throttle position sensor, need help

[E M Wynne]

Hi guys, I posted a question when I introduced myself...probably not the thing to do, anyway....one for the electronic boffins out there.
I have just installed a zpj4 into my old Renault Alpine, the engine has been modified to take 6no. Toyota 4AGE Blacktop throttle bodies & runs on a modified Renault 25 turbo ECU. done by a friend. The engine started first time... revs. but will not answer the throttle properly or tick over...back to my friend...it seems the Toyota TPS. is not compatable with the Renault ECU...he reccomends I fit the 24vl. TPS.
My question..from the TPS plug, what cable colours are the following,
1..constant 5volt square wave.
2..idle control.
3..wide open throttle.
With this I can get the car running properly & get her back on the road.
Cheers Eddie.

[noz]

hi Eddie,

I've never had a 24V so this is from the wiring diagrams only. It would appear that it has a potentiomenter on the spindle of the throttle plate with a cable from the pedal to the throttle plate. The throttle plate is therefore moved by the action of the cable. This is unlike my 2.5's which have a cable from the throttle pedal going to a potentiometer. There is no throttle plate. The potentiometer simply sends its signal directly to the ecu. Known as "Fly by wire".

In your case the spinle simply monitors the position of the throtle plate which is being moved by the cable.

I wanted to make that distinction because the spindle potentiometer method uses three wires connected to a potentiometer. The Fly-by-wire uses 5 wires and monitors the fully closed position (idle) with a switch as well as having a potentiometer. Your description above seems to suggest the functionality achieved with 5 wire. I may be wrong.

The three wires on the white plug are as follows:

Pin 1 - Green 33 - Supply from ECU
Pin 2 - Grey 34 - Common earth (common to 3 other ecu sensors)
Pin 3 - Green 11 - Potentiometer position (wiper)

In a potentiometer two of the connections are across the fixed resistance. These are pins 1 and 2. The middle connection is the wiper which gives a varying resistance when referenced to connection 1 or 2 but inversely to each other.

I've no idea if the supply from the ecu is a square wave. I can't quite see the necessity for a simple potentiometer. With only 3 wires I cannot see how you can get an idle signal unless at its rest position the potentiometer still gives a resistance. Maybe someone else with more 24V knowlede can assist?

Cheers

noz

[robertmnorton]

Hi Eddie,all a bit gobeldegook to me i'm afraid,only know the 24v in citroen designation as the SKZ but do have this tucked away in my files, hope it proves some use.
robertm

[E M Wynne]

Noz, Your reply does make sence...the 24vl. potentiometer is opperated by the throttle spindle & not the cable direct.. thus the variable resistance...your no.s
1 pin 33 would be the 5v constant sqare wave signal from the ECU.
2 pin 34 is my wide open throttle & connected to the MAP the IAC,& the mixture control.
3 pin11 is the idle & wiper motor.
the idle has constant voltage, which is set by turning the pot untill you get a reading of 0.5v. which when correct should give you a reading of 4.7/4.9 v at wide open throttle.I,ll try this set-up & let you know how things pan out.
Cheers Eddie.

[E M Wynne]

Robert, It is the Citroen engine & came from an XM...the SKZ is the Peugeot ZPJ4...I,ts my fault for missleading people..I know the engine better as the Pug.
Thanks for the PDF. it will be invaluable, as I have only what I know in my head about these engines.
Cheers Eddie.

[E M Wynne]

Noz, Just getting round to fix my tps problem...I now have 2 no.24vl. tps,s...& both are the same...tps plug, red, yellow, green...male plug into the tps. no numbers or letters on the plug...female inlet from the ecu...red, yellow, yellow, no numbers or letters on this either. Can you assist with a drawing of the plug with cable colours & positions relative to the plug oriantation & pin no.
By the way ..I,m a retired jock...now living in Holland ..but originally from Broxburn.
Cheers Eddie.

[Sharo]

Hi Eddie,
something bothers me - you are saying that TPS must have 5V square wave, idle position and WOT position. This setup (except from 5V square wave, which should be 5V constant voltage) is used on vehicles with mass airflow meter, but ZPJ4 uses MAP sensor (i assume you have installed it in the new intake body - this is essential) and exact position of the throttle plate must be obtained thus there is no such thing as WOT and IDLE position.
Anyway ignore the colors of the plugs - they may change inside the wiring. The easiest way to find which is pin No1 is with ohmmeter - the resistance between the No1 and No2 should NOT change when you press the accelerator pedal. Pin No2 is the middle one

[E M Wynne]

Sharo, I understand what you are saying....the thing is the engine is fitted with 6 no. Toyota 4age. throttle bodies & as such is fitted with a map sensor...1 bar Renault Megan..the ecu is a programable modified Renault 25 turbo & does rely on the readings from the tps to set the ign. & fuel curves...that is the reason I need to find the correct wire to suit 5v.constant the position in idle & wot.
Cheers Eddie.
ps. is it possable to set the tps , with no power ie. ign.of with an external 5v battery.
Eddie.

[Sharo]

Eddie, I probably misunderstand something in the initial setup
I have some documentation regarding Renault 25 - if you need it, i can upload some info. I have another question (i know we are running slightly off-topic):
What kind of engine is the ECU from? Because R25Turbo has Z7U engine which sounds strange to me, but has Idle switch, not TPS. I wonder how they managed to get decent power, and proper exhaust gases from this engine. Only Z7W, 752 and J7R have TPS similar to ZPJ4.
Anyway if this is the engine, TPS from ZPJ4 won't work, and you'll need Idle/WOT switch from R25.
Also i have some doubts for these throttle bodies - whether the ECU will receive proper signal from MAP sensor (it has to be connected to all 6 bodies simultaneously, or to have some kind of restrictor to smooth the reading) - probably it will be better to use some aftermarket efi - vems, megasquirt or similar.

This post has been edited by Sharo on October 01, 2010 09:59 pm

[E M Wynne]

Sharo, The ecu is a S101260201 highly modified by a friend who specialises in this type of mod...he copied some of the internals from 1 of my other ecu,s...I have engine no.2 off the original 3...which Renault sent to Hartge...mine is the only one to survive... for modification & installation in the Safrane bi-turbo...I wanted to keep the car as much as poss. Renault... I have a megasquirt with extra code & a set of cables from the US. My friend has a ZPJ4 tps. on his Alpine turbo & he reconds it works better than the 25 switch. I also built a vaccum chamber & all 6 runners are fed into this & from it I have map, fuel pressure, iac, & brakes. The engine starts & runs beatufully it just won,t answer the throttle & idle properly. By the way the Z7WX engine I have is MID-MOUNTED in my other Alpine & I,ll finish it when I get the dailly runner...the 6 barrel...running properly....the throttle bodies are of a non vaccum type
Cheers Eddie.

This post has been edited by E M Wynne on October 03, 2010 12:25 pm

[Sharo]

Eddie, i couldn't find anything about Z7W 701 ECU. But i guess it is the same as Z7W 700 ECU, since it uses also TPS potentiometer.
This is the way i think it should be:

ECU pin 17 -> GND -> TPS pin 2
ECU pin 16 -> 5V ->TPS pin 1
ECU pin 9 -> Signal -> TPS pin 3
Unfortunately the schematics i've got are very poor, and have no color information. You should find them by pin numbers.

edit: My mistake, it is pin 16 for 5V supply.

This post has been edited by Sharo on October 04, 2010 02:14 pm

[E M Wynne]

Sharo, That sounds about right...pin17 is my common ground...i,m usung pin 16 as my 5v. constant...& will set the tps. at idle & wot using pin 9.
I,m back in the workshop tommorow..big weekend festival here in Leiden this1,2,3,4, Oct. & I,ll let you know if it all works out. thanks for your help.
Cheers Eddie.