M50 starts! but WTF!

[fujioko]

I finally got a chance to start the M50 today! The engine fired right up, however I had to shut it down immediately.

Once started the engine races I’m not sure how fast the engine wants to go because I shut it off immediately after each time it starts.

I checked the throttle and cruse cables, I checked that the throttle is actually resting on its manual idle adjustment. The intake o-rings are new. The TB o-ring is good. The idle air valve is plumbed correctly and electrically connected.

I suspect the idle air valve is stuck or I have a massive vacuumed leak somewhere.

The old engine was very sick and I suppose the idle air valve had to be working overtime to keep that bitch running. I do recall the old engine did have functioning idle control.

Two questions:

Easy question ..What else should I look for?

Tough question… The idle air valve… is it a simple frequency /duty cycle type valve or is a stepper motor type valve?

Thanks

[fujioko]

Hi again,

Apparently no takers on advice…

Anyway I had a chance to pull the IAC (idle air control) and give it a look. Appeared good so I reassembled everything, however I put a new o-ring on the fitting where the IAC pipe mates to the intake manifold.

Long story short.. the car purrs like a kitten and growls like a tiger when ‘ya goose the gas. Ahhh the sound of the big six is awesome!

So at 275K the car has another lease on life. 110K on “new” engine, brand new clutch and new driveshaft… now I’ll need to take a lookie at the front suspension..

I would like to thank all those that offered advice on the other threads I started. The job of yanking the old engine and installing the new is no simple task. Certainly a lot more complicated than my E21’s I’m glad I gave it a shot!

[632 Regal]

so there was a massive air leak at the IAC?

[Jon K]

that's odd.

I would have pulled the IAC but left it electrically connected, and manual trim the idle with the set screw. That's what I'll be doing.

[fujioko]

Hi
I believe the IAC circuit was leaking at the manifold junction. It's the only possable answer.

After the car was repaired, I started it and warmed up the engine. I electricly disconected the IAC and sprayed "starting fluid" on all possable manifold leak points. I did find another minnor leak at the power brake nipple on the manifold.. The OE clamps were loosened during the disembly process. A quick and easy fix.

BTW pulling the IAC and hoses while the intake is still on the car is a real bitch