So I'm just going to come out and ask....
Edit: this is concerning the throttle position sensor wiring for a 059 based 1987 e24 with 745 turbo using MS1 v3 - trying to use a b35 round 6 pin TPS to replace the stock motronic 3 wire unit.... On with the question:
I have heard that the large black wire that houses 3 wires is to be ignored- it's a manual, so no need. That leaves 3 loose wires as pictured below- does anyone happen to have the intel on which is which? I guess my confusion comes from taking a 3 wire Manual TPS off my car as I have been advised to use the B35 tPS with "more wires"..... But I'm only going to use 3 - I can only imagine that these 3 wires are measure differently than the manual 3 wire I removed, or are potentiometered differently... Either way I don't want to guess and hook a random wire to a 9v battery and figure out the resistance- don't want to destroy it before I use it.
I will attach this to the 059 megasquirt pinout thread when I figure ( or more appropriately, someone assists in this brainbuster)
Thanks for your patience with this inquiry!
4 and 6 for idle position
4 and 5 for WOT position
Basically that E32/4 TPS is a combination manual transmission throttle switch and EH trans potentiometer in one unit. Also eliminates that problematic external EH trans white idle switch.
I can post up some scans of the schematic for the trans harness if needed from the book and for the TPS pin out to verify my findings. Just let me know.
You can pin the wires out to see whats what. The poten. is in the TPS itself. the ECU will supply a 5v reference, and there is an internal wiper arm which moves around depending on the position of the throttle blade, this applies resistance to the 5v signal. So 1 wire to the tps is a tps output from the 5v, which will give the ECU a 0-5v input, which allows the ecu to know the tps position. The third wire should simply be a ground to complete the reference circuit. So you should have 3 wires, 5v, ground and a TPS output wire. If your using megasquirt just twist the 5v and signal wires to the output and make sure it isn't working backwards, you may have to flip those wires till it reads in the right direction.
This is perfect stuff Eric and Scott- thank you both. That is exactly what I was looking for - the how AND the why so I can link this to the original topic and the MS FAQ and hopefully help the next guy. Ill keep you posted on the progress !
UPDATE (and question)
So I have everything going and I am running into a problem with this TPS – as you can see from the above picture- I had to re-connect my TPS to the harness as I bought it as a pigtail to use with my 059 harness.. then just bought the whole 179 harness (I like doing things the hard and expensive way) – I have connected and tested the wires and they produce the below functions-
I have hooked them up this way via the connector and via alligator clips (to remove the connector from the equation) I have also attached the 3 non-used auto trans wires, just in case.
What is happening is, when depressing the throttle, I am getting a reading on my Tuner Studio display as I depress the pedal… at about ½ to ¾ throttle there is a click and the MS shuts down, keep pressing and the MS stays shut down until you let off enough to pass this same point while letting off the throttle and it turns back on and boots up. I tried numerous configurations, but the one thing that remains is when pins 4 and 5 are connected- this occurs. I have tried with a different TPS of the same type and my extra manual TPS with the same result.
I am using MS1 with a goathumper adapter board with a 179 harness. There isn’t much to this… so I am thinking the issue has to be in the adapter board but I can’t seem to find out what is happening when it cuts off, because it just cuts off and reboots. I am thinking I will simply jump out of the adapter board to MS harness with my 5v wire and the TPS wire – ground pin 4 to the harness and see what I get… does that make sense or am I missing something? I am trying to get this thing tuned remotely and it is going well, if my sensors all work !
Thank you all for your help on ALL my current issues!
Edit... A little more poking found it is the adapter board and skinned wire.... I'm going to keep it out of the harness and deal with it.
I will post the pic I used to assure the proper pins are utilized by anyone whom stumbles upon this thread as it differs from what a lot of posts state- that was the original issue a while back.
Thanks for the PMs guys-
The pic and description I promised- now this can fade away to the archive until someone needs it.... thanks
I wouldn't read into this pic too much- it says 5 pins and there are obviously 6 - what it is pointing out is that pins 4,5,6 which are what the stock TPS is weird to, are incorrect -use 1,2,3
