TPI engine harness integration

280zxSheik · Apr 24, 2015

I'm trying to incorporate my tpi harness into my 280zx chassis and need some direction, should i be use the 280zx's original engine control relays? If so which relays? Do i need to use a gm relay center or buy a pricey aftermarket one? What can I remove from the tpi harness? What do I no longer need from the datsun original wiring or circuits? Can I eliminate the tpi fuel pump wiring and just keep the datsun stuff? How should I run the electric fans? What about the charging system, starter & how can I rear mount the battery?

grumpyvette · Apr 24, 2015

its almost always far less trouble and far easier to either run individual independent wiring , sensors and gauges and related sensors to the dash gauges or to buy an after market EFI controller for the EFI, thats been designed to have a great deal of flexibility, in how its being used, programed and what can or could be connected to it. rather than try to integrate the very limited flexibility and change ability of the GM CPU which is designed for a single application.
yes you can use the GM CPU, and gauges but its been my experience that its usually a P.I.T.A. to get it working and do the trouble shooting.
the TPI engine control computer design, is by today's standard's a dinosaur or truly ARCHAIC, its a minimum of 24 years old and several generations behind by todays standards the controllers are a bad joke, compared to standards used currently, fighting the issues is in my opinion a huge head ache and a waste of time, compared to the newer lap top controlled and tuneable or self tuning soft ware available.

http://www.megamanual.com/MSFAQ.htm#whatis

viewtopic.php?f=80&t=728&p=1025&hilit=dash+gauges#p1025

viewtopic.php?f=32&t=816&p=1201&hilit=temp.+pressure+voltage#p1201

viewtopic.php?f=35&t=3399&p=8970#p8970

bytor · Apr 24, 2015

I agree with Grumpy.. After digging into the TPI engine control computer and systems myself to understand the electronics involved and the code that drives the whole system.

http://forum.grumpysperformance.com/viewtopic.php?f=36&t=10946

I came to the conclusion that you would be much better off investing in a modern engine management system. I found the cost involved to purchase, ROM's, ROM burner, ROM reader or retrofit the TPI ECM so it can be programmed on the fly "flash" was not cheap. Then add the hassle of modifying antiquated programming language, limited parameter tables and dealing with restrictions in the code. It's just not worth it. Now, If I was trying to keep a car 'stock' then yes I would stick with the old school ECM. But in your case, probably not.

The TPI ECM are very elegant systems. GM engineers had to do a lot with very little resources "CPU, Memory and technology at the time". If you study the code running these engines, it's actually ingenious how the engineers put this all together. The TPI systems and code are predecessors to today's ECM systems. Today's ECM have a ton more processor power, more inputs and outputs, larger&more granular parameter tables and very easy to tune/program. The newer systems are much easier to interface with. Some of the aftermarket ECM offer wireless/Bluetooth connectivity options for your Iphone/Tablet. No more serial cables. That alone would convince me to go with a newer setup.

280zxSheik · Apr 27, 2015

Grumpy I appreciate your prompt response. As much as I would like to run an aftermarket system my finances won’t allow such expensive endeavors. So as an alternative I would like to build the individual independent wiring, sensors and gauge set up that you mentioned. I am running auto meter gauges instead of the stock Datsun stuff. I had a tuner build me a custom speed density chip, basically deleting the vats and emissions from the computer. For now simply getting the car operating safely is my priority and hopefully leraning about this stuff alone the way so I don’t have to scour the internet the next time I need help.

Bytor I’m not exactly trying to keep the car stock but I figure a TPI 350 in a 2900lb car won’t exactly be slow.

So, my friends, the 1st set of obstacles I’d like to address are what needs to be hooked up and how?1. Should i be use the 280zx's original engine control relays (fuel pumps & EFI relays)? If so which relays?

2. Would it be a better idea to use a gm relay center than use the Datsun stuff?
3. How much can I remove from the TPI harness? Can I eliminate the TPI fuel pump wiring and just keep the datsun stuff?

4. What do I no longer need from the datsun original wiring or circuits?
5. How can I wire my electric fan, What about the charging system, starter & how can I rear mount the battery?

280zxSheik · Nov 2, 2015

I have since solved number 5; I am running an electric fan and have set up my starter and rear mounted the battery.

My next two issues are with the radio harness, in that I have NO constant power, the schematic says that the constant power should be blue wire w/red stripe and ACC power should be yellow wire/green stripe. The car is a 83 280zx coupe, 5 speed.

Next I'm working on a TPI SBC swap and I'm getting no power to the fuel pump, distributor, fuel pump felay # 2 on the passenger side engine bay compartment,

I have power to the ECM, all fusable links, fuses and starter and most of my under dash relays are clicking. Two that aren't are the large gold one under the dash and the green one with the black, green, white and black stripe and blue w/red wires coming from it.

Also the EFI relay and most of its associated wiring has been removed. Since I'm now running the TPI SBC are these components still necessary?