Help Wiring 6-pin TPS

[bleblanc03]

I'm hoping for some help, please, with how to get the 5V reference for a 6-pin TPS on a manual transmission car.

I want to wire a 6-pin TPS (correct polarity, AEGS M20 part) so I can feed the DME and also data log throttle position.

I'll just reuse the wires from the switch part, obviously.

I have studied the pins in the ETMs and see that I need a reference 5V for the variable part. The signal will feed into my data logger, and ground I can figure...but, does anyone know where I can/should get this 5V from?


Why, you're asking? I'm overly curious and a glutton for punishment. I have a Zeitronix ZT2 that will log AFR, throttle position, and RPM.


My car has been running lean since I undertook a 2.7 stroker/cam/9.5:1 compression build a couple years ago. I assume I should just put an MSPNP on it with the simpler 3-pin M50 TPS...but, I want to know a bit more about what's going on before I just give in and scrap the factory management.

[e30m3s54turbo]

I’m also interested learning on the six- pin TPS. I have one on of my e30’s. It is a 1991 s38 b36 the ecu is MSII.

[TobyB]

Your 5v reference should come from your logger, as should the 5v ground for the TPS.

If the switches are in common with the DME, then logger ground should be bonded to DME
logic ground. If not, then it no matter.

Shoot us a part number for this 6 pin TPS?

I too have found that throttle position is very valuable once you start looking at data...

t

[bleblanc03]

Thank you for your reply, TobyB.

I should have included the BMW part no. originally. It's BMW part 13631707320 (Bosch part 0280120402). From an M20 car. [If you don't know, there's an M30 part that looks identical, but the M30 throttle rotates the opposite direction. So...don't buy that one for your M20.]

I'm waiting for a reply from Zeitronix as to whether I can use the +5V labeled "boost controller only".

If not, I guess I'll have to put a step-down voltage converter on a 12V feed...?

[TobyB]

Ideally, both the high and low reference sources would come from the logger, so that if one 'moves' the logger
moves with it.
If you can measure the resistance across the vref and ground for the pot, that ought to give you the
answer as to whether the logger can supply the current at 5v- honestly, if the pot is more than
500 ohms, I'd just do it- 10mA isn't enough draw to even notice, for things like this.

Thanks for the part number- that's a clean way to get throttle position for logging.
I've done things a lot less elegantly- just hooked a pot onto the linkage, and logged that voltage.


t

[arabalarca]

You’re on the right track conceptually, and your understanding of the ETM pinouts is solid 👍
The key thing to clear up is where the 5V reference should (and should not) come from on an M20 with factory management.

On the AEGS 6-pin TPS, the switch side is easy—as you said, you can reuse the existing idle/WOT switch wiring with no issue. The variable (potentiometer) side is where people usually get tripped up. About the 5V reference


On factory Bosch Motronic systems (M20 Motronic 1.1 / 1.3), there is no dedicated external 5V reference output intended for a TPS on manual cars. The DME does generate internal 5V references, but they’re reserved for specific sensors (AFM, coolant temp circuits, etc.) and tapping into those is risky:

• You can introduce noise into critical sensor circuits
• You can skew AFM or temp readings
• You risk damaging the DME if the logger backfeeds voltage

So the general rule: don’t steal 5V from the DME. The correct and safe solution


Since your goal is data logging only, the best practice is:

• Use the Zeitronix ZT-2 internal 5V reference output to power the variable side of the TPS
• Ground the TPS signal ground to the ZT-2 sensor ground, not chassis ground
• Feed the TPS signal output only to the ZT-2 analog input

This keeps the factory DME completely isolated and avoids ground offset or reference drift. You’ll get clean, stable TPS data for logging without interfering with Motronic. Wiring logic (simplified)

• TPS 5V → ZT-2 5V reference
• TPS Ground → ZT-2 sensor ground
• TPS Signal → ZT-2 analog input
• Idle/WOT switch wires → stock DME wiring (unchanged)

About running lean on a 2.7 stroker


What you’re seeing is extremely common on stroked M20s with cam and compression:

• AFM voltage ceiling
• Injector duty cycle nearing limit
• Fuel maps not scaled for displacement + VE

Logging TPS + AFR + RPM is a smart move before going standalone, not a waste of time. It’ll confirm whether you’re load-limited, injector-limited, or simply outside the stock map resolution.

Many people jump straight to MS without understanding why the factory setup fails. Doing it your way gives you real data—and that always pays off.

I’ve seen similar diagnostic approaches documented in longer-form BMW technical writeups on sites like

https://arabalarca.com.tr

where OEM management limits and sensor behavior are broken down in detail rather than just “swap to standalone” advice.

Short version:
✔ Don’t pull 5V from the DME
✔ Use the logger’s reference voltage
✔ Log first, decide on MS after

Curiosity rewarded—not punished 😄