I have a 1986 Cimarron V6 that has developed a problem starting in cold weather. (Still less than 88,000 miles on it!)
After starting, I have to punch the throttle up to above 1,000 RPM then back off and "play" it up and down until it warms up to two bars on the temp gauge. (Digital instrument panel.)
Then it will run fine and restart fine.
The V6 Cimarrons used a multiport, "batch fire" injector system with six injectors triggered in two groups of three. (This was so GM could use the same control system as the V6 with a dual injector throttle body.)
It also has a seventh "injector" called the cold start valve, located at the front (right end) of the engine, under the alternator. This is supposed to squirt in extra fuel when the ambient temperature is below a certain value and/or until the coolant warms up enough, which is apparently whatever temp is enough to put the second bar on the temp gauge.
The Check Engine light never comes on. I replaced the fuel pump this summer with a new one after it quit while I was in the turn lane in the middle of a five lane road. (Hooray for AAA!)
Today I took the alternator off, and the cold start valve, cleaned the electrical contacts, verified that the fuel pipe to it was clear, cleaned it up with a spray can of cleaner, checked the injector coil resistance, which is 5 ohms, and put it back together. I pulgged and unplugged the connector several times to ensure it's making good connection. And I filled the fuel rail up with the spray cleaner to get a straight shot of it to all the injectors.
After cranking a bit to flush the cleaner through, it fired up, but still acts exactly the same. :(
So my question is, what all is involved in the control system for the cold start valve?
After it's warmed up, it does run a bit rough at idle but smooths out fine with very little throttle. (I'm going to check the sparkplugs to see how they're doing.)
I like it because it gets a solid 25MPG, anywhere, all the time. (Probably do better after I get it all sorted out!) I just saw an advert for one of those gas/electric hybrids. They're finally telling the real world MPG, supposedly 60MPG for city driving but only SIXTEEN MILES PER GALLON on the highway! Hah! Get an SUV, most of them will beat that. ;)
Other work I've done on it. Replaced the Torque Converter Control solenoid valve. (WTH didn't GM do a recall or even a TSB on those! The damn thing's dangerous when it sticks and won't release the converter lockup clutch! Same thing on the 1988 Corsica I had.) Put a rebuilt alternator on. Sparkplugs and wires plus cap and rotor. New ignition module after the regulator died, sending 16+ volts through it from the alternator which also fried itself. Replaced rusted out exhaust and muffler behind the catalytic convertor.
With its white and silver exterior and cranberry interior, I call it the "Micro PimpMobile" or MPM for short. ;)