Idle super low, help! (924 base model)

Supreme · 07-06-2021, 08:10 AM

I have a 1979 924 and the idle is super low and chugging and rattling. The battery will not hold a charge as it's been sitting for a few months in a garage.

The alternator belt is also whistling when I accelerate. Let me know if I'm wrong, but I think if I could adjust the idle to 950 I could then drive it without killing the engine and the battery will charge.
I've been jumping the battery, taking her for a short drive, but when I park, around 5-10 minutes later, the idle is at it's lowest 100rpm and then it spittles and dies.

The gauges show a little bit of light on the dials, like the brake warning is lit up etc. But then it won't start again. Can someone help? Where is the ICV and what tool do I need to adjust the rpm?

Or is there more to do before she can hold a charge?
Here she is.

Supreme · 01:31 PM

Update: I found where the adjustment screw is. I got the idle to around 750rpm while warm and took a drive.
She felt strong, yet has a lot of squealing with the alternator belt.
Since I'm in Texas, I took her for some 93 octane and then she started right back up.

I was worried that the temperature was too high. It hovered at around 75% on the dial and would come back down to around 35-40% while driving. One thing the manual say is that when you turn the car off, a fan should continue to cool the radiator while hot, yet I didn't hear any when I parked.
I'm now going to look into what's required for a to pass a TX inspection.

944 Ecology · 07-07-2021, 06:16 AM

Your squealing belt is an indication that either the belt is too loose or the belt is worn out. In either case, it will resuilt in not driving the alternator enough to properly charge the battery. Replace the belt and tighten it until it stops squealing. Then check the output of the alternator with a voltmeter at the battery. It should be charging at 13.8 to 14.1 volts.

Supreme · 07-07-2021, 06:37 AM

Man, thanks. I had a feeling, but thanks for confirming.

Quote:

Originally Posted by 944 Ecology

Your squealing belt is an indication that either the belt is too loose or the belt is worn out. In either case, it will resuilt in not driving the alternator enough to properly charge the battery. Replace the belt and tighten it until it stops squealing. Then check the output of the alternator with a voltmeter at the battery. It should be charging at 13.8 to 14.1 volts.