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Thread: doesnt idle cold, hard start, IAC adjustment?

  1. #21
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    Quote Originally Posted by bootleggers deluxe View Post
    The fuel pump does run for 3-4 seconds and shut off, which i have considered a proper priming, but i guess i may be incorrect on this particular model.
    This is correct operation. It indicates the EEC has some life and is not a boat anchor.

  2. #22
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    I had some issues with the CFI on my '83 with a 5.0. Majority of the issues turned out to be the in tank pump faltering and when that was replaced it lived a few more years until the external pump started to die. I gutted all of it and went with a carbed 5.0 and a T-5.

  3. #23
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    click on my diy link and scroll down in there as well for specfic 87CFI info.

    although your ISC motor isnt showing signs of a pulse, i think you said you replaced it but........... there is another area that will cause poor running / idle.

    in the rear driver side of the cfi there is a gold vac line fitting about 2'' long bent at a 45deg.

    long story short,,, in all cases on all 3.8L CFI's in all instances where no one has been there yet,, get a CFI base plate gasket kit.

    remove CFI & EGR base plate.
    flip over the CFI and chip out all that crusty black buildup thats blocking off the path this vac line area needs to be open.


    Also,,
    someone mentioned testing fuel presure.....
    -connect fuel pres test up to the test port driver top left of CFI.
    -you need a long hose on your tester but.. duct tape the tester to your windshield. <per the shop manual.
    -drive care and pay attention to the fuel pres levels ""IN BETWEEN"" shifts of your transmissioin.
    -if during high rpm's during shifts the fuel pres gets anywhere close to 20psi,, replace the pump.

    *note - your CFI has a manual regulator. if its never been replaced then there will be a steel freeze plug on top. drill that out to reveal an allen head adjustment screw.
    see diy link below for how many turns CW or CCW = X amount of psi.

    on my old cfi car cured something that these cars were famous for right off the showroom floor. The shops had many complaints about "hesitation" off the line.
    customers complaining that they would push on the gas and for about a 1/2 second or so nothing happened and then the motor finally worked its way into working up the rpms. this is cured by removal of the CFI,, removing the four PITA phillups screws, removing poping out the injectors.
    start a sheet metal screw into the top of the injector then with pliars yank on the screw really hard. you will extract the tiny screen filter out of the injector.
    install injectors without the screens. test the car on the road and "hesitation Gone!"

  4. #24
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    i didnt forget about any of this, ive just been busy tryingto get my F350 back on the road so i can devote proer time to get the Tbird running properly!

  5. #25
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    The ISC motor is controlled by the EEC (Electronic Engine Control). When the ignition is turned off (and during a 5-10 second delayed dropout of the EEC power relay) the ISC plunger should extend to a fast idle setting for the next start-up.

    The ISC motor can be bench tested by applying battery voltage directly to the motor. The direction the plunger goes is changed by reversing the polarity of the battery voltage applied to the motor. If you still have the one you removed maybe you can play with it and see what it does.
    There are four wires on the ISC. Two are for the motor and two are for the ITS (Idle Tracking Switch).
    The connector drawing I added to the diagram is from the Shop Manual. You may want to double check it with your OHM meter to verify it.
    The ITS is operated by pushing on the ISC plunger tip.
    Attached Images Attached Images

  6. #26
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    ok guys, i got the F350 out ofthe shop and got some time to pull the Tbird in this morning. the findings are.... disheartening.



    so i went to tear out the throttle body and see about clearing out the passage that jcassity spoke of. heres the first issue i see....



    I'm pretty sure these wires at the front of the throttle body arent supposed to be bare.

    pulled the throttle body off, found this crap.



    yes, thats very wet.

    finally, checked that passage that goes from the driver's rear of the throttle body to the PCV Valve. very clean and free of debris. then i plucked up the EGR plate and found this.



    That entire passage is full of gasoline.


    Care to put some input in, peoples?

  7. #27
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    That's the fuel injector connector with the bare wires in your first pic.
    The red wire is battery voltage with the key on.
    If either of the tan wires has a bare spot touching ground, that will open the injector and let the gas flow.

    But I don't think that explains how the gas is getting into the PCV channel.

    The PCV valve has a hose on it that comes from the carbon canister that collects gas fumes from the tank. Pull that hose off and see if it has gas in it.
    I think you can pull the plastic piece off the top of the PCV valve that allows extra hoses. Then put the CFI hose on the PCV valve to take the canister out of the picture.
    Does the exhaust smoke like it is running rich?
    Last edited by softtouch; 01-15-2017 at 11:45 PM.

  8. #28
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    I finally fixed the idle on my Cat after reading this link, thanks to boomer for the pics and tips.

  9. #29
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    I have been having a lot of issues with this IAC, I currently can get it to retract but not extend by putting a hot jumper from battery to the yellow/black wire and the white/blue wire, Before replacing the relay under the dash I could not get it to do ANYTHING.
    I have checked fuses and replaced relays still nothing but Aggravation.

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