Help with M42 running issues

[Greg Mierz]

I recently installed a head on a 91 318is m42, Did the chain guides also. Car was brought to me on trailer. Now with everything together, it will start but not respond to the throttle properly or idle. All air hoses were replaced are seem tight. I can find no obvious air leak. The stomp test says 1215 or airflow meter. Tried another one no difference. The TPS switch seems ok, it has variable resistor as the throttle moves. The funny thing is when I disconnect the tps switch and start the car, it pegs to redline and the key must be turned to stop it. I am at a loss with this. Tomorrow I'll go back over everything again and see if I missed any thing. Any ideas?? The crank and cam sensors must be ok as it starts ok but won't react to the pedal at all, won't hold a steady rpm anywhere.

[gregslow318i]

the m42's cars had a resistor back between the maf and the main harness plug. does it still have that? also is a the iac installed correctly? also cam timing? I am finding it hard to understand why the car would raise jupe to the red line with the tps disconnected? is there something blocking the tb open?

[Greg Mierz]

Turns out the intake manifold was installed wrong. Had a big leak at #4 cylinder. That must have been the air source. Fixed it and all is well after fixing a loose water hose clamp. When all else fails, go back to the basics.