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  1. #26
    FEP Power Member fgross2006's Avatar
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    I want to ask if there a way to check the O2 sensor in real time while the motors running to see if its working or not?

    I know voltage fluctuates with rising temperature so if I back probe the voltage wire while the cars running what should I see? What's the range of voltage put out by an O2 on a 84 5.0?

    That's after I run a new wire from the connector to the O2. I still have to find a better path that keeps the wire away from the back of the motor

  2. #27

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    Check back this thread, post # 15, but in general, once warmed up, fluctuation should be above and below 0.5v, back probing with a multi-meter with the positive to the sensor's output and the negative to the battery negative...
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  3. #28
    FEP Power Member fgross2006's Avatar
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    Some new updates on this issue.

    I found 2 sellers that have both connectors I need for the male 2 prong connector and the female single blade O2 connector. Ill have them in a few days and will re solder all of them into place.

    I had tried the other day to run code reading on my car and the code reader acted funny. I thought it was shot so I got a new one. Today it gave the same result. When I connect it to the car and try to run a scan all the characters on the face light up solid and don't do anything else. I'm thinking now my ECM is failing because these code readers interface directly to the ECM through the 2 connectors in the engine bay.

    Look at this picture and tell me if this looks like the ECM is failing or at least not communicating with the scanners

    Attachment 116193

    Strange thing is that after re connecting and restarting the car a few times I did get the car to run a complete scan from start to finish. Ran three 11's with no codes at all. The car was actually running nice. Then just as the scan was finished the car hiccupped, surged for 1 second and the screen on the code reader went instantly to the way it looks in the photo above.

    I reset curb idle and drove the car for about a half hour with no problems. I'm thinking the ECM may be failing and that may be the intermittent bucking I have had happening lately. Which would explain why I have been having issues getting the ECM to communicate with the code scanners, 2 in a row. Any opinions?
    Last edited by fgross2006; 10-17-2017 at 06:07 PM.

  4. #29
    FEP Super Member xctasy's Avatar
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    I'd say a quick capacitor EECIV ECM test would be in order. That's what I'd do stat.








    But, you know, after Mike de CFi'd his 86, there was still the stock 02 sensor, which he checked using its original supply power and a multi meter.



    Quote Originally Posted by Walking-Tall View Post
    Remembered my camera can take video, and figured out how to do that today, enjoy, lol

    ~ Some AFR (mV from O2 sensor) video clips from today (don't mind the mess, we're testing gawldangit, LOL!)


    Idle, in Neutral and in Drive (14+:1):


    - Idles at 22"Hg (~650rpm) in Neutral and 19-20"Hg (~500rpm) in Drive


    Normal acceleration to 50KPH/30MPH (~15.5-16:1):


    - vacuum drops down to 8-10 with just normal acceleration, which is why the 8.5"Hg power valve was too soon


    Cruise @ 65KPH/40MPH (16.5+:1):




    Throttle blip on gravel, lol, and then a couple WOT's (~12.9-13.2:1)... on the lean side:


    - finally checked WOT after this with the pedal flat-on-the-floor and there was another ~1/4" pull required at the carburetor. So, in this video it wasn't actually going fully to WOT, which is also why it didn't kick down the 2nd time I trounced on it. I pinched a ~1/4" fishing line sinker onto the accelerator pedal end of the cable for that bit more pull. Now she opens wide.


    So yeah, I'm quite happy with her function, minus WOT. I'll feel better with PVCR's a bit bigger for ~12.5:1... to be continued...

    AFR vs voltage is



    They vary a little with modern oxygenated blends, and the EGR and down stream Secondary AIR alters the readings when cold or at cruise when warm too.

    What used to be 14.7 is now 15.1 at 0.50 volts

  5. #30
    FEP Power Member fgross2006's Avatar
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    Quote Originally Posted by xctasy View Post
    I'd say a quick capacitor EECIV ECM test would be in order. That's what I'd do stat.








    But, you know, after Mike de CFi'd his 86, there was still the stock 02 sensor, which he checked using its original supply power and a multi meter.






    AFR vs voltage is



    They vary a little with modern oxygenated blends, and the EGR and down stream Secondary AIR alters the readings when cold or at cruise when warm too.

    What used to be 14.7 is now 15.1 at 0.50 volts

    I was gonna back probe the connector and run the engine to get a reading but I guess rigging it up so I can drive the car and check the voltage while running would be even better.

    if the ECM is failing Id rather change it than try to open it up. I don't have that kind of skill set. But heres a vid I made of me trying to get the ECM to communicate with my Ford Code reader.
    I've been using this code reader as long as I have had the car. So I know what it looks like when its working. It starts out with three zeros to show its up, then the cursor blinks to indicate its linked to the ECM, then a number 8 should come up when it detects an 8 cylinder engine. Then a number 10 comes up at which point I snap the throttle all the ay, then it blinks while searching for codes.

    Right now the unit alternates between going blank, to a locked screen with all characters loaded, to briefly showing zeros but not starting the scan.


  6. #31
    FEP Super Member xctasy's Avatar
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    See below




    12.5 minute to 16 min mark, Koer

    Your ECM is not polling information to the 3145.

  7. #32
    FEP Super Member xctasy's Avatar
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    I'm with you on the skill set, my friend.

    I'd say its earthing out. The problem is techncially best sorted by the old break out box, and checking for the differences in voltages to the 60 pins. Its traditional to assume its the wiring into the ECU/ECM, not the unit itself, and that's the Standard Operation Procedure check.

    But I've seen lots of little things go wrong with them, and a quick, easy check is to quickly have it taken out by another, making sure you've got a begged, borrowed or stollen stnd in. Ok, maybee no stollen.

    If it were me, I'd ask around for a breakout box. Drop the 60 pin plug, and check the voltages.

    But its not me, so your right where Oberu was when his car kept taking a crap-out on trips.
    http://vb.foureyedpride.com/showthre...180792-A9l-ecu

    He ended up replacing the A9L ECU wit another one purchased off a forum member.

    The capacitors on the replacement one weren't too good either, but it runs and got him sorted.

    So network with other CFi-ers, and see if you can get the loadn of a stand in 84 ECU with the same batch code.

    Don't worry about the hassles, they recede when you get the basics right.

    Anyone here got a spare 1984 GT CFi ECU?

  8. #33
    FEP Power Member fgross2006's Avatar
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    Quote Originally Posted by xctasy View Post
    I'm with you on the skill set, my friend.

    I'd say its earthing out. The problem is techncially best sorted by the old break out box, and checking for the differences in voltages to the 60 pins. Its traditional to assume its the wiring into the ECU/ECM, not the unit itself, and that's the Standard Operation Procedure check.

    But I've seen lots of little things go wrong with them, and a quick, easy check is to quickly have it taken out by another, making sure you've got a begged, borrowed or stollen stnd in. Ok, maybee no stollen.

    If it were me, I'd ask around for a breakout box. Drop the 60 pin plug, and check the voltages.

    But its not me, so your right where Oberu was when his car kept taking a crap-out on trips.
    http://vb.foureyedpride.com/showthre...180792-A9l-ecu

    He ended up replacing the A9L ECU wit another one purchased off a forum member.

    The capacitors on the replacement one weren't too good either, but it runs and got him sorted.

    So network with other CFi-ers, and see if you can get the loadn of a stand in 84 ECU with the same batch code.

    Don't worry about the hassles, they recede when you get the basics right.

    Anyone here got a spare 1984 GT CFi ECU?
    Apparently this is a discontinued part. I spoke to cardone and they say they have none and no ETA when or if they will get more. Tried ordering on AutoZone and Advance Auto. both sites list it as available for home delivery only but when I try to order it kicks back saying none in stock.

    Amazon has one and 1 ebay seller lists one. The ebayer is half price of Amazon and lists it as a rebuilt but I have no way of knowing its rebuilt and not just old old stock

  9. #34
    FEP Power Member fgross2006's Avatar
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    Just to update this thread, I got very lucky and found both connectors I needed. I re used the original wires to the male connector out of the engine harness since they weren't damaged, just the connector was melted. I got a new female connector from local parts store and soldered a new wire for voltage and ran it behind the AC drier through a small hole I was just barely able to snake the wire through. I have no clue how Ford originally routed the voltage wire to the O2 without it touching the engine or exhaust pipes but letting it drape behind the motor was not good placement. On the underside of the car I zip tied the O2 connector to a stiffener brace. I put single strand wire loom the full length and it looks to be OK now.

    I fired up the car and checked the O2 status with a voltage gauge and 2 probes into the back of the O2 connectors voltage and ground lines. While I watched the car warm up to operating temperature I saw the voltage reading fluctuate between .950 to .035. There were times it spiked at about 1.05 and dropped to .005. But I ran to code scans and both came up all 11's.

    I do not know what the issue was the other day when 2 different scanners would not link with the computer but its not happening now and the car is running nice. I ordered a replacement ECM from eBay and if the symptoms of bucking happen again I will swap the ECM. There's no core charge on this purchase so I will keep the one I have and maybe send it out to Cardone to have it refurbished just to have a known good spare.

    I took 3 vidz of me checking voltage on the O2, I can post if anyone wants to see them.

  10. #35
    FEP Super Member xctasy's Avatar
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    Good man. Really good to hear. Glad you got another ECM.

    I'd love to see your videos.

    This is what I got told back in 1985 when I was discussing EEC with a Ford technician who fitted Propane Gas systems...he siad that any small voltage changes really upset the EECIV because its polling swinging voltage changes and then the didgital side takes over. You can't easily wreck whats inside, and its used to seeing 0 to 14.2 volt signals. The 60 pin plug sucks up all the systems sensors and its swinging voltages, and then the digital side of it "handles the racket".

    These days its the 3145 Code reader not pulling codes indicates something else earthing out. Most problems are three strikes and your out voltage related. The home run is when the digital side does the processing. It expects that the bases will be taking players on a regular basis. No balls and 3 strikes and your out indicate a sensor or wire problem.

    They say rocket scientists take short cuts, so do on board computer engineers, because at Ford, the on board computer systems and protocols were devised by the same people who lofted space craft and Patriot missles.

    If its not "polling", its likely to be an obvious connector. Block diagrams of what to check first don't always help out if the Diagnostic Trouble Codes cant even be feilded.

    I hope you are enjoying you ride. The 5 liter CFi Convertable has a lovely sound and a quirky, but "reachable" on board computer. You won't kill it.

    That system won't go off line like some of the feedback Carb Fords of the 1981 to 1985 era did, so keep persisting.

  11. #36
    FEP Super Member xctasy's Avatar
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    see Jeff Cook's notes on the three and four wire O2 sensors. The CFi computer differes for each.

    Quote Originally Posted by xctasy View Post
    JACook noted that the late CFi 5.0's had moved to an internal EECIV ECU controlled heated O2 sensor, so you can certainly fry something if the computer and O2 sensor aren't the same, its not just A9L's and Port EFi computers and O2 sensors.

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