MembersPage/PeepPaadam/AudiAFourTurbo (2006-10-23 06:41:21)

Car is from year 1997. It sports turbocharged 1.8liter inline four, has passive coil-on-plug ignition system and crank triggers: primary VR (60-2 wheel) and HALL as cam sync.

Also it is equipped with strange throttle body. Perhaps it's one unit TPS and idle valve? I took some measurements also: two pins have 5v supply, one pin has 12v supply and one pin had something like 10.x volts supply (measured when engine was not running, only ign. was switched on.

That's what it looks like.

A4TB.jpg

Looks like a newer version of InTake/ThrottlePlates/VAGElectronicThrottle


I connected all the sensors to VEMS unit and everything worked fine (including TPS) but the stock VR sensor. I put the 60-2 wheel specs all correctly (check the config : MembersPage/PeepPaadam/AudiConfig )but no rpm signal. When i switch from multitooth to coil-type, it shows 100rpm every crank rotation like it should (one trigger event per rotation) but in multitooth mode...nothing.


I might also innstall VEMS on such a 20vT so I'm curious #HansK:

A: Cam sync is one window Hall sensor.

Triggering problem serialnr ? orderid ?

Tried different settings but still nothing. Only in coil-type, it shows 100rpm like it should with one trigger event per rotation.

I tried to connect unit no. 620 (which was ordered with VR) and everything was ok: very good trigger signal and rpm reading!

Connecting HALL sensor wouldn't give ANY reading (even in coil-type).


Ok, when tried unit no. 620, I got nice rpm reading and decided to leave it there.

Yesterday I pulled the RS232 wire from engine compartement to inside of the car and apparently one of the wires was damaged causing weird readings in MegaTune and some corrupted settings.

Fine, fixed it and everuthing was fine except I got 0 rpm when cranking!!! And this time even setting to coil-type etc didn't do any difference. VR sensor wiring is fine, checked already, and I didn't make any changes in EC36.

Is it possible that I fried P259 chip somehow? I heard that frying this chip results 0 rpm when using VR sensor...

I tried to measure wether the fule pump channel (P259, i5) was working, and it was not. So it's pretty much sure that P259 chip is killed.

Can I remove it and put a wire instead to get rpm sensor reading again? How to do it, exactly what pins need to be connected?

A: You can wire your fuelpump to another output (than P259 outputs), you likely have injector or ignition outputs available for this. Just unsolder, or carefully cut the the TPIC6A259 (P259) chip away. This chip usually breaks down when grounding to the ECU is bad.

I don't need the ecu to trigger fuel pump relay. The problem is that when TPICA259 chip is dead, I don't get rpm signal with VR sensor.

A: Check the answer above once again ;) Easiest way is to carefully cut each pin of the chip, without harming the board. Very small wire cutter for example. Once the P259 is gone, LM1815 VR trigger will come alive.

Update: After consulting with MenbersPage/MattiasSandgren i cut just VCC pin of the p259 chip and I got VCC of the LM1895 chip normal again.

Got the car running also, though with off base timing and 3 cylinders (have to check the plugs).