Fluctuating Fuel Gauge
#11
09-16-2018, 10:42 PM
I say this with no sarcasm or insult. There is no logical reason the gauge does not work as it should. Things made by men can be repaired by men. Your problem is that logic fails when applied to Blazers. It makes no sense and can drive you insane. I've driven my '98 for 21 years. Around 2010 I finally accepted the statement "Oh, that's just what Blazers do." I've also accepted I'll be driving it in 10 years. I'm sure your '95 will still be roadworthy then. My fuel gauge has the same problem occasionally, my sister's 2002 does also. If you isolate the problem I would love to know the fix. Good luck.
#12
09-17-2018, 12:55 AM
Performed a search for wiring diagrams pertaining to your Blazer. None showed anything between the level sensor and the gauge. Found the following which I hope helps you in troubleshooting the issue.
General Motors Fuel Gauge Troubleshooting
Fuel gauge troubleshooting begins with isolating the problem either to the gauge, sending unit, fuse or wiring. The most common gauge problems are either a bad ground at the tank, or a sender problem. As with any electrical troubleshooting, it is best to check the fuse and all wiring connections are clean, tight and free of corrosion.The following process will require the ignition switch be in the “on” position for troubleshooting a fuel gauge issue. The first place to start is to check the ignition 12 volt power feed at the fuel gauge to see that it is powered up. If you DO NOT have 12 volts ignition on the fuel gauge, check the gauge fuse to see if it is good, and make sure the ignition switch is powering the ignition pink wire on the ignition blade of the switch. If you DO have 12 volts to the fuel gauge, the next step is to remove the fuel sending unit wire, and, with the ignition key “on”, ground the sender wire to a good chassis ground. The fuel gauge should immediately go to empty. Removing the sending unit wire from the chassis ground the fuel gauge should go directly to “full”. If the fuel gauge responds correctly, the fuel gauge and sending unit wire at this point are reacting correctly. Next, check the fuel tank float assembly to see if the grounding terminal on the float assembly has a good grounding point to the chassis. If the ground wire looks good, the problem most likely resides in the fuel tank float assembly, and may need to be replaced.
Here is a link that goes into greater detail. According to it the gauge might be a possible problem.
https://www.chevytrucks.org/tech/gasgauge.htm
Fuel gauge troubleshooting begins with isolating the problem either to the gauge, sending unit, fuse or wiring. The most common gauge problems are either a bad ground at the tank, or a sender problem. As with any electrical troubleshooting, it is best to check the fuse and all wiring connections are clean, tight and free of corrosion.The following process will require the ignition switch be in the “on” position for troubleshooting a fuel gauge issue. The first place to start is to check the ignition 12 volt power feed at the fuel gauge to see that it is powered up. If you DO NOT have 12 volts ignition on the fuel gauge, check the gauge fuse to see if it is good, and make sure the ignition switch is powering the ignition pink wire on the ignition blade of the switch. If you DO have 12 volts to the fuel gauge, the next step is to remove the fuel sending unit wire, and, with the ignition key “on”, ground the sender wire to a good chassis ground. The fuel gauge should immediately go to empty. Removing the sending unit wire from the chassis ground the fuel gauge should go directly to “full”. If the fuel gauge responds correctly, the fuel gauge and sending unit wire at this point are reacting correctly. Next, check the fuel tank float assembly to see if the grounding terminal on the float assembly has a good grounding point to the chassis. If the ground wire looks good, the problem most likely resides in the fuel tank float assembly, and may need to be replaced.
Here is a link that goes into greater detail. According to it the gauge might be a possible problem.
https://www.chevytrucks.org/tech/gasgauge.htm
Last edited by G0LFADD1CT; 09-17-2018 at 01:11 AM.
#13
09-17-2018, 10:00 AM
I have a 95 vin W blazer too, and I thought this was normal for them, there are so many wrong things with this vehicle that I have learned to live with those for a long time, mine have a 3/8 of a tank error, and not only that but once its lower than 1/2 tank be prepared for the engine to shut down while descending and braking due to lack of fuel.
I was planing to replace the whole fuel pump and sensor module to see if that would help but after reading this, now I know that could be a waste of money and time, Thanks.
I was planing to replace the whole fuel pump and sensor module to see if that would help but after reading this, now I know that could be a waste of money and time, Thanks.
#14
09-17-2018, 02:17 PM
I have a 95 vin W blazer too, and I thought this was normal for them, there are so many wrong things with this vehicle that I have learned to live with those for a long time, mine have a 3/8 of a tank error, and not only that but once its lower than 1/2 tank be prepared for the engine to shut down while descending and braking due to lack of fuel.
I was planing to replace the whole fuel pump and sensor module to see if that would help but after reading this, now I know that could be a waste of money and time, Thanks.
I was planing to replace the whole fuel pump and sensor module to see if that would help but after reading this, now I know that could be a waste of money and time, Thanks.
#15
09-17-2018, 02:59 PM
There must be something that smooths out the float movements to display on the gauge. When not moving the gauge it steady ... move a bit and the gauge swings back and forth following the rocking fuel level...
With all the experience here someone must know what the answer is.
With all the experience here someone must know what the answer is.
Your assumption is that You want to smooth out displaying of the float movements. I would say the problem is with an excessive float play. Smoothing it out is yet a simple task, as You can make a low band pass filter from a parallel capacitor/serial resistor. But it does not locate the problem, hiding it instead. Half measure.
As far, as I know (haven't been working on tank myself yet) the fuel pump + transmitter should be located in a tubular "well". Fuel movements from side by side of the well smooths the float readings even if the fuel moves roughly side by side of the tank in that time. The "well" should play a fluid capacitor role here. Have You been looking to Your pump assembly? Maybe, while performing a replacement, somebody removed the well, and there is Your problem?
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