Alec Bryant

I just got an 86 TPI 350 and 700R4 from a vette that was in a wreck. The car was junked and the people at the scrap yard were not careful with the hack saw and wires 112k on it and I only payed 350$ plus i got an aluminum driveshaft from an LS1 camaro. The wires are just hacked up. I just need from the computer up to where it plugs in. Now the fuel to air ratio is all the same on the tpis so would an 87-89 trans am or camaro computer and harness work. I have seen aftermarket ones and they cost more than what i payed for the entire drive train. I am certain I can find one on ebay or a junk yard. What will be my best bet and what will plug in and work! Its going in my 1990 firebird i'm swapping out the 3.1. Do not want to change my gauges or anything like that don't think i need to. The engine is really mint and I got an awesome deal. Going to do a compression test and I want to hear this thing run before I start rebuilding it and doping hundreds in performance parts.

I have pictures here of it if it helps: http://s1238.photobucket.com/user/am...in=true&page=1

I really want to hear this engine run any help would be awesome!!

John in RI

iTrader: (167)

Your trying to merge an apple and a coconut together and will have some work ahead of you to pull it off. No matter that they cut the wiring to the 86 Vett,... that harness wouldn't be any good to you anyway.

86 = MAF
90 = Speed density

What I would do if in your shoes is to find a SD harness from a 90-92 ThirdGen and then buy the parts needed to convert the engine parts from MAF to SD such as the Air cleaner parts, 9th injector block-off ( or correct 89+ runners/manifold, ect...) The 87-88 (maybe 89) wiring and ECM will NOT work...... & don't forget your car has a VAT system.

Adding to the project is the fact that your swapping from V6 to V8. That not only means that you will need a V8 tranny + a full compliment of V8 engine accessories,... ( radiator, Alt, front springs, ect...) but it also means that your factory 3.1 wiring is NOT a direct match for the 90-92 SP TPI wiring. Your going to have some re-wiring work to do before you can hear it run !

Alec Bryant

Yeah i was told about putting the set up in it. I have the Transmission to it. just need suspension and radiator. My Vats is bypassed. also would switching everything from MIA mean I need the newer computer re tuned? even though its the same engine. My neighbor has an 91 gta tpi 350 I can always reference. and with my gauges i would have to replace the knock sensor and ESC module with 350 ones right? not changing to the 140 mph gauge. also i was told about PCM pinpoints whatever they are.

John in RI

iTrader: (167)

Same engine - different fuel system.

You've got to get the proper 730 ECM with 350ci Prom and SD TPI harness. As long as you get the right ECM/Prom/harness there's really no NEED for a 'tune'. Yes,.. you will need the 350 knock sensor and ESC module.

You should get the connector schematics for the Firewall connector ( C100 ) and the dash-to-ECM harness connector ( C207 ) that are specific to the 91 Firebird. Once you do you will see what wires got changed from the V6 and the TPI systems. Thankfully for you; V6 and TPI wiring is much more similar to each other compared to TBI wiring. ( TBI is much different then V6 or TPI !)

Alec Bryant

That's good to hear it won't be a complete rocket ship build for me. Just curious I have not been given the option the switch the whole car to an maf system. I assume its harder than switching the engine to SD but what's involved in making the car maf?

mainstreetspeed

I just came across your post . painless wire made a stand alone harness and computer for street rod guys using tpi engines .If they still make it that would cure your problem
you might want to look into that

mainstreetspeed

also on the engine you got if it came from a corvette the fuel rail is different then one
for the fbody. you also might have to change your pickup in your fuel tank and the lines

Alec Bryant

my lines are brand new and changing them again. Pickups need to be replaced on the engine anyway. and the painless wire set up is very expensive 400$ and it needs more to work there is no way I am paying that. Ill find a junkyard setup if I have to but still very confused on the whole MAF and SD systems and what to do.

mainstreetspeed

speed density tpi works of the vacume of the upper intake if the tpi came from a car with sd it will have 3 vac ports on the side , maf had 2 . if you want to run a big cam sd
computers are effected due to the lack of vacume the engine has requiring custom chips. maf systems are more forgiving the work on air being pulled passed the maf sensor there for the can adjust to a point I have a 1985 iroc it was maf I ran a crane cam 224, 234 @.50 467 494 lift 114 center line to keep vac for brakes the maf system
worked perfect I drove it for years and ran 12.70 at 108 mph .the cam in my friends
ta was a roller 218 220 500 500 112 center line and it had problems idling it also ran
unbelievable rich .the ecm could not compensate for the vac lose from the map sensor.
find a Camaro our firebird 85 86 get the computer and harness . I pulled one from a junkyard for about 250 . I pulled it my self for that price they let me take every sensor
including maf sensor .when you do take the harness that connects to fuse box near the booster under the hood .

Alec Bryant

I thought only the vettes had the tpi in 85 and 86? so getting a camaro or firebird MAF setup would be fine considering my car is a 90 SD? And what about the 9th injector I keep hearing about, i heard the fbodys did not have them and I would have to plug it. and I plan on keeping my cam stock, just gona do basic bolt ons to wake it up I want the engine as reliable as possible without murdering my MPG. Also the engine still has all the sensors hooked to it even the part of the original harness where it all plugs into the engine. Could I just get a fbody harness and computer setup and plug it all in?

mainstreetspeed

if your car is a 90 it should have a key with a chip if it does you need a computer system from a 88 up f body with a vats 85 86 system wont work with vats

mainstreetspeed

Camaro firebird tpi had 9th cold start injector corvette did not that's why you need to change the fuel rail to Camaro firebird and the runners to Camaro firebird

Alec Bryant

i have an 86 steering column in the car with the vats tied in. Im going to bypass the 9th injector anyway so I am not gona bother with replacing my fuel rail. I am just worried with this MAF system running with my gauge set up

TTOP350

iTrader: (8)

Alec, Its me from FB that you have been PMing.
Pretty much everything on here is what I was talking about. Lots of work.

TPI is from 85-92 in the F-car and 85-91 in the vet, 85-88 9th inj, 85-89 MAF, 89 MAF no 9th inj, 90-92 MAP.

John in RI

iTrader: (167)

MAF or SD has no effect on your gauges - at all. If you install the proper sending units and have the proper wiring this is a non-issue.

The only thing that makes an engine a MAF engine of a SD engine is what gets bolted to it.

Your car is a 90,... in 90 GM was wiring MPFI and SD TPI in the Thirdgens. If your not great with wiring than the "simplest" way forward is to get a wiring harness that's compatible for your car and then bolt on the parts that match the harness. Because your swapping V6 to V8 the wiring might not be completely 'plug-&-play' but using a year-matching harness will minimize the re-wiring needed.

If you still insist on MAF system ( There are 3 of them in the F-body ) then print out the C100 diagrams from the 90 Firebird and the exact year MAF system you decide to use and then start trying to figure out how to re-wire the connections. The 2 important connections are C100 and C207. ( If you use an 85-87 engine harness than don't forget C221 too ).

Thirdgen MAF =
85 MAF ( with Burn off module -cold start )
86-88 MAF ( cold start )
89 MAF ( no cold start )


* BEST BET is to be sure that the engine harness you get is from a Firebird, particularly if the TPI harness you decide to use is a 85-89 because the camaro didn't have electric VSS till 90.

Here is a couple links the most Thirdgen C100 and C207 connectors.... ( I don't have the 90 Firebird, but the 90 Camaro version will be very close to your car. )

C100:
http://berlinetta.info/C100.htm

C207:
http://berlinetta.info/C207.htm


I have never converted from MAF to SD. But I've done a HUGE amount of wiring work. If you are not familiar with wiring than why overly complicate an already complicated swap. An example; Wiper wiring,..... from 88 to 92 the wiper wiring is located in the headlight harness,... but an 86-87 those wires are in the engine harness; so unless you use an 88+ harness your wipers will not work without re-wiring. You already want to ditch the 9th injector so your limiting yourself to a 89 ECM/PROM or a custom tune and probably that harness.

I fail to see the advantage in making your 90 run the MAF system. It's not as if you already have the MAF harness, ECM already. Want success - Keep it as simple as possible !!

TTOP350

iTrader: (8)

This^^^^^^^^^^^^^^^

Altho I like the maf over the SD in these cars I told him to stick with SD because of the year of the car.

Also a distributor from a bird would be a bit easier.

Alec Bryant

okay thats what I will do then and yes I am convinced to keep it SD, But for some reason I do not have the 9th cold start injector but its an 86 vette engine according to the numbers on the block. I dunno, I know of some 90-92 parts cars in my area I can scrounge around at. and I plan on checking out my neighbors 91 TPI engine on his GTA to see what on the SD will plug into the MAF sensors and all that that is currently on the engine.

Alec Bryant

Alright sounds good to me! thanks for all your help!

Fast355

iTrader: (2)

I think you have that backwards!!! SD is so much easier with these cars and not nearly the restriction of a MAF setup. I pulled the MAF off the last one of these I messed with and converted the stock 165' ECM to MAP using the Australian Holden aftermarket $12P code.

TTOP350

iTrader: (8)

Nope, I like the MAF better.