Fierhawk

I have a 1991 Pontiac Firebird 305 TBI. I have two problems in which I need answers. First is I had to put a push button start on the car to turn the engine. The key won't turn it anymore. I was wondering if the ignition switch could have gone out? Second is I can get the car to turn over with the push button but it won't stay running mainly because it is getting no fuel. I suspected fuel pump and bought one. The only thing that concerns me is everytime we would stop pushing the button to turn the engine over I would hear the fuel pump running. Any help is appreciated.

tripingeorge3

91 should have the chip in the key. either the chip is bad or your wires in the ignition lock have broken. use a volt meter to get the ohms of your chip, under the dash on your clolumn should be to white wires those are for they key, try touch both of those to each side of the chip on the key. more than likley have to bypass the chip. find the resistance on the key then use resistors to get the same reading as the chip or potentiometers(volume ***** from radio shack) .by adjusting the ***** u can adjust the resistance to match your key. may need 2 of the hooked in series. it works had my friend do this to his caddy.

Fierhawk

Thanks for the help. I'll try that out. Thanks again.

thunderstick

how long does the fuel pump stay running? sometimes it may run a couple of seconds because of the oil pressure built up turning the engine. usually caused by the oil press sending unit which cuts OFF your pump if you lose pressure... could be "sticky", going bad.

BigBadLou

iTrader: (3)

Just to clarify, the FPOP (Fuel Pump Oil Pressure) switch does not cut OFF your fuel pump ... quite the opposite, it turns it on when it senses oil pressure. It's a backup system, not a shutdown system. Feel free to search.

Lou

Fierhawk

It runs for a couple seconds then cuts off. I thank you for help. Now I at least have some things I can try out. Thanks again.

BigBadLou

iTrader: (3)

If it starts and runs for a few seconds, then it's not VATS as George suggested. I would get a fuel pressure gauge and test the pressure by the throttle body to see if you're getting enough fuel after startup.

Lou

thunderstick

understand that... i guess what i was saying is that on occasion when i'd shut my engine off, it'd run another second or two sometimes til oil pressure dropped off completely, but stands to reason that if the ignition was shut down, it shouldn't do that at all, right? cuz all power should be off at that time?

BigBadLou

iTrader: (3)

The FPOP powers the fuel pump independent of the ignition. As long as you have oil pressure, the fuel pump will be on.
(let's say somebody reaches underneath your car with a screwdriver and shorts the starter solenoid - if he keeps cranking long enough to build up oil pressure, the fuel pump will kick in)

So when you shut off your car, it's normal to hear the fuel pump for another second or two, as the oil pressure is slowly dropping after the shutdown. Then it reaches 0 and the fuel pump shuts off. Once again, that's perfectly normal.
It's a good backup system. Simple and useful.

Hope this helps.
Lou

Fierhawk

In a way it does. My only problem is that the car just turns over and sometimes acts like it wants to start but never does, and there isn't any fuel getting to the throttle body.

BigBadLou

iTrader: (3)

So if you have no fuel but you hear the fuel pump run (per your first post), you might have an obstruction. When's the last time you replaced the fuel filter? It could be clogged. Another problem could be a blown FPR (Fuel Pressure Regulator). It sits in the return line and keeps the fuel from returning so that the fuel pump can build up pressure. If it's blown inside, it will let fuel through with no restriction and the pump will never build up pressure in the throttle body.

What pressure did you see on the fuel pressure gauge? Did it rise with the fuel pump running at all? Did it drop quickly afterwards?

Lou