I have a 92 RS swapped to 350 TPI (yes tpi) A few months ago my car just died while i was driving it. I figured it was the full pump so I dropped out tank and did all that work to just find out i am only getting 8-9v back to the pump.

I am kind of new to working on cars, but with directions i can get it done so I need specifics please.

Basicly I need to know what I should be checking?

Battery Check Good btw

 

fuel pump relay...located on the drivers side...only whiteish one there...

 

ok.. i see 3 relays here.. all have the same part number? how can i tell what one i need to look at? of the plugs going into the bottom (not wires) 2 are grey 1 is black.. i dunno if that makes a diff.

 

i left a multimetter connected at the terminal for the fuel pump and even when i disconnected the 3 relays it was still showing 9v... i thought if i disconnected them it should have cut power.. am i missing something here>?

 

How did you power up the pump to test voltage?
You would have to hotwire the relay to operate full time so as to send power to the pump for testing. Pump only runs for 2 sec when the key is turned on then stops

Sure you are on the pump connection and not the gauge one?

 

Well the way I am testing is under the car where the fuel tank would sit there is a 3 prong connection (where the wires would plug in) the 2 slots i tested at the 2 closest to the driver side. being as it is just a connecter there are no wire colors or anything for me to tell the difference.

So basicly the way i am testing is i turn the key in on and have the meter pluged into the connector under the car.

 

Under your hood, there are a few relays on the drivers side of the firewall. One of these is your fuel pump relay. There are 5 wires going into the fuel pump relay. Red, Gray, Dark Green/White, Black/White, and Orange. That red wire goes a few inches and ends with a black test terminal. If you run a jumper wire or test light from that red terminal to the positive post on your battery, it bypasses the fuel pump relay. With it bypassed, check the voltage at the gray wire up over the axle. Just look at the harness before you unplug it, and see which terminal matches the gray wire. If you get battery voltage at the gray wire's terminal with the jumper in place, the wiring between the relay and the pump is fine.

Disconnect the jumper wire. Connect your DVOM between the terminal to the gray wire, and ground. Turn the key from off to run a few times, you should hear the fuel pump relay click and you'll have battery voltage at the voltmeter for about 2 seconds each time you turn the key. If you have voltage, then you don't have a problem with voltage.

If you don't have voltage, unplug the fuel pump relay and check for voltage at the orange wire. The orange wire should have battery voltage at all times. If it doesn't, look near the battery on the inside fender, you're looking for a black fuse holder, with two wires. It'll look like a connector, unplug the connector and there will be a 20 amp fuse. Is the fuse good? 12v at the fuse connector? If all that is good, try a different relay.

Keep in mind, as soon as your oil pressure sending unit detects oil pressure, it'll automatically bypass the fuel pump relay. So if the relay is bad, usually the only result is it takes the engine longer to start, but it still runs fine since the relay is only used to prime the pump at the first start.

 

Ok finally got back around to tinkering with this. I tested from relay to the back of the car and got 12 volts. Then i plugged the relay back in turned the key and i got 8 volts, but it held solid and did not turn back off. Just stuck at 8 as long as i left the key turned on. I did make sure i was plugged into the right terminals at the connector in the back. Also i tried to test the orange wirse and i couldn't get voltage, BUT i am pretty sure i was doing it wrong. I put the connect from the DVOM on the orange and touched it to each of the other points of the relay connecter and even tried touching it to the metal of the car.

Also i looked for that connector near the fender and i could not find it. I do have 2 wires from off the positive of the battery that just terminate? If thats not it I'm not sure where it is or if i am just missing it.

 

When you test the voltage at the relay, go from the relay to an unpainted ground or even the negative terminal on the battery. The orange wires that terminate off the battery cable might be the fuse holder. It'll look like this...


If you're not getting full battery voltage (check the voltage between the battery and ground, and then check it at the connector) try swapping the relays. The fan relays under the hood will all be the same style relay. You might lose a little voltage just from the length of the wire, but it should be close. If it's the same with another relay, you might want to check the resistance between the connection under the car, and the connection to the relay. It shouldn't be much at all. If the wire is shorted it'd pop the fuse. If it's corroded you may get a voltage drop. The trick is locating the problem.

 

Ok so i was testing the voltage at the orange wire (orange wire in pic above) and when i test it to ground i got nothing. So I tested it to the neg. term. of the batt. and still got nothing. Just to check i touched it to the positive and got 10.5v. So... that has me confused

I still can't find this fuse or connector by the battery. I pulled out the battery and looked all around, but did not find anything. Is it under the battery holding area? Posting pics so ya'll can see what i am looking at here. (below is where battery sits. wires there to headlights on passenger side.)

 

It sounds like you're not getting voltage through that fuse. What harness did you use when you converted to TPI?

Here's a couple pics of the fuse... The photos are from my Formula (Camaro similar) the diagram is from the 91 Camaro service manual.

 

The previous owner did the convert so i am unsure of what harness was used. Is there a way for me to get that info?

That fuse must be somewhere else because there isn't one around the battery area. is there a wire i should follow to try and find it?

 

After reading a few other posts on the board my understanding this fuseholder is supposed to be somewhere between the battery and the radiator. Well its not, also enless it comes off the neg post then it isn't there that i can find. Off my pos. term. i have 2 wires. 1 that goes down into the engine and the other that goes to the alternator. Now that one that goes to the altenator has this round thing on it.




This wire that I am holding is the one that went to the altenator

 

It could be anchored to the radiator support, or on the inner fender skirt.

Look around the radiator support and see if you've got a junction block. TBI and V6 cars used the junction block, and the wiring we're looking for might still be there if some just modified the harness instead of replacing it with a donor.

 

I found where it was supposed to be. I traced the wire back across and came to it sitting not connected to anything about 5 inches from batt. out of sight. Only thing it is was just the wire. No fuse. Wire is in pretty bad shape aswell. when i connected it and turned the key i could hear the relay clicking, but i still only get 8 volts in the back.

 

Is the fuel pump wiring in the back of the car wired to the fuel pump correctly or did someone wire it up their own way? It looks like the wiring is a bit of a mess. You might want to just get yourself copies of the wiring diagrams and see if you can figure out how they wired it up. I think there's a sticky somewhere on how-to convert the TBI harness to TPI. The 3.1L harness is really close to the 90-92 LB9/L98 harness too. There are a lot of options, and even from year to year & Camaro to Firebird things moved around. Without knowing what was used, you're kind of shooting in the dark.

 

Well one thing i need then is the diagrams.. but where can i get them?

 

The best source is going to be a GM service manual for your car. That would give you the 92 Camaro 3.1, 305 TBI, 305 TPI and 350 TPI wiring diagrams. You can buy them new from www.helminc.com but they're expensive. You can usually find them on Ebay for under $50. If you get lucky you might be able to come up with scans. It's a real PITA trying to hold a 4" thick book on a scanner trying to get a clean scan. Autozone.com has some diagrams for some cars, but you'd have to look.

 

well, i plugged in the fuel pump and turned the key and it is finally spinning. I don't think i am getting full voltage though and i think that is just due to the shotty wiring job of the last owner, but i can start replacing that. Now i can finally put my car back together after it has been sitting for months! Thanks for all the help!!!