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  1. #1
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    Default 85gt cfi vert. EXTREMELY cold natured

    Nature of the beast or is there something i can do? It wont fore and idle and i dont stay with it for a minute or teo and hold steady rpms. After that it will idle but low and rough and after 5min or so it idles normally. Everything is oem and untouched which surprised me.

  2. #2

    Default

    Trying to decipher that post is not easy. If I were you I would look at the cold engine throttle cam on the passenger side of the cfi. When the engine is cold and you put the throttle down to the floor and let off before you start does the cam catch nd hold the throttle open?
    1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
    Hooker Super Comp Shorty Equal Length Headers
    GT40 heads, Edelbrock 3721, K&N filter in stock dual snorkel,
    Comp cams XE254H, hypereutectic pistons, catted BBK H-pipe, full custom duals.
    3.73 rear. CS5 225/60/15 on 10 holes (street) Federal 595 rs-rr 225/45/15 on 10 holes (race)
    Everything else stock and fully functional.

  3. #3
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    Default

    Sorry. Fat thumbs and an iphone and didnt catch all the mis types. Ill take a look at that and see

  4. #4
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    Default

    First, are you starting it correctly? It needs to be started like a carbureted car!
    Fox Body/3rd Gen MCA Gold Card Judge
    84 SVO 24K miles, 85 Mclaren Capri Vert. 84 GT Turbo Vert.
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    15 F150 FTX Tuscany, 16 F250 Crewcab, 67 Tbird 47K miles

  5. #5

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    Yeah, but you don't need to keep pumping it
    1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
    Hooker Super Comp Shorty Equal Length Headers
    GT40 heads, Edelbrock 3721, K&N filter in stock dual snorkel,
    Comp cams XE254H, hypereutectic pistons, catted BBK H-pipe, full custom duals.
    3.73 rear. CS5 225/60/15 on 10 holes (street) Federal 595 rs-rr 225/45/15 on 10 holes (race)
    Everything else stock and fully functional.

  6. #6
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    Default

    Treat it as a true carb?? As in pumping the piss out of it before starting. Umm no

  7. #7
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    Default

    No, carbs are started by pressing the pedal to the floor once to closed the choke and to set the fast idle cam to on position. I forget if you need to press the gas pedal again slightly while cranking.

    Pumping does nothing as there is no accelerator pump on the cfi.
    Fox Body/3rd Gen MCA Gold Card Judge
    84 SVO 24K miles, 85 Mclaren Capri Vert. 84 GT Turbo Vert.
    88 Mclaren Mustang Vert 20K miles, 89 Mustang LX Sport Vert, 92 GT Vert.
    03 Mach 1 7900 miles, 74 Mustang II, 69 Mustang, 67 Mustang, 14 Mustang CS/GT,
    15 F150 FTX Tuscany, 16 F250 Crewcab, 67 Tbird 47K miles

  8. #8
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    Default

    Ok that makes sense. Ill try that in the am. I usually do give it a pump just out of habit from my jeep

  9. #9

    Default

    Yes, the single push to the floor is critical. Mine sometimes sets itself but rarely. After it is warm it doesn't matter of course. Then just turn the key... I am glad mine came with the owners manual. I never would have suspected until I started working on the cfi.
    1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
    Hooker Super Comp Shorty Equal Length Headers
    GT40 heads, Edelbrock 3721, K&N filter in stock dual snorkel,
    Comp cams XE254H, hypereutectic pistons, catted BBK H-pipe, full custom duals.
    3.73 rear. CS5 225/60/15 on 10 holes (street) Federal 595 rs-rr 225/45/15 on 10 holes (race)
    Everything else stock and fully functional.

  10. #10
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    Default

    Appreciate the heads up guys. Hope its just user error lol.

  11. #11

    Default

    I should warn you, cold idle initial rpm will jump up to 1500 to 1800 depending on the set screw so be prepared... It automatically kicks off that in 30 seconds or so. Then it will sit around 1100 to 1200 slowly dropping till the engine warms. If everything is working correctly warm idle in park will be 800ish and in drive 550.
    1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
    Hooker Super Comp Shorty Equal Length Headers
    GT40 heads, Edelbrock 3721, K&N filter in stock dual snorkel,
    Comp cams XE254H, hypereutectic pistons, catted BBK H-pipe, full custom duals.
    3.73 rear. CS5 225/60/15 on 10 holes (street) Federal 595 rs-rr 225/45/15 on 10 holes (race)
    Everything else stock and fully functional.

  12. #12
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    Default

    No worries there. Ive been holding it at 1500-1800 for a minite till it will idle under its own power. If i just fire it up itll die. Had an 85 tbird with the same setup but never had this issue. The car did sit stored for several years before getting new life breathed into her.

  13. #13

    Default

    Well, give it a try. Code reader would be my next move.
    1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
    Hooker Super Comp Shorty Equal Length Headers
    GT40 heads, Edelbrock 3721, K&N filter in stock dual snorkel,
    Comp cams XE254H, hypereutectic pistons, catted BBK H-pipe, full custom duals.
    3.73 rear. CS5 225/60/15 on 10 holes (street) Federal 595 rs-rr 225/45/15 on 10 holes (race)
    Everything else stock and fully functional.

  14. #14
    FEP Super Member xctasy's Avatar
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    Default

    A CFi is a fuel injection system that fits on a 2-BBL Motorcraft or 2-bbl Varaible Venturi intake 3.8 or 5.0. Its a hybrid twin point EFi system that heralded in Multiple Port EFi. Don't under estimate Fords latent smarts with this system.

    Ford had about 13 different kinds of calibration on the 5.0 2-bbl looking CFi from 1980 to 1985.

    They are really different in detail, with two kinds of ECU (EECIII or EECIV), three kinds of throttle body (small or large, with all the large ones missing IAC, and some of the smaller ones with different kinds of TPS signal).

    The TFi ignition system is linked to a higher degree on the 5.0, and it operates similar to the old 1980-1984 Duraspark III found on the earlier CFi 5.0's. The program codes were copied over from the 80-84 5.0's into the new TFi ignition, and the 5.0 HO is very special in how it is controlled.

    The CFi's for 3.8's have another kind of idle control system,a traditional IAC.

    The HO 5.0 CFi has only the throttle kicker and the choke looking device.

    The operation of the TFi EECIV 5.0's found in auto 5.0 84's and 85's is different to the other CFI 5.0'S.

    IIRC, some Califonia 84 Tbirds were still EECIII, and a 1985 3.8 CFi isn't the same as the 1984.5 or 1985 5.0 High Output CFi, or the other Standard Output CFi's found in the 140 or 150 hp 5.0's in the Cougar, LTD, Tbird or Lincoln Mark VII Conti or Mark VII LSC. Each has different important key points.

    The idle speed speed variance is a result of many other things, including the 6 degree ignition timing "Tip in" the 84.5/85 ho 5.0 CFi auto's have to control idle.

    The HO has a much, much looser 2350 rpm converter, all the other 5.0'S have 1650 rpm. A 5.0 auto 84.5 or 85 5.0 Capri or Mustang just ambling along on the curb idle can flare up and down RPM wise without the vehicle speed changing much. The other thing is the AOD has a ideal line pressure, which changes the way the car picks up first, and the rpm under load. The application of the hand vac pump setting at Point "A" as per the hood VECI diagram controls the idle pull down, and its all very complicated to understand what alters what from a cold start to full warm up in the first 5 to 10 minutes.

  15. #15

    Default

    "he HO has a much, much looser 2350 rpm converter, all the other 5.0'S have 1650 rpm. A 5.0 auto 84.5 or 85 5.0 Capri or Mustang just ambling along on the curb idle can flare up and down RPM wise without the vehicle speed changing much. The other thing is the AOD has a ideal line pressure, which changes the way the car picks up first, and the rpm under load. "

    That is interesting... I did not know, but I think I did notice that. I just haven't driven anything else with a 5.0 aod but my old 86 f150 with an AOD and that was decades ago.
    1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
    Hooker Super Comp Shorty Equal Length Headers
    GT40 heads, Edelbrock 3721, K&N filter in stock dual snorkel,
    Comp cams XE254H, hypereutectic pistons, catted BBK H-pipe, full custom duals.
    3.73 rear. CS5 225/60/15 on 10 holes (street) Federal 595 rs-rr 225/45/15 on 10 holes (race)
    Everything else stock and fully functional.

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