Results 1 to 3 of 3

Thread: GM '7427 PCM / Jeep Wrangler question

  1. #1
    Fuel Injected!
    Join Date
    May 2011
    Location
    Pocono's PA.
    Age
    50
    Posts
    370

    GM '7427 PCM / Jeep Wrangler question

    Have a Jeep Wrangler , SBC / 700R4 combo , '7427 PCM .

    Need to input a speed sensor to the PCM , I thought I have read somewhere that the '91 Wrangler VSS (the one with the cable pass through ) would output the correct PPM for the GM PCM , but I can't find where I saved the link . I will be using the 2000 PPM input on the '7427 like I do in my S10 V8 conversions.

    Does anyone have any idea if the Wrangler VSS has the correct PPM for the '7427 , or if there is a way to correct the siginal that the PCM would see from this sensor if it is the wrong one.

    Or should I just bite the bullet and order the JTR piece ?

    Thanks

    TOM
    1994 3500 Dually , 502 (509) , 264HR , Edelbrock MPFI , PFI '7427
    1992 S-10 434 SBC/Tremec - '7427
    1986 Monte Carlo SS
    1984 S-10 , SAS, 496/700R4/205 , D44/14BFF -'7427
    1980 Z-28 496/700R4
    1979 Corvette 496/700R4
    1977 Olds 98 Regency 403/700R4

  2. #2
    Fuel Injected! JeepsAndGuns's Avatar
    Join Date
    Sep 2011
    Location
    alabama
    Age
    41
    Posts
    1,702
    Dont quote me on this, but I think all YJ VSS's are 8 pulse. The 91 (one year only) pass through vss I think is a magnetic vss, while all the later ones are hall effect. But also I think all yj ecm's 91-95 interchange, so I dont know how that works.

    I am using the JTR 2 pulse VSS in my 79 cherokee with a 7427 pcm. I set the flag for "vss not from drac" or something like that, and it works just fine, speed reads correct. If you wanted to use the 8 pulse, I think you might be able to use one of those buffer/drac do-hickeys. I know they do something about taking a lager pulse count and outputting a lesser count. Hopefully someone on here that knows more about those can chime in.
    79 Jeep Cherokee, AMC 401, T-18 manual trans, hydroboost, 16197427 MPFI system---the toy

    93 Jeep YJ Wrangler, 4.0L, 5 speed, 8.8 rear, homebrew hub conversion and big brakes, hydroboost, 2.5in OME lift, 31x10.50's---the daily driver

    99 Jeep WJ Grand Cherokee limited, 4.0L, auto, 2wd, leather and power everything, 99% stock---the long distance highway ride.

  3. #3
    Carb and Points!
    Join Date
    May 2012
    Posts
    2
    I put a 91 4.3 TBI / 700R4 in my neighbor's 89 TJ, YJ, I don't know, but it had a cable-driven speedo. We replaced the speedo with an electronic unit from a later Jeep, and used the DRAC and VSS from the donor. I hooked the speedo to the speedo-output on the DRAC and it worked. Also calibrating the DRAC was straightforward as well, and easier than messing with gears and drive ratio adapters that are so often required on Jeeps with big tires. He had no trouble sourcing an electronic speedo, and it wasn't difficult to swap.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •