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tpi distributor

Discussion in 'The Garage' started by PeteH, Jan 5, 2006.

  1. PeteH

    PeteH 1/2 ton status

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    i'm putting tpi on my pretty much stock truck(84 engine). except i dont have a distributor. the wiring i have right now is set up for 85 tpi dizzy with the coil in the cap. would it be best to go to the junkyard, get a tbi dizzy(4 pin 6 pin ...?) and just connect the harness(connectors are different but nothing i cant find at the store)...or should i just get the external coil dizzy and just redo the wiring from my harness(i head it gives better throtle response)..

    also does anyone know what i need for the mechanical vss.
     
  2. NoSmog73

    NoSmog73 1/2 ton status

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    I would go with a small cap dist and external mounted coil (90 Camero) just for the firewall clearance since you dont have the dist yet anyway..
    And IIRC you need a 4k VSS ..
     
  3. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    Pete -- I would highly suggest upgrading from the 85 wiring / computer. The 85 setups use a 1 year only computer, and it is far from being totally reliable. it is a very easy upgrade to an 86 ECM, simply needing a `165 ECM, a few relays, and a bit of wiring changes.

    You can find details on the swap here: http://www.eecis.udel.edu/~davis/z28/ecm_swap/

    If interested -- I've got a few spare `165 ECMs sitting around here, both work fine. One has a chip, but I am not sure what it is for, so you'd probally want to buy a new chip for the engine you are building. You can have them fairly cheap. I can also include the connectors for you. As far as the relays go, I'd encourage you to use a set of mini-cube relays from Bosch rather than the big nasty looking things a stock TPI car used. They are far cheaper to replace, and are likely more reliable.

    You can find them fairly cheap, along with handy connector bases that clip together to space the relays out nicely at http://www.partsexpress.com/ -- They have excellent prices, regular specials, and good shipping prices. My package arrived in good order, and in very good time.

    You can use whichever distributer you wish with the TPI setup -- in cap, or external coil. I've used both, and less a connector change, they are totally interchangeable.

    Being an 84, your VSS is very easy to solve. Simply use the signal output from the green boxed optical sensor that is bolted to the back of your speedometer. It has several output pins that send out a 2k ppm signal that the 85 and `165 ECMs need, along with your cruise control.
     
  4. PeteH

    PeteH 1/2 ton status

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    sorry i wasnt very specific... its going in my truck(75) with my already carbed 84 motor.
    the tpi stuff is pretty much 85, but some newer year stuff too. so manifold hole enlarging is not a problem.
    anybody know when they changed over to roller cam? because if i get a dizzy thats setup for that then i have to get a new gear too.
    so i guess if i buy the smaller dizzy then i have to change the gear? didnt it only come in ones with roller cam?

    oh the wiring i have is setup for the 730 comp and the 4k pulse wire
     
  5. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    Cool, sounds like you are set up pretty good!

    I'm not sure about that rumor of the different gears. I've got a 89 305 dizzy in my 73 engine, and I've had no problems. Infact, I tried to put the gear from the 350's old regular big cap HEI, and the gear didn't fit on the shaft. It wobbled around, and would have shredded the cam up in no time.

    As far as 4 pulse signals go, you again have an easy (but more costly) option, and a more difficult option.

    The easy option is to buy a 4 pulse signal generator that goes between your tranny/t-case and speedo cable, then just run the signal straight to the ECM

    The more difficult, but far cheaper option is to have someone modify your 730's chip to change the VSS input type from the 4 pulse mechanical input, to the 2 pulse optical input. The 730 was used in many different cars, and can support either type of VSS input. You could then use the green optical VSS that is bolted to your speedometer.
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    4 pulse didn't come out until '90-91 IIRC. '85-89 are the same 2 pulse as the trucks for sure.

    Roller cam issue had to do with aftermarket cams as best I can understand. I have never heard anything saying that the stock distributors used a special gear. Roller cam introduction in cars was '87.
     
  7. PeteH

    PeteH 1/2 ton status

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    wow forgot to reply to my thread... well i'm gonna go the easy route and get the vss that ies into the speedometer and straight to ecm..

    as for the distributer, i'm going for the smaller( for the obvious space isuues.)
     

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