# Need VW TBI injection unit details



## yva (Feb 2, 2011)

I posted this on another subforum, but got no response. Perhaps someone here might help...

I am thinking about replacing my carburetor with FI system. I run 99% of the time on LPG, and I'll concentrate at that, so TBI injection will be fine (TBI unit has injector, fuel pressure regulator, TPS and idle control in one unit, so it seems that it is the simplest).


Can someone tell me if golf III TBI unit has stepper motor for idle control? I bought used idle actuator, and took it apart. 4 pin one has DC motor, two pins are used for some sort of positioning control. Does anyone know if 6 pin actuator has stepper motor inside?

And TPS has 4 pin connector. Why, three is enough?

Injector connector also has 4 pins, and 4 wires from it to the injector. Does it have two injectors?

BTW, I plan to use megasquirt for my project.


----------



## shurik06_83 (Oct 19, 2006)

i have a mk3 with the injection u are talking about but i have no clue how it really works 

if u want i can find u a manual for the tbi but it might not be in english


----------



## Eric D (Feb 16, 1999)

You'll need to secure some schematics or a Bentley shop manual.
You are looking for information for a Monojet injection system.

In North America, Canada and Mexico got it, the US did not.
It would be found in a Mk3 with 1.8L ACC motor.

Best of luck!


----------



## WaterWheels (Aug 14, 2005)

yva said:


> Can someone tell me if golf III TBI unit has stepper motor for idle control?
> 
> Yes
> 
> ...


.


----------



## yva (Feb 2, 2011)

@ shurik06_83:

if u want i can find u a manual for the tbi but it might not be in english.

It would be great! How big it is, can you mail it to me? Or perhaps you can put it somewhere, and post link to it here? If not I can setup FTP server on my PC so you can put it there.



@ WaterWheels:

Can someone tell me if golf III TBI unit has stepper motor for idle control?

Yes

4 pin one has DC motor, two pins are used for some sort of positioning control. Does anyone know if 6 pin actuator has stepper motor inside?

Two wires are for the motor and two for the idle switch which is part of the assembly (one is a ground really for the idle switch). Never had my hands on a six pin unit so I can't comment.

Are you sure than that 6 pin ones are with stepper motor?

And TPS has 4 pin connector. Why, three is enough?

Can't say "WHY", but two send information to the ECU. One is power to the TPS and one is a ground (shared with the coolant temperature sender.

Injector connector also has 4 pins, and 4 wires from it to the injector. Does it have two injectors?

There is also an air temperature sensor in the plastic injector mounting cap which uses the other two wires.

Cool, so I do not have to bother with positioning the coolant sensor.


----------



## WaterWheels (Aug 14, 2005)

yva said:


> Are you sure than that 6 pin ones are with stepper motor?
> 
> Cool, so I do not have to bother with positioning the coolant sensor.


Said I never had one in my hands and to be honest I have never seen a Volkswagen TBI with 6 pins for the idle connection. Yor question asked about a Golf III which I satetd yes to, not the 6 pin question. That I answered seperately. What year/model do you have one with 6 pins? I can only guess that it was done as a wiring change to give both directions complete seperate wire paths. But if you can post a part number or model/year I can dig deeper. These TBI units were used by many companies over the years with some changes to suit the companies engines and computers (ECU).

Don't understand about the comment you made about the coolant temperature sensor. Positioning of the sensor has nothing to do with the wires sharing the same ground path as the TPS. Can you explain better what you mean?


----------



## yva (Feb 2, 2011)

VW TBI with 4 pins idle actuator does not have the stepper motor, I took one apart, and I found DC motor inside. Two pins are for the DC motor, and two for the idle switch.

Since stepper motor must have (as far as I know) 4 pins (unipolar) or 5-6 (bipolar) I thought that 6 pins idle actuator has one.

Here is a photo:

http://images46.fotosik.pl/463/41c5fd900414c958.jpg

I asked about Golf III TBI because I saw one, and it looked that I could mount it on my BMW with only little modification. Not sure about year/model.

I do not think that they changed 4 pins unit to 6 pins as a wiring change to give both directions complete separate wire paths. Two are enough for DC motor, my guess is that they replaced DC motor with stepper motor for more precise controll.

The one I have (4 pins - with DC motor) is Bosch 0 132 008 600. I think that 6 pin models are:

Bosch 0 132 008 601
Bosch 3 437 010 915
VW 032 133 031
Citroen/Peugot 1920 3R

Since TBI unit has air temperature sensor I will not have look where to put one, fabricate mount for it... (Remember, I am replacing carburetor with FI system).


----------



## WaterWheels (Aug 14, 2005)

Have to admit I was mistaken about the motor. I keyed in on “motor” when reading your question and didn’t really pay attention to the “stepper” part. Yes the motor is a normal DC motor with gears to move the throttle and not a stepper version. But you have already discovered this be taking one apart. The idea of the wiring separating the two directions was just that, a guess that maybe it was done to make it more reliable or easier to troubleshoot or even so it could not be switched between older and newer models (some time I think some of the changes made to cars are just so you have to buy the newer items). I did find the 6 pin version wiring for a 95’ vehicle. I don’t deal with cars that new much so I never saw that version. The wiring diagram seems to indicate it has a Hall sender in it and a motor, what type I can’t say but you may be correct that it is a stepper now. It also lists a idle switch but does not show any switch in the diagram so I really can’t say what’s inside.

The air temperature sender is not where I would like one to be if I were designing my own system. It may be nice to have it right there where the air is entering, but it is also a blockage of sorts to air flow. But I have a feeling you are not all that concerned about this as a "performance" engine so it should be fine.


----------



## yva (Feb 2, 2011)

WaterWheels said:


> I did find the 6 pin version wiring for a 95’ vehicle.


Can you mail it to me, or a link where I can download it from?


----------



## WaterWheels (Aug 14, 2005)

See if this works:

http://www.zen17496.zen.co.uk/downloads/g3adzecu.pdf


----------



## yva (Feb 2, 2011)

Thank you.


----------

