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Pulling a TPI from an Iroc this weekend, any tips?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 72Blazerod, Oct 24, 2001.

  1. 72Blazerod

    72Blazerod 1/2 ton status

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    The engine is still in the 1987 IROC right now. The deal is that I have to pull it. So what are ALL the pieces that I am going to need to take out? I don't want to forget anything because the car is about 800 miles away from my house. Where is the VSS and how do I get to it? Should I try to get the fuel pump out of the tank? Any other info or descriptions of bits and pieces would really be appreciated!!!!!!

    Thanks guys, you're the best!!!

    Rod

    <a target="_blank" href=http://communities.msn.ca/72BlazerodsOldChevyTruckPage/photoalbums.msnw>http://communities.msn.ca/72BlazerodsOldChevyTruckPage/photoalbums.msnw</a>
     
  2. BurbinOR

    BurbinOR 3/4 ton status

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    First off, make sure you get the computer, all sensors, and of course the hardware (intake, plenum, throttle body, MAF) and keep in mind those TPI intakes only bolt on to post-87 heads, so you may even want the heads off the donor car. VSS is not necessary if you don't want it, you can have a chip programmed to remove it from the circuit, as well as the anti-theft (VATS) circuit. The fuel pump you can either go in-tank or external in the frame rails, I have a Bosch part number if you need it. I continue to use my stock '79 fuel tank with an external pump with no problems. Are you getting the whole motor? Anyway, also make sure you get the distributor (as it is a computer controlled one that the TPI ECM uses to advance/retard based on knock sensor input). Hmm, what else........well, if you are getting the whole motor make sure you get everything attached to it. Don't know where the computer is on those cars.

    Anyway, probably a good idea to use an aftermarket wiring harness than try to get the factory one. They are easy to hook up and are all labeled. I used Painless Wiring.

    The other guys will fill in what I forgot..........[​IMG]. Good luck.

    <font color=blue>'79 ONE TON TPI K5 - See it at---&gt;<a target="_blank" href=http://www.blazzinor.rockcrawler.com>www.blazzinor.rockcrawler.com</a>
     
  3. walt88

    walt88 1/2 ton status

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    <a target="_blank" href=http://www.thirdgen.org>http://www.thirdgen.org</a>

    35" All-Terrains... I don't get it.
     
  4. muddin4fun

    muddin4fun 3/4 ton status

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    Yes, get a new wiring harness. The factory botched that especially that year (I have an '87 IROC and am fighting with an electrical problem).
    Is the car totalled or something? IROC's are a special car to me *sniffle* Especially an '87. It's the first year for TPI.


    Peace and stuff [​IMG],

    Muddin

    <a target="_blank" href=http://www.geocities.com/muddin4fun79blazer>www.geocities.com/muddin4fun79blazer</a>
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    Make the factory harness work. Removing sensors and input that GM deemed necessary is not the way to get TPI to run right. An engine running at 3500RPM in 2nd gear has different requirements than when running 5000RPM in 3rd....(In other words, fuel requirements at 35MPH are not the same as those at 70)

    With that said, pull everything that is in any way connected to the TPI system. I'm still learning this myself, (already sent the check for my '91 Camaro setup) but you will need the basic, obvious stuff like intake, distributor, and the ECM. Everything connected to those should go too.

    VSS is connected to the speedometer, and should be located under the guages. At least thats where most cars and trucks 80-87 got there VSS readings from, attached to the speedo head. I believe there are some aftermarket VSS setups that you can buy to make it work with your older vehicle. Whenever they started converter lockup in trucks (700R4 and 350C) would have been about when they started with VSS in trucks, so obviously, thats at earliest late 70's, early 80's speedo's that are set up to accept VSS.

    Again, don't cut anything, just take it ALL. Heads are an issue IIRC, as the intake bolt pattern will be different than yours, unless you are running newer heads. I believe in '87 you'll have the two center bolts on either side vertical, whereas my '74 motor has them angled like all the other intake bolts. I was hoping to set the TPI system up on my truck as it is now, and just change intake when I put the Vortec/roller motor in, but it won't work, and not worth buying an "adapter" TPI intake for short term use.

    Good luck! thirdgen.org should be a real good resource for you.

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?
     
  6. muddin4fun

    muddin4fun 3/4 ton status

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    Whenever my dig camara comes back, I can take a pic of whatever you need as it sat in the camaro. Just let me know what you need [​IMG]

    Peace and stuff [​IMG],

    Muddin

    <a target="_blank" href=http://www.geocities.com/muddin4fun79blazer>www.geocities.com/muddin4fun79blazer</a>
     
  7. Mr.Chevy4x4

    Mr.Chevy4x4 1/2 ton status

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    F.Y.I. - '87 wasn't the first year for TPI in the Camaro, some '86's had it but only with the 305.

    '85 K5 : Run it til it breaks, then fix it and go again!
     
  8. HarryH3

    HarryH3 1 ton status Author

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    Make sure to get the MAF sensor. It's the 5 inch long black plastic tube with electrical connections that's mounted in the air intake tract, between the throttle body and the air filter. A new one costs right around $400, so I don't think you'll want to leave that behind. [​IMG]

    Take every piece of the wiring harness that attaches to the engine. Most of the wires go directly through the firewall to the computer. But a few of them go over to the fuse block, to provide power for the EGR control valve, emission canister control valve, etc. Pull the computer harness as one piece. The grommet just gets removed from the firewall, then you can unplug the computer and carefully pull the harness through the firewall.

    I wouldn't bother with taking the fuel pump. It's a real PITA to get out of the CamaBirds and you don't want to install an old one anyway. (CamaBird: generic term for F-body GM cars. Camaro &amp; Firebird. Basically the same car, slightly different body panels and trim.) [​IMG] Get a brand new pump so you know what you're dealing with. It's well worth the money to know that you have a good pump that will work well for the next 100K miles or so. [​IMG]

    I'm running a TPI from an '87 'vette, but I think that the TPI on the '87 CamaBirds was slightly different. Look closely at how the EGR works. On the 'vette it uses a tube from one exhaust port to bring the gas back up to the intake. If it works like that on the CamaBird engines then you'll also want that exhaust manifold. You might even want both of them if you need for the AIR injection system to work properly.

    <font color=black>HarryH3 - '75 K5</font color=black>
    <a target="_blank" href=http://www.angelfire.com/super/ThunderTruck>www.angelfire.com/super/ThunderTruck</a>
    It's a great day to be alive...
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    BTW, pretty certain '87 was a "standalone" harness, so no VATS or anything like that to deal with. '87 setup being slightly easier to adapt.

    Just trace all the wiring, and pull every piece that every wire hooks to. heck, off the wall idea, maybe even pull the entire wiring harness including fuse panel. You could make that work on your vehicle, and most, if not everything, unplugs to make its removal possible as well.

    Better to get everything you need, (and don't need) now, than miss one thing that you do need, and pay dearly for the part (if you can find it) later.

    Another way to think of it...if you removed everything electrical and TPI related off of that car, and were able to magically just drop it in your truck, it would work EXACTLY like it did in the car. (minus the chip programming) THATS what you are striving to get as close to as possible.

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?
     
  10. muddin4fun

    muddin4fun 3/4 ton status

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    Sorry...I was thinking 350 [​IMG]

    Peace and stuff [​IMG],

    Muddin

    <a target="_blank" href=http://www.geocities.com/muddin4fun79blazer>www.geocities.com/muddin4fun79blazer</a>
     
  11. BurbinOR

    BurbinOR 3/4 ton status

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    Guess to each their own. You do NOT need VSS nor VATS to have a perfect running TPI. Why mess with an electronic speed control if you don't need to? Factory harness will work but I personally don't think it is worth re-using. Better in my humble opinion anyway to get a chip made for YOUR special application. The application is different that a stock IROC anyway (lighter, different gearing, probably different trans, etc., you get my point) that a better way to go is a chip with your truck in mind.

    Just my opinion and my TPI guy's opinion. He's done 130+ of these conversions.

    <font color=blue>'79 ONE TON TPI K5 - See it at---&gt;<a target="_blank" href=http://www.blazzinor.rockcrawler.com>www.blazzinor.rockcrawler.com</a>
     
  12. dyeager535

    dyeager535 1 ton status Premium Member

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    To each his own, you are right.

    These are some of the things that require a vss input
    TCC lockup (auto)
    Upshift light (manual)
    IAC position learning
    Cooling fan control
    Determine if manual transmission is in gear (compare VSS vs RPM)
    Disable some idle speed control if manual in gear (see previous item)
    Disable idle learn if moving
    Enable idle learn if moving with manual in neutral
    Prevent DecelFuelCutOff if manual in neutral
    Prevent DecelFuelCutOff at very slow speeds
    Top speed limiter

    Looks to me like VSS is needed. Computer will throw a code if you disconnect it obviously.

    VATS is obviously anti-theft, and since his is 87, is not present in the first place.

    "perfect running" used one too many words.



    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?
     
  13. BurbinOR

    BurbinOR 3/4 ton status

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    First off, thanks for the English lesson. You're gunna [​IMG] be busy if you start correcting grammar on this board, Dorian [​IMG].

    OK, last attempt here. I run a TPI motor, my builder has 130+ TPI motors out there, and none have VSS operational. It is NOT needed with a custom chip. I assure you, my truck does run, has a computer, throws no codes, and has no VSS.

    <font color=blue>'79 ONE TON TPI K5 - See it at---&gt;<a target="_blank" href=http://www.blazzinor.rockcrawler.com>www.blazzinor.rockcrawler.com</a>
     
  14. dyeager535

    dyeager535 1 ton status Premium Member

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    I won't bother with english lessons, that would be like me complaining about others typing.

    I'm not saying it can't be done. I'm not saying your motor doesn't run. I'm just saying that the setup is not running "perfectly", if "perfectly" means that it is operating the exact way GM set it up. I also was not implying that a custom chip won't throw VSS codes. You would have to be incredibly stupid to disable VSS and not come up with a way to conceal the code that it would throw. What I am saying is that VSS is important enough, that were you to take a perfectly running vehicle, with VSS, and unplug VSS, the vehiclke would throw a code.

    If grounding VSS and putting the TPI into limp mode is how your guy has done 130 setups, more power to him.

    I already posted all of the things VSS is needed for, (even if its not needed to RUN...rev your car in park, theres limp mode) and it is not an on/off proposition. Is the throttle always just open or closed? Of course not. So how exactly do you convert a variable sensor into an on/off function, without degradation of performance? (which is, again, what we are talking about, correct operation and performance, not just "it runs")


    If you think that Vehicle Speed means nothing to the TPI setup, and after what I have posted you still think that, it would appear that nothing I say is going to change that.

    I'm done discussing this, unless you can somehow explain how you can get rid of the VSS, which is necessary to all of the functions I already posted, and somehow still make all THOSE functions work as GM intended. And while you are at it, you might as well explain how the curve for air/fuel necessary ISN'T any different at idle than it is at 50mph, since the computer no longer knows how fast the vehicle is moving.

    BTW I don't use smileys just because I haven't bothered to learn how to use them : )

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?
     
  15. TUBE BODY BLAZER

    TUBE BODY BLAZER Registered Member

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    An 87 TPI system is a stand alone system. You need to remove all of the factory ECM harness starting at the ECM not the motor it is easier to locate all of the wires that way. There are other wires that enter the harness and pass through such as the starter and alternater circuts that can be cut but do not cut anything untill you verify where it is going. The ECM harness will come out in one piece. Do not forget to remove all relays and sensors attached. On the 87 system there are the following, MAF relay, MAF burn off relay, fuel pump relay, ignition control, and the MAF. All others are located on the intake and plenum.Remove the intake, distributor, coil, thermostat housing, and a few inches of fuel line where it comes out of the fuel rails to get the fittings. Don't forget the ECM diagnostic port under the drivers side dash. You will also need the kickdown cable if you use a 700r4 trans. Don't bother with the pump, I use an autozone inline pump part # E2000 cost $68.00 and a lifetime warranty. I have all the wiring diagrams for the TPI system and they are very easy to follow, no two wires are the same color in the factory harness.You do not need the VSS system, it is not part of the TPI system.As far as problems with the wiring system go, almost all problems with the TPI are traced back to the injectors. With a multimeter set on OHMS unplug each injector and test at the injector, 17 to 12 is ok, all values should be close to each other. Below 12 is junk over 17 is also junk. I have a supplyer for rebuilt injectors. A matched set of 8 is around $250, way better than $90 to $175 each. It is not as hard as some people (ie.PAINLESS) think and not worth $300 for a harness. Test injectors before you buy, the price should reflect it if they are bad. Good luck, if you need any help or diagrams E-MAIL me, it can be done inexpensively and smoothly. One more thing, if you dont have 87 or newer heads just open the holes up so it lines up, I ran mine like this for 2 years with no leaks, the bolt heads don't sit flat but work fine. If you want you could have the manifold machined but then it won't fit easy with the new style heads if you change motors at a later time. My fingers hurt :)
     
  16. TUBE BODY BLAZER

    TUBE BODY BLAZER Registered Member

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    I am sorry but you are wrong the VSS system is Not used in the 87 TPI system. The TCC lockup is controled by the ECM in 4th gear only, if you do not hook up the wire you will NOT get a code.The IAC motor is set by idle speed (distributor input )
    and throttle position.The cooling fan control is also through the ECM and is set at 220 governed by the temp sending unit, on front of manifold. The idle values are NEVER disabled just overridden by the throttle position sensor. VSS is useless for anything but 4L60E trans or as a speed limiter and is not used on anything pre 93. ( for engine control )


    <P ID="edit"><FONT class="small">Edited by TUBE BODY BLAZER on 10/25/01 12:42 PM.</FONT></P>
     
  17. HarryH3

    HarryH3 1 ton status Author

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    I've got a TPI from an '87 Corvette. Indeed it does have a VSS input and indeed it does set an error code if you don't have the VSS hooked up. That's a quite a few years prior to 1993. [​IMG] It also has the VATS, but I think that was a 'vette-only feature in '87. It didn't show up in CamaBirds until a few years later.

    There are companies that will burn custom chips that ignore the VSS and/or VATS inputs. Those chips won't set the check engine light for a missing VSS signal.

    <font color=black>HarryH3 - '75 K5</font color=black>
    <a target="_blank" href=http://www.angelfire.com/super/ThunderTruck>www.angelfire.com/super/ThunderTruck</a>
    It's a great day to be alive...
     
  18. TUBE BODY BLAZER

    TUBE BODY BLAZER Registered Member

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    In the vette the VSS runs the digital gauges not the trans or the top speed limiter, it is not the same as in 93 and later models. The vette is a different animal alltogether with disadvantages in a custom use. The heads are different too, they have no EGR passages (that is why they have an exhaust gas tube at the rear passinger side crossing over the valve cover) The vette system may be used with a chip with VATS, VSS, and EGR delete. These systems may also be defeated with inexpensive kits from MID AMERICA DIRECT, a vette aftermarket parts distributor. The vette system is not ideal for custom applications. The only advantage is that the ECM is made to be mounted under the hood and is weather resistant. I have a 91 vette, the last year for the L98 ( TPI ) system, it has no VSS system. I have removed the EGR,and cats, have higher flow injectors, no air pump, and 383cid with a ported plenum. I run a factory chip and get no codes at all except at extended WOT runs in temps below 55 because of a slightly lean condition due to cubic inches not lack of sensor input. My blazer has the 87 comaro MAS system with no EGR, cats,or air pump,and higher flow injectors. I run a factory chip in it and the only code it has ever pulled up is for the MAS burn off relay which I replaced with the new desighn relay. The info i gave was for the F body system, I am sorry for any confusion.
     
  19. TUBE BODY BLAZER

    TUBE BODY BLAZER Registered Member

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    I forgot to mention that on the blazer I use all of the V belt accesories but if you want to retain the serpintine belt you can get the air pump bypass from Mid America or direct from Breathless Performance Products in Florida. They can also burn you a custom chip or answer any tech questions you may have. Also the air fuel ratio is governed by throttle position, the oxygen sensor, injector pulse width, and RPM. Wheel speed has nothing to do with it until 93 when speed was limited to 95 MPH, then it takes spark out not fuel. Also the air fuel ratio would be no different with 2500 RPM at 35 MPH in 1st gear than it would be with the same RPM at 70 MPH in 4th. One reason you get more fuel economy and power ( torque ) with the TPI or any other injection system is that the ECM constantly adjusts to maintain the proper air fuel ratio under different temperature and atmospheric conditions. That is why my vette will set a soft code ( the SES light does not STAY on ) when it bounces off the rev limiter at WOT when it is cold outside, not enough injector pulse width in the factory chip, even with the larger injectors, to compensate for the 383. Anyway, when my blazer still had most of a body, it was cool to pop the hood on some parts store punk who accused me of driving junk ! :)
     
  20. dyeager535

    dyeager535 1 ton status Premium Member

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    I think you have more reading to do. (thanks for the quote Executioner!)

    www.dorianyeager.com/index2.html
    Why insist on counting when the ring gear has the tooth counts stamped in?
     

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