have a 1992 rs with the 3.1L in it. It quit in driveway . tank is full.
I have been reading on here for a couple of days and did allot of checks on other stuff to no avail here is a list of things i have done.
1. checked 20A fuse on passenger finder
2. replaced fuel pump relay
3. replaced oil pressure switch ( in housing where oil filter screws on )
4. listened for pump to come on....nothing
5. checked to make sure tank has fuel
6. checked battery voltage (11.8V)

then I checked wires where they go through to fuel tank behind back seats under carpet. with key on I had 5.14 volts dc on the purple wire and .04 volts dc on the gray wire. and of course the black one should be ground.
I also tried applying a full 12 volts to the gray wire at the relay and where it goes through to the tank behind the seats.

just need some input before i start the dreaded fuel pump replacement!

 

anyone????

 

90-92s have a fuel pump test connection in the engine wiring harness just above the A/C box on the passengers side. I know its there on V8 TPI engines in Camaros near the brake booster in Firebirds. Run a test wire from the connection to the + side of the battery with a inline 20amp fuse. I can't remember with the key on or off. You should hear the pump come on if the pump is good. You also could have a VATS problem.
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If your starter doesn't work either its probably a VATS issue

 

Although this may not relate specifically to your vehicle, coming off the tank there may be a plug where the wiring from the sender/pump harness joins the body harness. You can pop the plug, and apply power/ ground from a spare battery at that point as well, maybe easier. Since you are likely to be flat on your back near the tank, you can hear the pump run as well.

 

Also, if your 730 ECM goes bad it could kill everything.

 

If it cranks without starting, then it may be the pump. If nothing happens (no starter noise), then might be VATS.

Best test in the world is to jack up the car in the rear, pull the connector to the pump (it's just on top of the fuel tank in the front), and put 12v straight to it there - you should hear the pump run.

On the pump, get a good one - no Autozone or Advance junk - goto Napa or Carquest - you don't want to do it again.

 

You can get a new pump from GM for $100 plus some change for the strainer.

Check your ignition switch with the key out. Look between the switch and the column to see if the 2 orange wires are broke. Design flaw from GM that replacement switches were redesigned to guard the wires.

 

thanks for the replies the engine turns over like normal just no fuel getting to it. My main concern is the voltage behind the rear seats. shouldnt it be around 12 with the key on? I will do the stuff you guys suggest today and thanks again for the input

 

That would eliminate the VATS being the problem. How many miles on this car? Clogged fuel filter? Do the test that I suggested or the other test others said and get back with us. You would think 12V would be there but without checking my manuals, I'm not sure. I always check them the way I mention before.
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Any codes?

 

I just checked the test connection with 12 volts from the battery and nothing. the camaro has around 200,000 on it. its been running great with good fuel mileage also. Im going to pull that plug and test it there in front of the tank. Im not sure about the orange wires behind the ignition switch. I really cant see them. I will look further! also when this first happened, i pulled the cap at the back of the mpi manifold where the fuel test port is and there was pressure. but I couldnt get the pump to start to actually test it.

 

Forget about the VATS because your starter is working.

Key on and off?

 

After trying to start the engine see if there you can get fuel out of the fuel rail test port.

It sure is sounding like a fuel pump especially with 200K.

If you tested the way I suggested with the key on and off it's your fuel pump.

Pull your codes and see if the ECM is working. I'm not sure if it could be your ECM but its possible
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Fuel pump work or they don't

 

I am able to pull codes. its the OBD 1 and i have a code reader for it. im leaning more towards the fuel pump also, but the only thing that i was concerned about was the voltage back there. maybe the pump is shorted and thats how it reads, im not sure. I guess i may as well start taking things apart as bad as i hate to

 

OBD1 can be read with a paper clip. Do you have a haynes or chiltons manual? If so it will tell you how to read the codes

 

We have a haynes manual, checked them a couple of days ago and they showed nothing for the fuel system.

 

It will show you how to pull and read your codes though.

 

thats what i meant, the codes that come up had nothing to do with the fuel system. there are some other codes i need to fix though.

 

It will only be 12 volts for about two seconds after the key is turned to the "ON" position. If everything is working properly, you would see 12 volts if you cranked the engine over. Set your voltmeter up so it's reading with the key off, then turn it on. You should see 12 volts, then watch it drop to nothing.

 

ahhhhh, I will have to try that first thing in the morning. I am to the point that I think its a bad fuel pump, I have been hoping for the best with Dokken10's great help ( ) I was even debating on cutting a hole to get to the pump (since im not keeping the original motor and stuff in it), and decided against that also, so i guess i will start taking the exhaust, and rear axle loose tomorrow

 

I'm not a fan of the cut out shortcut especially with TPI because of the rubber hose splice. Rubber hose is not rated for the higher pressures of a TPI pump. Yes, people have done it and it works.

Glad I could help.

 

Be careful when dropping the tank. I cut my finger pretty bad on one when the fill neck finally cleared and the tank dropped all of a sudden and the tank was empty. I also found it easier to drain the tank from the engine compartment at the rigid-rubber hose connection with a couple feet of hose that fits over the rigid line. 5/16" hose if I remember correctly. Its hard to drain it empty thru the filler neck due to the baffles in the tank.

 

well, I have done several in tank fuel pumps and hated them all, this looks like it will be the worse, I just got the 92 RS and an 86 IROC about 2 months ago and decided to make the RS into a street rod and keep the IROC all original
even though im not keeping the RS original I still dont want to cut it up and im going to do the fuel pump right as i have always dont in the past. I just wish it had the same pump as the IROC ( on the side of the block)

 

thanks for the advice on dropping and draining the tank........FULL TANK I just filled it too!

 

Mechanical fuel pumps on the block are so easy to replace.

To bad it wasn't your VATS or ECM. I always pray its the fuel pump relay but it never is.

 

well, I was sure hoping it was the relay or something easy , guess i have a good start on some new parts that may go bad sometime in the future sounds like it wouldnt hurt to keep them around. My wife kind of adopted the IROC so the RS naturally goes bad

 

My son gave me (dropped on me) a 90 RS with a 305 no power to the fuel pump! I am checking over all of the things that you guys suggested-and I did cut a hole to get to the fuel pump. l I intend to cover it with a piece of sheet metal. I think having an inspection port for the fuel pump will help in the future.

 

I too am having the same problem with my 91 rs 305, and I was actually getting online to post about it when I saw this post. But I have the same question as what was originally asked at the top of the thread. When I check the voltage at the connector (ground to gray?? wire) behind the seats I get the 12v for the 2 seconds the primer relay kicks in, and then it drops to zero as it should once the relay kicks off, but the voltage on my car between the ground and the purple (I think that's the color) wire reads 8.5 volts.


So the question I was hoping to see answered is...What should the voltage between the ground and the purple wire? Mine reads 8.5 volts when the key is on and he said his read like 5 volts? Does it need to be 12volts, and does it have any bearing on the operation of the pump to push gas?

Thanks in advance!

PS you'll have to excuse my not knowing exactly what the colors of the wire are.