1983 Lincoln MarkVI

I Have a Lincoln with a 302 With Throttle body injection and about 150K miles. The motor Still feels strong So I am not sure about internal Engine problems such as low compression or so on. The symptoms have been coming on
for some time. They started with on deceleration the car would die as it slowed between 25 to 10 miles and hour. If the car was driven very gingerly it seemed to be able to upshift into first gear fast enough to raise the idle and keep the car running but if it was slowed quickly to turn a corner, it would not upshift fast enough and the car would stall. I was thinking at first it was a vacuum problem or a EGR problem. Then a new symptom came and that was it would only idle if it was cold. as long as the High Idle cam was on the highest step, the car would run. Now it will only run if you hold the throttle up with your foot and as soon as you release the gas pedal, the car dies immeadiatly. as if it is an electrical problem. The car will fire after two or three cranks every time. I have taken it to one mechanic and was told that they could not get a signal from the OBDIII system and give up just before charging my 100.00 and telling me nothing in return. Anybody out there have any ideas on these old systems that might be of help please? Thanks for your time for listening Anthony
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As you said, you have a CFI(Central Fuel Injection) system and I don't believe that the throttle body has a high idle cam like a carburetor. Most fuel injection systems use an ISC (Idle Speed Control) which is a computer controlled valve which bypasses air around the throttle plates for idle speed control. I would suspect that device and try cleaning its internal passages before anything else is tried. With 150K miles, also check for play in the timing chain as severe stretch there could cause excessively retarded valve timing. In 1983 Ford used a form of computer engine control they called EEC III which had a first generation diagnostic system predating OBDII (On Board Diagnostics V2). Stan K. Anthony & Denise Akers wrote:

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FYI Stan, this throttle body has both a choke cap and fast idle cam. It also has a vacuum/electric dash pot.
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This is a very easy system. It is OBD1 not three. The "mechanic" most likely does not know how to access codes if it has any. First things first, the electronics only give it fuel and ignition timing advance, so making sure the engine mechanically sound is the first step. I would first check to see if the cam and crank are properly timed, i.e. the timing chain. Check fuel pressure, needs to be 40 psi. too high you can have the same symptoms you describe. An open EGR valve can also cause the symptoms. This engine has a cooler under the EGR valve, it was known to be a trap for carbon. When the carbon build up gets large enough it would break up and wedge the EGR pintle valve open. The fix for this is easy and cheap. Take off the EGR valve, and cooler, clean out the carbon. When you reassemble it back together put a piece of aluminum screen over the ports, the screen traps the carbon preventing it from holding open the EGR valve.

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I had an 83 Tbird with a 302 and throttle body with the exact symptoms you are reporting. Since the drive train in the two vehicles is the same for most purposes, I expect the fix will be the same as well.
I see that many people are pointing you to the EGR valve and it's possible that it is contributing to the problem, but I replaced/cleaned mine about 4 time without really fixing the problem. It just got somewhat better for a little while.
In the end, what I found was a modulator valve (could be a differnent name) on the transmission was bad. I'm not sure now (it's been about 10 years since I owned the car) whether the problem was that it wouldn't let the torque converter unlock at slow speeds or if it wouldn't let the trans shift into first at slow speeds. In any event the result was the same symptoms you describe and the fix was about $25 instead of $200+ (at the time) to replace the EGR valve.
Good luck.
On Fri, 30 Apr 2004 21:34:01 -0500, Anthony & Denise Akers wrote:

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yours was a 302 it should have the AOD.

Unless your bird has a C5 transmision there is no modulator valve.

The C5's converter clutch is centrifugal, no other control. So if it was not unlocking you replace the converter. The AOD does not have a locking converter. I dont know what fixed your car, but it was not transmission, at least what you were told.

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