I have a 1987 V6 Fiero GT and last night I was on my way into Portland when I ran out of gas. I recently bought the car and had never run it that low, but the gauge told me I had 1/8th of a tank left. How to I fix the fuel gauge so that it gives me a correct reading?
The 1/8 mark has been reported by many as the die in the middle of the road mark. Some recommendations that have come from Fiero owners:
Never go below 1/4 tank. Always fill the tank instead of buying a few dollars at a time and reset your trip odometer. Calculate your average fuel mileage and never go more than 150 miles or 6 gallons worth. 7 gallons on an 87 or 88 model. This is because there are about 2 gallons that are unusable.
The fuel pumps are cooled by the fuel in the tank and the fuel passing through it. Unless your pump has been replaced, it's pretty old and it can't withstand many overheatings before it fails.
For V6 Fieros I use fierofool's advice above and follow the "150" mark. Go off the odometer, always fill up when you hit 150 miles, rinse and repeat.
You'll find everyone and their mom that has owned a Fiero likely has had fuel gauge issues. Out of the four Fieros I have owned none of them have fuel gauges that read right, and my current one doesn't work at all. Closest one I had to reading right was my '88 Formula which also joined the 1/8th Club (TM).
Originally posted by tuckerfleischmann: ...How to I fix the fuel gauge so that it gives me a correct reading?
Returning to the above question which you'd asked at the outset of your thread, I suspect that the erroneous fuel gauge reading you'd experienced is more likely due to the fuel sending unit for the fuel gauge being faulty, rather than the fuel gauge itself.
Within this forum, two archived threads on this subject that may be of particular interest to you are:
Simple fix is to run the car down to where its ready to run out, then remove the clear face on the panel, then you can pull the needle straight off...its only a force fit. Then you just push the needle back on at the empty position. Nearly every cars gauge goes to full or even over full when you fill it, so the full mark isnt that important. Every car I remember Ive had would go 50-75 miles before the gauge would come off of full.
One eighth! You're lucky! I get gas every day. When it ran out it took only eight gallons to fill and the needle was between a third and a half tank. Roger has a point.
I suspect that the erroneous fuel gauge reading you'd experienced is more likely due to the fuel sending unit for the fuel gauge being faulty, rather than the fuel gauge itself.
The +/- 2 unusable gallons is about 1/8 of the capacity. Could be that the gauge is correct or very close.
I also never let a car get below 1/2 tank except on long trips. The saying I have is it dont cost any more to keep a car full than it does to keep it empty.
I also never let a car get below 1/2 tank except on long trips. The saying I have is it dont cost any more to keep a car full than it does to keep it empty.
I agree with you, Roger. I've a brother that buys $5 and $10 at a time because he can't bear to hand over the price of a fill up. Same with cigs. A pack at +$5 rather than $35 a carton.
If you're going to put gas in it, you're going to burn it out the exhaust pipe.
Joined the tank club for spring. Gauge only reads correctly @ half and below. Since the support bolts mosty surely will snap off I will use the trip odometer....vs dropping the tank for now. Unless I need a nice summer time challenge. Bill
Just had the tank out of my 85 GT. Installed a EP381 for the 3800 going in soon. New hoses and tightened up the hard lines on the unit. Redid some wiring. Same deal, c**t hair over 1/8 tank. The sending unit wiper was fine. Grounding the circuit makes it read empty. So good grounds are important. The crappy connections someone had made and the grounds weren't. Got rid of all of the butt connections and soldered it up. Cleaned the years of crust and works. Some times because the holes for the float shaft are worn, it doesn't complete ground and will go up more than normal while sloshing around. But good enough for me.
Sorry for not posting recently(even though I just get flamed anyway). Mom passed away April 30th. Born 1937. Step father and brothers were having their typical crap fest and I had to be the one that made sure things stayed civil. Still have lots to do but will chime in now and then.
I agree with you, Roger. I've a brother that buys $5 and $10 at a time because he can't bear to hand over the price of a fill up. Same with cigs. A pack at +$5 rather than $35 a carton.
If you're going to put gas in it, you're going to burn it out the exhaust pipe.
Yep, I never did get that. At the end of the week, he still has spent the same amount, and he had to bother with stopping for gas every day. I see it more with girls. Ive asked and their arguement is they only had time to put in $5-10. BUT, they dont get that they take more time having to stop and put more in.
isnt there a post somewhere talking about an adjustable replacement fuel gauge??
but im sure there's someone here that still remembers Ohms law and can figure out how to put a resistor or rheostat somewhere to re calibrate the fuel gauge????
Mine works correctly, as soon as it hits the red, I get real nervous because I'll be walking almost imminently. It shows I have 2 gallons left or so on the pump, but that is obviously unreachable. I've an 86GT.
The '88 GT I had ran out just above the 1/4 mark. Found that out on the trip home after buying it. Two years later I had to replace the fuel pump and took that opportunity to 'adjust' the float arm. Used the Armstrong adjustment method. It read correctly after that.
Simple fix is to run the car down to where its ready to run out, then remove the clear face on the panel, then you can pull the needle straight off...its only a force fit. Then you just push the needle back on at the empty position. Nearly every cars gauge goes to full or even over full when you fill it, so the full mark isnt that important. Every car I remember Ive had would go 50-75 miles before the gauge would come off of full.
Some sending units, I have cleaned, cleaned, cleaned, still reads 25 ohms at empty, try as hard as I could, still the same thing.
Just do as posted above, pull the needle and re-adjust, best fix for it, works every time. it's free to do. Pull the needle and re position it, done fixed.
On my road trip to the Pontiac Celebration show in Rhode Island, I follow the 200 mile rule..fill the car at 200 mile on the trip meter. The first tank, the fuel gauge read 1/2 and it took 7 gallons. The next 200 it read 1/4 tank and it took7 gallons, the next 200 it read 1/8 tank and it took 7 gallons, the next it read 1/2 tank and it took 6 gallons. Here is the Excel spread sheet of my data. Roughly 200 miles between fill-ups. The guess gauge is what it reads.
28MPG? How'd you do that? I'd need a tail wind, have to keep it around 55MPH, and be going downhill.
So, is yours the smaller tank, or why can't you run it another 20 miles or so?
I think on the highway stick shift 2.8 Fieros should get 27-29. Mine gets that even at 70mph (5 speed car). Not sure about autos, and I havent had an auto.
Actually I was getting about 32 mpg overall on the trip. The car has always gotten great mpg since I have owned the car, but on the road I'll be in 5th gear by 40 mph as long as I had room to get up to speed. At 70 mph, the car is running ~2500 rpm.
I think on the highway stick shift 2.8 Fieros should get 27-29. Mine gets that even at 70mph (5 speed car). Not sure about autos, and I havent had an auto.
88GT 5-speed.. I get 27-32mpg highway depending on what car/truck I am following behind
I get on average city driving 22mpg though... Very good gas mileage for that car in the city
Part of the 1/4 tank club too lol.. just fill up at 180 miles every time and youll never have a problem
On a road trip into a 25 mph headwind Saturday killed the mileage for that tank and I ended up rolling to a stop 2 blocks short of a gas station. The gauge said 1/4 full.... My usual highway mileage has been 30 (stick shift Formula), and this tank was 24.7! Surprise!!
[This message has been edited by Gall757 (edited 09-20-2015).]
My gauge worked just fine for years until it finally went, 86 SE, so when it went I went out back and got the one out of my 84 and swapped them. Now it runs out at a 1/8th as soon as it hits the hash marks.
So I agree with Roger, just pull the needle off and push it back on where you want it. That or always fill up and use the trip gauge.
Steve
------------------ Technology is great when it works, and one big pain in the ass when it doesn't
Yep, I never did get that. At the end of the week, he still has spent the same amount, and he had to bother with stopping for gas every day. I see it more with girls. Ive asked and their arguement is they only had time to put in $5-10. BUT, they dont get that they take more time having to stop and put more in.
On a road trip into a 25 mph headwind Saturday killed the mileage for that tank and I ended up rolling to a stop 2 blocks short of a gas station. The gauge said 1/4 full.... My usual highway mileage has been 30 (stick shift Formula), and this tank was 24.7! Surprise!!
As I've gotten older my tank (bladder) gets full long before my Fiero tank gets empty. 200+ miles is easily achievable in my 88GT 5 speed which gets over 30 mpg on the highway.
But to answer the OP's question the sender uses Zero ohms to indicate empty. As the cars age and crud accumulates on the sender the resistance grows and it will never get to zero. It's difficult to imagine how adding a potentiometer will decrease the resistance to zero. I guess you would wire a dead short in parallel and get it lower, but not sure that would work full scale, (probably not). The only accurate way to fix it is to replace it.
The Fiero Store is now selling reproductions but for $150 a piece. For that price I would just fill up at half and call it a day.
In 30+ years of driving everything from semi trucks to pick ups to cars and motorcycles, I don't think I've EVER had a gas gauge that was 100% accurate. You just learn the idiosyncrasies of your particular vehicle and adjust for them. I rarely let my gas gauge get below the 1/2 mark, just to be sure. I get 4-5 gallons at that point. Seems like it's pretty accurate but only at that particular point. Could be wildly inaccurate below that (or not).
My usual highway mileage has been 30 (stick shift Formula), and this tank was 24.7! Surprise!!
