I have a 91 rs 305 tbi, if i start the car it will die, unless i rev it. the injectors dont spray unless it is reved. I need some help

 

Sounds like a bad ignition module. The computer will not pulse the injectors unless it receives a good signal from the ignition module. Get an AC Delco one, not any cheap generic or aftermarket one. And dont forget the special grease that goes under it when you install it.

 

I tried that, and still nothing. I have tried everything I can think of , the fuel filter, tps. I can pour gas in the tb and it will start and I can keep it running if I peddle it, but the injectors wont spray at idel.

 

Does it stay running with the gas pedal held steady? Pumping the pedal will engage accel enrich, which will dump fuel into the motor.

 

are you gettin a good injector pulse and they are not sparying or no pulse and they are not spraying, couple be ecu.

 

No, if iI hold it steady it will not spray. The injectors look like they work fine when I rev the motor.

 

I need some help Im spending alot of money and still nothing. Any ideas ?

 

Had the same exact problem with mine. It was the small piece of hose which connects the fuel pump to the sending unit, it was deteriorated. Its a pain because you have to drop the fuel tank to replace it. Or it could be the pump itself. Mine would run if you sprayed starting fluid in the TBI or pumped the gas pedal. There is no easy way to check fuel pressure on the car.

 

You can check for fuel pressure but the unit costs like $40.

I just took my gas tank and fuel pump out today. If this is the original fuel pump, you need to change it. The hose on mine was disintegrated, which I hope caused my no start problem. You get good spray when you pump the peddle but not if you keep it steady? That doesn't sound like a fuel pump issue. Might want to try the TPS.

Disconnect the TPS and start it.

 

I replaced the fuel pump about a year ago so I think it is fine. I have also replaced the tps, but I pulled the codes and it has a 22 and a 53.

 

Im having a similar problem. my car will not idle for very log and then it dies. and when i am at WOT it sputters and it doesnt want to accelerate after about 90.

 

have we had any resolution here??? a fix to this??....I have a similar case...I can pedel it to keep it going...but thats it

 

i have this problem too but i did a 5.0 to a 5.7 engine swap. my fuel pump is too weak and injectors(305) are too small

 

At the same place most of you are, car wont start thought, at all I pour gas into tbi she fires up fine then squat, took a multi meter to the injectors they got power but no spray, replaced coil, ign module, nothing running out of ideas someone has got to have an answer lol. -Rev

 

'Z28

Get a test light (without battery) (about 5 bucks in auto parts store, DVM is too slow to react to pulses). Connect ground lead to the ground and probe the blue or green wire terminal of the injector connector. Test light should be lit when engine is stopped, ignition in run position.
Have a helper crank engine while observing light. It should be blinking on-off and injector spraying while cranking. If light remains steady on then ECM is not receiving DRP pulses from dizzy. Or Injector drivers are shot (not pulling to ground)

Do you still get Code 22 and 53??

//RF

 

Don't know much about Camero, but on Crossfire Vette, you need oil pressure or the ECM shuts off the fuel.

Make sure your Oil pressure sender and wiring are intact and working.

Hope this helps . . .

 

Ill try the testlight thing today, as for the oil presure yea everthing is hookedup and apears to be working. The last time i drove it began to sputter for a while almost like she was runnin out of gas, parked her and she just gave up, would turnin and turn and turn nothing, heard a loud click that i thought was the coil gona bad but the injectors wont send fuel far as i can tell. Ill try that and well see where she goes from there, thanks everyone...
-Rev

 

I would also verify that you have adequate fuel pressure at all times. You can do this by forcing FP to operate in test mode via terminal G of ALDL connector (apply +12Vdc from a fused source (10Amp). Connect Fuel pressure gauge to verify that 11 to 14 PSI for stock TBI is present. If you can not hear FP operating than you have to drop your gas tank.

//RF

 

ok, ill go and check those out, whats the best way to test the ecm? if it turns out that it might be that? is it a complicated install or disconnect connect, again thanks for all your help -Rev

 

If you cycle your ign key from stop into run position and SES light blinks on-off-on and if you can hear Fuel pump run for about 2 seconds your ECM is probably alive. Solid SES is not a good thing.
You can also place ECM into diagnostic mode by using paper clip to short A & B terminals of the ALDL connector. SES light should blink code 12 three times and any other stored fault codes. This is the simplest test you can run on your ECM.

//RF

 

I had all these problems when i replaced the motor in my 91 check the Map sensor.either the vacuum lines could be off or sensor is bad.Might wanna check there

 

OK i checked for error codes none show up... I used a test light on the injectores they blink on and off as they should i imagine when cranking, a friend of mine said jump te injectors to see if they squirt fuel and they dont, i disconected the fuel filter to check for pump life with key on and nothing, so i tested the power to the 3 wires running to the pump tan/wht pnk/wht and black ground i assumed was the neg and pink has power but the tan is dead any ideas what that could mean? I checked the fuel lines also, no fuel in could the MAP or TPS case the pump power to be shut off if so wouldnt they shut off the pink one as well. Well again all your help is greatly apreiceated everyone! Im getting tired of taking my 72 F-100 lol 10 bucks a day just to get to work and back is killing my wallet... Thanks -Rev

 

I'm not sure if the Map or Tps would cause the fuel pump to shut down.I know when I was having my problems the fuel spray in the Tbi was erratic and sometimes no spray at all.It ended up that my vacuum line to the Map senser was disconnected.I fixed it then it ran good for a time and the Tps went out.change both of those and iwas on the fast track to a great running rig.I was also getting codes,13,22,33,35,and44.I guess the Tps or Map could tell the ecm to shut the pump,down.If you have a book that givesthe codes look at code 44 or 45 and you will see the Map or Tps has a lot to do with the fuel delivery.This was so in my case.Keep me info'd on your progress,you've got me thinking ,Again ,good luck

 

'Z28

Wiring at the pump, depending on the year maybe:

A: BLK, ground
B: Purple #16AWG (or pink-white), fuel level sender unit to dash
C: Gray #12AWG (or tan-white), power to fuel pump

Check fuel pump relay and socket on the firewall - find gray wire. Remove relay from socket. Examine socket for damage and oxidation. You can force Fuel Pump to operate by applying +12Vdc to the gray wire with a fused jumper wire (10AMP). Use caution and proper safety procedures. With +12 on Gray wire Fuel Pump should operate (unless gray wire is broken between relay and tank). If it does not - time to drop gas tank and R&R FP.

//RF

 

When you say no codes, you mean only a code 12 correct? If you don't get a code 12 then the ECM is dead and you are running on the limp, limp home mode which is just a couple of resistors used to fire the injectors.