pauliep103

hi my name is paul i have an 82 vette c3 i have no fuel going to the carb i replaced the fuel pump i replaced the relay behind the seat it looks like im not getting any power to the pump on the relay the orange wire throws out power, i checked the fuses all are good can anyone tell me what else should i be testing or should i just go with a machanical pump

71VetteLover

Welcome to our great forum Paul. The '82's have their electric fuel pump mounted inside the gas tank. When you turn your key ON the ECM will power the pump for two seconds and then shut it off IF oil pressure isn't present. But if oil pressure IS present during that two seconds the pump will continue pumping, your engine will start, and continue running as long as oil pressure is present.

When you turn your key ON you should be able to hear your pump humming inside the gas tank for those first two seconds so have your wife or son or daughter or neighbor turn your key ON while you listen for its hum. Make sure the plug on the top of the oil pressure sender is firmly attached because a bad connection there will tell your ECM there is no oil pressure present and the pump won't pump after that first two seconds.

Antz81

A mechanical pump won't work with the 82 unless you've swapped the two throttle bodies out for a carb

DUB

If you do not hear the fuel pump running when you turn your key ON...

If I am not mistaken...the fuse for your ECM and fuel pump relay is in the battery box and NOT in the main fuse panel.

DUB

hugh9222

There is a large (I think 30 amp) fuse in the battery area. I have the same problem with my 82. I hope someone comes up with an answer. With the improving weather here in Houston I'm going to attempt to get mine running again but I'm not hopeful. Over the past two years I've replaced every replaceable component in the system except for the wire harness with no real luck. When in come to something electrical I have trouble changing a light bulb so I'm not optimistic. Final note you can change your fuel pump WITHOUT removing you tank. I've done it twice.

DUB

hugh9222,
If and when you get back into your problem....start a thread an IF I see it I can help you if you are having electrical problems.

All you will need is a test light, voltmeter and some wires for testing.

DUB

L-46man

Twin throttle body fuel injection has an in-tank higher pressure pump.

DO YOU KNOW IF IT'S TBI???

DUB

By the way the original thread starter wrote what was needing repair...they used the word 'carb'....and then also mentioned about the fuel pump replay which means that by assumption...they installed an electric fuel pump in the fuel tank.

IF the engine has carburetor and they are using an electric fuel pump...it will need to be regulated for the carb due to the pressure that it produces in comparison to a mechanical pump.

Hopefully the thread starter will come back and give is either better information...or not.

DUB

L-46man

I agree Dub...want to help the guy...I have a TBI 82 CE.

I completely understand his confusion...even 'mega Corvette parts ground zero' guys (no name on these forums) Had their webpage for the parts for twin cross ram TBI as TWIN CARBURETORS ...I called them on the carpet and they changed the website the next day.

Sigh....this has only been going on for 35 years! LOL

Unkahal

pauliep103

Sorry guys I didn’t have a phone for a few days I was thrown in the swimming pool by friend I just received my phone and seen the messages I have not touch the car since the last post it’s driving me nuts I bought a new pump also a relay and still no hum in the tank I do have a carburetor installed an fuel regulator I have changed out oil pressure switch yet I just ordered one. I really appreciate the help what kind of test can I do to hunt down the problem still no power to sender orange wire in relay shows power with a test light and also orange wire on pressure switch has power also do ya think the pressure switch might be bad

pauliep103

Do ya Recomend going with a machanical pump instead?? Where can I order a good one from

DUB

So this is telling me that the fuse ion your battery box is good (which is good) if you are getting power to the relay...BUT.

DO you have a wiring diagram for the 1982???

Having a wiring diagram and an volt/ohmmeter will let you trace wires and see if you have a broken or bad wire.

What type of tools do you have....such as a voltmeter and test light ??? I assume you have both. It 'sounds' like you are not getting a signal from the ECM to close the fuel pump relay and make it run. I am not at work so I can not see what circuit to look at.

Checking the wire that is coming out of the relay that is providing power to the fuel pump is where I would start. IF I am not getting power out of the relay that is supposed to go the the fuel pump is not there...then I would wonder if the problem is in the ECM or other wirng to the relay. There is a way to check the relay to see if the ECM is doing what it is supposed to do when you turn the key to ON.

I believe there is a by-pass override for the fuel pump that can be gotten to in the ALDL connector UNDER your ashtray area. I know the Tuned Port cars have this and if my memory serves me correctly your car should also have the terminal in the ALDL connector to get the pump running IF all wires are correct.

IF you plan on getting rid of the electric fuel and installing a mechanical pump you more than likely will need to replace the sending unit with one for a 1978-1981 or do a modification to extend the tube and filter so the fuel can be picked up from the bottom of the tank.

I have had a few of these 1982 where the sending unit electrical connector on the inside of the tank was bad and not allow current to get to the pump....even though I was getting it at the connector that plugs into the connector from the sending unit.

DUB

pauliep103

I’m going to get on it in the morning I see you know your thing I wish I could drop the car off to you lol , so today I also tested the plugs in the fuel pump and no power at all I pokes the wires mane thinking the plug was no good I was reading other peoples problem and a couple of them were mentioning the oil pressure switch they mention that it throws out 12 V to the relay tomorrow I am going to test the pressure switch first then I’m going to try the stuff you mentioned, thanks for the help. By the way are located in New Jersey ??

DUB

New Jersey....No...look under my screen name and beside 'Location :' is where I am at.

I will ask again...Do you have a wiring diagram??? Or a GM Service Manual for your 1982 Corvette????

Reason being...if you were to call me at my shop so I can walk you through how the system works...it is BEST of I am talking with someone who is looking a the same page of the GM shop manual or wiring diagram that I am looking at. Without having the manual or wiring diagram that you can clearly read... so I can direct you...so you then understand what is going on ....and we can get to a solutions much quicker than if you do not have anything.... is not worth my time. It is too hard for me to 'paint you a picture' over the phone when it comes to something like this.

Do you still have the diagnostic link connector (ALDL) under your ashtray when you take it out????

I am assuming that you still have a ECM (computer) in this car??? It is mounted in front of the battery. This is a MUST!!!!...unless you want to override the fuel pump and have it ON whenever you turn the key on.

DUB

pauliep103

I don’t hav a manual or scimatics I’m going to a friend today to get one printed out his shop I was suppose to work on the car yesterday but got caught up with other stuff and yes the ecu is their in the back of the car by the battery

DUB

Thank you for the reply. I need to 'refresh' my brain on it so i knwo all of the particulars that make the system work. I know it...but not each and every wire circuit and where they are located specifically in a connector.

We will get this working...that is for sure.

Asking again....Do you have the ALDL connector mounted to the floor board under your ashtray....this is important...because I would not ask if it weren't.

DUB

pauliep103

I will look when I get home from work

L-46man

Papawanna has free wiring diagrams....just ask him.

I made a 'grounding switch' for the ALDL under the ashtray....just a simple sub miniature switch with two gold pins that plug into position A+B (one being ground) on the ALDL...wanna get the codes....flip the switch! Then shut it off! easy peasy...love that little ALDL. These are the two LEFT MOST pin-outs. Good luck.

PS There is an entire TBI/ manifold set up on craigslist. PHX/ craigs/ corvette parts $250!!!!! good luck SIR!

cv67

is your oil pump switch working? If it shows less than min it may cut power to your fuel pump. Keep what you got and make it work, when right they leave the line pretty hard. KNow of a few guys going fast on these.

Bigredwing

This must be contagious. Now my fuel pump has quit. All I was doing wast testing the fuel sender unit using the Wilcox procedures. Fuel gauge has power just shows full all the time. At the tank connector I have .2 ohm at the tan wire and 115 ohm at the pump motor. Seems that the gauge should read empty with a .2 Ohm reading to me. I also get 8.5V at the tank connector for pump power. I think that is normal with the key ON. I tried 12 V directly to the pump motor using a battery charger but nothing happened with that too. Car ran great two days ago when I put it on my lift. What next?

Also, gauges work and show oil pressure while cranking and the battery compartment 20A fuse is good.