scottpeterd

1979 CIS. No O2 sensor.

As fall is here, I am addressing a cold start issue. The car fires up instantly. But I cannot press on the accelerator without it stalling. It need to idle for quite a few minutes before I rev the engine, or drive it. This is happening at 50 degrees F, as I am in the PNW. Our temps do not really go much below 30.

I have had the FD and WUR rebuilt, and new injectors installed about 5,000 miles ago. New fuel pump, accumulator and filter at the same time. All the vacuum lines have been replaced.

The cold start valve and related sensor are working fine. Yesterday I checked the AAV, and it too is working, and getting 12v for the heater coil.

I believe the only thing left is to test the WUR. I have the gauge kit.

Is there anything else I should be checking?

scottpeterd

Alright. Just finished the fuel pressure check. 20psi cold, 50psi warm.

So I have to conclude that this part of the system is operating withing spec.

Mrmerlin

open or richen the mixture screw CW about 1/16 to 1/8 of a turn, small changes
Use as 3 MM allen thats about 12 inches long tool will work

scottpeterd

I have the tool. By ‘open’, do mean lean it out?

79NINE28

1979 here...I feel your pain!
mine: very hard to cold start- many cranks but once warm fires right up.

Mrmerlin

79 your issue might be a clogged cold start injector,
add a bottle of techron and 6 oz of MMO to the fuel,
do lots of start stops so it has time to work

scottpeterd

Good one. I always think of injectors,, not the cold start when considering additives.

But it always firs right up, then stalls. So I was thinking the injector was working. But what else is there besides the WUR, AAV, CSI/thermotime and mixture?

scottpeterd

Just a thought here. The vacuum advance on the distributor went south a while ago. I have not installed my new one yet.

How does advance affect cold running? Fuel is cold and condensing on the intake runners. Perhaps slow tomreach the combustion chamber. So ignition advance may be crucial?

Petza914

Unlike the OP's issue, yours sounds like your cold start circuit is not working. There is a temp sensor on the water bridge that when cold completes the circuit to the cold start injector causing it to fire. It's also possible to have the plugs for a couple of the connections reversed. The plug that goes to the cold start injector is the only one with 3 wires and it should only see 12v when the starter is actually cranking and the engine is cold. The one that goes to the WUR and the one that goes to the Auxiliary Air Valve are 2 wires and should show 12v whenever the key is on. It's the one to the WUR and the the one to the cold start injector that can get mixed up by someone, and why you verify the 3 wire one is going to the injector - the one to the AAV is too short to reach the other connections.

I would also make sure your AAV is working correctly. If it's not opening when the engine is cold the car won't run. Remove it from the car, put it in the freezer then look through it to make sure it's open. The engine heat and the 12v from the electrical connector slowly close it as the car warms up. Since your car starts fine warm, I'm assuming it's closed, but may not be opening when cold.