So... that's the thing, you'll probabyl want to decide soon which direction you want to go. Going with CFI isn't "limiting" per-se, but you don't have a lot of performance options. There's tons of performance stuff for TPI systems. Anything that you need though, you can check Corvette Generations (do a search). They have hundreds of Corvettes and specialize in C4s and C3s. They will have whatever you need, whether that's an 84 engine harness, or something else.

Also... the harness itself for the ECM, isn't all that busy, once you take out all the other things like smog pump and stuff. If it were me and I wanted to keep CFI. I'd probably label everything as I took it off, remove the entire harness and lay it out on the kitchen or dining room floor, and slowly repair it and replace any of the connectors that area broken, etc... and then re-install it.

EDIT: It's easier (honestly), to re-do the harness when the engine is out, just because you can re-route everything on the motor as it's supposed to go. The engines usually get installed into the car as a unit with the engine harness already hooked up and plugged in. So doing it with the motor in the car makes it a bit more complicated, but not at all impossible. You just usually can get a cleaner look with the motor out (and fix all the other things like rear-main seal, check freeze plugs, oil pan seal, etc.). But you know... it starts getting it to the point where, do you want the car to run, or are you totally restoring it... and I have a hard time drawing that line sometimes.

 

I may need a link, I searched and got a bunch of random results for Wiki, Redditt, etc. No website named Corvette Generations.

 

It's crazy that it's so far down the search list, but here it is: https://corvettegeneration.com/

He's been in business for a couple of decades I think...

 

For the measly 25hp gain of TPI over Crossfire there is a heck of a lot of other routes to go that are less involved in time and money than a CFi to TPi conversion

You can gain that 25 HP with a poor intake port job and headers and keep it CFi

But like was mentioned above with the state yours is in, you need to figure out what route you want to go. Carb, FiTech, or Sniper2 might be easier with your butchered harness

 

I am starting to lean towards just working with what what I have for now, it will free up money for restoring the interior and other parts it needs. If I can figure out why the fuel pump stays on ( kinda funny I go from no fuel pump to now it wont shut off unless I unplug it) then I believe the car will run once the FPR is adjusted. The PS pump bracket came in yesterday, so now I have to get a pulley puller and pull the wheel off the broken bracket and swap over to the new bracket, then mount that, the resorvoir and alternator back up to the car. Maybe a running car by the weekend? New brake rotors and fluids are also planned. It makes more sense getting the car to be a driver first, then later I can do engine stuff.

 

Does the fuel pump stay on when you take the key out of the ignition?

That could be either your fuel pump relay, or the oil pressure switch. You'll want to troubleshoot with the manual that you just bought... but GM does some weird stuff with the fuel pump and the oil pressure sending unit. I can't remember which... it was either that it wouldn't allow the fuel pump to stay running (past the initial 10 second prime) if it doesn't detect oil pressure, or something to that effect. You'd think that it would shut off the fuel pump if it determined a LOSS in oil pressure while driving, but it doesn't do that for safety reasons because they assume you'll still want to be able to drive off to the side of the road, at the expense of your motor.

But that initially sounds like a fuel pump relay...

GM often uses the same relays for different things... so you might be able to swap out the fan relay with the fuel pump relay, and see if that fixes the problem (temporarily).

 

It comes on regardless of key, as soon as I plug the harness in at the back. I did not test the 10 seconds thing as I saw a fuel leak at the FPR, so I have been as far as about 3 or 4 seconds.

 

The "10 second thing" that I'm referring to, probably has a more appropriate name. But when you put the key in the ignition and turn it to the on position (but not yet starting it), in any 80s / early 90s GM car, it should engage the fuel pump, which usually lasts anywhere from 5-10 seconds before it shuts off automatically. This is to pressurize the line so that when you do start it, you already have fuel in the system and it's more ready to go.

But... if the fuel pump stays on, regardless of whether you have the key in the ignition... that absolutely is a problem with the fuel relay, or possibly the connection with the oil pressure switch. An easy way to tell if it's the relay is to find the fuel pressure relay, remove the relay and plug in a different relay that's the same size (usually the radiator fan and fuel pump relays are the same). I don't know where either of them are, but I would just search for "Fuel Pressure Relay location 1984 Corvette."

I just did a search but don't know if this is correct, it was on one of those pay for service websites: "The fuel pump relay is located in the engine compartment on the driver's side of the dash panel near the power brake booster assembly. It has a 5-pin connector with the following wire colors: A (2) Red wires B (1) Black/White wire C (1) Dark Green/White wire D (1) Red wire E (1) Orange wire."


Anyway, I've had this exact same symptom as you in at least 2 other 80s GM cars, including an F-body and a Fiero, and it was the fuel pump relay both times. The one in my 84 Corvette seems to work fine. As totally shot as my car looks, it actually only has 52k miles, but was allowed to sit outside for 4 years in upstate New York where the weather just destroyed the paint... and other than some really absurd add-ons by the previous owner (a second set of horns, another positive battery cable when there was a fire because they installed a 10-disc CD changer improperly), etc... it's actually very complete and relatively clean.

 

Thanks, I did previously locate the fuel pump relay and I put a test light on it and found power on 2 of the pins I believe. Maybe it was 3. I will have to reference that new book. I have to fix that fuel leak first before I try again to send fuel up to the carb though.

 

Ok so I found car side harness fuel pump power on the blue wire, just like the book says. With the recommendation of a forum member who also has a carbed 84, I picked up a heavy duty relay that he used to make my own circuit. I already have power ran to the back because PO had a sound system back there, so I will use that to get the relay tied in, and then send the trigger connection preferably to ignition if I can find it. With a plan for that I am just waiting to source a PS pump & pulley assembly, so that I can put all of that back together. Ordered an AC Delco alternator as well while I was at the parts store getting the relay. Who knows, maybe she runs this weekend?

 

Does anyone know if later-year C4 power steering pump/pulley/bracket assembly will work on my 84? I am having no luck finding a PS pump and pulley already mounted. I do have a replacement bracket purchased and ready to go. I was unable to get the original pulley off of the pump and actually bent the crap out of it trying to pull it off with a puller. So I need the pulley and a pump, because I can't get the pump I have off the bracket, due to how the bolts are. I was able to dremel off the head of one bolt, but I can't do that with the remaining bolt. It's so frustrating lol. I found a possible setup on ebay, but I can't get the seller to clarify with a picture of what I would receive, he just says "comes complete" and has a picture of a wrecked C4. I asked again for a picture of the part itself, but no response yet. If yall are bored and want to help source a good used setup that I can purchase, please let me know, it is holding me up lol.

 

If you put the threaded stud of the puller kit in the pump shaft for removal....that's why it didn't work and bent your pulley! The threaded stud is for pressing the pulley on...you want to use the beveled/flat tip or some kits have a shaft/pin with no threads...try again...sometimes it requires air/electric impact, but when using the proper parts of the puller kit...I've never not been able to get a pulley off. If this is not the case, please post pictures of your puller set-up! If you can get the pulley off, right now you only need a pulley and 1 bolt...those pulleys go for around $100 used on eBay and are showing up less and less. I just went through having to replace mine because I'm sure the previous owner incorrectly attempted removing the pulley and figured it out before distorting it too badly...but I just couldn't stand the little wobble mine had....fortunately a forum member helped me out and sold me one. You could post a WTB thread in the C4 parts section! And while you're in there, it would be a good idea to replace the pressure hose and return hose...they're likely original, leaking and hard....good luck, I'll keep an eye out for some parts for you👍

 

Why buy one? You can rent the puller from O'Reilly's, pull the pulley, push it on and return the puller for full refund of deposit. Done it more times than I'd like to admit.

 

Appreciate the input, I actually asked my son in law to do it as he offered, however he used the wrong kind of puller. I am going today to rent the GM bolt/stud/collar version and get it pulled off. I did see some pulley's as mentioned for about 85-100 on ebay, so I will just pick one of those up. I am headed to Utah for work tomorrow evening so I probably wont get to fire her up until after I return next weekend.

 

If you choose to replace the return line, the only source I could find recently was a Davies Corvette version, might have bought it through Corvette Central part #564371....when you get it, it won't look right, it's molded that way on purpose, so when installed it stays tight/tucked to the pump assembly


Davie's part# 536224
👍

 

Thanks, I imagine I will change them soon enough. Really appreciate the part numbers and source.

I ended up going to Harbo Freight and just buying the pulley remover kit. It took some wrestle but I got it off. I then was able to pull the ps pump off and got it mounted to the new bracket. Now I just need the new pulley wheel. After I get back from Utah in a week I should have the Vette going back together pretty quick. I still have the trigger wire and ground to connect on the cole hesser relay but that it is it. Once the ps pump, alternator and ps reservoir is all in, I dare say the car will run. Toying with the thought of ordering headers and new exhaust while I am away, because the OEM on there looks all crusty and likely has a leak or two. I will probably go with American Racing long tubers and a Borla setup. For interior stuff I found a guy parting out an 85 and I asked him to quote me all of the interior.

 

The replacement pulley for the PS pump was waiting on me when I got home from work today, so I grabbed the pulley kit and immediately installed the pulley onto the pump. With that done it is just now put everything back together, finish the fuel pump relay, and then fire her up and see what I got !!

 

Worked a lot on the Vette yesterday, man it is hot in my garage lol. Texas heat ugh, Only like finishing the alternator and tying in the ground wire for the fuel pump relay.

 

Wow I haven't been here in while lol. Life gets in the way sometimes. Anyway, I did get the Vette running and put back together but I did find another electrical gremlin done by the PO. Started the car up after finishing alternator and fuel pump and in my checks of looking to see if car is road ready, going through lights, blinkers, AC working etc, I found that engaging the turn signal shuts the car off. This was just too much for me. I know I shouldn't have given up, but I didn't right away. I came to the conclusion that the only real correction (and to keep from finding any other strange things the PO did) would be a new chassis harness and have all new OEM connections going to everything. I did find another harness, but life crap and time kept me from swapping it out. I sold the car sadly but I made some money on it. I learned a lot about the C4 platform working on this car, and if I had a shop with more space and a lift to work on it, I most likely would have kept it and swapped the harness over. I'm a little OCD about working in cramped spaces and working on that car with barely room to open a door I guess got the best of me and deterred me from swapping the harness over. The good thing is my wife got the message about me needing a dedicated work on car stuff area, and we went house hunting and found a place on 9 acres with a 40x60 shop!! We are working on getting it now, so excited !! I told her I want another Vette and she said to just get a nice one. I think maybe she is worried I will end up with another headache car lol. That being said I am now scanning the C4 for sale area. Mainly looking for 85-89 (because I like the dash design), pretty clean, no excuses cars. I would consider a LT4 car, even though I hate the dash design of the 90 and on C4. The motor is more important to me than the overall looks ( I know, I'm weird lol). I found a beautiful maroon 89 at a dealer in Dallas, but it sold before I could move on it.

 

aaahhh.. that's you in the ForSale checking in on that LT4. I like that car.. a lot. But, I'm in no position to buy anything. It looks nice, I hope it (or some other C4) works out for ya.