Fox T-Bird/Cougar Forums

Just purchased a California 1983 Cougar with 60,000 miles. Having a slight issue. Cold idle becomes wide open throttle in 4/5 mins. Will not kick down unless I shut the car off a few times. Pedal is not stuck. Car is basicly undrivable due to power blocking when shifting into reverse or drive at wide open throttle.

Had it towed to my garage and basicly was shown the door. California emmission car.....no access to diagnostic tools for the computer.  Was told to get classic plates. Pennslyvainia this means no longer needs to conform to emission testing. Then swap over to a carb. Or I can start throwing dozens of parts at the car.

Wouldnt mind the swap but this car is close to showroom condition. Dont know where or if I should start upgrades. The AOD just was serviced 50 miles after purchased. Was told a shift kit can wake it up for $500/$600

The intake and carb is a easy summit purchase.
However need to decide If I should use the dura spark module or a 60's point style distributor. Or should I just try to save the EFI?

My plan would always be to keep it original but that could break the bank.

That's why I had to make tough decisions in my project.

I can't help you with that style of EFI other then to suggest the idle motor (If it has one)

Lot's of knowledge here in the tech forums.

Could be a huge vacuum leak, or someone turned the base idle screw in. Try backing idle screw out till you see a slight gap where it contacts the throttle lever, then turn it in till
it contacts, and give it a half turn more. Should get you close if someone cranked it in too much. Count how many turns it takes when backing it off, that will tell you. I saw this happen before.

I'm guessing this is a 5.0L with EEC III?

I had a 5.0 EEC-iii car, it was archaic but there was a way to pull codes.  I can't remember how to do it but I believe chuckw was the one who told me how to do it.  The system is incredibly simple and should be able to be put back to operation easy.  One of its weaknesses was no fall back if a sensor was out of value.  Mine had a bad coolant sensor and it would only run with one injector unplugged it was so rich!

It is the EEC-iii 5.0 cleaned this fan shroud sticker gives all the info on tuning idle. Says anything over 50 Rpm needs the tv linkage adjusted. Takeing it that this was performed on a “Sun brand” scanner / ocillisocpe. I’m located near Pittsburgh so there are some better shops to take it too. I don’t want start blindly changing stuff. Once it’s warm I’ve driven her 260 miles one way at 75 not one issue. But its really just a 2 barrel Should make some power going to carb.....

However it’s a 1 owner car. Never been messed with. I know a 83 Mercury isn’t going to Pebble Beach or breaking records at Meguire. But I bought it to play with....more I drive it the more I like its floating suspension and silence in my pillow leather armchair. Maybe it will be collective.....almost removed the stereo....eh couldn’t thanks for advise. Always wanted this car since I was a child.

The fast idle cam is on the right side of the CFI.
It is a 3 step cam.
When the engine starts the vacuum pull down moves it from the high step to the middle step.
As the thermostat heats up it moves to the low step and then drops off the end of the cam.

The wire to the thermostat has 6-8 volts from the stator output of the alternator.

Do you still have the 1G alternator with the external voltage regulator?

If the alternator has been upgraded, maybe they didn't hook up the wire to the thermostat.

Is this the cam in question. I have no clue on terminology and is frustrating. I’ve dealt with bosh jetronic for years. This is out  of my knowledge. However there is a few positions that click. However it’s not moving at all between settings. When it goes wide open. I push the little cam over and it drops down to normal. My gut said this part was called a Idle control valve.

But I know it’s not. What do I call this at Napa so I can replace.

I believe you are looking at the top of the thermostat. That won't move.
Maybe these pics will help:

Yeah the “idle control rod” does not move at all. Cold hot or in between. However I can flick the cam and it idles down. What I’m reading 4square.com or fox mustang forum is it also works with ambient temperature. This car was in Monterey California and Southern California. So maybe it’s stuck. I’ll check in the morning see if vacuum is getting there. 61 outside Right now.

Or should I try adjusting the screw on the fast idle

Oh and there is 2 wires connected at the coolant thermostat. Alternator has wires going to a box so should be original. My first American toy. I’ve only messed with Datsun Z cars. Detroit must of had free wire and vacuum hoses given to them. Total mess. Starting to see why my 2.8 straight 6 had more power than this 5.0

    you could go this route, it's much easier. Just save your other parts!

Don't confuse the coolant thermostat with the CFI thermostat. It was called the electric choke on carbs. The wiring diagrams still call the thermostat heater the "choke heater"
The white/black stripe wire is the alternator stator voltage at the thermostat. This voltage is only available when the alternator is running.

83 EVTM pic:

My 83 TBird 5.0L will increase speed when warming up too but a blip of the throttle sends it back to normal.  I've had it since new and it started doing this in the later years. I'm guessing your's won't kick down with a stab of the gas pedal?

Nope lost my temper. Bashed “REALLY beat the living hell outa” the throttle in my size 13 steel toes .....40 50 times. Refuses to kick down.  It’s completely wide open. Hate to throw a rod. Today I had to restart the car 4 times. Then it ran flawlessly 75 mile. So next weekend I’m swapping over to carb.