Hello All:
I have a problem with my 85 Bird that I can't track down. It has a 2.8L MPFI with an auto trans. The problem is that when the car is first started, it stumbles and dies. When I finally get it cranked, it idles fair, but if you hit the throttle it dies. It does this until it starts getting warm, and gets progressively better as it warmer. It runs fine when it is at normal running temp (195-200). The other problem is that the electric fan will not come on at high temperatures. I thought that since the coolant temprature sensor controlled both the cold start injector and the fan that this must be it, but a new one did nothing. I replaced the fan relay also, but again no change. I have been researching the board for the answer, but I haven't seen this exact problem. I have staight wired the fan and I know it works, and I have jumped the red wire in the relay to the fan and it will work, but it will not work with the green wire even if the car is 240 degress+. I also grounded out the wires that plug into the coolant sensor making it "think" the engine is hot, but it will not do anything. have had a few people say it may be the ECM, but I am tired of throwing parts at it w/o knowing what it wrong. Any help would be greatly appreciated. Thanks,

 

I had a similar problem and for me it turned out to be the O2 sensor. Just a thought!

 

Going to ALDL connector and shorting Pins A to B, then turn ignition switch to ON, engine off, the cooling fan should be running. This event verifies ECM control is working.

The coolant sensor can be measured with a DMM with the Ohms scale, 3K-10K when cold, 200 ohms when hot, 200-220*F. Read into wire harness with DMM on DIODE scale to make sure there is continuity to ECM.

There also might be a coolant switch in the radiator tank to turn on fan or its relay.

Cold start injector is controlled by an 8 second ON switch (when cold coolant) located in the vicinity of the thermostat area.

 

OK, so if jumping the A and B terminal on the coolant temp sensor does not work, does this mean the ECM is bad. Also, if I am understanding what you wrote, you said the cold start injector only works for 8 sec, and the cuts off. If this is the case, then cold start injector is not my problem since it runs badly for 5 or 6 mins until it gets warm. Will the car run at all if the ECM was disconnected? Is there a simple way to do this, or another way to check the ECM? Thanks again,

 

No, not the coolant sensor, the ALDL connector under the dash, maybe above the gas pedal, might have a cover over it, Pins A & B on it.

Turn the ign key to "IGN", and the coolant fan should come on. Also, this will tell the ECM to display fault codes it has collected by blinking the "SES" light. The fault code table should be listed around here somewhere within this site.

Yes, cold start injector is only on for 8 seconds.

Car will not run without ECM.