ok guys from the forum..
i got a real deal here...or a big problem..? i dont know..

its a blazer s10 4.3 tbi injection.

the blazer didn't move in about a year...since these two weeks of hell...
the engine is ok...

i replaced..
1- ignition module
2- spark plugs
3- two set of injectors.
4- changed the pressure regulator.
5- the injectors pod.

what i have done..
1- quit the gas filter and see if the pump its working.. and it does..!
2- put gas directly to the tbi while tryin to start and the engines run..2 or 4 seconds until the gas is gone..
3- i checked the injectors plugs and see if i got some voltage when i tryin to start the car... and yup... i got voltage.
4- the fuses all are ok...
5- i turned the key ON... and manually i pulsate one injector with a homemade socket.. and it clicked!!!!. but no fuel...

what can be wrong???
please help ...

Adapt a pressure tester into the fuel supply line and verify that there is 11-13 PSIG standing fuel pressure.

If pressure is adequate, remove the injectors from the pod and clean the inlet screens. Varnish from sitting idle for a long period can blind off the screens and prevent fuel flow to the injector pintles.

Out of the four wires to the injectors , slpice a wire into the red one and give it power from the battry, should here the relay click on, drivers side bye brake booster,if it clicks then try to start it with the wire still hooked to the battry, might have a weak oil pressure sender, there set up if you loose oil pressure it kills power to the injectors

Can you feel the injector "click" while cranking the engine? As Blue Bowtie mentioned, check fuel pressure at the throttle body with the ignition in the RUN, (engine off) and CRANK positions, and also check the screen.

The oil pressure switch does provide an additional circuit to the fuel pump. The circuit was designed to provide more current flow to the fuel pump so it would operate at a cooler temperature and last longer. There is only one way that the oil pressure switch could shut off the fuel pump: While the engine is running, the fuel pump relay fails AND the oil pressure drops below approximately 7psi after the relay fails. Although it's possible, it's not probable. Make sure the fuel pump relay is supplying current to the fuel pump, then check the circuit from the oil pressure switch.

Can you feel the injector "click" while cranking the engine? As Blue Bowtie mentioned, check fuel pressure at the throttle body with the ignition in the RUN, (engine off) and CRANK positions, and also check the screen.

The oil pressure switch does provide an additional circuit to the fuel pump. The circuit was designed to provide more current flow to the fuel pump so it would operate at a cooler temperature and last longer. There is only one way that the oil pressure switch could shut off the fuel pump: While the engine is running, the fuel pump relay fails AND the oil pressure drops below approximately 7psi after the relay fails. Although it's possible, it's not probable. Make sure the fuel pump relay is supplying current to the fuel pump, then check the circuit from the oil pressure switch.

hello old master.

the oil sending unit / pressure switch is the one back of the distributor?

by two years, we have replaced the original pressure switch unit and replaced with a sunpro oil gauge.. and all these years the truck was in great shape.

do you recommend install a "T" fitting to have the original sending unit with the analog oil gauge?

about the click click of the injectors...
i have donde a home made connector directly to the injectors and do the same click with no gas.. while the key ON.(engine off)

there are two relays together in the side of the driver...
one of the fuel pump..
and the other??? is the sending unit relay?

i'll check the pressure of the gas just like you recommend..by the end of the line of the TBI unit.

any more ideas that i could try??

thanks all of you for all the help.. :)

The oil pressure sending unit is next to the distributor. It would be a good idea to "Tee" in the original oil sender simply for the additional circuit to the fuel pump.

You have determined that the injector works with your home made connector. Can you feel the injector "click" when the starter is engaged? This will check the circuits in the ignition switch, ECM, ignition module, etc etc, that are used when the ignition switch is in the START position.

Locate the original harness connector for the oil pressure sending unit:

1. With the ignition switch in the RUN position, the orange wire should show battery voltage.

2. With the ignition switch in the START position, the grey wire should show battery voltage.

3. When you first turn the ignition switch to the RUN position, the grey wire should show battery voltage for 2 seconds and then drop to zero volts.

Post the results of these 3 tests.

The oil pressure sending unit is next to the distributor. It would be a good idea to "Tee" in the original oil sender simply for the additional circuit to the fuel pump.

You have determined that the injector works with your home made connector. Can you feel the injector "click" when the starter is engaged? This will check the circuits in the ignition switch, ECM, ignition module, etc etc, that are used when the ignition switch is in the START position.

Locate the original harness connector for the oil pressure sending unit:

1. With the ignition switch in the RUN position, the orange wire should show battery voltage.

2. With the ignition switch in the START position, the grey wire should show battery voltage.

3. When you first turn the ignition switch to the RUN position, the grey wire should show battery voltage for 2 seconds and then drop to zero volts.

Post the results of these 3 tests.

hello old master..

yes i feel the click of the injectors while i crank..and it sound.. and i tested the inector connection with a fluke multimeter and shows voltage..

i'll do the oil sensor thing and i'll post..but i need to go tho the junk yard because this sensor have los for years..
but i'll post it.
thanks again..
:D

good news..

the injectors system it's like new..
they spray awesome...

the cause was the fuel pump...
the pump was OK... but the hose inside the tank was like gum..
it' felts like play doh!... there was a hole in there..this causes low pressure..
so i put a new pump, hoses, brakets etc etc...

thanks all for the advices .. your experiences.. and patience...

Nalgman

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