hello all quick question. I need to know how to check my oil pressure switch. here is the info on my Z28. I have the 305 tbi My car wont start just cranks all day long. I have tested most of the wiring now and so far no problems. I just cant seem to find any info on the oil pressure switch. Any help will be great.

 

You did check the ignition module, right? On these I am sur the switch is part of the pressure sending unit right above the oil filter.

 

modual tested good. checked firing order. has all new ignition cap rotor wires plugs starter and battery. has new fuel pump and relay. I am trying to see if my pump is bad oil pressure switch is bad or if my ecm is bad.

 

I had a similar problem once, but then I put gas in it.

J/k, but you might want to double check.

Later,
Jeremy

 

true true I actually thought of that one but I have some in there full tank now. From what I understand is that the fuel pump gets a signal from the ecm and the oil pressure switch. I may be wrong and barking up the wrong tree but I am not the brightest when it comes to cars LOL

 

Dave,

Are you getting fuel pressure?

You should be able to hear the fuel pump running in the tank for about two seconds as soon as you turn on the ignition (before cranking). If not, you may have a problem with the pump relay, pump fuse, or the pump itself. If the pump runs but doesn't produce pressure, you may have a clogged fuel filter ot internally leaking pressure regulator. Removing the pressure line at the TBI unit should give you a quick idea of whether or not the pump is running, but if it is you'll get a solid spray of fuel, so contain it if you can.

 

vader:
Thanks for the info. I have a new filter and a new relay fuse is not blown. I am in the process of trying to test pump I do not hear it turn on when I put the key in. I was told that under the rear seats was a connector I could add 12 volts to to see if pump works. No connector there and my pump has 3 wires black (ground) purple (goes to ecm) and grey (going to oil pressure switch) which one do I apply the 12 volts to to see if my pump runs or am I just chasing my tail? Another question I saw someone posted the firing order for about 12 engens does anyone have the correct firing order for the 305 and 350 92 Z28 engins?

 

1-8-4-3-6-5-7-2

 

thanks now I know my wires are correct LOL

 

Dave,

Stroked has the firing order nailed down (probably burned in his memory like so many of the rest of us). What you saw before was probably my list of common firing orders that usually answers most questions:



If you aren't getting the pump to run, you just found your problem. You don't have to get into the back seat to jump power to the fuel pump. You should be able to do it directly at teh ALDL connector, terminal 'G':



Connect a wire from terminal 'G' to a 12VDC fused source. With the ingnition yurned OFF, the fuel pump should run.



If that doesn't operate the fuel pump, you should try to jump power right at the tank connector, and make sure the ground wire at the tank connector has good ground contiinuity.

 

Vader
thank you again I dont have terminal g it is blank on mine so I figured I would just have to do it at the tank. Thank you for the pic you posted I appreciate it. I will be testing my pump today wish me luck I so badly want this car to run again.