Will not start, no power to the fuel pump

TENGX

MEMBER
1998 GMC SAVANA
5.7L
V8
2WD
AUTOMATIC
125,000 MILES

When you try to start up the van, it just cranks and doesn't start up. Plus, you can't hear the fuel pump on. We tested the electrical wires and found that the ground has power, but the fuel pump isn't getting any power. Tried a new fuel pump relay but still won't start up. Van has fresh battery and new fuel pump too. Double checked if fuel pump connections were right and they are connected correctly. What could it be?

4 Replies

KEN L

MASTER CERTIFIED MECHANIC
48,363 POSTS

If the ground has power you have found the problem, the only reason the ground will have power is because the ground connection is bad. Check the ground connection on the thermostat housing. Let us know what happens and please upload pictures or videos of the problem.

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Wednesday, June 8th, 2022 AT 12:01 PM

TENGX

MEMBER
3 POSTS

So, you're saying the fuel pump ground wire should read zero when using a volt meter?

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Wednesday, June 8th, 2022 AT 12:32 PM

TENGX

MEMBER
3 POSTS
1998 GMC SAVANA
5.7L
V8
2WD
AUTOMATIC
125,000 MILES

Okay, I asked this question before but put in some wrong info. When we try to start the van, it just cranks and doesn't start up. The fuel gauge stays stuck on full and doesn't come down. But if you're lucky, when the fuel gauge goes up and falls down right away, the engine will start up. When it doesn't start, you can't hear the fuel pump come on and the fuel pump isn't getting any power. The ground wire I stated earlier that it had power was wrong. It read zero like it should. Tried a new fuel pump relay but still wouldn't start up. Van has fresh battery and new fuel pump too. Double checked if fuel pump connections were right and they are connected correctly. What could it be? Crank sensor maybe?

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Thursday, June 9th, 2022 AT 5:54 PM (Merged)

KASEKENNY

MECHANIC
18,907 POSTS

Sounds like we have a pump issue, but we can't assume that just because we don't hear it that it is because you are not getting power.

Sometimes the motor will fail and will not come on at all when you turn the key.

So, the way to find out is to check the power at the pump or jump the relay after confirming you have 12 volts at the relay.

If you jump the relay and the pump comes on and the truck starts, then we may have a relay or control issue.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Let's try this and go from there. I am attaching the wiring diagram below for us to find out if we have power or not at the pump.

Let me know what questions you have.

Thanks

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