nothing special, non-modified 305 with the computer control quadrajet

recently i started to have problems under WOT, it would go through first gear fine, then bog out, and sometimes pick back up, made it very annoying to drive.
sometimes it was worse then others, and sometimes hapiened durring normal driving.

so i figgured my fuel pump was on its way out again, so i put in a nice new carter mechanical fuel pump.

so that didn't solve anything, so i put in a new fuel filter too, small improvement, but still not right.

and last night i was driving nice and gentle and it started to bog out going up a very small incline and i was just prety mad at the car by this time so i kicked it into neutral and reved it up and it had problems free-reving around 4000rpm so i let off and tried again and it went to 5000 just fine.

all said its weird, if i'm in the middle of accelerateing sometimes it will just quit climbing and stay at a certin rpm and then sometimes surge back and fourth. i'm at a loss here.

 

Sounds to me like you are not maintaining fuel pressure to the carb.
You might want to rig a hose and bottle of gas to the carb inlet and then do a fuel pump pressure check while the engine is running. There may be an obstruction in the fuel line(dirt, sludge, bad in line filter?) that is restricting the fuel flow. Also, since your 87 has an in tank pump and filter, they may be gummed up. I am replacing the tank, pump, and filter on my 87 Formula(same engine-LG4)and the in-tank filter was solid with built up crud. The bottom of the tank had about a 1/4 in of muck on the bottom(I bought the car new in OCT 86). So you may have a real restriction at the tank that is seriously hurting your performance. I'm not sure if you can disconnect all of your fuel lines and blow them out with air.

 

ok so it sounds like the same problem iam having cause its under wot.. the rest of the time its ok... where in an 85 is the fuel pump and filter.. still some what new to this and willing to do what ever it takes to correct my problem i am having thanks allot for any info

 

I'm not sure about any of the other f-bodies except the 87-GM found that there was an increased likelyhood of vaporlock on the 87 LG4 and there solution was to put an electric pump and "strainer" in the fuel tank. You either have to drop the tank(probably an 8 hour job in the driveway) or cut an access hole through the differential hump and carpet to get to the top of the tank in order to change the pump. There is an excellent thread about the steps to change the pump in the forum searches.
I used to work at the Mitsubishi plant in Normal, IL and we had a new car that wouldn't run right-turned out to be paper or cardboard that got into the main fuel line and practically plugged the whole fuel system. I'm guessing that the fuel line is obstructed somehow. Start at the carb fuel inlet filter and work back to the tank.

 

also i should add once in awhile i will get a gasoline smell in the interior when the car gets in one of its moods.

so the general gist of things that i'm getting is that i should drop the tank and change the tank-pump and clean all the crap that may be in my gastank out?

 

Yes, it is probably due.
On mine, since I don't have to drive it as a work car any more, I got a new tank($200 vs. $140 for boil out and sealing the original), a new pump, strainer/filter, adjustable panhard rod, poly bushings all around, new LCA's, new shocks and hardware, and a BW nine bolt w/3:27 posi and disc brakes to replace the 10 bolt, non-posi drum rear that came with the car. Since everything had to come down to put the tank in anyway, I sanded the rust spots and painted POR 15 under the whole rear body.
Anyway, good luck dropping the tank, it's a pain that you won't want to repeat!

 

worst part about all this is once i do it, i'll have to do it again down the road when i get around to converting the car to TPI.

guess i'll start collecting parts and tackle this next weekend...

 

If you're smelling fuel in the car, either you have a leak or you need to rebuild that carb. If the pump and filter are new, and the line connecting them to the carb is free of obstruction, that's the only logical solution. Either the carb is leaking through the gaskets, it's severely out of adjustment, or it's just so old that it needs to be rebuilt.

 

the carb was rebuilt back in summer of 2003.

it idles prety decent, often when its not warmed up it will idle close to 1000 rather then the 700 or so that i'm used to it idleing when warmed up.

also i just did intake gaskets on it aprox 3500 miles ago, and this problem has creeped up since, should i have replaced my carb gasket when i did this?

i'll have to try running the car directly from a alternate gas source before i go droping my tank out.

 

Before you go dropping the tank, disconnect the fuel line at the carb, place a rubber line onto it into a container, start it up (should idle for a minute or more from fuel in bowl) and measure how much comes out, about a quart in a minute?

If you've installed a stock type filter, pull it out and remove the small check ball-I've had them restrict flow.

Bad float or sticking needle and seat can allow the carb to flood causing similar symptoms. Look for fuel puddling on the intake on each side.

Oh, and check your choke pull off while you're there. Push the plunger in and hold your finger over the vaccuum nipple. Plunger should stay in.

 

so i was reading my service manual on the in tank pump, it claims it ought to be puting out 3psi to the mechanical pump.

so i bought a low pressure fuel gauge and hooked it up, at BEST i could get about 1.5-2psi out of it, but it was reading about 1psi most of the time. i think i may have found my problem...

 

Flow is more important than pressure for the in-tank pump. The mechanical pump will bump the pressure up for the carb. Pull the rubber hose loose and let it pump into a container of known volume.

On the other hand, if you're getting vastly varying pressure readings for the in-tank pump it could indicate an intermittent problem, electrical, clogged screen, pump going south, etc.