I'm putting the TPI motor from my 86 IROC into my 91 RS. I've decided to switch to speed density in the process. I will also be eliminating VATS and all the EGR/Smog crap. Would it be easier to modify the stock TBI harness to TPI, or modify the 86 TPI harness? Thanks

To swap over to TPI in a 91 camaro is actually quite simple if you don't mind spending some money. Street and Performance sells a kit to do this exact swap called the integrator. If I remeber correctly it costs about 800.00 after all is said and done (you will need to source a 1227730 ECU) the kit is simple and complete all the wires are already the right length. It comes with chip (they can make it to whatever spec you need) and a new knock sensor. I have personally done this conversion on my 92 RS when I installed my 383 and am happy to report everything worked beautifully. Your other option is to get a harness, ECU, Knock, and sensors from a junkyard. That can be time consuming though. Also depending on if oyur car is a stick or auto finding junkyard parts could be a little more involved than just calling up S&P and ordering the kit.
-hope this helps, any more questions feel free to e-mail me
(on my friends computer right now)
-Mike

I'm not looking to spend that kind of money, so I've decided to modify the stock harness.

It is possible to convert your existing harness....but it is a LOT of work. First of, your throttle body harness only has a two block ECU connector, the gm 1227730 ECU (or any TPI ECU for that matter) has a three block connector. So that being said step one is removing the entire harness from the car, unwrapping it, laying it out and getting to serious work on it. As far as working with the harness from the donor car.....you stated it was an eighty six. First off there are differences from year to year. I believe that if you want your speedometer to work correctly you'll have to add a devide by two buffer from the VSS signal. Since you are not keeping any emissions equipment that makes things a little easier, but that still involves laying the harness out and working on a wire by wire basis (since you said you wanted to convert to SD rather than MAF). The best advice I can offer you is to spend the money on either a Howell or a Helm gm fuel injection manual. I know howell offers a manual specifically for TPI (howell was the original author for a lot of the GM technical reference manuals). There is no substitute for good solid information and these books are quite a bit more detailed than your run of the mill chiltons or haynes. Once again good luck and if you need any help sourceing the reference material or any thing else feel free to let me know

-Mike

Thanks Mike. If I have any questions I'll be sure to email you.
Dwain

Check out Mikes site for a 165 to 730 swap.
http://www.eecis.udel.edu/~davis/z28/ecm_swap_730/


VSS should not be a problem. A 91 should have an electric speedo. Just follow the wiring diagrams for the 730 VSS.

VATS will need to be disabled in the bin. (simple flag switch)
EGR will need the enable temp raised to highest setting to disable.

You will need a yellow 32 pin connector to complete the swap. It can be found in most V6 Caveliers and such. Not a big problem to find. cheers, Bob

Well looks like it will be easier to modify the 86 wiring harness to speed density.

Check out this post
http://www.thirdgen.org/techbb2/show...hreadid=127238

according to that post it will take only a few minutes to rewire the maf harness

As Saturn stated the vss will not be a problem as the 730 ecm used a vss, you would have had problems if you wanted to keep the stock 86 ecm with your vss.

Also since you want to disable vats + egr check out the diy-prom board for more info on that.

How about an LT1 in a 91 RS.........






JUST A THOUGHT.........

Hey 385LT1 just wondering who's K-member that is......seen a few being offered by different companys but never seen one in a car. It looks kind of BMR red but I thought they were only doing the newer f-bodys. If it's not too much trouble I would really be intersted on your findings with installing that k-member (fit and finish...so on and so forth) and how much you picked it up for.
-thanks
-Mike

PA RACING

OK, I'm confused now. Maybe it will help you guys give me the best advice if I am more precise about what my plan is.

Swap the following parts from my 86 to my 91:
Modified TPI Engine (see sig)
T56 with working Rev L/O and NSS (speedo or electronics not currently hooked up)
86 Dash and Non Airbag Steering Wheel, however I want to replace the factory gauges with Auto Meter Gauges/Electric Speedo

In the process I would like to:
Convert to SD system
Eliminate all emissions, AC, heater bypass valve, and air diverter valve
Retain Serpintine Belt System (I have the delete pulleys)
Relocate Battery to spare tire well
Install my OEM dual fans (incorporating a switch to manually turn them on between races)
I would like to use a 99-02 LS1 Fuel Tank

Items I already have at my disposal:
730 ECM and yellow connector.
The 91 already has a map sensor which I can use (right?).
I have the harness from my 86 TPI which has the 2 other ECM connectors I need, as well as the injector branch circuit, TPS, and IAC plugs.
Delphi Connector catalog allowing me access to any Weatherpack or Metripack connector I would need.

Now with that information in mind, which harness would serve as a better foundation?

Also, should I use the 86 Distibutor or the 91? Which is better?
Thanks. Dwain

1. Start with the TPI harness and repin using the yellow connector.

2. The 91 with the seperate coil seems to be the favorite. Bear in mind that the 91 distributor (small cap) works with the LT1 intake conversion and Holley Stealth Ram should you decide to change intakes later on.

3. IIRC the LT1 ECM controls the reverse lock out on the T56. The 730 does not have this ability. I have heard of people hooking up to the brake switch but I am not positive of what output the tranny needs but more than likely requires 12V switched.

4. removing emmisions is as simple as removing the nessesary wire from the harness. The egr should also be switched off in the bin file.

cheers, Bob

By all means, THROW AWAY the crummy 86 harness!

In either case you will have to repin the ECM connectors for the 730. Do it to the TBI harness that is already in the car.

Do you realize how close the TBI harness is to a SD TPI harness?

In a nutshell, you split the 2 TBI injector wires into the 2 banks for the TPI; you lengthen the TPS and IAC wiring; repin the ECM connectors for the 730, add high pressure fuel pump, burn the chip to reflect your VATS/emissions/speedo changes, start engine and drive away. And it will look factory by leaving your original engine harness in place!

Thanks speartech. I'll just rework the 91 harness. I mentioned in another post earlier about rewiring the injector circits into a branch circiut for the additional injectors. I know that I'll have to lengthen the MAP and IAC wiring, and I'll have to reterminate and lengthen the TPS wiring and possibly the CTS wiring. Not a big deal to me. I also know I've got to upgrade the fuel pump (I gotta replace it anyways).

Can I reuse the existing TBI fuel lines (the hard lines) or do I need to swap them out from my 86?

Also, does anybody have a pinout of the 91 ECM connectors or a wiring diagram of the engine controls that they could post or email me?

Thanks. Dwain