How does one inspect the cold start valve?

[cutchaguy]

This is one thing that is bugging me as I try to work on my car. I want to eliminate all potential issues to my car starting fine, but not restarting after it is warmed up and driven around a bit.

Replacing the valve is not cheap, so I am looking for advice on checking it.

Also, I have a replaced fuel pump. When the key is on, the pump is just busy pumping away and it is loud and annoying. I saw a mechanical pump on PartsTrain.com, not an electric one, that looks like it is supposed to be there and the mounting bracket on it looks like it would fit on my car. It isn't expensive, but is it advisable? Any suggestions for a quieter, appropriate replacement? I don't trust what the PO did in this area.

[ga.spyder]

Keep in mind,I am not a ace mechanic but have been thru the f.i. system on our cars.If the pump is running with the key on,it isnt wired correctly into the ignition.It shouldnt energize until the flap in the AFM is moved.This is annoying,but not a disaster.The pump is just circulating fuel,and it isnt a issue except possibly in a accident.I drove mine for 2 years like that.
If the car is a 81 ,a mechanical fuel pump wont work.It wont have enough pressure for the f.i. system,even if it will fit.
If the car starts and runs ok first thing ,when cold,it probably isnt the cold start valve.It only activates when the engine is completely cold,and only works until the engine develops heat.There is a way to test it,which someone will chime in with,but I dont think its your issue.Try sending a pm to 'rlux' He is really knowledgable with these systems.Hope I didnt confuse you even more!

[cutchaguy]

I found this info, which may help me (others too?)
SYMPTOM ENGINE DOES NOT START/STARTS HARD WHEN WARM

Cause: Leaks in air intake system (false air)
Remedy: Check air system for leaks

Cause: Sensor plate and/or plunger not moving freely
Remedy: Check for free movement

Cause: Air flow sensor plate stop incorrectly set
Remedy: Check and reset

Cause: Electric fuel pump not operating
Remedy: Check pump fuse, pump relay and pump

Cause: "Warm" control pressure too high
Remedy: Test pressure

Cause: Fuel system leakage
Remedy: Inspect fuel system for leaks

Cause: Injector leaking, opening pressure low
Remedy: Check injectors on tester

Cause: Injected fuel quantities unequal
Remedy: Check for equal fuel quantities

Cause: Basic idle setting incorrect
Remedy: Check and adjust CO level


However, if cold start valve is stuck open, how do I check for this?

[cutchaguy]

Thanks Ga! Not confused much. I was, though by the parts place saying the mechanical pump fits all 124s, but something didn't seem right with that.

Going to go through checks I found and also get a new pump if reasonably priced.

[rlux4]

With the engine warm, take the cold start injector out and pointing it towards a container, have a helper turn the starter over. It shouldn't spray while the engine is warm. It only comes into play on a cold engine, and then only for a few seconds. The cold start injector is the only injector that has three leads going to it. The extra lead is because it also gets a signal (ground) from the thermo-time switch (under the intake manifold), so if it's not operating correctly, your issue could be either unit.
As far as your fuel pump goes, Craig is right, it should be wired through the dual relay to get it's run signal. The ignition switch is in "on" or "start" position which cranks the engine, which pulls air in through the AFM, which moves the flap, which causes the dual relay to send the 12V to the fuel pump. Your fuel pump shouldn't be that noisy. I can barely hear mine run even if I'm under the car right next to it. I've heard of people cleaning them to get it quieter. You could post for one in parts wanted if you can't find one affordable.
Ron