Hello all! Nice forum you have here.

Anyways, I have a problem that I was hoping to get advice on. I'll give the symptoms and what I've researched on the problem so far.

I was cruising down Interstate 24 the other day around 90mph and pressed the accelerator and the engine started sputtering, sounded like it was fixing to die. I backed off to around 90 again and it was fine. A repeat test proved the same thing, once again when throttled past 90mph, I believe around 4k rpms, the engine started to die. So I dropped down to 70 and it was fine all the way back to my exit. Wanting to know if the problem was universal through all gears at high RPMs, I stopped at a light and opened up the throttle enough to hit the target, problematic RPM range in first gear and sure enough, more sputtering around 4k-4.5k

Recap:
Sputtering Engine around 4k rpms universally, anything less is fine.

Things to note:
I recently replaced the 2ft section of "supply" fuel line in the back of the car and have inspected connections at the fuel pump, carb, and as far back as possible to the tank, I have also looked at the fuel pump and it "Looks" fine, even though everything looks fine from the outside. I have not tested the pressure on the fuel line though I doubt that would reveal any results unless I tested pressure at about 4k rpms which my neighbors wouldn't like very much. It's the stock L-82 350 engine, I can answer any other questions as needed. Also, does anyone know where the fuel filter is located in the 77? Pictures by chance? thanks.

 

Fuel supply issue. Could be pump, filter, carb issue, etc.. Need to get a pressure reading at the carb and watch as you hit that rpm range. Plug in a pressure guage and take the car to an area where you can ramp it up to the range and check it so as not to tick off the neighbors. Any chance the fuel hose you put in is collapsing? I tend to look at " cause and effect" when things pop up after changing something. (Fuel hose). If the prob wasn't there before that change, I'd investigate that first. Fuel pressure reading would certainly help you isolate that. Good luck to ya. You'll find it!

 

I'm betting on the sock inside the fuel tank. Time to change or just remove.

 

If it still has the Q-jet, the filter is in the inlet of the carb.

 

Replaced the fuel filter and the problem seems to be resolved, I'll keep you updated.

A friend told me that the new 10% ethanol in today's gasoline breaks up any present residual rust inside of tanks which can clog the filter, so we'll see if this problem re-occurs in a few months.

It was interesting to change the filter inside of the Quadrajet Carb, most of the ones i've done where external somewhere in the line between the pump and the carb.

PS. Sock in the gas tank? What's that?

 

Look into the tank via the fill cap, I too am breaking down at about 3500 rpm, was thinking ignition but now after reading your post I should take a look at fuel. I can see 2 "socks" in the tank at the pick ups, they are black. A friend told me they should be white. Anyone out there want to set me onthe right path here.

Rgds. Roger.

 

Not necessarily true. I had a problem with my '64 doing the same at the big end of the quarter. I put a pressure guage on the line and found only 3#. I changed out the fuel pump, the pressure came up to ~7# (even at idle) and the car runs great.

 

I had this problem when I was learning and we put the filter in backwards. Car ran fine, until I stepped up the RPMs.

You should have another filter inline lower.

 

I had the same syptoms. Turned out to be a short piece of fuel line at the pump that had kinked. The previous owner did not use the factory bent hoses there....

 

Ironic! I put mine in backwards too :P Car started and died and I thought to myself "Man, I bet I put that in backwards." I didn't pay attention when I pulled it out and I just assumed the rubber end should go into the carb, WRONG!

 

Check fuel pressure. I run a gauge at my carb, just for that reason. It's a quick look to eliminate a pressure problem.

BBTank

 

Does this mean dropping the tank? replacing the sock I mean.