i have a 92 rs 305tbi and it is having starting problems.it has a new bosch fuel pump and fuel filter and unless yuo pour some gas in it to get the motor to fire the injectors don't work, but once the motor fires the injectors will pick up but you have to feather the throttle real fast to keep it running and it will eventually die. i im out of thoughts on it please help

 

Do the injectors energize at all when cranking? If they are not firing when you crank the motor, it may be an indication that the ignition module is going bad, and not sending the proper signal to the ECM.

 

i have power to the injectors when cranking and also power to all the sensor tps and such but the injectors won't work unless the motor fires and to get it to fire i have to pour fuel into the throttle body

 

Is the fuel pump priming? Do you hear the pump run for 2 seconds when the key is turned on but not to start? Tried replacing the fuel pump relay?

 

yeah the fuel pump primes i have good pressure at my tbi

 

The second question is: does the pump come on when you crank the engine? Also, does the tach indicate any engine speed when cranking, or does it just stay at 0? Those two things will help pinpoint the problem.

 

yes the pump comes on when cranking the engine and the tach didn't work when the car ran before this problem but it does max out the needle on the tach when you crank it

 

could it be the regulator being bad and it doesn't build up the pressure needed for the injectors to work? basically just running through the tbi back to the tank?

 

More likely it would be a faulty pump. The brushes tend to wear out and lose contact on the commutator, which causes the pump to run slowly as the gasoline gets between and acts as a dielectric. This can reduce the fuel pressure to a point where the motor will not run. You will have to check the fuel pressure to confirm this. Should be at least 11 PSI or so, and it should not fall when the engine is revved. Sometimes you can tell without a gauge if the pump is bad. If the regulator in the TBI chatters when the pump is on or the pump does not noticably slow down when you pinch the return line, then its a good sign that its toast.

 

the fuel pump is brand new which always doesn't mean it is good but is there a way to check the fuel pressure without buying a $50 tester with the adapter that goes where the fuel filter is. im only 21 and don't have a steady paycheck

 

Not really, unless you want to install a fitting permanently in the supply line, which can lead to leaks and so fourth if its not done right.

When you do get the car going by priming it with fuel, what does the injector spray pattern look like? Is it a fine conical spray of droplets, or are they just dribbling?

Also, are the injectors firing when you crank the motor? You can tell by having someone crank then engine while you listen. To hear them, take a long screw driver and put the tip on one of the injectors while you listen to the handle side. Should hear 'click click click' as the engine cranks.

 

it sprays like a good injector( cone shaped spray) but you have to feather the throttle real fast to keep them spraying. not sure about them firing when cranking i will try that tomorrow and let you know but i don't think they are