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TPI Question

Discussion in 'The Garage' started by 79Stomper, Aug 31, 2004.

  1. 79Stomper

    79Stomper 1/2 ton status Premium Member GMOTM Winner

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    Have a lead on a TPI set up for 400 bucks complete. Bad thing is it is off of a 305. Will this still work for the 350? I know it would have the centerbolt heads no biggie but would it make a difference on the size of the motor that maybe a chip could change?
     
  2. Ruthven13

    Ruthven13 1/2 ton status

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    The only difference between the 305 an the 350 TPI units is the size of the injectors. The 305 comes with 19 lb/hr ones while the 350 uses the 22 lb/hr ones. The chip will have to be changed to use the different sized injectors.
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    Actually you can run the 350 injectors with a 305 PROM. My understanding is that since the injector sizing is proportionate to engine size, although the amount of time the injector is pulsed stays the same, since the injector is "larger", fuel delivery is not as much of an issue as it might otherwise be. In any case, I've been running the 305 ECM/PROM on my 350 for about 1000 miles, and it has given no indication it is being starved of fuel. Plugs look good, no pinging, no codes. I guarantee it's not OPTIMAL, but it will work until you can get a PROM burned that works better.

    You would definitely need 350 injectors though, and if you haven't priced them out, you might want to. I would expect that used "good" injectors will run you $25 each unless you find a real steal. IIRC around $60 each new, although I'd check on that first.

    The ESC module is another difference 305 to 350, and that is another $50 or so if you buy GM.

    You will probably be better off finding another setup that comes with 350 specific stuff. These prices are why finding a complete unit you can use is typically much more cost effective than piecing together something. You should be able to get a complete 350 setup for $500 or so. Check over at thirdgen.org in the classified section. Probably have multiples of what you need/want.

    You can also look for the very first TPI manifolds, as they were "old style" intake bolt pattern, which will save you some hassle and perhaps money.
     
  4. 79Stomper

    79Stomper 1/2 ton status Premium Member GMOTM Winner

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    Thanks, /forums/images/graemlins/thumb.gif that is the info I was looking for so back to my quest for Fuel Injection.
    How old am I looking for on the intake anyways and could I put a newer setup on the older intake?

    James
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    Newer setup will fit on the older base yes.

    I thought it was '85-86, but for sure '85 is what you would need. I thought '86 was "new style" intake bolt pattern, but I also seem to recall that two years of base fit the older heads.

    Personally I say get a newer setup that lacks the cold start junk. ("ninth injector") Dunno why GM didn't figure it out earlier, but it's unnecessary, done through the PROM later on. '87 was still cold start, thirdgen.org probably has the data you need for what years had cold start and which didn't. 1989 comes to mind as first year without cold start however. My PROM/ECM is cold start vintage, but the cold start hardware is not there, and as expected, cold start takes longer than it should.
     
  6. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

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    Well youll have to get a new PROM anyway.
     
  7. CaveBlazin

    CaveBlazin 1/2 ton status Premium Member

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    James if you are still talking to me I can get you a SUPER deal on a Painless wiring harness. I also have alot of places were you can go get complete FI kits for around 300 just give me a call sometime /forums/images/graemlins/waytogo.gif
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    Well, that's my point. With the MAF setups, you don't necessarily HAVE to get a new PROM.

    I'd never get it into your head that it should just be run as it comes, however, until that time where you can spend the money on a new PROM that is "correct", more than likely, if the donor is for a 350 with the same transmission, performance will be at least acceptable.
     
  9. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

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    NO NO I understand, but he'd ned a new prom because of the anti-theft thing. Guess I fergot to write that. /forums/images/graemlins/crazy.gif
     
  10. dyeager535

    dyeager535 1 ton status Premium Member

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    Ahh yes, can't forget that. /forums/images/graemlins/smile.gif I did too as a matter of fact.

    VATS causes a problem on the later stuff, which is probably right when cold start was abandoned.
     
  11. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

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    yeah when I completed my TPI converson, My new chip was in the mail and I couldnt wait to see how it ran with the stock chip. I cranked and cranked forever, but it wouldnt start, so I retraced my wiring and EVERYTHING. Then after a while I realized it woulndt becaus of the VATS. /forums/images/graemlins/doah.gif I felt so dumb, and wasted a lot of time. Fired right up with the new one! /forums/images/graemlins/waytogo.gif
     
  12. dyeager535

    dyeager535 1 ton status Premium Member

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    Not to get too far off topic, (well, I am) but as I understand it, VATS is a module seperate of the ECM?

    VATS requires a key with a certain component in it, and that key is "coded" to that module, correct?

    Since the module has input into the ECM, I can't believe the ECM input is "coded" FROM VATS. If it's not, I think it would be a really cool anti-theft idea to tie the VATS to ECM wire into the key-in-ignition setup that some trucks had....the one that tells the door buzzer the key is in the ignition. So without a key, it won't complete the VATS "circuit" and thus won't start.

    Of course, that sounds too simple, the ECM input from VATS IS probably coded or something to prevent what I had thought of.

    Sorry for the off-topic, but if it can be that easily worked around, it would be less of an issue to get a later TPI setup.
     
  13. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

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    The VATS is tied in with the igniton switch, and/or column, if i remember correctly. The problems I see is 1 youd need thos epieces out of the car, 2 the aftermarket harness's dont have wires or anyhitng for them.
    Yes it would be really cool to tie that in and have it working, but i think its probablly more trouble then its worth, espically if you need the stock column. /forums/images/graemlins/frown.gif
     
  14. dyeager535

    dyeager535 1 ton status Premium Member

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    But the stock stuff relies on resistors or something that are "calibrated". I'm suggesting to ignore/remove all of that, and use the input to the ECM that was originally FROM the VATS module, (IE, I suspect one wire to the ECM tells it the key is the right one, and thats it) with the stock truck key buzzer setup.

    If I had a wiring manual that covered VATS, I might be able to discern if thats possible. If it's a simple 12volts the ECM needs to see so that the ECM thinks VATS is working correctly (with the key) it should be simple to wire that into the existing truck key buzzer.

    Aftermarket harness would obviously cause a problem. /forums/images/graemlins/smile.gif
     
  15. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

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    I see. I can try and print you out the wiring diagram, let me know.
     
  16. dyeager535

    dyeager535 1 ton status Premium Member

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    If you can, just tell me what the ECM needs to see on that wire. (if there is just one ECM feed wire) Should be on the schematic for VATS, if you have it.

    If there is a seperate VATS module, my idea would work, if it's integral with the ECM, forget it lol.
     
  17. tunedportk5

    tunedportk5 1/2 ton status

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    theres only one wire for vats and you have to put the correct ohm resistor on that wire to ground
     
  18. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

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    Ill try and let you know on wed, thats the next day I can get to NO DATA (ALL DATA).
     
  19. dyeager535

    dyeager535 1 ton status Premium Member

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    [ QUOTE ]
    theres only one wire for vats and you have to put the correct ohm resistor on that wire to ground

    [/ QUOTE ]

    So there is no seperate VATS module outside of the ECM?
     
  20. tunedportk5

    tunedportk5 1/2 ton status

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    I was reading a little more about it and theres one wire that goes to a VATS module that send a signal to the ECM, it says the signal is a 0-5 volt, 30 Hz square wave with a 50% duty cycle. /forums/images/graemlins/confused.gif
     

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