A few days ago, after finishing the wiring, I started up the car. I was hopeful of the performance of the new injectors, but was immediately let down. the M42 stumbled and refused to hold an idle. After a few inquiries to the right sources, I set about testing sensors and checking the function of various parts. At Jake's suggestion, Jay and I wired up the M42's check engine light and did a "stomp test". This is a simple procedure that involves stomping the throttle five times with the key in the "On" ("FAHRT" on the ignition) position. The M42's ECU will then begin to blink in sequence to give you a set of fault codes. The single code that we received pointed us in the direction of either an air-flow meter (AFM) failure or a vacuum leak.
Here is the Check Engine Light that we wired up. I have to say; having my car tell me what is wrong with it is a new thing to me.
We tested the AFM to find no problem with instructions from the guys on www.m42club.com.
Once that was done, we began searching for a vacuum leak after I hurriedly ordered new manifold gaskets. A little carb cleaner found the leak on the #3 intake runner. Once removed, Jay found this gnarl on the mating surface.
I can only assume that the manifold was dropped at some point in it's life. The possibility that this has always been a leak point makes a lot of sense about how the car has acted in the year since I've had this engine.
Jay carefully filed the lump smooth and we resinstalled everything with new gaskets.
Dudley and I bolted everything back together, torquing the intake to about 20 ft-lbs. She started right up and settled into a nice idle of about 800rpm.
Also, I made a plug to go where the heater box used to be. I'll be adding a modern HVAC system to the car later, which won't need this giant hole in the firewall.
Note the piece that was ground away to fit the glove box.
I used some closed-cell foam as a gasket between it and the body and I used a little RTV to seal things up on the inside.
Dudley and I took the car out for a test drive and she runs smoooothly. So, I'm almost ready for the roadtrip to Vintage.