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tpi wiring?!!

Discussion in 'The Garage' started by primerk5, Dec 30, 2005.

  1. primerk5

    primerk5 1/2 ton status

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    Has any one used the original wiring out of a camaro/fire-turd with a tpi setup?? Modified of course. So all you use is the stuff you need. See this is my version of the budget beater, (trying to keep it as cheap as possible.) A buddy gave me everything for the tpi conversion except, 5.7 fuel injectors, presure line from tank/sending unit/fuelpump to engine, and wiring.
     
  2. HarryH3

    HarryH3 1 ton status Author

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    Mine is from a 1987 Corvette, but the "conversion" was actually pretty simple. 98% of the wiring runs direct between the engine and harness, so you don't need to make any mods to that part. You need to connect a few power wires, the ignition wire, and a crank reference wire. However, if you don't already have the harness, or can't get one for nearly free, your best bet is an aftermarket harness that comes ready to install.
     
  3. primerk5

    primerk5 1/2 ton status

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    your setup looks great(checked your site) I was hopeing that I could just adapt the engine harness from the camaro into my blazer fuse box.
     
  4. HarryH3

    HarryH3 1 ton status Author

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    The harness is almost standalone, and will mostly feed through a single hole on the passenger side of the firewall. I added a second, small fuse box to handle the extra power needs for the injection. It really helps to have the factory service manual and shop diagrams for the donor vehicle. That will make life much easier for you.

    Do you have a wiring harness? Your first post makes it sounds like you don't.
     
  5. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    If you are running MAF, you can't do this, but I was able to intergrate all the extra circuits I needed directly into my existing factory fuse box! Makes for a nice clean install that looks totally factory :)
     
  6. 1979jimmy350

    1979jimmy350 1/2 ton status

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    if you are using a speed density setup you can modify a truck TBI harness and add a few wires i am doing this right now for my 74 using a 89 TBI harness
     
  7. primerk5

    primerk5 1/2 ton status

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    Ok. I don't have the camaro harness yet. I'm waiting till my buddy brings me out all my parts for the tpi setup. Unfortunatly I was under the impression until lastnight that it was a speed-density setup. But he told me that he is giving me the mass air flow setup. He wants to save his speed-density setup for his later use. He also said that he read you can use the mass air flow ecu with the speed density setup. You have to change a chip in the ecu. He read this in a tpi swaping guide written by a guy by the name of Chuck Monday. He is going to mail me the book so I can read up on the swap and get everything I need. Now, as I said I don't have the wiring harness yet but I do have a connection to get one from a parts yard but there are only a few corvettes and some camaros. So hopefully he will have this setup too me nolater than febuary. (he lives in Indiana, and I'm in Maryland.) I'm definatly going for that factory look. I was hopeing to mount the ecu in the tray behind the passenger side dash. there is some emission control unit there now.(not hooked up of course) Hearing that the wireing can be routed through that side is a sigh of relief. I just want to run all my main power wires through the fuse box.(for the factory look.) Unfortunatly my truck is a carbarated model from factory (85 blzr) so I don't have any of the tbi wiring. The help you are giving me is great! That way when its done and I hit the key all I have to do is adjust the timing.
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    I'd prefer the speed density setup if you can get one, but if not, oh well. It just makes plumbing the intake much easier.

    Go over to thirdgen.org, there are links in the tech section to the '85 and '86 wiring diagrams. Those will give you a feel for what you are in for. You will need the auxillary fuse panel, but you can run the feeds to it right off of the stock fuse panel. The later trucks have plenty of spare terminals that operate when the TPI needs them to. TPI is VIN 8 or E, one is 305 one is 350. Wiring is almost identical. '85/86 only has one TPI V8 VIN though.

    The '85/86 (I think '86) base will also save hassle if you are bolting it on to older heads...'87-up intakes aren't a drop in fit (bolt angle differences) and although they can be made to work, it's just easier to use the earlier intake. A set of L98 heads wouldn't be a bad mod either though. :)
     
  9. 1979jimmy350

    1979jimmy350 1/2 ton status

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    if you want to run speed density all you need is a gm map sensor plugged into manifold vacum and a 730 ECM
     
  10. dave_90_blazer

    dave_90_blazer 1/2 ton status

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    and new ECM connectors, ect
     
  11. botboy

    botboy 1/2 ton status

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  12. primerk5

    primerk5 1/2 ton status

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    thanks for that link it will be really helpfull. I've already decided now that I'll stay with MAF system. My only question on that will water intake mess the MAF sensor up???
     
  13. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    MAF and offroading don't really go well together. The MAF doesn't like excessive dirt, moisture, or vibration much, so there is a chance you may wreck it fairly quickly if you wheel your rig pretty hard.

    I personally decided to go to speed density right away, just for the ease of air ducting, and the lack of having to worry about the MAF busting on me or something. A new MAF will cost more than a speed density conversion by far.
     
  14. dyeager535

    dyeager535 1 ton status Premium Member

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    If you get enough water in the intake to mess up your MAF, you've got other problems. If you've got it ducted well, your MAF won't see any water unless you are on your way to drowning the engine.

    I have a hard time believing stories about MAF's being bad when used on trucks. The main thing is that day to day driving in any vehicle introduces a huge number of vibrations and jolts, and the MAF is somewhat damped by the rubber intake. (at least in my case)

    If anything, MAF failures that have been reported in trucks are PROBABLY due to old age or bad aftermarket pieces. If stock MAF's on cars can last 10+ years, I'd expect to get at least half that in a more vibration prone environment. Of course, that would be assuming a brand new OEM quality piece.

    There are thin film MAF's, they may do something to reduce failures as well. However, as was pointed out, the first time your MAF dies, you are better off going MAP. Which is a good reason to start out MAP if you can. (plenum is setup for it for one thing, along with the wiring differences)

    MAP sensors are something like $40, MAF's are over $100 easily.
     
  15. primerk5

    primerk5 1/2 ton status

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    oh, I was just going by the information on the chevy thunder page. It said that the MAF system allows for more engine wear and upgrades unlike the map system that dosent respond well to upgrades at all. Now Im not planning on doing any major internal work for a while. So I should be alright. But I do have an rv cam so Im hoping I won't have to do any tuning to get this thing to run right. Looks like I'm still considering what system I'll go with now.

    Heres that page if you want to see what I was talking about.
    MAF and Speed Density
    MAF sensor systems were used on the tpi cars from 1985 through 1989. The maf sensor is a special device with its own miniature computer. The sensing wire in the air stream is heated to around 100 degrees Fahrenheit above the temperature of the incoming air. As the air is drawn across, it tends to cool the wire, the sensor then tries to maintain the heated wire at its preset temperature, the potential or difference is converted into a voltage that is used by the ecm along with other sensors to calibrate the proper fuel injection rate. What makes the MAF sensor unique that is is capable of measuring the exact weight of the air due to the effect that humidity, temperature and barometric pressure, and rate of flow has on how fast or slow the cooling effect takes place on the sensing wire. It is extremely accurate. To keep this sensing wire accurate is that when the engine shuts down, a special relay heats the sensing wire to 1000 degrees F, to burn off any oil and grime from the wire. The MAF system will allow for wear of engine components, and still perform over the lifespan of the engine. The MAF system will also tolerate a change of around 10% or so in flow rate due to cam, head and exhaust modifications.
    The MAF system did have some minor changes over its life. 1985 MAF system was unique, as it had the MAF controller "piggyback" on the ecm. The ecm service Number was 1226870, and had a separate prom with a 32K chip and separate calpak chip to act as a back up limp home mode in case of ecm failure. This harness and computer will not interchange with the later harness/ecm systems. In 1986 the separate MAF controller was eliminated and the ecm service number changed to 1227165. The prom and calpak was combined into one module. The prom capability was changed to a 128K. This remained unchanged until 1989, when the cold start injector was eliminated and the cold start enrichment was added to the prom calibration. Another thing to remember on the 1988 and later ecm's will have the VATS (Vehicle Anti-Theft System) encoded on the prom.
    Speed density was installed on the 1990 and later TPI engines. This eliminated the MAF, and depended on the MAP sensor, O2 sensor, coolant sensor, air temp. sensor and TPS to calculate the fuel requirements. The ecm service number was changed to 1227730, and the prom memory was increased to 256K. This is due to the fact that the ecm had to do some serious number crunching to get the fuel requirements as accurate as possible. It is to be noted that the speed density system is calibrated to that particular engines configuration. The system is not forgiving when it comes to modifications, or when the engine components degrade over time, changing the way the ecm reads the MAP, which is based on reading the amount of vacuum or engine load. If you use this system and have anything more than a basic stock engine, you will need a new prom chip made.
     
  16. dyeager535

    dyeager535 1 ton status Premium Member

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    MAF cannot take into account things such as heads, cams, etc. Fueling and timing are still not controlled by the MAF, and as evidenced by my motor, it will run, but not correctly.

    MAF is supposedly more forgiving of engines changes yes, thats general consensus, but if you are swapping to a non-stock application, tuning is going to be necessary to get it right either way.
     

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