Accel Enrichment w/ Variable TPS

[ZenitramNaes]

Hello all,

I've had my MS running for around a year now, I was determined to get a variable TPS running instead of the switch style so I could experiment with accel enrichment. At the time I couldn't find all the pertinent information regarding such a install.

As of now I have the stock m30 TPS and I'm trying to get the m50 variable TPS working.

BRN/ORG is Ground
BRN/BLK is WOT Signal
BRN/BLU is Idle Signal

Assuming the above is correct, then I shouldn't be having a problem. From what I can remember from last year though, I tried the above and couldn't get the variable to work.

I'm curious if any of you are running a variable setup and if you did, I'd be curious to how you wired it.

For reference, I have a 55 pin DIYPNP 1.5v board.

Thanks for the insight.

[MercyFlush]

Hello all,

I've had my MS running for around a year now, I was determined to get a variable TPS running instead of the switch style so I could experiment with accel enrichment. At the time I couldn't find all the pertinent information regarding such a install.

As of now I have the stock m30 TPS and I'm trying to get the m50 variable TPS working.

BRN/ORG is Signal
BRN/BLK is GRN
BRN/BLU is 5v reference

Assuming the above is correct, then I shouldn't be having a problem. From what I can remember from last year though, I tried the above and couldn't get the variable to work.

I'm curious if any of you are running a variable setup and if you did, I'd be curious to how you wired it.

For reference, I have a 55 pin DIYPNP 1.5v board.

Thanks for the insight.

Hey,

I just picked up an E36 Auto TPS myself for my DIYPNP 55 Pin too. When you say you couldn't get it to work did you make sure to not just wire the tps in to the harness, but to also hook the corresponding pins on the 55 Pin Bosch connector to the actual DIYPNP board? otherwise you'll not be getting anything from the tps (also make sure to remove the pulldown resistor that was needed for the old switch).

All you should need to do is hook the DIYPNP vref to the pin that goes to the tps vref, then the grounds, then have the tps signal pin hooked into the DIYPNP TPS Sig edge connector.

Let me know how you go, as I'll be doing this myself in a few days :D

[MercyFlush]

Just a follow up. Just now I finished installing my Variable TPS basically it's as simple as I suggested in my previous post.

TPS SIG goes to Pin 52
5v goes to Pin 53
GND goes to Pin 19 (You might not need this, but it's safer if you just hook it up) THIS is probably your issue

Make sure to remove the resistor that you probably have hooked into the TPS SIG going to ground otherwise your tps will read wrong.

Good luck ;)

[ZenitramNaes]

Wow man, thank you. You made it sound so simple. I think what I was trying to do was to use the 5vref from the old AFM wires or I was trying to use the old TPS wires. I didn't know where to pull the 5vref. Did you run new wires all the way back to the ecu?

[ZenitramNaes]

The thing about the M50 TPS that I just realized, it has three wires for the variable and an other three pins for an on/off type of switch. I was trying to use the switch types wires previously without knowing (the non shielded wire).

So with some research I found the follow:

M50 TPS

Pin 1: 5v (black)
Pin 2: Signal (brown)
Pin 3: Ground (yellow)

M30 TPS

Pin 1: Idle Signal (Brown/Blue)
Pin 2: Ground (Brown/Orange)
Pin 3: WOT Signal (Brown/Black)

And with your pin out:

5v: Pin 53
Signal: 52
Ground: 19

I should have this completed today, I'll get back with some results.

[ZenitramNaes]

Having trouble calibrating the TPS in Tunerstudio. The blue bar that's in the calibrating screen never goes higher than 25% full, while I have about 12 when it's closed and 137 when fully open. The TPS gauge doesn't seem to be working right either. I'll be looking over all my wiring to ensure everything is correct.

[MercyFlush]

Having trouble calibrating the TPS in Tunerstudio. The blue bar that's in the calibrating screen never goes higher than 25% full, while I have about 12 when it's closed and 137 when fully open. The TPS gauge doesn't seem to be working right either. I'll be looking over all my wiring to ensure everything is correct.

Good idea, if you're getting something in TunerStudio you know it's at least half right! I sent you a PM with some more info!

[EatsHondas]

Here's how I wired mine, works great with no problems. No new wires for me. I spliced another tps connector into the existing TPS wires while being sure to switch the two wires as mentioned in the excel file. That way if shit happens and I need to Motronic quickly (I have to DD my e30), I simply swap back to the e30 tps and plug in the other connector which is still wired correctly for Motronic. Same idea for my wideband and IAT, spliced into the appropriate wires so my engine harness is modular between MS and Motronic.

[EatsHondas]

Forgot the file, sorry.

[MercyFlush]

Here's how I wired mine, works great with no problems. No new wires for me. I spliced another tps connector into the existing TPS wires while being sure to switch the two wires as mentioned in the excel file. That way if shit happens and I need to Motronic quickly (I have to DD my e30), I simply swap back to the e30 tps and plug in the other connector which is still wired correctly for Motronic. Same idea for my wideband and IAT, spliced into the appropriate wires so my engine harness is modular between MS and Motronic.

I did the same :), makes it easy if you just plug and play. I'll add my last PM to him as reference too, it was all about diagnosing the connection of TPS. Could help someone I suppose

M50 TPS

M50 Pin 1: 5v (black) = M30 Pin 3 (Brown/Black) = Harness Pin 53 = Edge connector 5v (DIYPNP)

M50 Pin 2: Signal (brown) = M30 Pin 1 (Brown/Blue) = Harness Pin 52 = Edge connector TPS (DIYPNP)

M50 Pin 3: Ground (yellow) = M30 Pin 2 (Brown/Orange) = Harness Pin 19 = Edge connector GND (DIYPNP)

Maybe grab your multimeter and put it in ohms mode and confirm the following:

1. Meter in Ohms and measure across M50 TPS Pins 1 and 3 and record the value. For the sake of explanation I'll assume the result was 4.5 Ohms (Yours is probably different).

2. Fist off don't touch the throttle. Meter in Ohms and measure across M50 Pins 1 and 2 and record the value. Measure across M50 Pins 2 and 3 and record the value. These two values should equal the result from part 1, or close to it. Lets say, 4.4 Ohm(1&2) and 0.1 Ohm (2&3) = 4.5 Ohms (Test 1)

3. Meter in ohms measure across M50 Pins 2 and 3 and while doing this actuate the throttle (twist with your hand or have someone help etc.) The reading should go either from ~0 ohms to 65% of the initial reading (or a similar span of ohms depending on the adjustment of the tps the starting point will be higher of lower ohms).

4. Hook your wiring all back up and check the ohms on the harness connector with your meter in Ohms over the pins 19 and 52. When you actuate the pedal you should be getting similar values to Step 3. Do the same for Harness Pins 19 and 53, this should read the same or similar value to step 1.

If you do the above and yet the tps still reads wrong in the megasquirt then I urge you to check the wiring from the harness connector inside the megasquirt DIYPNP to the daughter board (the big blue board you construct when you get the DIYPNP). Make SURE you have removed the 1K resistor that's grounding the tps signal from the old style switch otherwise it's not going to work right!

For what it's worth my values are 203 to 619 counts with the tps calibration. Using the values from Tests we can deduce what the counts *SHOULD* be using some maths. But in reality it'll not be exactly this. But should ballpark you for diagnostics.

Using M50 Pins:

VOutput = ((Resistance of Pin 2 to Pin 3 (Signal)) / (Resistance Total (Pin 1 to Pin 3))) * VInput

Using the values I selected above of 0.1 Ohms for Pins 2 to 3 and 4.5 Ohms for pins 1 to 3 and input of 5v
VOutput = (0.1 Ohms / 4.5 Ohms) * 5v = 0.0222 Ohms * 5v = 0.111v For 0% throttle

Now if you pressed the pedal to the floor, resistance of Pin 2 to 3 would go up to, idk, somewhere near 3.5 Ohms lets say.
VOutput = (3.5 Ohms / 4.5 Ohms) * 5v = 3.888v for 100% throttle

Now to calculate the counts we simply divide the full range of voltage (5v) by the total number of counts, in this case 1024. so 5v/1024 gives us 0.00488v per Count

therefore:
0% throttle counts = 0.111v / 0.00488v/Count = 23 Counts (rounded up)
100% throttle counts = 3.888v / 0.00488v/Count = 797 Counts (rounded up)

[ZenitramNaes]

Thanks guys, I've been chasing a ignition stumbling problem I've had ever since I installed wasted spark, so that's had my attention over the last week or so. I never figured out why I wasn't getting correct numbers from the TPS in TunerStudio. Thanks for posting that Mercy, I posted it in my build thread but forgot to post it here.

.

What pins did you use exactly?

[EatsHondas]

The numbers in the two left-hand columns of the Excel sheet are pin numbers (that I used) for both the Motronic and Megasquirt connectors.

[Golfer_705]

Cant calibrate TPS

Great write ups! I'm in the middle of installing an e36 TPS into my e30 with a DIYPNP V1.5B. I have it mounted, spliced a second harness for the e36 TPS. I removed TPS Sig resistor to ground and connected TPS sig to pin 52, VREF to pin 53 and grounded pin 19.

When i try to calibrate the TPS in Tuner studio i get a steady ADC reading of 260. the ADC reading does not change as the throttle is moved.

I have tested the TPS, its sweep is between 1.2K ohm and 4.4k ohm (mounted) and increases steadily as the throttle is opened. With the DIYPNP disconnected i get the same ohm readings from the from the engine harness (ecm side) as i do testing directly from the TPS. With the tps and MS connected the tps sig tests between 1.1V DC to 4.2V DC depending on throttle position. VREF tests at 5.1V DC.

Any Suggestions why i cant get it to calibrate? Thanks in advance for your help getting this sorted out. :)

[MercyFlush]

Great write ups! I'm in the middle of installing an e36 TPS into my e30 with a DIYPNP V1.5B. I have it mounted, spliced a second harness for the e36 TPS. I removed TPS Sig resistor to ground and connected TPS sig to pin 52, VREF to pin 53 and grounded pin 19.

When i try to calibrate the TPS in Tuner studio i get a steady ADC reading of 260. the ADC reading does not change as the throttle is moved.

I have tested the TPS, its sweep is between 1.2K ohm and 4.4k ohm (mounted) and increases steadily as the throttle is opened. With the DIYPNP disconnected i get the same ohm readings from the from the engine harness (ecm side) as i do testing directly from the TPS. With the tps and MS connected the tps sig tests between 1.1V DC to 4.2V DC depending on throttle position. VREF tests at 5.1V DC.

Any Suggestions why i cant get it to calibrate? Thanks in advance for your help getting this sorted out. :)

Good to see you've gotten close!
It sounds like you're getting the proper inputs (+5v and GND) to the sensor, and output. I would suggest checking the wiring from the DIYPNP 55pin to the main board, you could have accidentally wired it wrong or something. Sometimes we just miss things that are usually very obvious hahaha.

Fwiw, an ADC count of 260 is about 1.25v or so, so that to me sounds like it's floating (not connected). Definitely check the 55pin to the main board, and manually check for continuity between the 55pin male side (toward the harness) to the tps input on the mainboard of the DIYPNP (directly to the input hole which has the silkscreened tps marking).

If that still does not work for you, try and probe 5v to the tps input on the diypnp (run a wire from Vref to tps, but make sure to not short anything). You should get an ad count of 1023 or so. If you still don't get a value which makes sense then I recommend looking at the immediate area of the board around the tps.

[Golfer_705]

Good to see you've gotten close!
It sounds like you're getting the proper inputs (+5v and GND) to the sensor, and output. I would suggest checking the wiring from the DIYPNP 55pin to the main board, you could have accidentally wired it wrong or something. Sometimes we just miss things that are usually very obvious hahaha.

Fwiw, an ADC count of 260 is about 1.25v or so, so that to me sounds like it's floating (not connected). Definitely check the 55pin to the main board, and manually check for continuity between the 55pin male side (toward the harness) to the tps input on the mainboard of the DIYPNP (directly to the input hole which has the silkscreened tps marking).

If that still does not work for you, try and probe 5v to the tps input on the diypnp (run a wire from Vref to tps, but make sure to not short anything). You should get an ad count of 1023 or so. If you still don't get a value which makes sense then I recommend looking at the immediate area of the board around the tps.

Thanks for the reply MercyFlush

Testing the DIYPNP shows TPS-pin52 0ohms VREF-pin53 0ohms and ground-pin19 0ohms. TPS-pin53 680K ohm VREF-pin52 680K ohm TPS-ground 10.62K ohm and VREF-ground 1.042K ohm. I'll put the DIYPNP back together and try jumping VREF direct to TPS sig and see what I get.