[T3] Idles on 2; runs on 4

[Elroyyy@aol.com]

Hello listers.

Here's an odd one -- at least I couldn't find anything like it in the 
archives.

About a week after a tune up, my car began to act funny. It started running 
rich. And the warmer it got, the richer it ran, until it was extremely 
difficult to start and keep running.

Everything has tested out OK. I'm stumped. From the beginning:

She's a 1973 FI MT Squareback.
I ran the tune up; it consisted of an oil change, valve adjustment, plugs, 
points and condenser, adjust timing, check idle. This was not my first tune up. 
Everything was great for a little more than a week and then she began to run 
rough. At first, she just wanted her accelerator pedal feathered at the light 
to keep the RPMs up. A little later, she wanted the pedal tickled to keep from 
stalling. Eventually she would stall and I'd have to crank her over and over 
until she'd catch, blow petrol-smelling smoke, then continue.

Since I'm an avid reader of the type 3 list, I knew immediately that if the 
car runs rich it must be a problem with the Voltage Regulator of the Cold Start 
Valve. I ruled out the CSV because I live in Southern California and the 
problem doesn't happen until after the car has been started.
So I connected my trusty VOM to the battery and got 12V. As the car 
approached medium RPMs, the VOM began to read higher and higher and leveled off just 
shy of 14V. But that's what it's supposed to read! The Voltage Regulator is not 
my problem.

Checked the fuel pressure - 29 (I like to split the 28-30 right down the 
middle).

I had a virtually identical 73 T3 that I sold just a few weeks ago. So all my 
"spare" FI components are gone. I have a local repair shop that is very 
competent in things Type 3, so I limped the car over to him. 

He tested a known-to-be-good Pressure Sensor and nothing changed. He cleaned 
the trigger points and nothing changed. He retested for spark -- it's fine all 
around.

But he discover that the injectors for 1 and 3 were spraying too much fuel on 
each impulse. This is particularly troubling because the paired injectors are 
1&4 and 2&3. The injector wires were reversed on each side and 2 and 4 
started shooting too much fuel while 1 and 3 were fine. This tells me that it's not 
a problem with the injectors themselves.

Next, he called to ask if I had another ECU we could try. The short answer is 
no. She's a 73 with an "E" system (brain, pressure sensor and throttle valve 
switch all match). The only ECUs I have are a "D" and a blank. There is no 
part number anywhere on the blank. So we tried them both.
The "D" brain didn't seem to affect anything. The blank, however, was another 
story altogether. Instead of pushing out too much fuel, this brain allows no 
fuel to 1 and 3 while she idles. But when she gets a little gas, she'll run 
fine on all four.

Personally, I don't think the problem lies within the ECU. But I'm open 
minded enough to consider it as a possibility. I have a spare "E" ECU on the way 
but it won't arrive until some time next week. Anybody have any ideas?

Thanks in advance.

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