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New 700, lock up options...

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by ftn96, Apr 19, 2001.

  1. ftn96

    ftn96 1/2 ton status

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    Option 1, put it in and have lock up only in 4th with big cooler

    Option 2, have Swap wiring harness from old so ECM can control lock up with option to cancel lock up, with big cooler.

    The main reason Im asking is that when I get around to the motor swap I was debating removing all computer controls.

    Help me brothers...oh and sisters

    Will work for beer, parts and tools.
    90 Jimmy 350TBI-700R4-241-33" BFGs-10 bolts w/4.10's
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     
  2. Wheels

    Wheels 1/2 ton status

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    Two companies that I would recommend are Painless and Fitzall. B&M has a lockup kit that is more pain than its worth. TCI makes one also. The recommendations that I got was the Painless wiring kit. It has a solenoid and harness that goes into the valve body and TCC lockup on the pump. There is a 3-4 pulse switch that monitors 3-4 upshift and completes the circuit for the TCC to lock up. The brake switch is replaced with a dual contact switch (fit mine with no modifications) and a vacuum switch that completes the circuit when engine vacuum stabilizes (cruise). Real simple to install. The only mod that I did was to add a second switch (dash mounted) in line with the circuit (brake switch side). When mine went to lockup, if the tranny wasn't warm enough, it would jump in and out of lock up a couple of times. I looked at another option to run a thermostat controlled vacuum switch in line with the vacuum hook up (this is the signal to send the torque convertor to lock up) but the engine temp will run up faster than the transmission temp and would still cause it to jump in and out. The Fitzall kit is basically like the Painless kit. Painless ran $140. Didn't price the Fitzall kit.
     
  3. ftn96

    ftn96 1/2 ton status

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    Wheels, I have the TCI 700. It came with their universal wiring harness. It can give me lock up in forth only or I can control it manually in 2,3 and 4th.
    Or I can swap out the old harness to allow computer control.
    I wouldn't really mind the 4th only other than gas milage and heat. But with a big cooler. The heat wouldn't really be a problem. I would just be worried about the life of the clutches.
    But I guess I could get a different lock up kit.

    Will work for beer, parts and tools.
    90 Jimmy 350TBI-700R4-241-33" BFGs-10 bolts w/4.10's
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     
  4. Blue85

    Blue85 Troll Premium Member

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    Now why would you want to get rid of all computer controls?

    To with Option 2, use the ECM harness and let the computer do what it was designed to do. Leave the computer in and enjoy the many benefits of you EFI.

    <font color=green>"MAN THOUGHT HURT BUT SLIGHTLY DEAD" --Providence (R.I.) Journal</font color=green>
     
  5. ftn96

    ftn96 1/2 ton status

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    Blue, that is what my gut is telling me to do. But even though I work in the computer world, I still trust good old mechanical means of operation and control. But on the 90 models, the computer doesn't control a whole lots like the ones these days. I was just thinking in the future about swapping in a preformance motor and most of them as far as I know are geared toward pre-computer control.
    But Im not a real engine performance know all.
    But I think I will keep the computer control.
    My next question is, if you can help me..... is what would be the difference in the 4th gear pressure switch that came in the new tranny and the one that is in the old one?

    Will work for beer, parts and tools.
    90 Jimmy 350TBI-700R4-241-33" BFGs-10 bolts w/4.10's
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     
  6. Blue85

    Blue85 Troll Premium Member

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    If you swap to a performance motor, you can always get a custom chip for that engine and use the same TBI. If you start running out of fuel delivery, you can get bigger injectors and/or a different pressure regulator to increase the fuel pressure.

    As far as the pressure switch, I'm not really sure what your question is. If both transmissions have a 4th pressure switch, they are the same thing, in the same place on the valve body. I have the wiring diagrams for all of the 700 R-4's, but I'm not sure which one the early TBI trucks used. I think that it used the 4th gear pressure switch as a signal to the ECM, but the ECM always has direct control. One neat thing about this is that you can wire a switch to lock your converter in any gear to increase compression braking when you want it to. However, the converter clutches are kind of wimpy compared to the "real clutches" in the transmission. You can't put a whole lot of torque through it.

    Does anyone have details on the wiring and which switches are present in a '90 transmission?

    <font color=green>"MAN THOUGHT HURT BUT SLIGHTLY DEAD" --Providence (R.I.) Journal</font color=green>
     
  7. ftn96

    ftn96 1/2 ton status

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    Well, my questions is based on what TCI told me. They said for me to use the Computer controls I would have to swap out the wiring harness from the old to the new one and I would have to take my old 4th pressure switch out and put it in the new one. I'm assuming the new one has one in there. I was wondering what the difference in the 2 are. But hell there TCI 700 may not have a 4th pressure switch. Is the 4th pressure switch in the pan on outside?

    Will work for beer, parts and tools.
    90 Jimmy 350TBI-TCI 700R4-241-33" BFGs-10 bolts w/4.10's,
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    Well, thats not true. Spark advance, lock up, emissions purge, mixture and probably a few other things are controlled by the ECM.

    So basically dumping the ECM means=loss of lockup (possibly) and mandatory change to a non electronic carb and distributor. (unless you buy an aftermarket wiring setup if someone makes one, which does not accomplish anything over the stock setup) Maybe even increase of emissions since anything related to computer at that point would be dead.

    ALTHOUGH on the trucks, I'm not sure when they went from having a standalone computer for the TCC, to integration with the ECM...probably when the trucks got mixture control solenoids and TPS in the carbs, if ever, or when they went to TBI.

    I would definitely stick with stock. 4th gear switch thingy is all Blue : )

    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
     
  9. Blue85

    Blue85 Troll Premium Member

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    I don't think that the trucks ever got the electronic carbs. I know that the cars got them all through the early 80's, but I have never heard of a "dancing needle" carb in a truck.

    I'm still not sure a 1990 transmission had a 4th pressure switch. Some ECM 700's didn't have any wiring inside except for the solenoid. Others used a 4th pressure switch in series with the brake pedal, which in turn was all parallel to the ECM signal. There is also one setup where the 3rd or 4th pressure switch gives positive to the solenoid and the ECM grounds it, some of which use the 4-3 downshift switch to disengage the solenoid, as well. If you do open that tranny, please take some notes as to the wiring, because a lot of late model k5 guys on here are having lockup issues. All you need to do note on which end they are mounted (only the TCC pressure switch was ever mounted on the front end of the valve body), approximately what position and where each of the wires goes, including the letter of the connector terminal.

    All of the pressure switches are on the valve body, inside the pan, although they can be mounted aftermarket in the pressure test ports, outside the case.

    <font color=green>"MAN THOUGHT HURT BUT SLIGHTLY DEAD" --Providence (R.I.) Journal</font color=green>
     
  10. ftn96

    ftn96 1/2 ton status

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    Man now you all have me really confussed. Im gonna go take the digi cam out there and take the pan off the new one and post some pics.

    Will work for beer, parts and tools.
    90 Jimmy 350TBI-TCI 700R4-241-33" BFGs-10 bolts w/4.10's,
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     
  11. CrazeeBush

    CrazeeBush 1/2 ton status

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    I don't know how much help I'll be, but when it came time to rip off my computer controls, I thought that the comp[uter controlled lockup on mine as well. NOT TRUE. granted mine has a carb. There is seperate wiring on mine to control lockup. We can get together and compare the wiring differences one day if you want. I'll be in town this weekend if you wanna gimme a call, not sure what I'll be doing, but if I'm free I can help.

    BuSH

    -JoSH
    crazeebush@aol.com
    <A target="_blank" HREF=http://josh.coloradok5.com>http://josh.coloradok5.com</A>
     
  12. redbeast

    redbeast Registered Member

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    My 85 has a 305 with a mixture control solinod ( dancing needle ) on the a quadrajet. it also has a knock sensor as well as a ecm to control the mixture and spark advance but thats all it controls.. I have swiched my tcc control to manual control that way I can control the lockup not the governer or tv circuts in the transmission..I also put a vaccum switch in line to kill tcc under low vaccum ( WOT ) conditions.. jus my .02 cents worth to the topic... RG.......

    1985 Blazer, 305 soon to be a TBI 350, 700r4, msd ign, 3.43s, headers, 31x10.50x15s
     
  13. Wheels

    Wheels 1/2 ton status

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    With the TCI kit in there you may have all the you need for right now. If you want to manually run the TCC, you may need a vacuum switch that runs off engine vacuum or you can bypass this and run a switched (ignition) 12 volt wire down to the tranny. Run it from the fuse box, to the brake switch (NC contacts) to the dash switch, then down to the tranny. If I remember right the TCI solenoid is internally grounded so all you'll need is the 12v switched source. As far as the wiring in the TCI tranny it will be different from your original tranny. There are about 23 different setups and depending on the year and model of the original tranny will depend on the wiring schematic. Most run a 4th clutch lock up signal while some incorporate a 4-3 downshift etc. Either way they all show pin A as the 12 volt input. Some dont use B, some use B but not D, some use all three. Hope this helps.
     
  14. ftn96

    ftn96 1/2 ton status

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    Well, you'll are gonna laugh at this. I talked to my dad last night and he gives me a great vote of confidence. He says Man why did you buy one of those pieces of $hit. You shoulda got a TH400. F the overdrive. Well, old man, its a little late for that advise. LOL!!!!

    Will work for beer, parts and tools.
    90 Jimmy 350TBI-TCI 700R4-241-33" BFGs-10 bolts w/4.10's,
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     
  15. dyeager535

    dyeager535 1 ton status Premium Member

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    Found this, although not sure this helps out at all. I think the TCC and pressure switch varied widely between the years, but its something. Shows how simple TCC is in the tranny. Bottom is 700. http://www.dorianyeager.com/index2.html
     

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