Poor starting, looking for ideas, Problem Solved. Another win for the World Board. Options

[Gudhjem]

I've been trying to avoid posting this, since I figure everyone's tired of "my car wont start" posts. But, I've reached the end of my rope, I'm out of ideas, and I need some new ones.

I've got a '73 2.0, stock FI, except for a Crane x700 ignition.

Sometimes it starts right up, but often, about half the time now, it wont. The starter cranks, turns over the engine very quickly, but the engine just wont "catch." It just keeps cranking. It acts as if I forgot the rotor or am out of gas (I didn't and I'm not). Happens warm and cold (though possibly more often warm). I can't think of anything I've done to the car that coudl cause this (no engine tinkering to speak of), and it seems to be getting worse. Today, it did the same thing and after cranking for about 15 seconds, seemed to backfire from inside the case. It blew off the little rubber fitting that sits next to the oil filler cap (the one I'm pointing to in the pic). This happened twice.

The kicker is that once it starts, it runs like a champ. I mean really well - smooth all the way thorugh the range, plenty of power, no smoke out the exhaust, relatively smooth idle at about 800, etc. That forutnatly (or maybe unfortunatly) eliminates most of the reasons why a car wont start. I don't need to worry that my plug wires or injector leads are crossed, or that my plug wires are bad, or my coil is bad, or my Fireball isn't working, or my injectors are not squirting, or that I have no compression, or that I have no fuel pressure, or that my timing is way off, that I have a bad connection or ground somewhere, or that my dizzy is in backward.

Here's what I've tried:
checked timing
checked fuel pressure (set it to 29lbs)
verified spark at the plugs
removed cold start valve wires
replaced spark plugs (0.028")
replaced coil (bosch blue)
replaced spark plug wires
replaced cap and rotor


Seems to me that since it runs so well once started, the MPS and temp sensors or brain could not be the causes. It does look wet when I pear down the throttle body (inside the air distributor thing the throttle body sits on), and although the plugs I pulled were black and a little bit moist, they were not really fouled. So I have spark, I have timing, and I have fuel, I am suspicious that it must be a mixture thing, but don't know where to go with that, and again, it runs so well when it starts.

Any ideas?

--Steve

[Gudhjem]

Thanks for the replies.

The ignition switch was replaced about a thousand miles ago. Anyway, even if bad, I don't understand how that could explain my symptoms. The solenoid engages and the starter cranks with no problem whatsoever. The ignition switch has done its job then hasn't it? What involvement does it have in actually having the engine "catch?" Once the engine does start, it never dies, such as if the ignition switch were losing contact.

I have tried starting with the accelerator pedal depressed all the way (before turing the key on to avoid the TPS squirting in fuel). I think this migh tbe helping a little bit, and so that's the way I've been starting the car ever since this problem started appearing. It definitely is not solving it though. It can still crank away until the battery starts to die even with the throttle wide open.

I have disconnected the cold start valve. It's still plumbed in, and the thermotime switch is still connected, but the wires to the CSV are not connected, which I would think does the trick, doesn't it? I don't want to hassle with actually having to remove it and plug the hole in the air distributor that would leave.

As for CHT cold resistance, I have a new CHT sensor I can swap in. I'll go ahead and do that.

I have not checked the MPS vacuum integrity. I suppose that's my next step (never done this, but I'm sure a good explanation is on this site somewhere).

Again though, the car runs well once it goes. I didn't think that would be possible with a bad CHT sensor or bad MPS. Maybe it is?

I do suspect a rich mixture, and yes, although the car's spent lots of time idling in the garage lately, it does seem that my gas mileage is crap.

Can a rich mixture make the car hard to start and yet allow the car to run well? Is it unusual for the air distributor (the thing below the throttle body) to be wet inside?

[SirAndy]

I have tried starting with the accelerator pedal depressed all the way (before turing the key on to avoid the TPS squirting in fuel). I think this migh tbe helping a little bit, and so that's the way I've been starting the car ever since this problem started appearing. It definitely is not solving it though. It can still crank away until the battery starts to die even with the throttle wide open.

That's not what he meant. Don't keep your foot on the throttle. Simply press the throttle all the way down once before cranking, then release, then try to start. Don't keep your foot on the throttle while cranking the engine.

A leaking cold start valve could cause your engine to flood. Disconnecting the wires may not prevent it from leaking fuel. You need to disconnect the fuel supply to the valve.

(IMG:style_emoticons/default/popcorn[1].gif) Andy