Volkswagen 1.6i strange problem - Fixed

I didn't have time to get the throttlebody plug today, I cannot fix the ground wire because its broken off from the pin inside in the plug, i would be able to get 1 from the junk yard tomorrow. I did try checking for voltage again on Pin 1, which states in the diagram that I have, Pin1=+12v, I am now getting 0.05V from that wire...
If I disconnect Pin1 from the ecu plug and put a direct 12v onto it, I noticed that the stepper motor moves back and forth rapidly causing thee idle to fluctuate even more, so I am guessing that Pin1 is not suppose to have a constant 12v supply and the ecu probably regulates the voltage according to other signals.
I think we need to know how this component actually works in order to find the problem.

I will however try to get a decent throttlebody plug tomorrow, reconnect all the wires and then check from there, because there could be bad connections on the other wires causing a voltage drop somewhere across the line therefore correct values are not being sent to the ecu or to the tb.. (I dont know if that makes sense, does it?)

I have found a wiring diagram

ECU PINOUT:
Pin17 - Common sensor ground
Pin14 - TPS 5v Ref
Pin41 - TPS Signal wire
Pin16 - Throttle position switch (open or closed switch???)
Pin10 - Throttle position switch (open or closed switch???)
Pin2 - Idle control motor +12v
Pin26 - Idle control motor ground

Ok I'm busy at work today I'll sit down and look it over after work . Definitely get that plug fixed a bad ground will cause all sorts of problems!

Sent from my SM-N920P using Tapatalk

Ok I will appreciate that man, I cant seem to figure this diagram out, will definitely need some help.

I have tried to simplify that diagram abit, however, the operation of it confuses me.. i do not know which way current flows and how it works.

Sorry, theres a mistake with Pin 4;18. it suppose to be map output signal

I have drive by cable passat coming in this weekend that I believe will be that same throttle body I can put my scope on it and give you my readings. I seen that Tyler explained the wiring diagram . He touched on it but I wanted to mention again that the closed throttle switch will have some small voltage when open don't test with snap throttle just slowly raise off of full closed throttle to wide open and there should be a big jump it appears as though it should be 5v max not 12v

Sent from my SM-N920P using Tapatalk

Hi Ben

I have fitted on the new throttlebody plug, all connections are now good. I also retested and got the following readings:

Key On Engine Off - plugged

Pin1 - 0v (its grounded, suppose to be +12v)
Pin2 - 0v (ground)
Pin3 - throttle closed=0v, throttle open=+-11.8v (Throttle opened very little it jumps to 11.8v)
Pin4 - 4.89 (ref)
Pin5 - throttle closed=4.26v, throttle fully open=0.67v (voltages decreases gradually if throttle opened gradually)
Pin7 - 0v (ground)
Pin8 - 3.66v

Engine idling - map sensor unplugged (car dies as soon as its plugged in)
Throttlebody test - plug connected
Pin1 - 2.5-3.7v (when revved jumps to 1.4v)
Pin3 - 0.06v (jumps to 13v when of idle)
Pin4 - 4.9v
Pin5 - 4.07-4.11v
Pin7 - 50mV
Pin8 - 3.07v (when revved jumps to 2.9v)

NOW THAT GROUND IS FIXED - WHEN TPS SIGNAL WIRE IS DISCONNECTED THE IDLE IS SMOOTH

I got this from Autodata - I think It shows how to test components.. All of these tests match with the values I got.. i Just couldn't do the scope test for the idle control motor

Yea your readings look normal it's getting ground through motor

Sent from my SM-N920P using Tapatalk

KOEO what does map sensor read I. Measuring blocks I'm not sure which block it's in ...

Sent from my SM-N920P using Tapatalk

KOEO

1034.0 mbar which is normal here, Air intake temp when engine hot 40deg Celsius

After repairing tb wiring, I did a tb adaptation again and now the tb is at 2.7degrees when the throttle is closed

Ok good I want you to disconnect the map sensor and take a vacuum reading from its port if possible with engine idling

Sent from my SM-N920P using Tapatalk

Thats not possible because the map sensor has a diameter of 13mm and i dont have any pipe that size to hook up to a vac gauge. I can get a vacuum reading of the fuel pressure regulator that runs of the intake manifold.

Im going to have to this tomorrow because i dont have just a vacuum gauge, Im going to have to use the boost gauge of my personal vehicle.. I would do it now, but the weather is terrible at the moment

Ok when you can get a reading elsewhere and also verify that there is vacuum at map sensor port with your finger if you can't come up with an adapter (just to make sure it's not plugged or something causing the map not to see vacuum)

Sent from my SM-N920P using Tapatalk

Yes there is definitely a reading at the map, the map sensor basically mounts into a hole thats machined into the manifold. Its not plugged, i noticed when I removed the intake manifold to replace the gasket (though there was a leak).

KOEO the map reads 1034mbar thats atmospheric pressure. If i start the car, it decreases to about 400-500mbar which indicates vacuum of about 0.6bar. Snapping the throttle to WOT the most I have seen it drop to is 37mbar which is about 1bar of vacuum.. Just random throttle snaps show around 200=300mbar which is around 0.7-0.8 bar. That does sound right, don't you think?

What I don't understand is that, why when the map sensor is plugged in, the car stalls. It only revs up if the pedal is pushed right down to the floor, if i try to accelerate gradually it sounds as if its starving for fuel or the timing is badly retarded, and it dies.

I suspect that it is starving for fuel when the map sensor is plugged in, IF the timing was retarded wouldn't it backfire..?

But when the map sensor is unplugged the car burns very very rich. Could it be possible that the ecu has lost its map/tune? It is an original ecu though

I just noticed that this car has an ADY engine block. And that is a 2.0L block with a 1.6L cylinder head. To my knowledge a 1.6 cylinder head has smaller combustion chambers than a 2.0L head, hence a higher compression ratio..But according to vcds this car has a 1.6L ecu.

In my country alot of people do these conversions but info on the conversion is limited, And I do know that people remap/tune their ecu for a 2,0 engine..
Is it possible that I am experiencing an issue because of the standard 1.6L map/tune on a 2.0 block?

I doubt it it would likely just run lean with an unmoded ecu

Sent from my SM-N920P using Tapatalk

Can it run so lean that it doesn't allow the vehicle to idle or rev up unless wot?

Sorry for the stupid question lol, this car suppose to be delivered tomorrow, I am kind of stressing..