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Regardless, he's got one of those California-emissions electronic controls that nobody else has, has anybody actually pulled the codes and diagnosed the entire thing?
MCU was pre-EEC-III. I had MCU on my 1982 Ford LTD (full-size car with 302). The MCU controlled the feedback carb (V V 7200 2-barrel on that engine) via a stepper motor, controlled the air injection system, would signal the DuraSpark ICM to advance timing if high coolant temperature was reached, canister purge solenoid control, throttle kicker solenoid.
MCU inputs were: O2 sensor, coolant high/low temp switch, ported vacuum switch, and a really neat looking Zoned Vacuum Switch array.
The ZVS sat on the fender, had a vac hose from intake manifold to it, and it had 3 or 4 different brightly colored small cylinders sticking up from it, they were vacuum switches, the array would report intake manifold vacuum in ranges depending on which switches were open/closed.
Codes could be read by counting blinks of the engine dash light. It may have had the underhood test connector like EEC-IV did, I can check that, I have an Actron code reader that blinks/beeps, I think it may have mentioned that it works with MCU also. Somewhere I had to trigger the test, a bent paper clip, so I'm thinking it had the test connector. When I had the car, I did not have any code reader then. Mine always blinked out the code for "lean", no matter what I did.
When I had it, I had to pass a two speed idle sniffer test every year. Right before the test, I would unscrew the stepper motor from the side of the carb, free its plunger up with a bit of Gumout, put it back in, and go for the test. Always passed, with a good margin, too.
ctubutis brings up an excellent point... how do they know the MCU is bad? Good chance they don't have a clue, and point to a part they don't understand as the culprit.
EDIT - Oh yeah, there it is! The test connector. Its gray, just to the viewer's lower left of the MCU in the pic above. Same test connector as EEC-IV, just Gray rather than Orange
MCU was pre-EEC-III. I had MCU on my 1982 Ford LTD (full-size car with 302). The MCU controlled the feedback carb (V V 7200 2-barrel on that engine) via a stepper motor, controlled the air injection system, would signal the DuraSpark ICM to advance timing if high coolant temperature was reached, canister purge solenoid control, throttle kicker solenoid.
MCU inputs were: O2 sensor, coolant high/low temp switch, ported vacuum switch, and a really neat looking Zoned Vacuum Switch array.
The ZVS sat on the fender, had a vac hose from intake manifold to it, and it had 3 or 4 different brightly colored small cylinders sticking up from it, they were vacuum switches, the array would report intake manifold vacuum in ranges depending on which switches were open/closed.
Codes could be read by counting blinks of the engine dash light. It may have had the underhood test connector like EEC-IV did, I can check that, I have an Actron code reader that blinks/beeps, I think it may have mentioned that it works with MCU also. Somewhere I had to trigger the test, a bent paper clip, so I'm thinking it had the test connector. When I had the car, I did not have any code reader then. Mine always blinked out the code for "lean", no matter what I did.
When I had it, I had to pass a two speed idle sniffer test every year. Right before the test, I would unscrew the stepper motor from the side of the carb, free its plunger up with a bit of Gumout, put it back in, and go for the test. Always passed, with a good margin, too.
ctubutis brings up an excellent point... how do they know the MCU is bad? Good chance they don't have a clue, and point to a part they don't understand as the culprit.
EDIT - Oh yeah, there it is! The test connector. Its gray, just to the viewer's lower left of the MCU in the pic above. Same test connector as EEC-IV, just Gray rather than Orange
We had a guy named Ralph here who had this setup, he was someplace in the northern half of California IIRC. I miss him.
As for pulling the codes, yes, I also see the connector, at one time there was a YouTube video of some guy pulling codes on this kind of system but on a Lincoln sedan. Most likely the code definitions & procedures will be the same as those used by the later EEC-IV system, this stuff evolved over time and that would be my opinion.
I'm not sure what question we are trying to answer. However, if you remember I said that you have one of two Calibration #'s - either 3-51R-R10 or 3-51S-R10 - both of which take the same computer. And your carb # fits perfectly as both use the same carb - E3TE-GA, which is what you have. So, as shown below, you need computer E3TZ-12A651-B1A or B2A, both of which go under the Motorcraft # DY-432.
So it sounds like the part that would work is obsolete....
Originally Posted by Gary Lewis
I'm not sure what question we are trying to answer. However, if you remember I said that you have one of two Calibration #'s - either 3-51R-R10 or 3-51S-R10 - both of which take the same computer. And your carb # fits perfectly as both use the same carb - E3TE-GA, which is what you have. So, as shown below, you need computer E3TZ-12A651-B1A or B2A, both of which go under the Motorcraft # DY-432.
I'm not sure what question we are trying to answer. However, if you remember I said that you have one of two Calibration #'s - either 3-51R-R10 or 3-51S-R10 - both of which take the same computer. And your carb # fits perfectly as both use the same carb - E3TE-GA, which is what you have.
So, as shown below, you need computer E3TZ-12A651-B1A or B2A both of which go under the Motorcraft # DY-432. Where did you get these part numbers from? They are incorrect. Neither is shown in the Calibration parts list.
The part number is: E3TZ-12A651-T .. Engine Air Fuel Ratio Control Assy (Motorcraft DY-432)
This is the same part number I listed in post #15.
I took the ID number off the original (E3TF-12A651-B1A - pictured in post #1), crossed it over using this chart:
So it sounds like the part that would work is obsolete....
Yes, about everything on these trucks is obsolete. But that doesn't mean you cannot find one. Maybe used, but if it hasn't been damaged it'll work as well as a new one.
And with some simple test equipment, like an analog volt meter, run the MCU self-test as per manual with engine off, then again with engine running, to acquire the MCU Service Codes. Then follow the manual to run through the appropriate Quick Tests. The E/ED manual will be much much more in-depth than the little book that comes with any aftermarket code reader that can read MCU will be!
Note -- for the 1983 model year, be sure that the word TRUCK is on the cover of the E/ED, and it is not the CAR-only version. Prior to 1983, both car and truck were combined in one E/ED. But by 1983, the cars and trucks were starting to diverge emissions equipment-wise, so they split the manuals into separate CAR and TRUCK E/ED manuals. But have seen a combined CAR-TRUCK manual, too. But a 1983 CAR-only E/ED would be of no help for this truck.
The enterprising person would also have the print-out of the failed emissions test in their hand, as that should show the test conditions, test limits, measured values, and highlight the parameters failed, and by how much.
I really doubt that one would be so lucky as to find multiple mechanics that know anything useful and correct about the MCU control system of 34 years ago. Would be extremely lucky to find ONE still alive, and still in the business!
I unfortunately have a 1982 van with this MC also. I guess that means at one point this van had a Feedback carburetor and all of the BS that goes along with the EEOC system. Problem is it has all been dismantled. The smog pump is gone, the charcoal canister is disconnected, the O2 sensor is disconnected, and I don’t know if this computer is even connected anymore. All I know is that it runs like crap and very very rich fuel mixture that it smokes and coughs. The good news is in my state I can get a cast classified as a classic automobile and I don’t have to pass emissions, I just don’t know how to get it running and idling right now without all of the system. I should add that it now has a non-feedback carb on it and a distributor with the vacuum hose. Any and all insights on how I should proceed to fix the idling and running rough and smoking problem would be helpful
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