The car will just crank and not start until I pour gass into the throttle body. Then have to rev engine in order to keep it alive!!!After dropping from 1500RPM the car stalls. The injectors don't fire when trying to start the car but once it is on and runnig perfectly above 1500RPM, it does shoot gas just fine. Could it be the throttle position sensor??? Plugged injectors????? Please help me!!!!!!!!!!

 

'red

If you want someone to help you need to post all the details about your ride. Year, make, miles, engine size, trany, injection type, modifications, when and under what operating conditions problem first occurred, etc etc.

//RF

 

The car is a 1992 Firebird!!! 305 engine in it. Throttle body injected!!! And it was runnig perfectly and then it just didn't want to start again!!!

 

'red

From your description it appears that it most likely a fuel delivery related issue. Over time in tank Fuel Pump FP will get tired after 15 years of pumping, but most likely in tank rubber hose between FP and feed through has ruptured. You can do simple stuff first - replace fuel filter. While replacing filter perform a fuel pressure check. You can rent fuel pressure tester from most auto-parts stores. TBI system calls for a steady and conservative 9 to 13 PSI, but it requires a continuous fuel flow.
Fuel pump replacement requires gas tank removal not an easy task for one person.

//RF

 

How can it be a fuel related issue if it runs perfectly once it is on and runnig above 1500RPM??? Isn't the pump either on or off????

 

If you ask that question, then the car needs to be taken to someone to figure out the problem

Im not bashing on your skill, but this isnt the best time to learn how to trouble shoot a fuel/no start condition.

 

When was the last time the TBI was overhauled, there are plenty of filter screens that could get plugged up along the way. You may need to diagnose the problem yourself unless paying mechanic is an option rates vary per hour though. You have to go thru the process of elimination, fuse, relay, plugged filter, TBI unit needs overhauling, the list goes on!

I had the same problem a week ago, pour gas in TB and it would start but after it dropped in rpm it died, my results were little to no FP, my gauge showed 1 hash mark which would be like 2 psi and then it dropped to 0. My pump didn't quit working because the fuel varnished or the pump was old, the filter sock had disentigrated and plugged the pump little by little eventually stopping it completely. I have a pulsator and spacer on my assembly and no rubber hose.

 

be careful it could end up like the 92 I bought. My buddy was having the same problems with this car. He poured gas down the tb to start it. Since this was the only way to start it. Then had his son sitting in the car reving it while he poured gas down the tb. He dropped the gas can it burst in to flames. Luckily his other son was standing by with a fire extinguisher. Only real damage was all the crap left by the fire extinguisher.

Since I just wanted a manual car with a v8 I bought it for a low price. Didnt bother trying to get it running since a motor swap a hevy mods were on the way. lol

 

I agree with RFMaster. Start with the fuel filter and replace it. Quick, easy, and inexpensive to do yourself. After that unfortunately I would say fuel pump. There is a rubber hose inside your gas tank that attaches to the fuel pump that will disintegrate over time. My fuel pump went out on my RS and once I got into the tank that hose was like tar in your hands. You could tackle this yourself or pay big $$$$ to have a mechanic do it for you.

 

ok i have replaced the fuel pump completely and the filter too. sme problem happens!!!please someone help me!!!what alse could it be?? where is the fuel relay located at???where is the fuse at??could it be the ignition module???where is that at???need help quick

 

IF YOU THINK IT IS A RELAY hold on take a step back turn your key on and
listen to see if you can hear your fuel pump kick on 1

2 check your wiring going to the fuel pump with a wire tester
it happend to me.and i found out I had a weak battery and a bad alternator

 

Slow down turbo...

1) You did not check fuel pressure before you've replaced FP and filter. That's not a good troubleshooting technique.

2) Depending on the model year fuel pump relay may be located on firewall. To see if your new fuel pump is functional connect a jumper from the 'G' terminal on the ALDL to a 12VDC source. The pump should run as long as jumper is connected to +12 source. Make sure that you use a at least 20 Amp fused source for this test. You can make a jumper cable from cig lighter to the ALDL terminal. When you make a connection you should hear pump turn on. If you have a fuel pressure tester connected at TB inlet port you should see 12 to 14 PSI. You still may have a pinched fuel line and replacing FP did not solve anything.

3) TPS sensor is nothing but a variable resistor. To verify that its functional turn ignition key into run position, but do not start engine. Connect DVM negative lead to engine ground and positive lead to Pin B of TPS (dark blue wire). Make sure that you have good contact. Measure DC voltage with throttle closed - should be 0.3 to 0.6 Vdc. Move throttle slowly by hand - voltage should increase linearly up to about 4.3 Vdc at WOT. To make a good connection you may need to push a test lead by connector back insulation, around harness wire. Do not cut any wires to make this measurement!

Post your results.

//RF

 

Fuel pump was a good guess and a common problem.

I agree it sounds fuel related but there are a number of things that can cause it as RF is mentioning. You to follow the step RF is mentioning. If that doesn't work, I believe the fuel pump is connected to the oil pressure switch as well. (Definitely TPI, but I would assume TBI as well).