Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Topic: Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III (Read 32890 times) previous topic - next topic

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #15 – July 11, 2011, 02:31:36 AM

I'm thinking an EGR problem... you mentioned the NOx test failure... that generally indicates the EGR system isn't working correctly due to being gunked up with carbon or not opening due to a leaking diaphragm. Since the EGR also affects the idle if it activates while idling or leaks past the pintle, I can't really help diagnose, it's going to depend on which EGR system Ford used on that year's engine. My books aren't much help telling which yours has. Definitely, check for vacuum leaks through the system though, it's a good idea any time there's an idle issue.

I'm not sure if this is applicable... but a roommate of mine had a mid-80s Escort with the CFI setup. His problem was that the engine would idle correctly, but if you tried to drive off it acted just like low fuel pressure, extreme surging of engine power, like maybe a plugged filter or bad fuel pump. We changed the fuel filter and I checked his fuel pressure and it was fine. After a LOT of research I found a note on a mechanic's website mentioning a CFI Escort which they called a factory tech in to fix... turned out that the problem was part of the idle positioning system. The actuator that set the throttle position also had an integrated switch, when the throttle closed down (foot off the pedal), it hit that switch and changed the fuel delivery system over to lean-burn to reduce emissions at idle. His switch was bad, and he was essentially trying to drive with it in lean-burn, which does NOT work well. :) Changed the throttle positioner, about 90 bucks, and he got a working car. Just a thought.

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #16 – July 11, 2011, 02:39:10 AM

BTW this Chilton's I have that covers your year of engine looks to have the same throttle actuator, the ISC [Idle Speed Control] DC motor actuator. The lean-burn mode control switch is internal to the device, not separately changeable. I checked it by hooking an ohmmeter to the switch contacts on the ISC connector (with it disconnected) and hand-actuating the switch, and it was intermittently working. it's odd that that lean-burn functionality is barely mentioned anywhere in the various things out on the Net... I'd likely never have fixed his car if I hadn't stumbled across that note.

Long post is looooooong...

Reply #17 – July 11, 2011, 05:21:10 PM

Quote from: softtouch;363177

The output of the MAP sensor for EEC-IV is not a DC level. It is an oscillator and the frequency changes with pressure changes.
However baro and manifold pressure should be the same when the engine is not running.

It's true that the output of the EEC-IV MAP sensor is a frequency, but the signal output of the EEC-III BMAP sensor is a DC voltage according to my multimeter readings. I get nothing for frequency, but when applying vacuum to the ports I get a voltage signal that goes up and down. I thought that the sensor on this car uses a frequency signal too, which is why I bought a new multimeter with frequency.

What I meant by "reference voltage" is the voltage coming from the EEC module to the sensor that initializes the sensor, not the incoming signal. This is 9V for the EEC-III and 5V for the EEC-IV.

Unfortunately, without a table or curve to look up the pressures, I have no idea how accurate my sensor is. Tables for an EEC-IV MAP sensor are easy to find, but not so for the EEC-III BMAP. I have four wires coming out of my sensor: ground (black with white stripe), 9V reference (orange), barometric pressure signal (dark blue), manifold pressure signal (green).

I did find a manual for a scan tool that says the "self test" initiates when the voltage reading from the BMAP jumps over 6V and that with the engine off the sensor should read less than 3V. The manual wasn't clear if this was just the barometric signal referenced to ground or the voltage difference between the two signals. If it's the difference between the signals I'm fine, if it's not, then my car is continuously running the self test (not likely).

Quote from: camelid;363182

I'm thinking an EGR problem...

My initial thought as well, and the EGR was severely gunked, but giving the whole ERG system a cleaning and test was the first thing I did and the problem persists. I have some pictures on my phone, but now it's not working... Maybe after cleaning out my phone's IAC and replacing the ECT sensor I'll upload them.

Quote from: camelid;363182

...it's going to depend on which EGR system Ford used on that year's engine. My books aren't much help telling which yours has. Definitely, check for vacuum leaks through the system though, it's a good idea any time there's an idle issue.

It's a SONIC EGR (what does SONIC stand for???) mounted on a spacer between the manifold and TB with a cooler and a position sensor Tested, retested, triple tested, the EGR itself and the EGR position sensor are good.

My second thought was also vacuum lines, I didn't find any leaks in the original system, but I broke two of the stupid nylon vacuum lines while working on it. I since replaced all of the nylon lines with steel line and standard rubber vacuum hoses. I have no vacuum leaks.

Quote from: camelid;363183

BTW this Chilton's I have that covers your year of engine looks to have the same throttle actuator, the ISC [Idle Speed Control] DC motor actuator. The lean-burn mode control switch is internal to the device, not separately changeable. I checked it by hooking an ohmmeter to the switch contacts on the ISC connector (with it disconnected) and hand-actuating the switch, and it was intermittently working. it's odd that that lean-burn functionality is barely mentioned anywhere in the various things out on the Net... I'd likely never have fixed his car if I hadn't stumbled across that note.

Chilton's just seems to get worse with every new edition. I swear, every Chilton's for every Ford seems to be the same. They just cut and paste sections for the different features. I too have a Chilton's manual for my car, I use it for a coaster. (The only useful thing in it was the capacities chart, which is also in my Ford shop manual.)

Only the 3.8L had a DC motor throttle actuator. The 5.0L had a vacuum dashpot for the throttle kicker and vacuum linear actuator for the fast idle cam (part of the "cold enrichment" system I think). I replaced the diaphragm in the fast idle cam actuator and tested the throttle kicker dashpot. Both definitely move when the computer flips the solenoid that controls them (both are on the same vacuum line), so I'm fairly sure they're good.

I would try replacing the dashpot, but the car seems to be idling now. My O2 sensor was apparently the key to the large surge. However, I still have a slight surge (about +/- 50 RPM) AND the car won't idle low. When I adjust the idle speed, following the directions on the emissions sticker on the fan shroud, it gets down to the desired 550 RPM and stays there just fine (plus the small surge I mentioned before). Then if I turn off the car and restart the idle will either:
1) Be super low (under 300 RPM! It can idle at under 300 RPM! ...for about 10 seconds) and the engine stalls, forcing me to mess up my idle adjustment to get it started and stay on.
2) Be super high (900 to 1000 RPM) for about 2 minutes and then drop to 650 or 700 with a +/- 50 RPM surge.

Now here is my dad's theory, which I don't really agree with, but let's see what you guys think:
He thinks that the thermostat is either a 165 degF or the hillbillies (previous owners I rescued the car from) removed the thermostat all together causing the following:
1) The EEC-III wants the engine to stay at a particular temperature while idling, which is probably over 185. (Say, 195 or something.)
2) With no thermostat (or a low temp. one) and a halfway decent radiator the temperature never gets there so the computer ups the RPM until it does.
3) 2 minutes later the O2 sensor kicks (non-heated O2 sensor, so ridiculously long lag in initial start readings) in and screams "Too much! TOO MUCH!" at the EEC-III while the ECT (engine coolant temp.) sensor is screaming "Not enough! NOT ENOUGH!" (It's rare that my temp gauge rises above 180.)
4) Conflicted the EEC-III decides to settle somewhere in the middle, slightly favoring the O2 sensor in the interest of being "green", at 650 to 750 RPM.

My dad figures my problems would be solved with a new thermostat and possibly a new temperature sensor (of which I do have a spare....somewhere).

Any thoughts on that idea?

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #18 – July 11, 2011, 11:51:21 PM

EEC3 wow that's amazing it still keeps going! Excessive nox is usually an indicator of egr but you say you've thoroughly cleaned and vacspooge tested the egr. I remember having to take off the cfi tb the egr spacer plate and egr cooler and cleaning them all with a pipe brush. Also if there was that much carbon, the air charge temp sensor needs to be inspected and/or replaced. Tps should be adjusted to 1 volt and if replaced the small spring put back into position. Pull the dist cap and rotate the engine counterclockwise to take all the slack out of the timing chain and note the position of the rotor. Rotate the engine back clockwise and see if there is excessive slack before the rotor begins to move. The bmap used to be a high cost item and should be tested closely BEFORE replacing. Way back when EEC3 vehicles came into the shop it was 2 hour diagosis time vs standard 1 hour. Your are on the right track, keep trying and testing!

Mike

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #19 – July 12, 2011, 12:02:42 AM

Well, checked the thermostat and it was fine. If anything it was opening late instead of early, so I replaced it. Test drove it. Temperature still doesn't breech 180. Anyone know how a car can sit there and idle for an hour at 700 RPM with the thermostat closed and never reach a temperature over 180? Cuz I'm starting to think this engine defies both logic AND physics.

BTW, some helpful information I discovered recently that might be helpful/useful to people with the same year/system of Ford:

1) Bosch, original manufacturer of the O2 sensor (aka EGO sensor) for my car, say that mid 80's Fords and lower that use single wire O2 sensors should have those sensors replaced every 30,000 miles. Supposedly it'll help keep the MPGs up and make the smog tests easier to pass.

2) While the EEC-III does supply the BMAP, TPS, and EVP (EGR Valve Position) with a DC reference voltage of 9V, it DOES NOT supply the ECT and ACT temperature sensors with a reference voltage. The EEC-IV supplies its temperature sensors with a 5V reference and then measures the voltage drop across the sensor. This causes some confusion and some manuals and online materials say that the EEC-III supplies a reference to these sensors as well. However, the EEC-III, near as I can tell, is actually measuring the resistance of these two sensors directly. The black wire with the white stripe going to both of these sensors connects to pin 14 (I think that's right...) of the EEC-III module and the engine ground, this is like the COM lead of a multimeter. The other two wires (green with white stripe for ECT and green with yellow stripe for ACT) act like the red lead on a multimeter for the ECU for each sensor. This is backed up by Ford's shop manual which has a wiring diagram indicating the black and white wire to be ground and the other two wires to be signal for those sensors. With that kind of wiring the only way the sensors can give the EEC-III information is if the EEC-III is measuring the resistance of the sensors directly like a multimeter.

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #20 – July 12, 2011, 07:57:59 PM

Checked the CATs. They're clean and clear. Engine still surges and idles high with them removed as well.

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #21 – July 12, 2011, 09:09:54 PM

Checked codes again and for the first time I got a code 1-2, which is ... "RPM Out of Spec" ... NAW! REALLY!?!? ....uggg.... :disappoin

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #22 – July 12, 2011, 11:18:26 PM

Okay, I think I've got it (like I haven't said that before). What is this relay: E3SB-9G483-AA? It was mounted to the driver's side fender wall, right next to the Duraspark III module. It also has "10 MIN." stamped into the top of it. One of the wires going to it had come undone. With that wire plugged in, 10 minutes after a cold start the idle goes down to 550 and holds with just a little bit of surge (20-30 RPM). I'm happy that it's finally doing SOMETHING right, but what the is this magic relay? What does it do? It's not in any of my shop manuals, including the factory manual, and a search of the general part number (9G483) reveals it do be... drumroll please ...a relay. Woo. Now I'm just waiting for the engine to cool down so I can put the cats back on. Tomorrow, if it's still running right, I'm going to take it in to smog again.

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #23 – July 13, 2011, 11:25:55 PM

Does your car have the standard 5 wire ignition module? I am wondering if there may be something unique for California emissions.

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #24 – July 13, 2011, 11:53:39 PM

Quote from: softtouch;363400

Does your car have the standard 5 wire ignition module? I am wondering if there may be something unique for California emissions.

Yeah, it's a five wire. 2 on one connector, three on the other.

This morning it ran perfectly. 550 RPM at idle with the timing at 10 deg BTC. I ran into the house to proclaim victory and came back outside to find the car back at 650 RPM and 20 deg BTC again. I have the feeling my wacked timing is what's causing the high NOx in my smog test too.

I know that the base timing is set to 10 BTC, where it's supposed to be.

I'm told by the sticker on the distributer that my timing is non-adjustable, but just for the sake of arguement, what would happen if I tried to adjust it anyway?

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #25 – July 14, 2011, 01:28:10 PM

EEC IV can add 20° on top of the base 10° for a total of 30°. So I'm not sure 20° is excessive.
I am curious how you set the base timing on Duraspark III. Since the CPS pulse goes directly to the EEC, there is no way to get the EEC out of the picture.

On EEC IV the CPS (PIP) goes to the ignition module first and then to the EEC. You disconnect the spark out pulse from the EEC to set the base timing.

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #26 – July 14, 2011, 04:17:04 PM

This suggestion is in the grasping at straws category.
The two wire connector on the ignition module has a red wire and a white wire.
The red has 12v with the ignition in RUN. The white wire has 12v with the ignition in START.
12v on the white wire retards the spark while cranking.
Can you back probe the white wire at the connector to make sure it does not have 12v on it when the engine is running?
This is on the off chance the EEC wants to advance the spark to more than 20° and can't.

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #27 – July 15, 2011, 02:58:55 PM

I checked the base timing by turning the crank to 10 degrees and then checking the rotor position.

I since discovered that though I cannot adjust the timing I can adjust the rotor position. Which kinda feels like the same thing to me. After playing with it a little bit, the timing did go down to 10 degrees, but eventually the computer adjusted it back to 20 degrees. There's gotta be a sensor somewhere or some other thing telling the computer that it wants to be at 20 degrees. The wierd thing is, I thought the whole point to the EEC system was to adjust the timing for different RPM to improve emissions, efficiency, etc. But it's 20 degrees at ANY RPM. Shouldn't the computer be advancing the timing with higher RPM and retarding it with lower RPM?

Quote from: softtouch;363438

This suggestion is in the grasping at straws category.
The two wire connector on the ignition module has a red wire and a white wire.
The red has 12v with the ignition in RUN. The white wire has 12v with the ignition in START.
12v on the white wire retards the spark while cranking.
Can you back probe the white wire at the connector to make sure it does not have 12v on it when the engine is running?
This is on the off chance the EEC wants to advance the spark to more than 20° and can't.

This is actually a good idea and falls more in the "well I've tried everything else" category. I'm gonna go try it right now.

I'm also going to try to make a trip to a junk yard soon to see if I can find a CPS and maybe an EEC-III module (just in case). Also, though I have 3 Duraspark II modules for a 5.0, I don't have any Duraspark III stuff, so I'll need to keep an eye out for that kind of stuff as well.

Oh and some advice for all you guys with early 80's Fords. KEEP THOSE EGRS CLEAN. I just found out a new one will run you over $140 and that it's such a "rare item" that CarQuest and anywhere else will charge you FREIGHT to get over here. This is for the SONIC EGR valve, without the position sensor or cooler. Fortunately my 3.8 bird uses the same EGR, so I kinda have a spare.

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #28 – July 15, 2011, 03:35:19 PM

Voltages on the two wire connector are on/off at the appropriate times.

Idle Surge - 1984 5.0 Thunderbird, CFI, EEC-III, Duraspark III

Reply #29 – July 20, 2011, 02:44:39 PM

Well, still working on it.

I bought a complete set of 1984 Mitchell Manuals (via eBay) for the purposes of figuring out this problem. I now have a decent wiring diagram and resistance values for most of the sensors and other components.

Still, it does not give any method for testing the BMAP or the EVP. My EVP resistances match those for the EEC-IV test provided in the Mitchell manual and I'm not supposed to put an ohm-meter on the BMAP.

I would take a break from this and work on other aspects of the car (suspension, body work, interior, etc.), but I don't want to put much more money into it if I can't drive it around legally (I need to pass smog).

I've even gone as far as to verify that the EEC-III computer and the calibration module are stock (they are), just to make sure somebody didn't at one point try putting a calibration module from a H.O. Mustang or a truck in it.

There is also a note in the Mitchell manual on the first page for "Continental, Cougar, Mark VII & Thunderbird With 5.0L CFI":

"NOTE: The EEC-III system was used for the first 120 days of production for California Job 1 vehicles."

So the EEC-III was used on Thunderbirds ONLY in California and ONLY for the first 120 days. Hey! That makes this a RARE car!

...woot?