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Need Help! Car boggs down, fuel delivery issue. 350/4bbl

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Old 10-06-2016, 01:50 PM
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Car: 82 Trans AM Firebird
Engine: JASPER 350
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Need Help! Car boggs down, fuel delivery issue. 350/4bbl

running around in circles with this issue. this is the second mechanic to look at this issue. do his tests. and pass it.. I feel like this guy did a bit more than the last. he said he blew out the gas lines, adjusted the carb, pressure tested the fuel pump.
I just drove for an hr, 30 minutes to a friends house, 30 minutes back. When i hit the highway on the way back, i noticed a little bogging down. i eased up on the gas, and it seemed to get the right amount of gas because it was reacting fine a few moments later. after about 20 minutes on the highway i get back on side roads. I noticed the car bog down after i took off from a red light, again, it drove, i eased off the gas and managed to get home.

this picture is of the car running, i couldnt load a video to thirdgen.org. its getting enough gas to run, but it was bogging down minutes before i managed to get her home... Then i have these times where the fuel filter is loaded w plenty of extra gas. I need to know why theres such a fluctuation in fuel delivery.

im noticing the fuel just spitting out the minimum amount of keep the car running, when i give it gas, there doesnt seem to be enough fuel ready at the filter level and it boggs down.. thinking removing the tank is the next bet. No mechanic felt the tank needed to be replaced. but My father mentioned, someone put sand paper in his tank many years ago, and they couldnt figure it out till the tank was pulled.

latest mechanic said theres a very small chance it would be the sock or pickup on the sending unit.. i just dont know. need this fixed correctly because this breaking down everytime i drive this car is getting old quick.

350/ edlebrock 4 bbl, mechanical fuel pump. should be stock tank, but i purchased a replacement from an 87 GTA.

Im now in rush mode to have it ready for the foliage cruise. Any help would be greatly appreciated.

Old 10-07-2016, 01:05 AM
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Re: Need Help! Car boggs down, fuel delivery issue. 350/4bbl

i thought anything 87 had a electric pump in the tank. Visually that doesnt look like enough flow to feed a carb'd 350. id be looking for a blocked strainer in the tank or for the mysterious pump that many don't think exist (myself included) until you pull the little sucker out.

I'm not saying that there is definitely one in the tank, but you if you scored an 87 tank and someone used the assembly off the 87 tank for whatever reason, AND if by chance there is a dead one in there, it seems to be a bit of luck as to whether or not your mech pump will pull through it or not. Mine didnt pull through it, some stories on here have people running dead ones for ages with no issue.

could simply be your mech pump dying too...
Old 10-07-2016, 10:29 AM
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Re: Need Help! Car boggs down, fuel delivery issue. 350/4bbl

How about a plugged canister or does it have plugged fuel vent filter by the tank?
Old 10-07-2016, 11:12 AM
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Re: Need Help! Car boggs down, fuel delivery issue. 350/4bbl

If it still has the pump in the tank that could be a problem. On my 89 I put a built 355 in it with a carb. It would run ok most of the time and other times not. It definitely had problems pulling fuel through the intank pump. I removed the in tank pump and extended the pickup tube and I had no more problems.
Old 10-11-2016, 09:02 PM
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Re: Need Help! Car boggs down, fuel delivery issue. 350/4bbl

Have you put the car on jack stands and taken a look under it for something dumb? That fuel filter is fine, but maybe there is another fuel filter before that one somewhere hidden that could be clogged? Maybe the fuel line moved and is pinched up against something? It sounds dumb but its free and you might find something stupid. I'd also try blowing the fuel line out with compressed air right behind the filter. If it runs better afterwards then you know there's some junk in the line and the tank and you need to drop and clean the tank and lines out. It might be a waste of time, but I'd rather spend an afternoon doing that before I throw money at it
Old 10-12-2016, 01:50 PM
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Re: Need Help! Car boggs down, fuel delivery issue. 350/4bbl

you don't mention whether this was originally an LG4 carbed motor

are both the fuel feed and return lines run along the passenger side framerail? Are they BOTH hooked up to the mechanical fuel pump?
Old 12-09-2016, 02:28 PM
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Re: Need Help! Car boggs down, fuel delivery issue. 350/4bbl

was a failed mechanical fuel pump, seems to work good now. havent driven it much, need to swap my auto for a T5 this winter.
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