Hi, I was just reading the "standard catalog of Firebird" and noticed that in 1982 these cars started out with 16 gallon gas tanks, then in 1983 the capacity was increased to 16.1 gallons, it remains that way until 1985 when it dropped to 15.5 gallons and remained that way until 1992 when third generation production ended.
What was the reason behind the fuel tanks change to a lower capacity?

 

Was that the time period when they started going to fuel injection and needed an intank pump??

 

'85 was the first year that you could get TPI, so I'd say the need for an in-tank pump on some models and the drop in capacity are probably related.

 

I'd blame mpg/epa.
GM for years has limited gas tank volume for mileage.

 

I guess the pump in the tank started with the 83 HO motors.
My 84 has both pumps.

 

I don't understand. Why would you reduce the tank size for mileage? I can't see 5 gallons making that much of a difference. I am assuming you are meaning they did it to meet "CAFE" standards,right?
Supposedly wasn't that the reason some cars got those horrible plexiglass t-tops too? And why after 88 (I think) you couldn't get a 350 and t-tops? To save on weight?
Once again another example of far too much government interference in private industry. Small wonder the cars look like plastic tonka toys today

 

Why would someone want both an mechanical and electric in tank pump on a carbed car? As another member had suggested here, why didn't GM just reroute the fuel lines so they did not have a vapor lock issue? We didn't have "helper" pumps in the tanks of cars prior to this.

So what happens on your 84 when the in tank pump goes out? Can you still keep driving it with a mechanical pump?

I had a couple 82 and 83's before and none of them had an electric pump inside the tank, and I never had any vapor lock issues and I live in California where it gets hot in the summer.

 

I am inclined to agree with your theory.

 

For The Camaro's The 1985 Brochure Shows The Sport Coupe And Berlinetta Got 15.5 Tanks And The Z28's And IROC's Got 16.2 Tanks.

Maybe Is Was Similar As The Base Firebird/Se Vs The Trans Am.

 

I would guess a misprint, I have changed out both and never noticed a difference.

 

Wow there must be alot more in my tank than i can fit. i usually fill up around 1/4 and i can only fit 10-11 gals.

 

Interesting,according to Standard Catalog Of Firebird all models got 15.5

 

For the record, the Crossfire and US Iron Dukes had in tank fuel pumps from day one.

 

Yes,I was aware of that since Cross-Fire and the Iron Duke were both TBI cars.
TBI and TPI cars have electric pumps on the tank.

 

Even with the tanks being identical "full volume" could be artificially limited with the vent to force the nozzle to shut off early.
Again for weight/mpg/CAFE reasons.