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94 Caprice no start

05-26-2016, 01:33 PM
I have a 94 Caprice L99 4.3L V-8 won't start . Car has been sittig about a yearwith a full tank of gas. I parked it because I was having hard start no start issues during rainy or really humid weather assumed it was the opti distributor . The car would start after prolonged cranking. Saved up for parts now I have no fuel pressurs at the schrader valve I pulled the fuel filter it was clear no fuel there with the key on. I can feel the relay click and hear the fuel pump cycle but only after I ( bump the starter ) but no fuel pressure.

05-26-2016, 03:49 PM
First make sure you are getting 12v at the fuel pump. If you do you might have to pull the pump there is a filter (sock) on the pump that might be plugged.

05-26-2016, 03:52 PM
Is there a check valve in the tank? Could I use compressed air blown back from the filter location to clear the filter?

05-26-2016, 06:40 PM
Their should be a check valve in the pump.

Tech II
05-27-2016, 07:43 AM
You can also spray carb cleaner into the intake, to see if the cars starts and runs(as long as you spray)......this will verify it's a fuel delivery problem.....

If you have battery voltage at the fuel pump circuit, with no pressure, then you need a pump.....I usually use a test light,,,,disconnect harness to tank...attach test light to the fuel pump circuit leads.....turn key to on...light should come on for 2 seconds and go out......then crank vehicle and it should be on steady......the brightness should be the same as when you put the test light directly across the battery....if it is dimmer, then could be a bad fuel pump relay(contacts), or a bad ground....

05-27-2016, 07:50 AM
Thanks TechII I think I read somewhere I can test for voltage from the connector in the trunk. Is that correct ? Do you know the color of the lead I need to check?

05-27-2016, 07:52 AM
I did spray starting fluid and it started!

05-27-2016, 01:13 PM
I'd say it is your fuel pump not getting power. It could be the fuel pump itself, it could be the fuel pump relay or even the oil pressure switch on the engine. Check all wiring in affected areas. Verify that all body grounds are intact. Check fuses.

You can always probe the wiring from the pump itself to see if juice is getting to it - if so, suspect the pump.

When you turn the key, the fuel pump should kick on and shut back off after 2 seconds, if the engine is not started. The fuel pump also gets power passed through the oil pressure switch during cranking & if something is wrong there, no start.

Check: Connections, relay, oil switch, pump.

j cAT
05-31-2016, 07:59 AM
I did spray starting fluid and it started!

since the starting fluid got it to run then a fuel problem.many NOW have wiring problems . the driver side of the trunk is how the pump wires are routed. the ground near the driver side trunk hinge is also a cause.

under the hood next to the fuse box is a red prime wire. connect a fused power wire to it this will keep the fuel pump on then check for voltage at along these in trunk wire that feeds the pump motor. the wire will be the biggest wire size .

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