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tbi help!!!!!!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by ROCKBUGGYK5, Jan 15, 2002.

  1. ROCKBUGGYK5

    ROCKBUGGYK5 1/2 ton status

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    hey guys im in the process of going to tbi and i have a couple of questions, this is what i was told i will need, do i need all of this stuff or can i do away with some of it, its on a trailrig only so here goes

    tbi unit and injectors
    manifold absoulte pressure sesnor (MAP)
    throttle position sensor (TPS)
    idle air control valve (IAC)
    engine coolent temp sensor (ECT)
    intake air temp sensor (IAT)
    o2 sensor
    egr valve
    knock sensor
    distributor
    coil
    engine comp (ECM)
    adapter to bolt to my current edelbroke intake

    heres my questions do i need all of that stuff, ive heard u dont need the knock sensor, or the egr valve, also whats the intake air temp sensor and where is it located, who makes the best aftermarket harness, and i need to run an external fuel pump who makes one, and what pressure is needed to run a tbi setup, i heard the holley black pump will work and do i need a regulater, and also do i need special fuel hose, and last but not least after i get all of the stuff and the harness how hard is it to hook up
    adam thanks in advance

    ROCKBUGGY K5 38S LOCKED AND CHOPPED
     
  2. Chris Demartini

    Chris Demartini 1/2 ton status

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    <font color=blue>You do need the knock sensor. It creates a small amount of voltage when the engine knocks, it tells the ECM when to retard the timing if it "hears" the engine ping. You dont need the EGR. The intake air temperature sensor tells the computer the temperature (density) of incoming air. The colder the air, the more dense it is and the richer the fuel has to be to compensate for it since more air molecules will be entering the engine. The computer reads this and all the other sensors to deterimine the fuel mixture and spark timing. You can run and inline pump or a factory in-tank pump. Use a factory harness, its only a few wires to hook up and its cheaper than an aftermarket harness
     
  3. ROCKBUGGYK5

    ROCKBUGGYK5 1/2 ton status

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    so where is the intake air tempertare sensor located on the motor, and where is the knock sensor located in the block, and will my pre tbi 350 have a provision for a knock sensor, also what pressure is needed and who makes the best inline fuel pump, and do i need specieal hose

    ROCKBUGGY K5 38S LOCKED AND CHOPPED
     
  4. azblazor

    azblazor 1/2 ton status Premium Member

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    My son and I are in the final stages of this conversion ourselves. The knock sensor is on the side of the engine and threads into a hole in the water jacket that had a plug in it. Our block is a 77 400SBC. We have a holly inline pump, $120. Most books say use special hose but the local part guys say regular hose is rated far in excess of TBI pressures which are ~ 15 PSI. I don't know about the Intake air temp, our donor 1989 TBI doesn't seem to have it. And I have been pouring over the diagrams for a week now. We will fire ours up this weekend.
    Mark

    <font color=blue>azblazor</font color=blue>
    <font color=orange> 79 K5 454-FI / 4L80E, NP205, D60, FF14, 4" lift, 9K Warn </font color=orange>
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    Some are running without them, but GM thought a TBI only tank was a necessity, unless you have already tackled that problem some other way. I'd say if it was a trail-only rig, I wouldn't chance it with a stock un-baffled tank, but thats me.

    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. azblazor

    azblazor 1/2 ton status Premium Member

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    Regarding the baffled tank. We have an 87 baffeled tank with good baffle, but the pump and sender was trashed. So it was cheaper to get the rig up and running by putting an in line pump in. We are going to install what some other guys use, that is a reservoir between the high pressure fuel pump and the tank. It is fed by a cheap low pressure pump. It is a little more goofing around, but it apparently works well and is much cheaper than buying a new in tank pump and sender. Of course if you already have a good in tank one or can get a good deal it wouldn't be worth the effort.

    <font color=blue>azblazor</font color=blue>
    <font color=orange> 79 K5 454-FI / 4L80E, NP205, D60, FF14, 4" lift, 9K Warn </font color=orange>
     
  7. ROCKBUGGYK5

    ROCKBUGGYK5 1/2 ton status

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    no i have a fuel cell so a stock tank is out of the question im going to use the holley inline pump, az are u planning on using a regulator? so i dont need the intake air temp thing, and if i do where the hell do i get it, is the knock sensor on the passenger or driver side

    ROCKBUGGY K5 38S LOCKED AND CHOPPED
     
  8. HarryH3

    HarryH3 1 ton status Author

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    The knock sensor is on the passenger side. But it may also be in the top of the block, back behind the distributor. I don't remember what year they started putting them up there. On my '87 Corvette engine, it replaces one of the drain plugs on the passenger side of the block.

    You pretty much have to run all of the various sensors, unless you want to get into custom computer chip programming. If the computer doesn't get the correct inputs from the sensors, then it will set the check engine light and go into limp-home mode and not run as well as it should. [​IMG]

    <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. HarryH3

    HarryH3 1 ton status Author

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    Oh yeah, check a factory shop manual to get the proper torque specs for the knock sensor. I've read that if it's too tight, then it picks up more "noises" from the engine than it should. This makes it tell the computer to retard the timing, even though it isn't really hearing any engine knock. [​IMG]

    <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...
     
  10. azblazor

    azblazor 1/2 ton status Premium Member

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    The fuel pressure regulator is part of the TBI "carburator". The air temp sensor is not on my TBI wiring diagrams for either a 1987 or 1989 chevy truck. I also have a 1993 GMC Suburban which doesn't have it and I have a 1994 TBI 454 factory setup in my 1979 K5 and it doesn't have it. The only temperature sensing I know about on these truck is the coolant sensor. The knock sensor on our trucks is on the passenger side block below the exhaust manifold.

    <font color=blue>azblazor</font color=blue>
    <font color=orange> 79 K5 454-FI / 4L80E, NP205, D60, FF14, 4" lift, 9K Warn </font color=orange>
     
  11. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    I agree with Dorian. If any way possible, I would go with the factory baffled tank (or similar) if you run an in-tank pump. I searched long and hard for one to put on my K30 TBI swap but, the outside saddle tanks that I need were only made in '87 half tons and up to '91 in "V" series trucks, which means they are almost non-existent in the bone yards. So, I'm using a converted diesel tank. [​IMG] If your not running an in-tank pump, then I would do the secondary staging tank as already mentioned on this thread.

    I run the in-tank pump due to the lower cost (roughly half in most cases, I can put in a new one and carry an extra for the price of most in-lines) AND the in-tanks reportedly last over 50% longer on the average. Only problem with in-tank is you need to build in an easy access mechanism (access door) so you don't wind up dropping a full tank out on the trail to change the pump.

    Russ

    85 K30 CUCV, 350 TBI, TH400, 205, D60/C14, 4.56 Locked
    Some day: 4" lift, 44" tires, massive cutting, shorter wb and rear overhang.
     
  12. BurbinOR

    BurbinOR 3/4 ton status

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    The factory torque setting for the knock sensor is 14 lb/ft. Only way to get it is to use a crowfoot end wrench on your torque wrench............been there, done that. Tight fit too !

    I'd also try to use a later model (90 and up) knock sensor from a Corvette, the boys over at thirdgen.org say it has a narrower range and will not send false detonation signals.



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

    BurbinOR 3/4 ton status

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    The MAT (manifold air temp) sensor is used on TPI motors and is located at the rear of the plenum, on the driver's side. Don't think it is used with TBI. It is the same part number as the CTS (coolant temp sensor), again at least on TPI motors, tho I think it is the same number you will use.

    All those items you listed are needed unless you want to have a chip programmed - any sensor you take out will send a code if it isn't 'seeing' data from it.

    There are quite a few guys that don't use the knock sensor over at thirdgen.org............most do it simply to eliminate one variable when they are prom tuning. Not 100% sure how they bypass it, might be as simple as running a jumper wire.

    EGR valve I'd keep as it does keep combustion chamber temps down and mileage up.

    Looks like the guys have everything else covered. Good luck..........[​IMG]

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

    azblazor 1/2 ton status Premium Member

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    Where do you get your in tank pumps and how much do you pay??

    <font color=blue>azblazor</font color=blue>
    <font color=orange> 79 K5 454-FI / 4L80E, NP205, D60, FF14, 4" lift, 9K Warn </font color=orange>
     
  15. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Well, I haven't gotten any yet, I'm using the one I got with my TBI tank (with a busted plastic baffle). It is a Delco but I will be putting a new one just like it in my emergency kit. I originally planned to use an in-line pump to simplify things and the price range I mentioned is based on my experience checking around before I decided to get an in-tank. There are less expensive in-line pumps (like the Holley Blue) that reportedly hold enough pressure for TBI but they are not "rated" or marketed for TBI. However, the better units (Delco for instance) were over $200 each IIRC. The Delco in-tank unit was something like $70 I think. Even the cheapest "will do" in-line pumps are at least as much as the better in-tank pumps.

    This was about 6+ months ago when I was at that stage so the prices may be off. I mainly just remember getting prices and suggestions from many different sources and thinking "Forget that, I can put in a new pump *AND* carry an extra for what a good in-line will run." Plus the in-tank pumps can be found anywhere while many parts houses I called did not carry the after-market in-line pumps. So, here I am, with an in-tank pump...

    BTW, I saw a web site today where a guy is using a Ford Mustang factory in-line pump on his TBI equipped truck. Says he likes it and it works just fine. I guess that would fix the after market availability problem.

    Russ

    85 K30 CUCV, 350 TBI, TH400, 205, D60/C14, 4.56 Locked
    Some day: 4" lift, 44" tires, massive cutting, shorter wb and rear overhang.
     
  16. ROCKBUGGYK5

    ROCKBUGGYK5 1/2 ton status

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    alright im going to run the holly black inline fuel pump, so i dont need to run a regulator?, the throttle body will regulate itself?, also i c 2 fuel outlets on the back of the throttle body, which side is the pickup and which is the return, passenger or driver, i got all my parts today im siked
    adam

    ROCKBUGGY K5 38S LOCKED AND CHOPPED
     
  17. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    IIRC, I was told that the fuel pressure is ok up to about 20 psi. Over that, and you over-drive the TBI's internal regulator. Seems to me like the input is on the passenger side. Just look for the larger line, one is slightly larger than the other. Good luck.

    Russ

    85 K30 CUCV, 350 TBI, TH400, 205, D60/C14, 4.56 Locked
    Some day: 4" lift, 44" tires, massive cutting, shorter wb and rear overhang.
     

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