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  1. #1

    Default T5 Swap in 84' T-bird complete, car will not crank

    I have recently converted my Thunderbird from the AOD to a t5 out of a 88 mustang gt. Everything is hooked up excluding neutral sensing switch and reverse light harness. (Wanted to make sure the car strarted before I did any permanent wiring.) The car has power and all electrical devices power on, but the car won't crank. I have been researching the Clutch Safety Switch as the possible culprit, but I cannot find the two plugs that plug into my pedal assembly. (Out of a 89 mustang.) I have searched under the dash for hours and am convinced these wires do not exist on 5.0 automatic thunderbirds. I currently have the aod transmission harness plugged in and have the 2 Crank and Park wires jumped. Still no crank. Is there a way to bypass the clutch safety switch without having access to these two plugs? I havent tried jumping it from the solonoid yet but i've been under this car for over a week and want it running. Am I better off trying to source a manual transmission harness?

  2. #2
    FEP Senior Member
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    You need to find the neutral safety switch wires at the transmission and jump them, to get it to crank. As for the clutch pedal wires, they will need to be added, tied into the transmission wires you jump. Jumping the wires will allow you to get it to crank, but will need to be run to the clutch pedals and wired through that switch to be right and safe.

  3. #3
    FEP Senior Member
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    Jan 2011
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    I don`t know about the AOD cars, but I converted 2 Fairmonts from C4s to T5s, and the neutral safety switch was bolted to the transmission case on the drivers side, and there was a 4 prong plug that passed thru the trans tunnel, about 10-12 inches behind the gas pedal. 2 wires were for the neutral safety operation, the other 2 for the reverse lights. The T5 trans will have a switch on the drivers side of the case, to operate the reverse lights, on the other 2, I just made a short jumper wire to bypass the neutral safety. Since the 78 and 79 Fairmonts did not have a clutch safety switch, I seen no need to add one. I have been driving manual transmission cars and trucks since 1973, and out of about 15 different stick shift vehicles, only 3 were new enough to have came with a clutch safety switch, never has been any issues not having a clutch switch. Just be certain that you are jumping the correct terminals to make the starter engage.
    1978 Fairmont 2 door sedan, 428CJ 4speed. 9.972ET@132.54mph. 1.29 60 foot
    Replaced the FE big block with my 331/4 speed in my Fairmont, best 10.24ET @128 MPH.
    1985 Mustang LX hatchback NHRA Stock Eliminator 302 4 speed best in legal trim 12.31@107 mph, but has gone 11.42@115 with aftermarket intake, carb, and iron Windsor Jr. heads.New for 2012! 331 cube SB Ford, AFR 185 heads, solid flat tappet cam, pump gas; 10.296ET@128.71 mph, 1.37 60 foot.
    1979 Zephyr Z7, all original 302 auto, 2nd owner.

  4. #4

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    Quote Originally Posted by dynodon64 View Post
    You need to find the neutral safety switch wires at the transmission and jump them, to get it to crank. As for the clutch pedal wires, they will need to be added, tied into the transmission wires you jump. Jumping the wires will allow you to get it to crank, but will need to be run to the clutch pedals and wired through that switch to be right and safe.
    Yeah, this is what I did. I believe auto cars got somewhat different harnesses than manual cars. Mine has a '90 Mustang auto harness and when I converted to manual, at first I used the NSS circuit to the NSS on the trans like as if it was an auto (confused the guy at Tires Plus with that one ) and had no clutch safety switch. But I later took the NSS circuit and ran it to the clutch safety switch instead. Does the job!
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Focus ST
    '14 Ford Fusion SE Manual

  5. #5

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    As of now the car cranks but won't fire. I have fuel pressure at the throttle body and spark. I'm thinking that the crank sensor is to blame since my tach is showing no rpms while cranking. Any pointers?

  6. #6

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    Run codes.

    Nothing in the transmission has anything to do with running.
    2 1986 cougars (both 4 eyed and 5.0)
    1 1987 cougar

  7. #7

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    Quote Originally Posted by Thomas8497 View Post
    As of now the car cranks but won't fire. I have fuel pressure at the throttle body and spark. I'm thinking that the crank sensor is to blame since my tach is showing no rpms while cranking. Any pointers?
    How did you solve no-cranking to cranking now? I presume T-Bird's got CFI? How/where did you check for and find spark? Car ran okay prior to the transmission swap? What else has been done with the car? Distributor moved or out? You mean the Hall Effect sensor? If applicable, run KOEO for any codes, but I'd check all the fuses, the fusible links, the ignition connections at the coil and distributor, the cap'n'rotor, and the coil and plug wires for continuity, before throwing sensors at it. FWIW, I don't believe my tach moves at all while cranking either.
    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/

  8. #8

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    I solved the cranking issue by jumping the two neutral safety wires on the aod harness and plugged it back in. My car does indeed have cfi. Ran fine before the swap. Checked for spark at number 5 cylinder plug wire. Other than the swap the car is stock. Didn't touch anything else during the swap.

  9. #9

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    Grounds from firewall/elsewhere to bell housing bolts?
    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/

  10. #10

    Default

    As of now, I got the car running. (Gas tank was bone dry... I took some heat from the guys for that...) Took the car out a few nights ago to test everything and she shifts smooth.

  11. #11

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    Great news!
    Brad

    '79 Mercury Zephyr ES 5.0L GT40 EFI, T-5
    '17 Ford Focus ST
    '14 Ford Fusion SE Manual

  12. #12

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    Hows the power? My 87 tbird was way different. I could spin all the way through first and half way through second. With the auto I could barely spin a tire in gravel. Second I hit pavement the tire would hust stop. Not even a chirp.
    2 1986 cougars (both 4 eyed and 5.0)
    1 1987 cougar

  13. #13

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    The power is exactly what I'd expect 140 to the crank to feel like haha. Next step is a carb conversion and possibly some aluminum heads!

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