84 5.0 EEC-III Engine dies at idle randomly, rough idle at times, runs great at speed September 09, 2011, 02:04:41 AM 1984 T-Bird 5.0 EEC-III (one of those "special" California 1984 5.0's with the EEC-III system). Just wanna give the "your number one" salute to Ford and California for that "special" honor grrrrr....anyways.....The car went in for its smog and of course, it failed. HC at on the 50/15 test and high NOx on the 50/15 and 25/15 dyno tests. So I spent some bucks on it....plugs, wires, coil, cap/rotor, air filter, a bottle of seafoam, and a oil change. Played with the vacuum switches under the coolant bottle and got the egr to work (had no vacuum) and throttle kicker/dashpot did not have any vacuum ( so that works now too). Which helped with the idle speed with the a/c on. So took it back over today, the NOX dropped down, the CO2 levels were awesome, the CO levels were good....but HC still too high. The smog tech pulled the coil wire, and cranked it. The HC pegged the machine at 10,000 ppm which he said indicated that the cats were dead (cats were replaced 2 years ago). The other PITA problem that has been driving me nuts is the idle. It will start up cold and idle great. It will run on the highway great. You come off the highway, and come to a stop.....it will die. Starts right back up and idles fine. Go the next light it will be fine......or it will die...you never know what mood its gonna be in. Sometimes when it dies, it will just crank and fire. Other times, you have to open the throttle before it will start, and then run.Example today.....started up...ran fine for 45 miles on the freeway, got off...died. Restart...went to the next two lights it was fine. Sat for 45 min. Start it up...dies. Restart...dies. Restart...idle low...dies. Restart...hold pedal and brake..runs..get on the freeway for 40 mile drive....runs great. Get off...dies...restart..dies (does this 5 times). Finally hold the pedal and brake..for about 2 miles of city driving. Car sits for 20 min at destination. Start it up, starts and idles...but like ....then just shuts off in park. Restart and let idle...for about 2 min...then just dies. Restart and get on the freeway, runs great 20 mile drive. Get off idles wonderful, goes two stop lights and waiting for the light to turn green, its idle quality gets worst til it just dies, restarts easy. Talked to some people, said its the ignition module, so I replaced it this afternoon. Took it out to dinner tonight, idle not that smooth, and died twice. WTF!!!! Some times it idles awesome, other times...like , other times...it will idle like and then the rpm drops lower and lower till it dies, and then other times it will idle fine and just die like flipping a switch. So....new plugs, wires, cap/rotor, egr position sensor, ignition module. The tps tested out at 1.96v at idle, and seems linear as I moved it open on the DVOM. Running out of ideas. The state will give me $1000 bucks to hand the car over to them, but I like the car and have waaaaaaaaaaaaaaaaaaaayyyyyyyyy tooooooooo much time invested in the car to just give up on it now. Plus, the car is kinda cool :DAny ideas????? Quote Selected
84 5.0 EEC-III Engine dies at idle randomly, rough idle at times, runs great at speed Reply #1 – September 09, 2011, 09:42:28 AM On my 5.0 EFI car, the tps should be 1.0 volt or LESS at idle. Quote Selected
84 5.0 EEC-III Engine dies at idle randomly, rough idle at times, runs great at speed Reply #2 – September 09, 2011, 11:28:43 AM Keep in mind that it's a EEC3 system, so it runs a 9v reference voltage. Quote Selected
84 5.0 EEC-III Engine dies at idle randomly, rough idle at times, runs great at speed Reply #3 – September 09, 2011, 07:27:18 PM wow can't belive they still test you out by me anything older then i think 97 is exempt Quote Selected
84 5.0 EEC-III Engine dies at idle randomly, rough idle at times, runs great at speed Reply #4 – September 09, 2011, 08:38:42 PM 1975 and older are exempt. It uses to be 30 years and older were exempt. Quote Selected
84 5.0 EEC-III Engine dies at idle randomly, rough idle at times, runs great at speed Reply #5 – September 10, 2011, 10:18:42 PM Well I got it to read codes today, had a code for the coolant temp sensor and the egr position sensor. The egr position sensor is new, so there is probably some crud in the valve. Picked up a new CTS today, put it in tomorrow. It started up this am and ran like a million bucks. As it warmed up, the idle quality dropped and then it started its random shutdowns B.S. Such a simple system, yet such a PITA to get and info on it and work on. Quote Selected
84 5.0 EEC-III Engine dies at idle randomly, rough idle at times, runs great at speed Reply #6 – September 11, 2011, 05:07:20 PM Put the temp sensor in.....same code. Pulled the egr and the sensor, both clear. At wits end with this eec3 madness. Quote Selected
84 5.0 EEC-III Engine dies at idle randomly, rough idle at times, runs great at speed Reply #7 – September 12, 2011, 07:59:34 PM Read this thread.http://www.foxtbirdcougarforums.com/showthread.php?31660-Idle-Surge-1984-5.0-Thunderbird-CFI-EEC-III-Duraspark-III Quote Selected
84 5.0 EEC-III Engine dies at idle randomly, rough idle at times, runs great at speed Reply #8 – September 13, 2011, 01:50:52 AM I've replaced the ignition module, and same thing. Mine isn't so much a surge, but more that the idle drops (almost like a misfire) here and there and sometimes, it dies like turning the key off. It's died while running the self test and the PCM is still flashing codes back. Quote Selected
84 5.0 EEC-III Engine dies at idle randomly, rough idle at times, runs great at speed Reply #9 – September 16, 2011, 02:21:45 PM Update.....So after replacing.....Cap/RotorCoilPlugs Wires02 SensorTPSIgnition ModuleCoolant Temp SensorMAP/Baro Sensor Cleaned the Intake Air Temp SensorBottle of Seafoamand fuel pressure is at 41psiDisconnected the purge solenoid to clean it out....its "was" good...until I broke the nipple off of it. So i have the port on the TB base capped off for right now. Its idles like a total POS.It starts up and idles fine. About 30sec-1min later it starts it BS. You can watch the idle kicker and the Choke Pulloff drop out and back on when it does its idle drop. The 02 sensor voltage goes up (rich) when it hiccups. In park, it idles but still does it just barely. Put it in drive, and it starts to out. Turn on the A/C...and it gets worse whenever the compressor turns on. There is like literally nothing left to swap out. No vacuum leaks that I can see or hear. The idle has been set and reset and reset following the emissions label procedures and just good ol' "it close enough" procedures.....same result. It starts up cold perfectly, it warm starts perfectly.....until after that 30 sec window. I have disconnecting the egr vacuum line same thing....Unplugging any of the sensors and the car dies.....so their working. The only codes that this remedial PCM gives me is ECT shorted or out of range and EGR Position shorted/out of range. Yet both have been replaced and the EGR valve was taken off, didn't see anything wrong. Whats the up with it? Anything....I mean anything else you guys and can think of? Quote Selected
84 5.0 EEC-III Engine dies at idle randomly, rough idle at times, runs great at speed Reply #10 – September 16, 2011, 04:02:27 PM Check voltage on your tps, make sure no deadspots. My TC did same thing with random dying at stop lights and idle issues. Quote Selected
84 5.0 EEC-III Engine dies at idle randomly, rough idle at times, runs great at speed Reply #11 – September 16, 2011, 05:09:10 PM The tps is brand new as in less than 24 hours old. Same issue with new and old tps. Quote Selected
84 5.0 EEC-III Engine dies at idle randomly, rough idle at times, runs great at speed Reply #12 – September 17, 2011, 03:51:07 PM Pull the connector off the ECT and check the voltage on the two wires.With the key on:The Signal Return, black/white wire to EEC pin 19 should have close to 0 volts.The ECT, light green/yellow wire to EEC pin 21 should have close to 9 volts. (I think) Quote Selected
84 5.0 EEC-III Engine dies at idle randomly, rough idle at times, runs great at speed Reply #13 – September 18, 2011, 08:14:06 PM I think you should try to find out why the EEC is detecting an ECT sensor problem. That's why I suggested checking the voltages above. Quote Selected
84 5.0 EEC-III Engine dies at idle randomly, rough idle at times, runs great at speed Reply #14 – September 18, 2011, 11:16:02 PM The voltages were correct. After letting it run, for a while, t would idle down to about 350rpm for a while dead smooth with the a/c on....then back up to 550rpm perfect.....then do its hiccup stuff and/or die. If it dies, you have to open the throttle a little to get it to restart, or it will just crank.It only does its BS once it warm, and only after about 2 min after it restarts. Quote Selected
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