I'd check the pressure of the pump, you can rent this at an auto parts store or buy your own. You'll need to hook up the gauge to the inlet line, or somewhere between the fuel pump and tbi. Get that reading.


Also since you changed the pump, change the filter. Since it starts with fuel I would like to "diagnose" your problem as being fuel related.

Fuel pressure.. and filter... Then try again.

 

Fuel pressure needs to be 9-13 psi. Fuel pressure regulator spring could be weak or the diaphram could be broken. You could pick up a rebuild kit as it includes everything you need to rebuild the regulator. You do not have to use the whole kit just the items you need. You do not need to remove the TBI from the car to rebuild the regulator as it is on the top of the TBI. Remove the injectors and remove the top. If you have a Noid light you can make sure that both injectors are pulsing. TBI is very simple it should not be to hard to figure out what is wrong. The hard part with the 1st Gens is that there is no fuel pressure test port. I purchased a test kit that I can hook up inline at the frame rail where the fuel line is attached to the front crossmember before it goes up the engine. I have since got an Inlet adapter that has a provision a tee to add a fuel gauge. Now I can monitor my pressure gauge any time by looking at the gauge. If any one is interested i got the adapter and gauge from CFM Technologies.

http://marine-performance-parts.com/...rformance.aspx

 

Alright heres a question. How do you check the ohms on the throttle position sensor which has three wires, and how many ohms should a working one have? Same question for the oxygen sensor.

 

TPS can be measured with volts using a scan tool. Not sure how to do it with Ohm meter. Scan tool for the O2 sensor as well.

 

I need to know which wires to contact with the multimeter.

 

SCAN tool connects to your OBD port and will monitor the TPS voltage at IDLE and throughout the pedal range. The SCAN tool can also monitor your O2 Sensor. I do not know how to hook up a meter directly to the TPS. You might be able to hook up to the TPS with a multi meter but it is something I am not familier with.

 

You got to find the wire, I forget which one it is.

Just hook up the black on the volt meter to ground and try each one. The reading should be around 1V for closed throttle and up to 4.5 to 5VDC for full open throttle, basically your looking for a smooth consistent rise while you open the throttle.

Key on engine off when you test.

If the reading is jumpy, or loses voltage while slowly opening the throttle to full open you could have a faulty TPS.

 

check your iac valve i had a tbi 2.8 and 4.3 both nightmares but got them running right after alot of handy work test inspecting and checking

 

i have a 91 4.3 blazer and have the same exact problem with it still trying to find the source of the problem my buddy says it may have something to do with the connectors hes coming over today to check the voltage will post later to let you know

 

In my experience, when the injectors weren't spraying, it was either the ignition coil gone bad, or spark control module in the distibutor. I didn't read through the entire thread, but if you're not getting any spark, or fuel, one of the two may very well be your problem. Both inexpensive/easy to replace.