i'm going from a 91tbi to 89tpi and want to know what brands are out there and which ones are the most complete?the most popular is painless wiring but i'm not sure of thier quilty.i thought about a used harness but you never know whats been done to it,and i don't want to go through the hassel.also will i need to use a 89tpi computer?

 

Use a 90-92 ecm and change it to a MAP system, instead of the MAF
Do you own harness, you can use most all of you old harness and just swith things around at the connectors. If you wan to not chop the harness then use a used one. I've some the original wire harness to different sytem several times now, the first was a PITA just cause it took so long. GM makes the best harnesses, period, I've know of 4 or so guys that spent 5-600 for the perfect harness and spent more time getting that right then redoing then oem one.

 

I converted my LG4 (carburated) to a '92 TPI and used the Painless Wiring. What a pain in the a$$ is was. I had to rewire some of the ECM connectors for my speedo, PassKey, and a few others, not to mention, I had to cut it in half and add 3 feet to each and every wire so that it would be long enough to use like a factory harness. I spent a whole day soldering. Not fun at all. If I could go back and do it again, I would use a factory. Not to mention, the painless harness has your fuel pump relay, ECM/harness fuse, MAP sensor, and timing bypass connector all under the dash (don't like that at all).

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If you live in Southeastern US, check us out!
South East Thirdgen


ASE Master Tech + L1
Savannah, GA

'87 Trans Am
S/D TPI retrofit including functional PassKey,
22# injectors,
JET AFPR,
Ported Plenum,
TB Coolant Bypass,
SSM SFC,
Boxed LCAs,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
KYB Shocks

'97 Bonneville SSE

 

im using a Street & Performance Electronics
tpi wiring harness. told them what all im
using (emissions or not) motor/trans combo
and whoosh harness... no fuss no muss
cranked the first time...
just my experience.
airdeano

 

airdeano>how much did your harness cost?for the extra long painless tpi maf it's like $400.how long did it take to get it?

 

The extra long Painless may not be what you need. It is intended so that the ECM can be mounted under the seat instead of the dash, and you may still run into similar problems. There are factory wiring harness for MAF systems for sale on ebay for way less. Just do a search for "TPI"

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If you live in Southeastern US, check us out!
South East Thirdgen


ASE Master Tech + L1
Savannah, GA

'87 Trans Am
S/D TPI retrofit including functional PassKey,
22# injectors,
JET AFPR,
Ported Plenum,
TB Coolant Bypass,
SSM SFC,
Boxed LCAs,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
KYB Shocks
-->14.97 @ 94.9 MPH<--

'97 Bonneville SSE

 

www.howell-efi.com is all you will ever need. Bill Howell was one of the engineers who designed the EFI systems for GM. They make a harness that will DIRECTLY bolt-in your car, hook into your (IP) Harness and all. HTH's

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88 Monte SS 355 TPI/LT-4 HOT CAM/AFR Hydra-rev/ T-56 6-Speed

 

I used the Painless in my 89 RS when I pulled the Tbi and put in the TPI. I was not painless! The quality is good but I got the short version. One day I'll pull the harness and go with a longer one. Sounds like Street and Performance is the way to go!
I will say the tech support at Painless was excellent, they talked me through many problems.

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Rob P
89RSconvtZZ4TPI
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

What PROM did you use? How did you set-up the pass-key system? Did you get one from a donor car or buy a kit?

 

Anyone have experience with Fuelinjection Specialties? I was going to go with a harness from them because they are less expensive then Speed and Performance. ANyone?

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If the women don't find you handsome they should at least find you handy
88 GTA Notchback with 91 gfx and ROH Snypers
Aftermarket T-56 (pain in the A$S but worth it)
Lots of things to do still

 

The PROM is kinda funny. I went into the parts department at work and said "give me a '92 Trans Am PROM w/ the LB9 engine/ auto tranny.". Well, they came back and told me I had two options. One for 15" & 16" wheels, and one for just 16". Well, I figured that the 15 & 16 was the "regular" one, and the 16" only may be a "high performance" (as high performance as GM gets!) so I got that one.

As for the PassKey, I bought a used Passkey module, pulled the code from it using a PassKey/VATS interogator, then using a '92 wiring diagram, wired it into the vehicle. Then I ground out the lock cylinder hole in the steering column ('88 and prior is to small for the larger PassKey cylinder) and installed that. I also installed the start inhibit relay and wired that in series w/ the P/N switch. Got a new key cut and it fired right up.

------------------
If you live in Southeastern US, check us out!
South East Thirdgen


ASE Master Tech + L1
Savannah, GA

'87 Trans Am
S/D TPI retrofit including functional PassKey, 22# injectors,
JET AFPR, Ported Plenum,
TB Coolant Bypass, Custom Cold Air,
SSM SFC, KYB Shocks, Boxed LCAs, Wonder Bar,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
-->14.97 @ 94.9 MPH<--

'97 Bonneville SSE

 

what kind of problems with the pass key am i going to have here?i'm going from 91 tbi 305 to 89 tpi 350?

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1991 banditt2 firebird #130of#600

 

You should have no problems. Not sure if the '89 TPI used the PassKey or not. If it did, it should be a direct hookup, just make sure the blue "fuel enable" wire goes to the right pin in the ECM connector, and if the ECM didn't use it, then you won't have to worry about it. I know GM used PassKey in '89, but not sure what engines got it.

------------------
If you live in Southeastern US, check us out!
South East Thirdgen


ASE Master Tech + L1
Savannah, GA

'87 Trans Am
S/D TPI retrofit including functional PassKey, 22# injectors,
JET AFPR, Ported Plenum,
TB Coolant Bypass, Custom Cold Air,
SSM SFC, KYB Shocks, Boxed LCAs, Wonder Bar,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
-->14.97 @ 94.9 MPH<--

'97 Bonneville SSE

 

Don't quote me on this, but I think all the 89 cars got the passkey system. My 89 RS with the L03 has it. As far as harnesses for a TPI, I bought a used one complete with ecm and chip for a whole lot less than the aftermarket ones. As you can see from the guys that have bought aftermarket ones, they don't just hook right up. Since I have the passkey system, I made sure to get an 89 harness and ecm. As long as you go 89 or newer on those two parts, you shouldn't have a problem. I'm no wiring guru, and the original harness makes it very simple. All you have to do is figure out what each plug goes to and hook them all up! If you ask me, that sounds like the most "painless" way to do it!

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89RS w/350 TPI; 69RS/SS w/450 HP 350/Muncie 4-Speed "Too weird to live, too rare to die."