Need help with MSD TCM wiring

[FLFrank35]

Building a '35 hot rod truck with
a Holley Sniper EFI (550-510) on a BluePrint crate Ford 306,
a Ford 4R70W with the MSD Atomic TCM (2760),
and a Lokar automatic electronic sport shifter.

Anyone with similar components that can help? I've reached out to Performance Automatic, BluePrint and Holley/MSD but haven't had any luck. I believe I have all the wiring diagrams but do not quite understanding were to physically make some of the wire connections. I think I have the EFI wired correctly, but trying the integrate the TCM is proving to be difficult for me, specifically on the TCM 12-pin JAE connector:


Pin 1. Overdrive Cancel - I don't have a button for this. Do I need this since the shifter has manual/bump-shift mode? Can I ignore this wire?


Pin 2. TPS Ground reference - I believe this is basically a chassis ground, right?


Pin 3. Calibration Select - ??? Have no idea.


Pin 4. Manual Bump up/Manual mode select - Does this get connected to one or all of the Red wires (open circuit) of the shifter micro-switches?


Pin 5. TCC Lock - Does this go to the brake switch...Brake OFF side? Or someplace else?


Pin 6. Speed Out - Does this go to the speedometer?


Pin 7. TCC Unlock - Does this go to the brake switch...Brake ON side? Or someplace else?


Pin 8. TPS 5V - I think I know this one...I have an EFI and this is for carb so I don't think I need this so I tied it off.


Pin 9. Manual Bump Down - Does this get connected to one or all of the Blue wires (closed circuit) of the shifter micro-switches?


Pin 10. 12V Ignition - I think I got this too...Switched on 12 volt from ignition switch or other switched-on source.


Pin 11. RPM/Tach In - I took this signal from the EFI Tach Output.


Pin 12. - TPS Signal In - Not sure were to connect this. Don't see anything coming from the EFI that indicates TPSsignal.

[TxMike64]

Nothing I can find cross references to MSDs harnesses. I did find the following diagram in my notes:

131498

Maybe this is helpful...?

[TxMike64]

Pin 1. Overdrive Cancel - I don't have a button for this. Do I need this since the shifter has manual/bump-shift mode? Can I ignore this wire?
4R70W AODE and AOD only have a three position selector shaft (L, 2, OD) so a momentary switch is needed for the OD Cancel function - if you want to use 3rd.

Pin 2. TPS Ground reference - I believe this is basically a chassis ground, right?
Sensor Ground is to the ECU/Sniper not to chassis ground. You will need to contact Holley to figure out how to get the Sensor Ground.

Pin 3. Calibration Select - ??? Have no idea.
I'm guessing this is MSD specific - probably for tuning or diagnostic use.

Pin 4. Manual Bump up/Manual mode select - Does this get connected to one or all of the Red wires (open circuit) of the shifter micro-switches?
If it's not referenced in the diagram I posted above, you'll have to contact MSD.

Pin 5. TCC Lock - Does this go to the brake switch...Brake OFF side? Or someplace else?
This should connect to your TCU.

Pin 6. Speed Out - Does this go to the speedometer?
I'm guessing this should connect to your TCU, as the TCU needs a VSS reference. It might also be able to be daisy-chained to the speedo.

Pin 7. TCC Unlock - Does this go to the brake switch...Brake ON side? Or someplace else?
This should connect to your TCU.

Pin 8. TPS 5V - I think I know this one...I have an EFI and this is for carb so I don't think I need this so I tied it off.
This is not for carb, this is the 5V power supply for the 4R70W to operate correctly - also called sensor-level voltage, or reference voltage. It must be a clean regulated 5V supply, and usually the best place to find it is at the TPS (Throttle Position Sensor). You will need to contact Holley to figure out how to get this 5V Reference Voltage.

Pin 9. Manual Bump Down - Does this get connected to one or all of the Blue wires (closed circuit) of the shifter micro-switches?
If it's not referenced in the diagram I posted above, you'll have to contact MSD.

Pin 10. 12V Ignition - I think I got this too...Switched on 12 volt from ignition switch or other switched-on source.
Yes, a 12V switched power source.


Pin 11. RPM/Tach In - I took this signal from the EFI Tach Output.
Correct, EFI Tach Output.

Pin 12. - TPS Signal In - Not sure were to connect this. Don't see anything coming from the EFI that indicates TPSsignal.
The TPS has three wires: Sensor Ground, 5V Reference Voltage, and the Output Signal. You will need to contact Holley to figure out how to get the TPS Signal from your unit.

[TxMike64]

Well, near as I can tell by a quick scan of the manual (as found here summitracing.com/global/images/instructions/sne-550-510.pdf (https://static.summitracing.com/global/images/instructions/sne-550-510.pdf))

Your Sniper system won't interfacing with the MSD TCM. You'll have to call Holley.

-----------------

Just found this: https://forums.holley.com/showthread.php?22217-Sniper-EFI-amp-electronically-controlled-transmissions

The consensus is you'll have to add an external TPS to your Sniper for your MSD TCU.

[FLFrank35]

Nothing I can find cross references to MSDs harnesses. I did find the following diagram in my notes:

131498

Maybe this is helpful...?

Thanks for the effort! I have that diagram and the connections were pretty idiot proof, along with a couple other harnesses. But I also have the 2760 harness with it's diagram and I've figured out most of the connections, with the help of the others, but I'm not quite sure were to connect the TCC wires. I know they're for the Torque Converter Clutch (TCC Lock On/Off), but I don't know were to physically wire them. I have the 4R70W which is automatic so I think they go to the brake pedal switch:confused: ...

Thanks again!

[rapidray]

I might be able to answer some of your question, however I have only installed an MSD in GM products. You do require a TPS 5volt reference signal and ground. I am not sure your Sniper model supports it however. The diagram that shows the reference signal and ground for the Holley sniper it is on page 17 of the Sniper installation instructions that are on the net (the files are to large for me to post here) they are pins A and B of the Sniper mating harness PN 558-492 8 pin connector. Now on to the MSD controller: Pin 1 will go to a momentary ground switch that you will have to install. Pin 3 is a calibration select wire that puts the transmission in the aggressive shift mode it connects to a always on ground switch that you will have to install. Manual select pin 4 goes to a momentary ground. I think you could connect it to the blue wire on the upshift of the Lokar shifter. Pin 5 goes to a always on ground switch that you will have to provide. Pin 9 will go to the downshift switch on the Lokar shifter. Pin 7 goes to the brake switch. Going through the Lokar instructions I noticed that for some reason the manual mode switch is always on, if so you could connect pin 3 to that switch. It would be easy to check the switch with a ohm meter or just call Lokar. Hope this helps! Ray

[FLFrank35]

Thanks. I read that thread and came to the same conclusion, but before I did anything I contacted Johnny at BluePrint Engines. He spoke to his tech rep at Holley, and they recommended the Casper TPS Breakout harness (108103). It's harness gets plugged in to the right side of the Sniper throttle body and then the 3 wires (TPS ground reference, signal and 5v) get connected to the MSD TCM.

Everything I've read said NOT to share a TPS signal, and somewhere else I read that the Sniper wasn't built to work with an automatic trans. But since Johnny ordered the trans to go with the engine as a package, and consulted with his Holley tech, I have to go with that recommendation...so, hope it works (fingers crossed).

But I still could use some clarification on a couple things...

- Pin 1, Overdrive Cancel...I don't currently have this installed. I've seen it in other vehicles I've driven but never really paid attention to it. Is this something I really should install?

- Pins 5-7, you say go to the TCU. Just to be clear, I have a MSD TCM (Transmission Control Module)...same thing as a TCU? Because they come OUT of the TCM. I spoke to Holley/MSD and was told I don't necessarily need to use the TCC Lock/Unlock features.

Thanks for your help!
Frank

[TxMike64]

Thanks. I read that thread and came to the same conclusion, but before I did anything I contacted Johnny at BluePrint Engines. He spoke to his tech rep at Holley, and they recommended the Casper TPS Breakout harness (108103). It's harness gets plugged in to the right side of the Sniper throttle body and then the 3 wires (TPS ground reference, signal and 5v) get connected to the MSD TCM.

Everything I've read said NOT to share a TPS signal, and somewhere else I read that the Sniper wasn't built to work with an automatic trans. But since Johnny ordered the trans to go with the engine as a package, and consulted with his Holley tech, I have to go with that recommendation...so, hope it works (fingers crossed).

Yeah, if that's what Holley Tech recommends, and the guys at Blueprint say, then go for it. I don't think Blueprint would recommend it if they didn't think it was the right thing to do! Plus, all the related threads I read were saying not to tap-in and share the signal. We don't know what's in this Breakout Harness (diodes, filters, etc) so it may not be just tapping into the signal and dropping the reference voltage (this output is measured in milivolts, so any addition to the circuit will affect it).


- Pin 1, Overdrive Cancel...I don't currently have this installed. I've seen it in other vehicles I've driven but never really paid attention to it. Is this something I really should install?

If you won't use it there's no reason to add it. I was always annoyed when manually shifting from 1st(L) to 2nd, then 2nd to the next and it wouldn't hold in 3rd, dumping into 4th(OD) too soon for my liking.


- Pins 5-7, you say go to the TCU. Just to be clear, I have a MSD TCM (Transmission Control Module)...same thing as a TCU? Because they come OUT of the TCM. I spoke to Holley/MSD and was told I don't necessarily need to use the TCC Lock/Unlock features

I'm rethinking this, it's probably to manually control the TCC Lockup solenoid. This is sometimes done for drag racing and using a chassis dyno. It's not necessary. If you don't use the OD Cancel or the TCC Lockup features, just make sure you cap and heatshrink the ends real good.

[FLFrank35]

I might be able to answer some of your question, however I have only installed an MSD in GM products. You do require a TPS 5volt reference signal and ground. I am not sure your Sniper model supports it however. The diagram that shows the reference signal and ground for the Holley sniper it is on page 17 of the Sniper installation instructions that are on the net (the files are to large for me to post here) they are pins A and B of the Sniper mating harness PN 558-492 8 pin connector. Now on to the MSD controller: Pin 1 will go to a momentary ground switch that you will have to install. Pin 3 is a calibration select wire that puts the transmission in the aggressive shift mode it connects to a always on ground switch that you will have to install. Manual select pin 4 goes to a momentary ground. I think you could connect it to the blue wire on the upshift of the Lokar shifter. Pin 5 goes to a always on ground switch that you will have to provide. Pin 9 will go to the downshift switch on the Lokar shifter. Pin 7 goes to the brake switch. Going through the Lokar instructions I noticed that for some reason the manual mode switch is always on, if so you could connect pin 3 to that switch. It would be easy to check the switch with a ohm meter or just call Lokar. Hope this helps! Ray


Thanks Ray. My installation manual only goes to page 16! Upon further examination, it's only the "Quickstart Manual." So I looked, and found, the document you referenced...good stuff. However I only have the 7-pin connector (558-490) and the 10-pin connector (558-491), so hopefully I can get by with just those.

As for the pins...

Pin 1..Do I really need, or want an Overdrive Cancel? I've driven vehicles with O/D cancel but not sure that it's necessary on an automatic hot rod..is it? I thought that was mostly for towing. Your opinion?

Pin 3..Was told it's optional but not needed, per Holley/MSD.

Pins 4 and 9..Spoke to Lokar and studied the instructions and watched a video. I think I got this.

Pin 5 and 7..Was told by Holley/MSD tech that I don't need these but I thought, like you, that they probably work with the brake switch. I'll check this out further.

Thanks again! Really appreciate the help!
Frank

[FLFrank35]

Yeah, if that's what Holley Tech recommends, and the guys at Blueprint say, then go for it. I don't think Blueprint would recommend it if they didn't think it was the right thing to do! Plus, all the related threads I read were saying not to tap-in and share the signal. We don't know what's in this Breakout Harness (diodes, filters, etc) so it may not be just tapping into the signal and dropping the reference voltage (this output is measured in milivolts, so any addition to the circuit will affect it).



If you won't use it there's no reason to add it. I was always annoyed when manually shifting from 1st(L) to 2nd, then 2nd to the next and it wouldn't hold in 3rd, dumping into 4th(OD) too soon for my liking.



I'm rethinking this, it's probably to manually control the TCC Lockup solenoid. This is sometimes done for drag racing and using a chassis dyno. It's not necessary. If you don't use the OD Cancel or the TCC Lockup features, just make sure you cap and heatshrink the ends real good.


Mike,

Wow! This is all good info!
Thanks for your insight, because I'm new to all this. It's really been helpful!

Thanks again!

[rapidray]

Mike, I think you could get away without pin 5 but I would recommend using pin 7 (pin 5 cannot be connected to the brake switch as it requires a always on ground). Keep in mind that I have not installed this on a Ford product. Pin 1 you should use, older cars sometimes located this switch on the end of the turn signal lever (overdrive on/off) As for splitting the wires for the TPS switch in my experience that is a definite no/no!!! I guess you could try it however keep in mind the TPS switch recalibrates on every key on/off event according to your manual (if true this could cause mayhem LOL). I would probably use an external TPS switch like this one TCI Remote TPS 377450 if necessary. I would like to see a picture of your throttle body. Does it look like this one? IF so the component on the left is the IAC and the one on the right is the TPS. If it does what about the IAC (idle air control valve) is it necessary, what controls it? (I am curious about this could you let me know) The TPS and IAC setup are listed in your setup manual and are adjustable with your handheld. Don't get too frustrated as these problems always come to light when mixing components, they are usually solvable however. Also if the Electronic Lokar shifter can use Pin 3 why not try it? Ray

[FLFrank35]

Mike, I think you could get away without pin 5 but I would recommend using pin 7 (pin 5 cannot be connected to the brake switch as it requires a always on ground). Keep in mind that I have not installed this on a Ford product. Pin 1 you should use, older cars sometimes located this switch on the end of the turn signal lever (overdrive on/off) As for splitting the wires for the TPS switch in my experience that is a definite no/no!!! I guess you could try it however keep in mind the TPS switch recalibrates on every key on/off event according to your manual (if true this could cause mayhem LOL). I would probably use an external TPS switch like this one TCI Remote TPS 377450 if necessary. I would like to see a picture of your throttle body. Does it look like this one? IF so the component on the left is the IAC and the one on the right is the TPS. If it does what about the IAC (idle air control valve) is it necessary, what controls it? (I am curious about this could you let me know) The TPS and IAC setup are listed in your setup manual and are adjustable with your handheld. Don't get too frustrated as these problems always come to light when mixing components, they are usually solvable however. Also if the Electronic Lokar shifter can use Pin 3 why not try it? Ray

Hey Ray, Frank here. I think you confused me with TxMike64.
Anyway, thanks for the suggestion about the overdrive. I guess I'll look into installing that.
As for not splitting the TPS signal, that's what I read about it too...that you should NOT split it. However, as I stated in another post, when I questioned the BluePrint Engines rep, he relayed what his Holley tech contact said...I can use the Casper TPS Breakout harness (see pics) http://www.casperselectronics.com/cart/index.php?route=product/product&product_id=355. He said they don't want people slicing into the Sniper's wiring but the harness was developed to split the TPS signal correctly. I don't know anything about it and your experience falls in-line with what everyone else says, but if BluePrint and Holley says it'll work I figure I'll give it a try. I did look at the TCI Remote TPS but I couldn't figure out how to mount it...I guess that'll be plan-B if the Casper breakout doesn't work.

I don't know about the IAC...that's another new thing for me. :confused:

Here are the pics of my setup...
Left side131608 Right131609 Original TPS connection 131610
The Casper TPS Breakout 131611 131612 The Casper's gray goes to the transmission controller's 5V, blue to the signal-in, and black to the ground.

Thanks again for your help and encouragement; I've been feeling like I'm in the weeds with a lot of this.
Frank

[rapidray]

Frank, TXMike64, sorry for the confusion! I'm an old guy so it happens! Personally I have had no luck splitting sensor wires when working with millivolts but if they all say it works I would definitely go with it. They engineered the product so they should know. You didn't send a picture of the rear of the throttle body where the IAC is located. I sure am curious however. My curiosity is in regard to the connections, where they go and how all the components work together. Things like this get my attention when we encounter them at the shop (usually the vehicle shows up on a hook) so I must enjoy being tortured LOL. Hang in there and don't worry it will all come together eventually. Ray

[FLFrank35]

Frank, TXMike64, sorry for the confusion! I'm an old guy so it happens! Personally I have had no luck splitting sensor wires when working with millivolts but if they all say it works I would definitely go with it. They engineered the product so they should know. You didn't send a picture of the rear of the throttle body where the IAC is located. I sure am curious however. My curiosity is in regard to the connections, where they go and how all the components work together. Things like this get my attention when we encounter them at the shop (usually the vehicle shows up on a hook) so I must enjoy being tortured LOL. Hang in there and don't worry it will all come together eventually. Ray

Sorry I didn't include a picture of the rear of the Sniper. It came already installed on the engine and I only connected the fuel lines, otherwise I haven't touched the back. I don't even know what that connector is for:confused:
Here it is..
131654

Thanks,
Frank

[rapidray]

Frank, that should be the idle air control valve. It controls idle speed under various engine operating conditions (A/C on, return to idle speed etc.) The full explanation and various adjustments are on page 56-57 of your manual. Hope this helps! Ray

[FLFrank35]

Frank, that should be the idle air control valve. It controls idle speed under various engine operating conditions (A/C on, return to idle speed etc.) The full explanation and various adjustments are on page 56-57 of your manual. Hope this helps! Ray

Yes, it helps. It all helps me at this stage 😁
Thank you again,
Frank

[rapidray]

Frank, happy to help, just hope I am leading you in the right direction. I would like to suggest one other option. I don't know at what stage you are in your build, but if I was ready to start the engine I would install the Sniper system standalone initially (without splitting the TPS) You could still get the wiring ready. Holley has built baselines into the system for initial start and in the manual. I am not familiar with Blueprint engines and so don't know what kind of break in procedures you are to follow (but it could be important and should be followed). I would then make sure I have no fuel, oil,cooling or ignition problems and the engine starts and runs well. This way you have a baseline to fall back on. I would then plug my handheld into the system go to the TPS screen and note the readings (0-100% hopefully). Plug the splitter in and again note the readings (the engine does not need to be running). If the same you should be good to go. Ray

[FLFrank35]

Frank, happy to help, just hope I am leading you in the right direction. I would like to suggest one other option. I don't know at what stage you are in your build, but if I was ready to start the engine I would install the Sniper system standalone initially (without splitting the TPS) You could still get the wiring ready. Holley has built baselines into the system for initial start and in the manual. I am not familiar with Blueprint engines and so don't know what kind of break in procedures you are to follow (but it could be important and should be followed). I would then make sure I have no fuel, oil,cooling or ignition problems and the engine starts and runs well. This way you have a baseline to fall back on. I would then plug my handheld into the system go to the TPS screen and note the readings (0-100% hopefully). Plug the splitter in and again note the readings (the engine does not need to be running). If the same you should be good to go. Ray

I hadn’t considered doing that but it’s easy to do. I can simply unplug the breakout TPS signal harness, run the engine a bit, and plug it back in later. Great idea! Thanks!
Frank