Crank no start 1996 LT4
Thread Starter
Intermediate
Joined: Mar 2018
Posts: 25
Likes: 1
From: Toronto
Crank no start 1996 LT4
I have a 1996 LT4 and the car cranks but won’t start. I have no fuel pressure at the fuel rail when I crank the motor. I can’t hear the fuel pump priming.
I changed the fuel pump, and the fuel pump relay. The fuse is fine. I replaced the sending unit 2 years ago. Not sure what to try next. Any suggestions would be appreciated. Thanks.
I changed the fuel pump, and the fuel pump relay. The fuse is fine. I replaced the sending unit 2 years ago. Not sure what to try next. Any suggestions would be appreciated. Thanks.
Drifting
Joined: Apr 2020
Posts: 1,925
Likes: 610
From: Orange, CA
Any codes from the CCM? Can you get the dash to go into diagnostic mode?
https://tech.corvettecentral.com/201...trouble-codes/
Unlike most cars where the fuel pump is driven by a main relay energized with the car, on the C4 the fuel system is energized by the CCM. If the CCM is malfunctioning or the wiring is bad, it can cause the fuel system to no longer energize. That's the first thing to check, just to be able to rule it out.
If you can rule that out, then it's time to bust out a multimeter and trace the wiring back from the fuel pump relay to see if there's power. And if not, see if you can trace to where the missing power comes from.
And as always, reminder that you can grab a FSM off of RockAuto for $20 and it's worth every single penny if you intend to keep your car and work on it yourself.
https://tech.corvettecentral.com/201...trouble-codes/
Unlike most cars where the fuel pump is driven by a main relay energized with the car, on the C4 the fuel system is energized by the CCM. If the CCM is malfunctioning or the wiring is bad, it can cause the fuel system to no longer energize. That's the first thing to check, just to be able to rule it out.
If you can rule that out, then it's time to bust out a multimeter and trace the wiring back from the fuel pump relay to see if there's power. And if not, see if you can trace to where the missing power comes from.
And as always, reminder that you can grab a FSM off of RockAuto for $20 and it's worth every single penny if you intend to keep your car and work on it yourself.
Thread Starter
Intermediate
Joined: Mar 2018
Posts: 25
Likes: 1
From: Toronto
Today I checked the voltage at the tank and got close to 12. There is definitely power to the pump. So I pulled the 2 year old sending unit and put power to the new pump and it ran. I also put the old pump back onto the old sending unit and put power to it, and it ran as well. I decided to install the old rig because the pump was louder and easier to hear, and the car fired up and runs!
I don’t trust it, I hope its not intermittent. Lets see if I get stranded.
I don’t trust it, I hope its not intermittent. Lets see if I get stranded.
Drifting
Joined: Apr 2020
Posts: 1,925
Likes: 610
From: Orange, CA
Glad to hear you got it running, and here's hoping it works out!
Thread Starter
Intermediate
Joined: Mar 2018
Posts: 25
Likes: 1
From: Toronto
Just a follow up. My car is running great, and somehow the level float is magically working again! Looks like the aftermarket sending unit I installed failed after 2 years. For those looking to replace theirs, I don't recommend using the Liland sending unit.
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