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strange TPS wiring issues
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E30IS



Joined: 26 Jun 2008
Posts: 105

PostPosted: Fri Mar 27, 2015 3:03 am    Post subject: strange TPS wiring issues Reply with quote

im trying to wire in a new penny and giles hall effect TPS.

the TPS came with no plug/connector just the 3 wires.

so on the harness side ive identified:

1) the ground (middle wire on a 3 pin Bosch style connector) that gives continuity between it and the metal chassis/body

2) The +5V reference wire (using a multimeter i get 5V on one of the outer pins when grounded to body.

3) therefore the other wire on the harness is the signal.

my issue is that once i connect the sensor into the harness i no longer get the 5V reference between the 5V wire and ground it drops to 1.6V.

if i remove the sensor ground wire from the harness leaving only the 5V and signal wire from the sensor plugged into the harness i do get 5V its just when i put the sensor ground wire into the harness i dont get the 5V ref

basically i cant get any sort of signal out of it.

yet when i connect it to a 12V battery to bench test off the car it seems to produce the expected signal.

i am able to get a different brand TPS to work properly so the harness doesnt seem to have anything majorly wrong

what am i doing wrong, does the P&G sensor need something different?
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David Ferguson



Joined: 21 Aug 2006
Posts: 59
Location: Paso Robles, CA

PostPosted: Fri Mar 27, 2015 8:56 pm    Post subject: Reply with quote

You should look up the exact details for the P&G part number in this document:

http://www.cw-industrialgroup.com/getattachment/42e067a7-d2f3-4b9c-962f-8490230a72ff/

There are various outputs and wiring options. Don't guess.


Also, you should be sure you understand the wiring on your harness. Can you back-probe the connector with known good sensor attached and verify the signals?
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E30IS



Joined: 26 Jun 2008
Posts: 105

PostPosted: Fri Mar 27, 2015 10:30 pm    Post subject: Reply with quote

David Ferguson wrote:
You should look up the exact details for the P&G part number in this document:

http://www.cw-industrialgroup.com/getattachment/42e067a7-d2f3-4b9c-962f-8490230a72ff/

There are various outputs and wiring options. Don't guess.


Also, you should be sure you understand the wiring on your harness. Can you back-probe the connector with known good sensor attached and verify the signals?


the wires on sensor i know are correct, they are reasonably clear, i have seen the specs, and i have bench tested it and it works fine. i have also had a couple other different brand sensors bosch, wabash etc working but they are the resistive track type

perhaps there is a resistor in the harness wiring so the contactless inductive signal gets screwed up? electrical theory is not my strength

in the specs it says

"Load resistance 10KΩ minimum (resistive to GND) " im not sure how to check this or what it really means

http://www.jenvey.co.uk/home/accessories/throttle-position/jenvey-dynamics/tps-p-g-contactless-lh-tp8lh/pdf-drawing
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bbs16



Joined: 28 Nov 2009
Posts: 25

PostPosted: Sat Mar 28, 2015 12:37 am    Post subject: Reply with quote

Expect you've tried it but what happens if you don't connect the output wire to the cars ecu do you get your expected signal out then?
Think some Hall Effect sensors need an external pull up resistor.
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E30IS



Joined: 26 Jun 2008
Posts: 105

PostPosted: Sat Mar 28, 2015 1:18 am    Post subject: Reply with quote

bbs16 wrote:
Expect you've tried it but what happens if you don't connect the output wire to the cars ecu do you get your expected signal out then?
Think some Hall Effect sensors need an external pull up resistor.


yes still no signal,

how does one add a "pull up resistor"? or perhaps there is a pull up resistor that needs to be removed given the sensor worked with a simple 6V battery which didnt have one?
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bbs16



Joined: 28 Nov 2009
Posts: 25

PostPosted: Sat Mar 28, 2015 4:27 am    Post subject: Reply with quote

After re-reading the data sheet it's not talking about a pull up resistor as I thought. As you say it talks about the minimum "load resistance" All can think of if you disconnect the cars battery and put a multimeter across the signal to the ecu and ground to measure what resistance you have.
Would it be worth tracing the wires back to the ecu just to make sure nothing has been wired in ie resistors? as it's strange that the supply voltage drops to 1.6 volts with the Hall Effect on in place. Is the ecu capable of supplying enough current to power it? although the sheet does say <25ma.
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Grocerius Maximus



Joined: 02 Apr 2006
Posts: 300
Location: McKinney TX USA

PostPosted: Sat Mar 28, 2015 10:59 am    Post subject: Reply with quote

Quote:
im trying to wire in a new penny and giles hall effect TPS.

the TPS came with no plug/connector just the 3 wires.


You haven't identified any wire colors or positions, sounds like it isn't wired correctly. Some ECU's put a 5v bias on outputs, just because it has 5v doesn't mean its the 5v supply. Don't assume anything, VERIFY vehicle wiring before going further.
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E30IS



Joined: 26 Jun 2008
Posts: 105

PostPosted: Sat Mar 28, 2015 3:39 pm    Post subject: Reply with quote

Grocerius Maximus wrote:
Quote:
im trying to wire in a new penny and giles hall effect TPS.

the TPS came with no plug/connector just the 3 wires.


You haven't identified any wire colors or positions, sounds like it isn't wired correctly. Some ECU's put a 5v bias on outputs, just because it has 5v doesn't mean its the 5v supply. Don't assume anything, VERIFY vehicle wiring before going further.


purple was 5v
brown was GND
green signal

i know the wiring on the harness because ive just connected up a different sensor until i can sort the issue. also i did check the various combinations incase but basically i get zero output no matter what i did
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E30IS



Joined: 26 Jun 2008
Posts: 105

PostPosted: Wed Apr 01, 2015 12:28 am    Post subject: Reply with quote

So i added a 5K resistor to ground on my simple bench test setup that uses a 6V battery and it seems like i am able to reproduce a similar effect that i am seeing on the car plugging into the actual harness.

am i right in saying this seems to suggest there is a pull down resistor somewhere in the system that needs to be removed?

where is it likely to be located?
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joe90



Joined: 19 Mar 2013
Posts: 382
Location: under the car

PostPosted: Wed Apr 01, 2015 2:09 am    Post subject: Reply with quote

Why are you using 12v on it when it's a 5v sensor?

You've probably blown it up?




Common TPS wiring for many jap cars, eg Mitsubishi, there's a 5v power feed to it, ground at the other end, the signal varies between the two depending on position.
Output is 0v to 5v depending on position.

By "load" they mean the input resistance of the ECU which the signal is feeding.
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Buzzard



Joined: 14 Dec 2004
Posts: 221

PostPosted: Wed Apr 01, 2015 4:22 am    Post subject: Reply with quote

Can you measure the +5v pin directly at the ecu whilst sensor is connected?
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E30IS



Joined: 26 Jun 2008
Posts: 105

PostPosted: Wed Apr 01, 2015 5:42 am    Post subject: Reply with quote

joe90 wrote:
Why are you using 12v on it when it's a 5v sensor?

You've probably blown it up?




Common TPS wiring for many jap cars, eg Mitsubishi, there's a 5v power feed to it, ground at the other end, the signal varies between the two depending on position.
Output is 0v to 5v depending on position.

By "load" they mean the input resistance of the ECU which the signal is feeding.



was 6V, its not blown up
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E30IS



Joined: 26 Jun 2008
Posts: 105

PostPosted: Wed Apr 01, 2015 5:45 am    Post subject: Reply with quote

Buzzard wrote:
Can you measure the +5v pin directly at the ecu whilst sensor is connected?


i can try.

it seems the tps, IAT and coolant temp sensor share the same ground and 5V source according to the ECU wiring diagram
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keithmac



Joined: 14 Nov 2010
Posts: 233

PostPosted: Wed Apr 01, 2015 10:23 am    Post subject: Reply with quote

Maybe the 5v sensor supply from the ECU doesn't have enough guts to run the hall sensor?.

I've only come across a few hall effect sensors but they were all 12v and the last in had to run via a pull up resistor (as has been said earlier).
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bbs16



Joined: 28 Nov 2009
Posts: 25

PostPosted: Wed Apr 01, 2015 2:11 pm    Post subject: Reply with quote

What make of ecu are you using on your car?
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E30IS



Joined: 26 Jun 2008
Posts: 105

PostPosted: Wed Apr 01, 2015 3:45 pm    Post subject: Reply with quote

its a wolf v500 in the car

testing on a bench is done using a 6V dolphin battery


Last edited by E30IS on Wed Apr 01, 2015 11:52 pm; edited 2 times in total
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joe90



Joined: 19 Mar 2013
Posts: 382
Location: under the car

PostPosted: Wed Apr 01, 2015 9:17 pm    Post subject: Reply with quote

LOL you're not going to run much off one of those, too much internal resistance.
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E30IS



Joined: 26 Jun 2008
Posts: 105

PostPosted: Wed Apr 01, 2015 11:47 pm    Post subject: Reply with quote

joe90 wrote:
LOL you're not going to run much off one of those, too much internal resistance.


whats got too much internal resistance?
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FPSeth



Joined: 03 May 2010
Posts: 52
Location: Right next to YUL

PostPosted: Sat Apr 11, 2015 10:02 pm    Post subject: Reply with quote

E30IS wrote:
David Ferguson wrote:
You should look up the exact details for the P&G part number in this document:

http://www.cw-industrialgroup.com/getattachment/42e067a7-d2f3-4b9c-962f-8490230a72ff/

There are various outputs and wiring options. Don't guess.


Also, you should be sure you understand the wiring on your harness. Can you back-probe the connector with known good sensor attached and verify the signals?


the wires on sensor i know are correct, they are reasonably clear, i have seen the specs, and i have bench tested it and it works fine. i have also had a couple other different brand sensors bosch, wabash etc working but they are the resistive track type

perhaps there is a resistor in the harness wiring so the contactless inductive signal gets screwed up? electrical theory is not my strength

in the specs it says

"Load resistance 10KΩ minimum (resistive to GND) " im not sure how to check this or what it really means

http://www.jenvey.co.uk/home/accessories/throttle-position/jenvey-dynamics/tps-p-g-contactless-lh-tp8lh/pdf-drawing


You guys have to get down to ohms law and basic electrical diagnostics here- there are only 3 possibilities for this voltage drop - and one of them you tested for when you unplugged the signal wire and tested it with your multi meter. So first take your multi meter on resistance scale, unplug the sensor and measure the resistance across the 5 volt lead and the ground lead. From what you posted above sounds like you should read close to 10k ohms there. If you read much less than this then get a new sensor- if you do read 9k-10k ohms then you must have a pathetic 5 volt ref signal that shows 5 volts on your very high impedance multi meter but doesn't have enough current to maintain 5 volts across a 10k ohm resistor. In that case try the test again with a clean 5v ref straight out of the ecu.
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E30IS



Joined: 26 Jun 2008
Posts: 105

PostPosted: Mon Apr 13, 2015 5:55 pm    Post subject: Reply with quote

The issue is definitely 5V ref, the P&G sensor works fine and outputs correctly on a different car where the 5V ref is maintained at 5V with sensor connected.

Even on a regular resistance pot type BMW OEM TPS sensor the 5V ref is dropping to 2.3V or so with the sensor plugged in and hence the open and closed voltages don?t offer a good resolution for tuning, yet it still functions in a ?useable? manner .

I have temporarily abandoned trying to get the P&G sensor working and trying to sort the root cause being the 5V supply. I guess as said I should check 5V at the ECU side with the sensor connected.

One chap I spoke with suggested I should get an alternative 5V source besides the ECU and feed the signal back to the ECU but I will prefer to go forth the most logical path first which is investigate why the ECU doesn?t operate as expected.

i have not had the chance to look much into it recently
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