My '89 began to stall at low speeds. Since the car is 17 years old I repaced the fuel pump, fuel regulator, and filter. Now the car won't start. the pump is pumping over a half pint of fuel at the manifold when 12 volts is applied for 15 seconds and the pump comes on for 2 seconds when the ignition is turned on. The car will run for several seconds if I spray starting fluid in the manifold. Apparently there is not enough fuel pressure at the injectors. Please help, thank you.

 

...well, there are a few "must haves" when you own a vette.... a factory "helms" service manual and fuel pressure gauge. you have fuel but apparently don't know the pressure on the fuel rail. it sounds by the quantity of fuel that you may have enough pressure but, that guess is not all inclusive so, get a fuel pressure gauge and attach it to the fuel rail at the shrader valve and tell us what the pressure is.

you also have to have spark and air and i will assume that your air filter is not a block of clay that hasn't been changed in 15+ years so, lets eliminate that......what's left?..spark.

ignition coil, ignition module rotor cap, spark plug wires, and spark plugs.........all need to be checked. i would to a "standard tune up if you haven't done one recently. however, if it were my car, i would (after checking the plugs) replace the coil and if that didn't get her going, the ignition module under the rotor in the distributor.

however, it stumps me in that the car will run with "fuel" manually sprayed into the throttle body. double check as to if you have the correct pump and not to be insultive but, check if the filter is installed correctly. i doubt that the injectors have all taken a "dump".

 

You need to get a fuel pressure gauge! Hook it to the fuel rail and turn on ignition and see the pressure readings. You can buy a gauge from a local parts store around $40. You obviously have spark and air or it wouldn't run on the shot of starting fluid! Your problem is fuel delivery related, so get those readings and post so we can help better w/full info.!

Thanks,Matt

 

....agreed....

 

Check your injector fuses!

 

There is no fuel pressure at the rail only a little trickle of fuel comes out when the shrader valve is pressed. Is the little fuel pump in the tank suppose to bring the pressure up to operate or does it get help from another source? The new pump does deliver over a half pint in 15 seconds at the manifold but won't bring the pressure up at the shrader valve. All fuses check OK.

 

This tells me that, somehow you know there is fuel at the fuel rail. When the key is initially turned to the on position, the fuel pump relay energizes the fuel pump. It will only do this for 2 sec. then shut off. You will need a fuel pressure guage attached to the schrader valve on the right hand side fuel rail. When the key is turned on, note the pressure reading. You can manually energize the fuel pump by connecting a jumper wire from the + side of the battery to terminal G on the ALDL. This will run the pump until removed. You can use a test light at the fuel pump fuse and at the connector above the fuel pump while powering terminal G.

Also as suggested, make sure the fuel pump connections are correct, make sure the filter was put on correct, and that the spring and diaphram are in right. If you can spray starting fluid into the intake and it run, then you have a fuel problem, as of now. You can push the schrader valve down and fuel should come out (under pressure), but you want know how much pressure is there without a fuel pressure guage. The oil pressure switch is a back up to the fuel pump relay and will start the engine when 4 psi has been met while cranking.

Try these few things and get back.

The fuel pump is just what it says. If it is working correctly, and you have no obstructions in the feed line (clogged filter, bent fuel line), it should give you a pressure reading with a fuel pressure guage. When you say "manifold" which part are you describing?
You should hear the fuel pump prime when the key is turned to the on position, and will only prime for 2 seconds then cut off. Make sure you have fuel in the tank and also visually check for kinks in the lines. Get back with more info.

EDIT: The tools needed are voltmeter, fuel pressure guage, and some troubleshooting skills

 

When the ignition switch is turned on the fuel pump comes on for 2 seconds. I disconnected the fuel line at the rail (near the intake manifold), applied 12 volts to the fuel pump for 15 seconds and over a half pint of fuel came out. Does the pump itself bring the pressure up to operate? I'm thinking it might be a bad New fuel pump.

 

You really need a pressure gauge to troubleshoot correctly. I recently had to replace BOTH fuel pumps on my ZR-1 (went bad from sitting), and the new ones pumped fine, just at 11lbs (45-55 required). It would'nt start well and then would hardly run. Don't confuse volume with pressure. Carburators work on volume, fuel injection works on pressure.

 

Lets see here. That is 2 pints a minute. Two pints a minute is 120 pints an hour, or 15 GPH. Even with a conservative duty cycle, you're going to have a hard time supplying 8 injectors rated at 22 GPH or more. Plus your 1/2 pint was at unregulated pressure. I'd say there is definitely a fuel delivery problem.

RACE ON!!!

 

I think you will need to get a fuel pressure guage, make sure the fuel pump is wired correctly, and try again. A fuel pump can be bad even if it is new. If everything is working correctly with the lines and wiring, I would say you have a bad pump.

 

 

I replaced the new fuel pump with the old one and it started. I bought the new pump from a reputable auto supply, it is either defective or the wrong part was in the box. The little guy gets the shaft again. Thanks for your help. After I replace the pump with a new working part I'll let you know if I still have a stalling problem.

 

What was wrong with the old pump? Does the new one look like the old one? I hope you got it running and if any questions, let us know.

 

Welcome to my world!

 

Be sure you did not mix up the inlet and outlet fuel lines, I have done this twice and when I switch the lines around, the engine fires immediately. Good luck, Dave

 

But you didn't get a half pint of fuel out if it in 15 seconds, or even 15 minutes, with it hooked backward, did you?



Do some fuel pressure TESTS to help determine if it is a fuel pump problem, at all. A little trouble shooting could end up saving big money. Don't just throw parts at the problem. Diagnose and FIX it.

RACE ON!!!

 

I bought another new fuel pump and the car started and has not stalled. My mistake is I assumed the first new pump I bought would work correctly, it pumped out the correct amount of fuel but woud not hold pressure. I decided to replaced the fuel pump and regulator first since the car is 17 years old, before I broke down on the side of the road.

 

Wow - junk out of the box - been there more than once (usually at Home Depot). Tell us the brand and where you got it so we know what to avoid.

 

Not at 1/2 pint per minute is wasn't pumping "out the correct amount of fuel".


When a fuel pump starts to fade, the problem begins at higher speeds and/or under heavy acceleration, where more fuel is needed and the demand for the maximum fuel volume is greater and harder to supply. Your initial diagnosis, especially the pump, seems a little hasty. The "shot gun" approach may have actually worked for you, in this case.

RACE ON!!!