I'd like to tap the knowledge base her for just a moment please. I have a 1973 450-SE and every now and then on the first start of the day it fails to idle up like it should. Just kinna stumblesalong till it gets warm. What I need to know is: 1-What is the device and where is it located that tells the ecu to perform a cold start and idle?
2- At what temperature should this device be signaling for a cold start mode?

Thanks for your advice

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Had I known I Would Have Lived This Long, I Would Have Taken Better Care of Myself----Don

I assume it's a Djet system?
the temp sensors are placed in the aircleaner snorkle ( air temp ) and in the front of the intake manifold ( water temp). Check your cold start valve to make sure it's not leaking .
Idle speed from cold is controlled by the auxilliary airslide valve ,with is that round upright thing in front of the aircleaner with the black hoses conected to it.
If it's a Kjet it wont have a ECU ,just a thermo-mechanical warm up regulator.

Thanks there---It is a D-Jet system.. This will give me something to start with --Nowwhere is the cold start valve located? Thanks again

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Had I known I Would Have Lived This Long, I Would Have Taken Better Care of Myself----Don

when you stand in front of the engine it's on the Top right front of engine,it has a wire,and a hose running to it. It's held in place with two socket head bolts. With the engine warmed up; turn the engine off,
Undo the two bolts and carefully lift it clear. Block the hole where it fits. restart the engine and check the end of the valve,it must be dry with no drips whatsoever.

just try and unplug that sensor on the air filter and let me know if that changes things?

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Ron
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My old pappy used to tell methat even a turkey could fly if the wind was blowing just right, and I proved it today. In between sessions with the weed-eater and the lawnmower I started tracing wires and vacuum lines. On the drivers side of the fender well sits a device somewhat like a beer can with an electrical cable connection and a fiber wrapped hose. Both these ran back and down behind the engine. Following the hose to its destination, I found it was full of ruptures and disconnected from its attaching point. Using some good old redneck savvy, I whipped out the duct tape and did a half way repair of the offending creature. Plugged it back on the barb and started the beast up. Seems to be back to normal as far as hot idle but I need a cool morning to check the cold idle situation. I plan to go to the auto parts place in the am and get a piece of hose and give it a good Italian tune up to burn off the plugs that are probably sooted up. I love it when a plan comes together. More after I get some vacuum hose.

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Had I known I Would Have Lived This Long, I Would Have Taken Better Care of Myself----Don

It's a MAP sensor. MAP means Manifold absolute pressure. It registers the vacuum in the manifold to regulate the amount of fuel the engine gets while you driving,so as the vacuum or "manifold pressure" changes ,it sends a signal to the ECU so the engine gets the correct amount of fuel.As you have found out,if the MAP sensor isn't getting the correct signal ,the ECU doesn't know how much fuel is required and just goes to full fuel . Buy a new piece of hose and get it running properly.

Ain't it amazing how a 1 dollar piece of hose can bring the mighty beast to it's knees. Replaced the rascal and all is well. Thanks for everyone's input.

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Had I known I Would Have Lived This Long, I Would Have Taken Better Care of Myself----Don