fuel pump
Thread Starter
Burning Brakes
Joined: Jun 2007
Posts: 765
Likes: 49
From: West Palm Beach,Florida
fuel pump
My 96 LT4 wouldn't start. Has gas. Hooked up pressure gauge and there is ZERO psi. Needle didn't move a single mm. I don't think I here the pump either. I was trying to find a simple answer to the following question but couldn't. How do I check for 12 volts at the connector to the sending unit. which pins do I attach voltmeter to to get reading. Car started fine last time I used it but has been sitting over a year due to back surgery. Please help ,I am no great mechanic
Safety Car
Joined: Jun 2010
Posts: 4,564
Likes: 1,676
My 96 LT4 wouldn't start. Has gas. Hooked up pressure gauge and there is ZERO psi. Needle didn't move a single mm. I don't think I here the pump either. I was trying to find a simple answer to the following question but couldn't. How do I check for 12 volts at the connector to the sending unit. which pins do I attach voltmeter to to get reading. Car started fine last time I used it but has been sitting over a year due to back surgery. Please help ,I am no great mechanic
Grey and Green were both power wires for the LT5 on the base cars only one us used. Can’t remember which.
Thread Starter
Burning Brakes
Joined: Jun 2007
Posts: 765
Likes: 49
From: West Palm Beach,Florida
Yes ,its good. The weird thing is that there is zero pressure readings. The needle didn't budge. There is no reason for anything to have gone wrong since I literally haven't driven in 3 years. unless I'm buying gas with ethanol from a mislabeled pump. I have changed the pump 4 times.This may be my fifth. Each time pump was destroyed by rust from ethanol. Maybe I will try one other than Racetronix
Thread Starter
Burning Brakes
Joined: Jun 2007
Posts: 765
Likes: 49
From: West Palm Beach,Florida
Thanks for that. Now if I connect the voltmeter to the appropriate pins ,will I get 12 volts only for a few seconds when I turn in on.Or will the 12 volts be constant?
Heel & Toe
Joined: Jan 2023
Posts: 15
Likes: 3
From: Alameda County Ca.
I have a 1986 C4, convertible. I searched on YouTube with the phrase "cranks but won't start". I found lots of information about the fuel system and how it works. For my car the fuel system works in two stages. First when you turn the key to the run position the fuel relay is energized and provides power to the Fuel Pump for a few seconds. This pressurize the fuel rail. When the key is turned to start the engine starts and the oil pressure comes up and the the oil pressure switch closes and powers the fuel pump until you turn off the key. Good luck.
