Fuel Level Gauge

[L8RH8R]

I bought my 99 Tahoe (OBS) approximately two months ago. The fuel level gauge moved back and forth (millimeter) so fast it was an orange blur and not consistent. I replaced the gauge cluster and that DID NOT fix the problem. I recently replaced the entire fuel sending unit with a new Delphi unit and now the truck won't start and the fuel gauge remains inaccurate. I checked the fuel pressure and it ranges from 48 to 50 psi. According to the Chilton book this is normal (low end). I'm going to put the old unit back in and that should solve the issue of the vehicle not running, but what about the fuel level gauge. Any suggestions. Thanks.

 

[SunlitComet]

the buzzing is usually the cluster so it should have been fix but keep in mind in the 99 the level sender feeds the PCM and then pcm sends the signal to the cluster unit. If you have fuel pressure like that it should start. Is there anything else you might have disconnected like an ignition cable?

---------- Post added at 07:58 PM ---------- Previous post was at 07:57 PM ----------

perhaps your stock security system is getting in the way after your disconnected the battery. You did do that right?

 

[Gzes]

Mine goes nuts all the time but did you get into the gas tank and switch the sensor? That should solve the problem. if so then follow the sensor up and try to find what could be the problem til you fix it. Or just let a mechanic deal with the headache?

---------- Post added at 10:01 PM ---------- Previous post was at 09:58 PM ----------

Mine goes nuts all the time but did you get into the gas tank and switch the sensor? That should solve the problem. if so then follow the sensor up and try to find what could be the problem til you fix it. Or just let a mechanic deal with the headache?

Damn u beat me to the first response lol

 

[L8RH8R]

The only things that were disconnected were the wiring harness, fuel lines, and two vapor hoses (one on each end of the tank). I was not aware there was a sensor inside the tank. The sensor that is on the back of the tank was reconnected as well. I dropped the tank and disconnected the fuel line and it shoots a two foot stream. As previously stated the pressure is what it is. I was told there are several different pumps for the year model. My main goal was to fix the fuel gauge. Look what that got me. I've been working on vehicles most of my life but never experienced some of the problems I have with this truck. I love it but I'm frustrated. Ugh. Thanks again for the responses.

 

[SunlitComet]

The in tank sensor is for fuel level. What is your security light doing during this whole process?

 

[L8RH8R]

Haven't looked at it. Admittedly i did not disconnect the battery when i did the work. i did have the check engine light come on but reset it. I forget now what it said but believe it had to do with a sensor.

---------- Post added at 10:32 PM ---------- Previous post was at 10:29 PM ----------

Just tried to crank it. No start. The security light comes on momentarily(as usual) then goes off.

 

[SunlitComet]

Can you get the code again?

 

[L8RH8R]

Gimmie a second, i'll try. I'm also going to disconnect the battery and see if that resets anything.

 

[SunlitComet]

if ignition is good and fuel pressure is good the one or two immediate things that can cause a no start a malfunctioning crank sensor or perhaps the security system.

---------- Post added at 08:36 PM ---------- Previous post was at 08:35 PM ----------

try for code before disconnect.

 

[L8RH8R]

No code. The truck was running fine before i replaced the fuel pump assembly. This just stumps me. A friend of mine told me had once messed with several pumps before fixing the problem. I also bled the fuel system to no avail.