stallion8797

I've been in the process of removing the AC, AIR, and replacing the waterpump, so I've had teh battery disconnected for some time now. Today I got everything back in place with the correct belt (that was the hold up) and the battery was completely dead. I threw a charge on it and the car cranked over, ran for a little and stalled. I tried to restart and nothing. I hear a lot of air being sucked in, but no fuel. Any suggestions?

RRT vette

Did you confirm any fuel pressure with a fuel pressure guage? Do you hear the fuel pump prime with in two seconds of the key being turned "on"?

stallion8797

Fuel pressure is good. I heard the pump the first time I tried to start it, ticking away and all. But after that nothing.

vinnies87

Do you have power to the injectors, you can ohm them to see if your even getting charge there, then check the battery, charging it doesn't always mean you have enough power to start...

jfb

Charge the battery overnight, then measure the voltage across the batt terminals during cranking. It must not fall below 9.0 volts or the battery is discharged, cable connections are poor, or the battery is at the end of its life. Batteries are fully charged when the no load batt terminal voltage is 12.9 volts or above and discharged at 12.0 volts or below and linear inbetween. Never let lead acid batteries sit for long periods (4+wks) doing nothing. Batteries self discharge up to 1% each day even disconnected and lead sulphate collects on the plates during discharge. Lead sulphate is at first soft and will be converted back to lead and sulfuric acid upon charging, but letting it sit, it hardens and then will not convert. A fully sulphated battery will not draw current when charging and is then a door stop. Buy a battery tender and keep your battery fully charged for a normal battery life. Every deep discharge in a car battery makes it lose some of its amp-hour capacity and continued cycling makes for the equivalent of a motor cycle battery.
Since you can crank, I doubt the battery is defective, but still perform the diagnosis above. See what error codes are stored. Engines need spark (and at the right time), fuel and air (and in the correct ratio) in order to start and run. Use your timing light during cranking to determine if you have spark and at the right time. Measure the fuel pressure at the shraeder valve on the end of the fuel rail after you turn the ign to run for longer than 2 seconds (because the fuel pump turns on for 2 seconds and shuts off). Watch the fuel pressure with the ign off. If it falls rapidly, you may have a leaky injector causing a too rich mixture to start. Unplug an injector and connect a noid light (available at parts stores) or a low power 12v lamp like a side marker light, across the injector plug and crank the engine. The light should pulse indicating that the injectors are being pulsed by the ECM.

stallion8797

I'm convinced the fuel pump is completely not functioning now. Is there any other reason other then it breaking that it might not work?

jfb

Measure the fuel pressure, THEN you can be convinced. And, sure there are many reasons why the fuel pump won't run. To begin with, check with an ohmeter the fuel pump fuse. Measure the voltage on both fuse block clips, one should have 12v on it. If none, then the fuseable link is blown. Jump 12v to the fuel pump and see if the pump runs, then you know if the pump motor is ok, and if it is, then jump 12v to the grn/wh wire on the pump relay. The relay should close and the pump run. Real measurements tell you where the problem is, clairvoyence doesn't.

stallion8797

So this is where it stands at the end of a long day. There is no fuel pressure at the rail. I can not hear the fuel pump turn on. There is power to the relay, but no power to the electrical connection at the pump. I tried running a power wire from the battery to the G terminal on the ALDL and that did nothing.

I doubt this has anything to do with it, but when the AC is removed how many wires should be unplugged. I have three, is this too many? The security light also stays on when the key is in, is that normal? It's been so long I don't remember. I will have some more time Tuesday to play with it, but would love to have it running by tomorrow. I have parts that need to go on so I can hit the track before the end of the month. Thanks for all the help thus far.

jfb

Try the diagnostics one post above your last one. Jump 12v to the fuel pump motor, this proves the fuel pump is or is not defective, assuming the motor ground is ok which you should also check. Jump 12v to the grn/wh wire (thats the color on my 87) to activate the relay which will prove that the relay is or is not defective. Measure the fuel pump fuse with an ohmeter, that will tell you that the fuse is or is not defective.

RRT vette

jfb is correct with his statment. I see you ran a jumper wire to terminal G and it did nothing (make sure the wire is connected good). This bypasses the fuel pump relay and sends 12v directly to the pump. You should have 12v at the fuel pump connector at the top of the tank with terminal G energized. If not check the fuel pump fuse (10a) as suggested and replace if needed. You can also run 12v to the fuel pump side of the connector and listen for the pump or even take the fuel pump out and run 12v directly to it. This will rule out ciruitry or the pump. Now, you can even use a short jumper wire, disconnect the fuel pump relay, and put one end of the wire in the first prong of the connector and the other end in the last prong of the connector...this will bypass what the relay does. Try some of jfb and my suggestions and see what you get.

rick lambert

check the fuse first, even if your fp relay was bad ,the fuel pump would get power from the oil pressure switch and energize the fuel pump after cranking caused the oil pressure to reach approx. 4 lbs.

purplewindworm

When a battery dies, the voltage goes down and the amps go up. This is basic ohm's law, since the resistance is always the same. This is why so often you hear people say that their battery went dead and consequintly the power window motor burned up, or the power antenna no longer works, or fuel pump went out. I think that your bad battery had something (if not everything) to do with your fuel pump.

stallion8797

Well i tested the fuel pump and it sputtered out like a water fountain. I'm guessing that's the issue. So do I get a stock replacement or something better?

rick lambert

Helps to state the year and any mods....but the stock pump will be good for most applications. Don't forget to get the sock too, it's like $10. I bought my last one at NAPPA, and that was around 5 years ago...still going strong.

RRT vette

HERE is where I got my fuel pump for my 86, it came with the sock and strainer.

coupeguy2001

A long time ago, in another galaxy,far far away, GM found out that they bought cheap fuel pump relays.
When the car doesn't start, the fuel pump relay probably isn't working, so at the back of the block on corvettes, there is a oil pressure sender, and a fuel pump switch. It's that goofy looking round thing with one wire on it behind the distributor.
If the fuel pump relay fails, continue to crank the engine, and the oil pressure switch will make the ground to run the pump.
If the clip on the fuel pump has been broken off, the connector on the fuel pump relay on the firewall slides down about 3/16 of an inch and the relay doesn't work. check those before changing the pump.

rick lambert

" If the clip on the fuel pump has been broken off, the connector
on the fuel pump relay on the firewall slides down about 3/16 of an inch and the relay doesn't work". I think you might be referring to the clip holding the fuel pump relay to the connector.

stallion8797

I'm positive it's the fuel pump. I went ahead and purchased the pump and wiring harness through racetronix. Does anyone have experience with these guys?

RRT vette

No, never purchase from there. Did you apply 12v to the fuel pump outside the tank to make sure it's the fuel pump?

stallion8797

Yea I pulled the fuel pump out and tested it with the direct connection and it pumped very poorly. I then hooked it back up to the car and checked what happened when the key was on, and it was the same thing. So my conclusion was that it wasn't pumping hard enough for the fuel to be efficiently used.