AlexLaumeyer

My 73 delta 88 is having a bogging issue once in a while. The car could be cruising at 60 and then lose power like it’s not getting enough fuel and then go back to normal. An event (by event I mean the bogging) usual lasts about a second or so. I just replaced the fuel filter in the carb and have looked to find no other inline fuel filters. I have found a fuel leak in a part of the fuel line and fixed it although it did not help. Any ideas on what’s going on? I believe I should get my carb cleaned and rebuilt but I need reassurance on the issue.

Sugar Bear

There shouldn’t be other filters except for the sock in the tank. If the fuel level in the tank doesn’t affect it then it probably isn’t the sock. A blocked sock symptom is that the problem gets worse as the level decreases. Check all of the rubber fuel hoses for cracking closely including back at the tank.

The described symptom could be a failing fuel pump, if it is ancient change it and have the carb done. Specifically don’t allow someone to install a replacement/rebuilt carburetor, gets yours done by a specialist. You won’t be disappointed.

Timing and dwell in order? Has it been tuned lately?

Good luck!!!

AlexLaumeyer

I’ll try replacing the fuel pump tomorrow.
I never had to tune the carb other than changing the choke to an electric choke. I did have to retard the timing a little bit as I tuned it to a vacuum gauge which fixed my dieseling issue. Conveniently the issue popped up about an hour or so after the ignition tune and it ran a lot better before it started bogging/surging.

Sugar Bear

I’d set the dwell and timing accurately before doing other things. The dieseling may be due to other reasons e.g., idle too high, engine running too hot, carbon buildup or low octane fuel. Replacing an old fuel pump probably cannot hurt though.

Good luck!!!

AlexLaumeyer

The engine idles smooth (when it doesn’t surge) at 700-750 depending on how cold the motor is. I have a 180 thermostat and after the ignition tune I did, ended up fixing my dieseling issue. Probably making it run cooler and getting rid of the hotspots that are common with engines that are too highly advanced on ignition. I do believe it’s the fuel pump that’s causing my random surges. Luckily the car hasn’t died while driving but it has gotten pretty close to it. I’ll post an update tomorrow after I replace the pump. Thanks for all the help!

leftlaneonly

Might this be a float problem in the carb

gs72

Have you had the top of the carb off recently? I once had a bug get into the float bowl while i was working on the float level one evening on a old truck I had. I didn't notice it and put it back together. The next day while going down the freeway it bogged hard and started surging then backfired and started running normally again. It did this for a week before i investigated. Turned out the bug would get sucked over one of the main jets and cut the fuel delivery in half. The backfire would blow it out of the jet. Not saying thats your problem but it could be something similar.

rocketraider

What brand points/condenser/rotor/cap did you use? And were they new OLD stock or recent production? What condition is the distributor's internal wiring?

There are any number of emissions devices on a 1973 455 that could cause a hiccup like you describe.

If you don't have it, get an original paper copy of 73 Olds factory Chassis Service Manual.

73aussie455

Sticky needle valve would be the first thing I would be checking. Dirty or worn needle and or seat.
Or, float level could need adjusting after near 50yrs, too low, running out of fuel at highway speeds.
Either way a specialist rebuilt carby would solve the issue.
Find a 4bbl manifold from a wrecking yard and put on a reconditioned Rochester Quadrajet 4bbl 800cfm, was an option in '73 for your 455 Delta.

AlexLaumeyer

Replaced the fuel pump with a different one from oreillys. That fixed the issue. Never heard of mechanical pumps that slowly went out and not just fully. Usually from my own experience if a mechanical fuel pump is bad, it won’t pump a drop of fuel. One day it’ll work, the next it won’t.
Thanks again to everyone who replied!

Sugar Bear

Glad to hear...seen it twice, on a '70 Cadillac and a '75 98 Regency. The '75 Regency was a triple silver sedan hardtop, awesome looking car but NO power/acceleration due to smog equipment.