Tahoe fuel pump issue

[tnasphalt]

We have multiple tahoes. 02 up to 05, 70k miles to 260k miles. same problem.

for no reason the truck will not start. It will crank fine but not start. Pressure from fuel pump reads ZERO. Seems to happen when the truck is below 1/4 tank of fuel. Keep it above 1/4 tank, no problem. if it wont start, you can add 2-3 gallons of fuel and it'll start fine. you can run it dry if you wanted to, but if you shut it off, good chance it wont start if you're under 1/4 tank.

With this one unit, it wouldn't start, let it sit about 15 minutes and tried again. fuel pressure read 40psi, started fine with only 1/8 tank. No problems with the guages, they're right on.

when it wont start, seems as the pump is not getting power.
Only thing I can come up with is a glitch in the security system that is shutting the pump down but that doesnt explain it starting if you add a couple gallons.

any ideas or experiences?
thanks. chris

[taillight]

Sounds like something wrong with the pick ups. Maybe a crack.

[tnasphalt]

The fuel pump is not cycling, like there's no power.

[taillight]

Sounds almost like there are 2 problems. Even with the pump off you should have pressure. If you have 0 there must be a leak. When you turn the ignition switch on the pump should run. There is nothing about the amount of fuel in the tank that would stop it. It sounds like 2 bad pumps. Test for voltage to the pump when you turn on the ignition. The check valve in the pump could also be leaking.

[tnasphalt]

Thats the thing.... no pressure and no power at the pump. I've been leaning toward a problem with the security system. However, a couple of the trucks have avoided the problem by not letting it get lower than 1/4. When it happens, they've been able to add 2-3 gallons of gas and it starts which shoots down the security issue. however, I've had the other one have the problem, add no fuel (only 1/8 in the tank) and it starts on its own. makes no sense

[maxwedge]

Burnt connectors at the pump harness are very common here.

[02'Z71]

What you have undoubtedly is a bad fuel sender assembly, or "fuel sending unit". My 02' had this same issue at 50k. This liquid level sensing device stilll resonates when the tank is empty showing your at a 1/4 -1/8 of a tank. The tank is in fact on empty but your guage indicates differently. (Given your pump is ok), you should be able to add gas and start, but you may need to hit/slap/pound the underside of your fuel tank with an open hand. This will get you started. Part is warrantied covered.

[tnasphalt]

Negative. We have been able to start the one without adding any fuel. Also, they are 26 gallong tanks. We've been able to completely fill the tank by adding 16-18 gallons which tells me there is fuel and the guages are accurate.

[taillight]

When you have the problem, check for fuel pressure with a guage.

[tnasphalt]

we have zero pressure when the problem arises. There is a small delco sensor at the top of the pump that has an electrical connection on the outside of the pump but nothing inside, no connections of any kind. looks like it might be a pressure sensor....any ideas?

[taillight]

That is a pressure sensor. Nothing to do with not starting. Like maxwedge said check the pump connectors. Also check for voltage to the pump.

[carlos80]

Originally Posted by tnasphalt

we have zero pressure when the problem arises. There is a small delco sensor at the top of the pump that has an electrical connection on the outside of the pump but nothing inside, no connections of any kind. looks like it might be a pressure sensor....any ideas?

Any solutions to your problem? Have an 02 with 70k 5.3, same problem. Already has new pump, new connector and filter in it, but the problem s still the same. This one, however I can hear come on, just no pressure, towed it a couple of days ago, as soon as i got back in it it started right up.

[tnasphalt]

We replaced the fuel pump and have had no further issues. There is a small "pressure sensor" on the top of the pump that I think was the issue. Based on what you're saying, either we got lucky or the pump you put in it had the same problem as the original.

[envoyxuv]

Originally Posted by tnasphalt

We replaced the fuel pump and have had no further issues. There is a small "pressure sensor" on the top of the pump that I think was the issue. Based on what you're saying, either we got lucky or the pump you put in it had the same problem as the original.

The small delco/delphi pressure sensor on top of the fuel sender is used by the engine computer to test the evaporative emissions system. Has nothing to do with the fuel pump running.

[Deadboy]

Hey
My brother has a 97 tahoe and it has the same problem. The funny thing is after hiting the tank with a rubber hammer the car starts right up. Could it be the pumps wires?


Does anyone have a pic or know exactly were the pump is? and will i have to remove the tank to get to the pumps connectors?