Redspider

Hello Corvette owners,
I’m new here today. Yesterday I bought a 84 vette. It has a new 350 engine.
He started to change the intake over to a GM TPI. (I have no idea what the TPI came off).
I have the wire harness, the computer, intake, rails everything. I just don’t know where to go from here?

Is there a step by step info page of someone doing this?

Thanks for any help.

DanielRicany

You Would better Off Buying The Original Items And doing A carb Swap. Less Work.

383vett

I've got an 84 with a miniram. It's not that hard if you can follow wiring diagrams in a service manual.

FASTAZU

It can be done, I've done an 80-82 & 84. 80 & 82 were very easy just added after market harness and F-body ECM for the electrical. 84 took a long time you need both 84 & 85 service manuals to run down the wiring if that's what year the parts came from.

JackDidley

QWS did it. Seems like it was no problem for him.

Redspider

All I want is for the thing to run. I really don't want to put a ton money in it.

I got a box of parts with the car. In the box was the old crossfire intake and carbs. They are in rough shape.

Just to make it simple, I wonder if putting it back stock is the way to go?

It will take some work to get the old carbs clean and looking good.

Ive seen some are porting the intake and they say that helps out on some horse power?

GKK

Yes, installing the stock Cross-Fire manifold and duel Throttle Bodies (Not Carburetors), will be easier to do if everything is there.

Porting the Stock CFI intake manifold, will do wonders for power!...

FASTAZU

CFI Stock VS Ported

Redspider

That porting looks great! hole size is huge!
Im really leaning toward the crossfire to be put back on.

Is that all the porting thats done? (intake holes)?

Im good with tools do it myself or send it out to a pro?

FASTAZU

here is a lot of great info. on the CFI its in the C3 section 82 had the same setup.

http://forums.corvetteforum.com/c3-t...solutions.html

vetteoz

Easily done at home with the right tools

http://www.technovelocity.com/chevyh...rt_polish.html

Tom400CFI

Port the runner from it's entrance, to it's exit. Floor, walls, ceilings. The more metal you remove, the more power your engine will make. You can't go too far until your go through somewhere, then that is easily repaired w/epoxy. If a port matching job, as is commonly done to CFI intakes (porting just the end of the runner by the heads) you can get a noticeable gain. With a FULL porting of the runners, optimized base timing and fuel pressure, you can pick up ~30 hp or more.

91tpiman

Is it Mass air flow or Speed density? That would be your first step. What is the service number on the ecm? 85-90 should be Mass air flow,but the 85' is unique.

GKK

85-89 TPI Vettes use Mass Air Flow, 90-91 TPI Vettes use Speed Density.

qws

First Congrats on your car.
If your even thinking of tearing all the harness out and ecm just for a TPI set up ..... DON"T BOTHER.. Its a waste of your time and money for the little gain your going to get. Its still a restrictive set up.

Now.. if your gonna go the route of Miniram,SuperRam,HSR on a modified engine then its a different story.

Easiest way to convert a CFI to Multiport Injection
Use the EBL lockers ECM with port mod, Get it Hammed or Repin the ecm connector yourself.
Plug in... Make about 5 min's worth of changes to the some connectors at the engine... relocate one wire at the ecm. And your done.

MrWillys

I personally would make the swap to TPI, but I may be a bit biased. The TPI develops more power where most people use it daily than any other intake. Is it restrictive above 4000 RPM? Yes, so as long as you drive above 4000 RPM most of the time then don't use it. Also, the 84 ECM has never been hacked, so any custom programming is out of the question. Either use the 1227165 mass air, or the 1227730 (Camaro) ecm's. To me there's not enough there in the stock 84 to waste your time.

here's a great site for additional support:
http://chevythunder.com/since_its_inception_in_1985.htm

Redspider

Thanks everyone for all you input!
Asking for more input.

Heres my new love hate Relationship with this car:
The previous owner has done the following:

He has taken out the original ECM (I have it) (1226026) out. Cut the wire harness that went with it. And tossed it.

He has a TPI harness and computer that he started to install. From what I can find it came from a 90-92 Camaro/Firebird. It looks to be in excellent shape.

Here’s the shake down: Do I:

A) Just finish what he started? Wire harness engine side will be a breeze. It’s all labeled.
Dash side I’m going to be lost. It will take some research.


B) Put the old CFI back in? Throttle body will need work. It will need new injectors, wire harness that was tossed.

Here’s some pics of my mess.







Heres the old

MrWillys

Go with the TPI without question. Get some valve cover paint, and put the stock ones back on. The TPI is from a Camaro as noted by the fuel line position as it exits the unit. Tell me the fuel rail number on the drivers side rail, and I can tell you what it came off of. You'll need to check everything as you go along. You never what this guy did.

Redspider

Thanks for your help MrWillys!

Fuel rail read 0915 HUZ 17085052

I'm worried about wiring. Everyone says its hard. Looks like plug and play for most of it. (I must not be understanding something)

MrWillys

The 17085052 rail is from a 85 thru 87 305 Camaro. The manifold is exactly the same, but injectors, and the fuel pressure regulator spring pressure are not. Choose an injector, and get an adjustable cap for the regulator. You will need a custom programmed memcal anyway to at minimum eliminate the VATS from the memcal. make sure the programmer understands the injector, and let him recommend pressure. hint, look at my website linked in my username.

Wiring is not that hard. You can get the Painless harness which is the best in the business, or go with a cheaper one from a guy like www.fuelinjectionconnection.com (do NOT let him provide a memcal), but if you choose the cheaper just make sure you get every circuit YOU want. Red, or orange wire is a constant hot, and the pink with black strip goes to a key on, and hot while cranking. You'll have to get a fuel pump, so i'll recommend the Walbro 255. You could trace out the harness you have by following these:

http://www.chevythunder.com/199091_c...227727_ecm.htm

http://www.chevythunder.com/fuel%20i...ts.htm#1990-91 speed density (Corvette ecm #1227727)

once you get done you'll realize how easy it was, and have a great running system capable of 400 + HP if properly tuned to a custom build. Or, just a great running stocker.

oh yeah, you'll need to split your VSS wires coming from the trans, and run them to the ECM. keep them clear of ignition wires as much as possible.