M52TU IDLE Problems

[sebe20]

Would explain the INPA Analog readings from the MAF i postet in August. with 0 kg/h airmass

[pazi88]

Yes the maf is totally dead. That error code description shows virtually no maf voltage at all.

[sebe20]

currently it somewhat 'runs' with a maf from china which has two diodes or resistors in them. Doesn't take any gas and surges but car can somewhat be moved.
I ordered some parts from the bmw dealership, aswell as a obd2 canbus adapter for inpa from ebay (since i didn't have my own). And since im about to tear into the engine already, i decided to do a bit more maintenance before more stuff breaks:

• coolant temp sensor
• intake air temp sensor
• camshaft sensor 1
• camshaft sensor 2
• crankshaft sensor
• mass airflow sensor
• fuel pressure regulator
• o-ring's for injectionvalves
• o-ring for throttlebody
• 3mm and 7mm plugs

Thanks so far for your help pazi, i'll keep you updated once i get to work on the car.

[sebe20]

The thorttle flap shouldn't open at all when you turn on ignition. It should stay closed. Even when you press little bit thorttle it should stay closed. On very low thorttle positions m52tu uses only icv to rev up engine. So that points even more to faulty thorttle body. Have you made sure that the electric connector to thorttle body is clicked in all the way. If you don't fully rotate the connector to locked position, it causes all kinds of throttle flap problems.

I should've investigated this much more than i did. Because today i went to shop to test a few things. (disconnecting vacuum hoses, opening the oil lid and what not)

First Problem was no fuel :stupidsign:because it ran out of gas, im to blame...

Main Problem the throttlebody seems to be opened just a little. After i disconnected the throttlecable the car idled just fine and sounded fantastic. There are only a few error codes remaining regarding the TB (see my inpa screenshots) With Code 172 and 173


So is my throttlebody trash and where do i find a Throttlecable with the right length? currently im using the E34 525i series one.

[sebe20]

So i built my own tb cable. Hopefully this will be the final fix of this. Just in case im going to get myself a spare tb to swap if the old one is busted.

[sebe20]

^this worked aswell with fully locking the tb connector in place...