‘74 1.8L L-Jetronic Cold Start Low Idle, Mystery solved! Options

[Van B]

Ok fellas, here’s the run down Aux Air Regulator (AAR) and Cold Start Valve (CSV)/injector both work fine. Many of you have also been keeping up with my high idle issue that we figured out.

But yet, when the car is cold, i.e. room temp, I don’t get the high idle I should on start-up. Instead she cranks a bit and then lumbers to life. Idle lopes around 700-800rpm and then smooths out as it warms.

In all other aspects of operation, the engine seems to be pretty happy.

Thoughts? Experience? (IMG:style_emoticons/default/confused24.gif)

-Van

See post #419 on page 14 for a synopsis of the outcome.

[Van B]

I read those pages earlier today and successfully didn’t get my head around it!
Bottom line for the tests conducted today. Both vacuum lines are staying connected. Good that what you’ve found confirms that stance.

Also, just tried a cold start and I’m right back to where I was before the spark plugs. I’d be really annoyed right now, if it wasn’t for the fact that the car is running so much better! I’m inching ever closer to getting all 76 ponies back in action! Getting plugs that seat properly made a noticeable difference and then retiming added a little more.
I mean it’s all good right? But as far as low idle on cold start, I’m right back to where I was after solving the high idle mystery.

Oh, one other thing. I used my fancy new timing light to get an empirical rpm measurement. When it starts I get a 700rpm idle. As it warms up, it climbs to the 850rpm I have set. It takes about two minutes to increase that 150rpm.
I’m aware that this is an inference, but 2min is how long it took the AAR to close when I bench tested it a few weeks ago.

Ugh, I hate being dumber than the mid-70’s!