So I'm back with another question, this time regarding the fuel gauge. My Blazer (4.3, automatic) has had some fuel gauge issues for about as long as I can remember. For last few years it has done some goofy things. 1) When driving down the road it will suddenly drop to EMPTY on the scale and the low fuel light comes on. A quarter mile down the road and it comes back where it was and light goes out. It can do this every few minutes when it wants to, and sometimes will go for days and not do it. MOST of the time when it's working it seems accurate enough, considering that I think it reads a little on low side but has been pretty consistent even so. Then sometimes it will read down close to EMPTY even though I know it has at least a half tank or so. As I'm driving along if I watch it closely it will slowly creep up to about where I think it should be. It's not very consistent with that problem, happens maybe once or twice a month. Then most of the time when I first start it in the morning the gauge reads EMPTY and light is on. Put in gear, pull out of my yard and stop to close the gate. As soon as I put it in park the gauge comes to life. That's almost an every day occurrence. Can happen multiple times during the day. A few years back the fuel pump went out so I had a that replaced. It's my understanding that the float unit is part of the pump assembly and was replaced at that time. Even so, the gauge issues never changed. 2) The odometer, trip meter, and shift display have been wonky for years as well, where the display will go out and come back whenever it decides to. About a year or so back the odometer stopped working. The display continued to come and go, but the numbers never changed. Then it would start working for a while and stop again.

I finally got fed up with it and ordered a (supposedly) reconditioned instrument cluster programmed to what I GUESSED at to be the approximate mileage now. 195,000

So I finally got around to installing it today and was surprised that when I turn the key on the gauge reads EMPTY and the light is on. Start it up, put in gear, move the truck, stop, put it back in park, and the gauge comes on. Now what the hell is that? I grew to expect it with the original cluster, but not with a totally different unit.

Anyone care to comment on that?

 

Sounds like a bad ground somewhere which is difficult to find. When you replaced the fuel pump, did you use a generic off brand pump?

 

I had the pump replaced at a repair shop. I'm not sure where the part was sourced.

Also, on the ground possibility. The fuel gauge and digital display are the only units that are anything less than steady in performance, all the rest seem fine. Now on a couple of occasions during the last year or so the whole cluster had what I would call a brain fart. this happened twice I think. When I turn the key on the gauges all kind of went nuts. Most of the warning lights came on, the tach needle jumped fully to the right, and it was obvious the unit was having some kind of seizure. Turn the key off, wait a few seconds and try again, things settled down. Started it up and drove off as usual. This happened at least twice, so I got the idea the cluster must have some internal issues and started hunting for a trustworthy replacement. Took me a little longer than expected to get that far. I just installed this one yesterday and haven't driven the truck on the road since so I don't know any more about it yet.

 

Was it doing this before you changed the pump?

 

The erratic action of the gauge? Yes. I was hoping a new pump/sender might correct that but no cigar. That led me to the gauge itself as the bulk of the issue. I was using the trip meter, zeroing it out after each fill up. Keeping mental track of how many miles were displayed there added to the gauge reading I could more or less tell if the gauge was reading correctly or not. When the digital display and odometer went south that made the concept a little bit tricky.

 

How old is your battery? Has it been tested? I had a Cruze many years ago that some weird things with the gauges and lights. It started fine and ran good except for the erratic gauges. Turned out it was the battery, and a new battery fixed all the problems. I never would have guessed that the problem was the battery.

 

I've replaced the battery a time or two since all this started. No change there.