650 installation is too big a file for this forum..

Ok, have you got online storage like one drive or google drive? You can sick it there and create a link to it which you can post here.

That trans tune sound correct.

Not enough info in the block diagram. But that should covered off in the manual.

Can you do data logs and 2 way control (force outputs on etc) with the 2650 software?

Does this work for you? Sorry if it doesn't, I'm not the most pc literate....

https://drive.google.com/file/d/18HX...fl0E8KJQ4/view

https://drive.google.com/file/d/18HX...ew?usp=sharing

You can do data logs and 2 way control with the PCS software. There are options for paddle shifting etc.

This might work for you to download the software;

https://drive.google.com/file/d/1ong...f4auvRwlx/view

https://drive.google.com/file/d/1ong...ew?usp=sharing

All worked. Thanks for that. Are you able to post the bin file as well?

Will be honest this is the first time I've used this software. I've always wanted to get stuck in and learn about it. So hopefully between the back and forward of this forum we can get you fixed up.

Worst case scenario will be that I have to get you in touch with someone that has done a lot of installs before. I have his details and will pass them to you if we get stuck.

and the .cfg file they sent you too please

The manual makes it look pretty easy. Just some basic stuff to check off. I'm sure ZG have already been through this with you...

Are the TPS and engine RPM coming through cleanly and can you see them reading correctly in the PCS logger.

Is the torque table set up right> Just remember 50% TPS is not 50% effective area (throttle blade opening). It will be something like 20% effective area.

Brake light connected and working. Logs cleanly in the PCS logger?

Calibration B enabled in the digital input selection but not wired?

The engine RPM should be displaying correctly and cleanly on the PCS logger.



Is the PCS TCM-2650 actually controlling the solenoids or is it just a acting as the can gateway device and taking the TPS, RPM and load and broadcasting it to the 6L80 TCM?

Attachment 123152

Attachment 123153

I really appreciate all the time you are giving me with this! The above bin files are very similar, both have been checked over and amended by Jim at ZG. (There is a compare file function on the PCS software).

https://drive.google.com/file/d/1OV1...w?usp=drivesdk

Hope the above gives you the .cfg file.

Below is a datalog link. It should open up the PCS datalog software and you can then tick whichever input boxes you wish to monitor.

https://1drv.ms/u/s!AvYJGSX0WE3IkCsZ...tqx8C?e=5Jvxh8

I hope my issues give you a good insight into the PCS TCM-2650, so that at least you get something out of helping me!

The logger shows engine RPM, TPS and calculated vehicle speed absolutely fine, I haven't had an issue with that, from memory. The PCS monitor gauge is not great at showing the initial movement on tiny throttle openings, but the voltage readings are very sensitive.

The torque table was last adjusted by the tuner I visited on 20th July. I have no rolling road information, as it never made it onto one. The tuner said the torque was approximately 450 lb/ft / 610 Nm and the bhp the same. I believe he got this from the HPT software? The changes he made did help, but you might spot some glaring errors?

I don't think my mate wired in the brake light and the tuner didn't pick up on that either. My mistake, I thought it was optional.

Below is a scanned copy of my block diagram, where I've marked (illegibly?!) what is connected. The 'x' are where the PCS TCM-2650 connector has empty terminals.

Attachment 123158

I think my mate and I were going to connect the digital input for Calibration B to the blue wire coming from the 'Power' switch on my Commodore's transmission tunnel. That blue wire is now disconnected from the LS1 ecu, but it was the power mode switched wire for the old 4L60e.

Looking at the PCS software, I'm trying to work out whether it's digital input 1 or 6 which can't be used, if you see what I mean? I need to look at the actual wiring properly, but having 3 small children on summer holidays makes for short opportunities to get stuck in! Also, whilst getting the engine tuned, the radiator's plastic side tanks decided they'd had enough, so I'm currently waiting for a replacement to arrive (early September, apparently).

My understanding is that the TCM-2650 is just the CAN gateway device. The fine tuning of the 6L80 TCM is still done through the OBD2 via HPT etc., I think?

At this stage, would you think I'm having electrical issues, rather than a 6L80e mechanical issue? When I got the trans, the remaining fluid was pinky red and has since had a new filter and all new fluid, which was still pinky red when I checked the fluid level before going to the tuner. I am using the very shallow standard VXR8 pan, with the oil lines going to my Commodore VX radiator oil cooler.

That's very interesting what you say about the TPS effective area. Mostly for aesthetics and only slightly for performance, I bought a second-hand but never used 100mm TB from the same guy I got the RHS heads from. As mentioned by my tuner, the larger throttle body, with a 112LSA cam and operated by throttle cable, makes for some compromises with low speed driving. The blade isn't drilled (although I saw that the standard LS1 blades are all drilled!).

Thank you, Michael

I’m doing one of these swaps on my Gen 5 viper soon, so I’ll take a look at this later when I get time and help any way I can.

Thank you too, much appreciated

We don't see many Vipers, of any generation, here in the UK.

Ben knows his shit. Hopefully between the 2 of us you'll get sorted.

Will look at all your stuff later, busy like you... Still could be transmission, but does sound electrical for now.

Thinking out loud... Just to double check, you can still program and log the trans with hpt from the obd port? If yes, then how is the can bus wired? I would have thought you would severe the can link to the vehicle so that there aren't multiple trans messages on the bus confusing the TCM.

I'm feeling more confident of getting somewhere, now I have yours and Ben's assistance....

The T43 plug connector has two sets of CAN bus twisted wires and the block diagram shows how the diagnostics port and the usb connector for the PCS software are wired, which makes some sense to me...

Jim says the PDS gear display just monitors the CAN bus, it doesn't send anything out. I thought I'd try driving it without that connected, just in case, but that'll have to wait until the new radiator is fitted.

I think I'll start by checking that none of the digital inputs are earthing etc.

There is one piece of pertinent information I have neglected to mention......the guy who helped me with the mechanical side of the conversion also did a lot of the wiring. On one occasion, whilst I was with him at his garage, he accidentally blew a fuse on the OBD2 circuit, because the battery / ignition was on as he passed the depinned connector through the bulkhead. We replaced the fuse and were able to read the trans tune etc., so didn't think too much of it. I do wonder if this spiked something somewhere...

Hmm, not ideal, but if he's just hit the 12V wire and blown the fuse things might be ok. CAN is quite robust.

Any unused inputs should be selected to disabled. For example you have dig in 6 set to cal b but nothing shown on your wiring diagram. Floating dig inputs can cause all sorts of chaos sometimes.

And double check with ZG on how the CAN should be wired. As far as I read everything, the trans should be exclusively connected to the PCS. If it can see the BCM and ECM then it'll be getting messages on the bus that are the same ID as the PCS messages.

Also noticed in your bin that you have can inputs selected and have wired those same inputs physically to the PCS. The manual states that is not allowed. Your log also shows manual mode switching in and out rapidly.

I managed to have some free time this afternoon, spurred on by you mentioning the manual mode switching in and out.

It's funny (debatable) how often you can't see the wood for the trees when working on your own car (maybe that's just me?!). As soon as I looked at the digital input wiring, which is in the passenger footwell, it was obvious that one of the inputs was in use, by virtue of it not being present.

The only Digital Input connected to anything is Input 1, enabled on the PCS software as True Manual Mode, but actually being connected to pin 33 on the blue PCM connector (on my Commodore, a brown wire, function identified as TCC brake switch signal). When I check the 'button type' on the PCS software for Digital Input 1, it is set to momentary, which I believe is correct for the brake switch function (but not, of course, when it's thinking it's the Manual Mode switch). This might explain a lot of my issues? My mate would have used this connection as it was the same function for the old 4L60? Or would you suggest a different way of connecting to the brake switch circuit?

Whilst I'm mentioning ecu connections, I currently have pin 21 Red connector, VSS high signal, connected to pin 17 on the TCM-2650, the zero crossing output in the speedometer output area, on the block diagram. The TCM was originally wired with the speedo output coming from 41, but Tre-Cool moved his to make his Commodore VX work, so I copied him... The dash speedo does move, (the dial is in KM/H but was at some stage adjusted to read MPH) but barely reaches the 30mph mark and sometimes flickers around lower than that. I think I just need to absolutely copy Tre-Cool, but got a little lost and am also wondering if his reads KMH or MPH anyway. Anyway, I don't think this is an issue for the trans functioning, just something I need to get the cruise control working again. Pin 20 Red is VSS low signal, currently disconnected.

This is the PCM pinout info I'm using. The wiring colours aren't always the same as on my Commodore, but otherwise it appears accurate. http://www.mrk-motorsports.com/pdf/9...%20Pinouts.pdf

I have disabled all the other digital inputs and all the analogue inputs (except for input 1, which is the TPS). In the Input 1 failure values tab, the 'voltage to assume' is a limp home figure, I guess? Attachment 123284

I have two laptops, both with the same ZGP Universal TCU Software version loaded on them. The smaller of the two laptops was bought specifically to take in the car, so it has most of the bin files etc on it. The other laptop had the software loaded first and for some reason is a much 'fuller' version than the other one. When you downloaded the software, did you get this many expandable tabs? Attachment 123285 Or does yours look more like? Attachment 123287

The fuller version shows all sorts of interesting features, especially in the clutch control, adapts and torque management tabs. It may be that they're all/ partly irrelevant, because the internal 6L80 TCM has all that info as part of the map, but surely I should use this software to load the bin file when the time comes?

The two bin files attached to my last post were both from Jim. I think he was experimenting a little, as you say, one of them had the CAN and hardware conflicts. This is the bin file after my little adjustments. Attachment 123290 It's a shame I can't do any testing until the radiator arrives!

I'll can check again when I'm back next Monday, but I believe the CAN is only wired from the 6L80 to the trans OBD2 port and the USB connector.

These are my mate's workings for the TCM-2650 connections into the PCM / vehicle harness:
Attachment 123291

Thanks again for your support and for reading all of this!

One other tab I checked earlier on was under Setup Info and CAN setup - the Misc Mode Settings tab. Do any of the options look wrong for my application?

my 2c, coz im tired. the TCU software is a bit hit and miss & 1 version can make changes needed that the other completely fucks. So be careful making sweeping changes.

I ended up moving some of the wires around on the original as built harness to use the pwm outputs for relays etc. trans tune wise u setup the speedo values as needed. the ecu side is where you go to town fudging it so the speedo works properly.
Attachment 123302
Attachment 123303
Attachment 123304

Speedo Output pulse is set to 2000 in the PCS universal TCU software.

i suspect you might need to go back to the original tcm file to un-fck what you have been changing. I learnt the hard way that what the software says your changing is not correct. It's a custom firmware loaded on the tcm2800 as such it's still in a universal configuration.

send me a pm and i'll email you the bin file from the vx commodore i did.