Car runs good and has a good idle but the car gets about a few miles to the gallon Should I buy a fpr? 1989 FireBird was a tpi setup converted into Carb. 327 sbc. Has forged pistons, Stock cam, Edelbrock performer intake, Edelbrock 1406 carb (600cfm), Polished and Ported 305 heads, Steel tubed headers, Accel Distributor. Fuel system uses stock tank with a hose to mechanical fuel pump to Fuel Filter and into the carburetor. Car has AC delete. 400 turbo transmission and the rear end has a 3.27 gear ratio. Please HELP

 

Fuel pressure regulator with a return line.
Mallory part number 4309.
Set pressure about 5 or 6 pounds.

 

is the in tank pump still there and functioning? if so, take it out and replace it with a chunk of hose.. if it's hooked up all it's doing it trying to jam 50+ psi of fuel into the mechanical fuel pump, which isn't designed for that.
are you still running the stock return line?

let's pretend the fuel system is fine for a minute.. how does the car run?
how is it tuned- ignition initial timing and total timing.. how much vacuum advance and is it hooked to ported or manifold vacuum?

how is the carb set up? is it calibrated to your engine and are choke and idle mixture screws properly adjusted?

what are the actual specs of the engine? compression ratio? which "stock cam" does it have in it?

how do you drive it? with 3.23 gears and no overdrive it's gonna be revving a little bit at highway speeds and if you pretend you are at the starting line at the drag strip at every stop sign and stop light you are gonna use a lot of gas..

does it have a torque converter with a higher than stock stall speed? a 3000 stall will make for some hellacious holeshots, but it's gonna slip when going down the road without a lockup feature.

is the speedo properly calibrated for the gears and tire diameter? you might be getting 15mpg but if the speedo is reading low due to being set for 4.10 gears then it will calculate out to less than 10mpg..

 

So i should have a fpr? I'm getting one today. No electric pump just a hose into the tank. I honestly don't know what the "compression" is because I don't have gauges. Or how to figure out stall speed. I never had a man in my life to teach me. I'm here on ThirdGen to learn because i have passion for racing and love working on cars.

 

Your mechanical pump has an internal regulator. Unless it's a high-pressure racing pump, you're fine with just that.

 

well this is where you start the process of learning- while my dad and grandpa were both mechanics, i learned most of what i know from reading a lot of car magazines and just diving in and figuring stuff out.. this was in the dark ages before this thing called the internet (late 80's and early 90's), so i was on my own wandering around in the darkness. my cousin and i once swapped 4 (yes- 4) perfectly good 350's into his 78 Cutlass in one afternoon because we didn't understand the concept of a distributor being 180 degrees off.. we just lines up the line on the balancer, dropped the distributor in pointing at the #1 terminal, and watched the epic fireballs come out of the carb before deciding that the engine must be junk and pulling it back out again.. but that's how you learn. i was 14, he was 15. learn by doing- don't be afraid to do something because it might not work. if you get lost, then go to teh internets and ask a few questions, but eventually you've just gotta learn it by doing it.. it's actually pretty hard to break these engines unless you try really hard, so don't be afraid to attack a carburetor with a screwdriver or move the distributor around to see what happens..

this stuff is actually pretty simple once you understand that the engine is just a 4 cycle (suck, squeeze, bang, blow.. but the "smart" people say intake, compression, ignition and exhaust- i like my wording better) air pump and that the ignition and fuel systems play simple yet critical roles in allowing the engine to do it's thing.. once you understand the basic physics that allow the magic to happen, it becomes pretty easy..

 

Really poor gas mileage is often due to the timing curve. Does the Accel distributor have a vacuum advance hook-up? If yes, use it. If not, you will never get good MPG, but we can make it better. Let me know about the vacuum advance and then we can go from there.

 

[novaderrik] Thanks for understanding and show compassion. That means a lot to me. I'm learning a lot because I love cars and I'm learning from error. When I put blood and sweat into my 89 it's an amazing. I found a leak in my fuel line and replaced it and slowly tuning my carb. I think I should pick a fuel pressure gauge up before i try to cut down on fuel flow. I think I should also get a functional fuel gauge but not sure how to yet. [pancherj] Yes it has vac advance and it it is hooked up to my 1406 carb ported (timed) vacuum. Should I go to manifold vacuum ?

 

yes.. go to manifold vacuum.. you want LOTS of timing under low load and cruise. my car shows 45 degrees on the dial back timing light at idle in gear.. once you mash the loud pedal to the floor, the vacuum goes away and the vacuum advance retards itself, which leaves only the mechanical advance to keep it out of detonation under load.

 

Should i hook up my Transmission vacuum to timed ?

 

No. That always goes on full manifold vacuum.

 

Do you have a timing light? You need to check the advance at idle (with the car warmed up and in park and the idle turned as low as it will go without stalling). Check it with and without the vacuum advance hooked up. When you go to check it without, unplug the line and cap the nipple on the carb where the hose was hooked. Report back and tell us what you find.

 

the transmission modulator works best when hooked up to the port in the manifold right behind the carb... any other port won't have as good of a signal and could cause weirdness in the shifting.
the vacuum advance works best on a fitting at the base of the carb that has full manifold vacuum.