M50 few troubles

[dcc318i]

I just finished up my m50 swap in to my 318i the other day
Today was my first day driving it all was fine until about 30 mins into the drive it would start to sputter when under load
My thought is I need a o2 sensor
Would having no o2 sensor cause this? Or is it hard to tell ?



Also i had a problem wiring my electric fan up
Do people use the original wiring for the aux fan that run through the normal and high speed relays?

Another problem I need to solve is my coolant gauge doesn't read any thing
Anyone know which wires should be wired for this ?

Any help is greatly appreciated

[mitchlevy7]

In terms of the fan the answer to your question is yes. People run it through the aux fan. Theres a thread on here with good instructions and diagrams on it. Id link you if I wasnt on my phone.

For the gauge, you need a rethreaded brown top sensor. If you are not putting the sensor directly in the head the sensor needs to be grounded as well, otherwise theres just 1 wire on a 2 wire connector that goes to it. The blue coolant sensor is for the ecu.

The sputtering under load could potentially be an 02 sensor once its open loop. Your are not running an o2 sensor at all?
Your engine needs feedback on how its runnning.

Sent from my SAMSUNG-SGH-I337 using Tapatalk

[justin_l_]

Possibly a bad coil causing misfire under load, o2 should have no effect on it.

Factory wiring is adequate, there is a multi page thread on it.

Coolant gage should be through the c101

[dcc318i]

Okay thanks guys I'll have to check out the fan thread and put in the o2 sensor in.
Ill have to look at whAt wire I have the coolant wired too.
I couldn't really find a wiring diagram for a 85 318 but if the coolant gauge is the only thing not working then that's pretty decent