I have a 68 firebird 350 2 bbl 4 speed Previous owner added a 4 barrel and had issues with it ever since I purchased the car as a project car so started with a non runner
I added a edelbrock performer intake and went thru the 72 q-jet My problem was previous owner cobbled a 68 2 barrel throttle cable and that didnt have enough length to properly open the throttle. Replaced the cable with a proper 4 barrel cable and it ran like a beast! At least for a little while
The car started cutting out at higher RPM's...Car would pull strong thru 1st and 2nd, but shift into third...while accellerating, it would fall on its face
Another pontiac buddy told me its a fuel delivery problem, and suggested replacing the fuel pump. I took off the old pump, and replaced it with a new autozone... Nothing...Car is not getting fuel to the carb now. I turned the motor over by the crank to line up the eccentric and there was a little resistance but the pump bolted up, connected the fuel lines...and no fuel
I pulled the new pump off and put my old pump on Again...No fuel to the carb Is there a trick with the eccentric to the fuel pump rod? What am I missing?
Maybe the pick-up sock plugged? Filter in the carb inlet plugged? Needle valve stuck closed? Did you disconnect the fuel line at the carb and crank the engine to check if the pump was getting fuel to the inlet? I recently had a quadrajet that was getting no fuel, I suspected the pump but when I disconnected the carb inlet line and cranked the starter [coil wire off] the pump worked well. It was a stuck needle-seat.
Chased carb/pumps issues. Told my engine builder my "thoughts", he told me , "how do you KNOW it's the pump, you have a fuel pressure gauge?" Lesson learned. Best way to narrow your issues with fuel delivery is install a fuel pressure gauge. You can install a permanent electric one, or run a rubber hose type temp one, but until you can verify FP thru all ranges, you are only guessing...my experienced 2₵
If the rubber fuel lines have not been changed recently it would be a good time to change them all. Todays gasoline does not play well with older rubber hose as well as older accelerator pumps and needle and seats.
I have never had this issue but here are a few thoughts on it.
I'm a little lost on the "I turned the motor over by the crank to line up the eccentric and there was a little resistance but the pump bolted up, connected the fuel lines...and no fuel" Not sure what you mean by this.
If the eccentric is in the down possition then putting the pump in is a PITA. If the eccentric is up then it goes in pretty easy.
Also if the gas all fed back into the tank then priming it may take a bit of cranking.
I would take a small gas cantainer and run a short hose from the pump to the gas container and also run short piece right out of the pump for testing. Shouldn't take much cranking then to see if everything is working.
Not sure there is a good way to verify that the eccentic is moving the fuel pump arm. Maybe if someone else knows they can chime in.
As was mentioned the fuel sock and hoses may be suspect. I bought some special race hose that is made for todays fuel its blue in color and very stiff. No chance of it collapsing and pinching off gas due to pump suction. And as also mention todays gas can do bad things to the inside of these hoses if they are old. When I pulled the sender on my tank the fuel sock crumbled on me.
I also had fuel starvation with my car. The q-jet has very small bowls and combined with the stock fuel line and g-force while accelerating it causes issues same as yours. For me it was the top of 2nd gear or about 4800 RPM or so. The only thing I did was run a new 1/2 line and RobbMc Sender. I still have the same small cannister stock fuel pump. I did add a return line to my car also.
Many people have had really good luck just running an electric pusher pump back by the tank. This has several advantages with todays gas and how easily it evaporates. Lot less pumping and cranking after the car has sat for a while..
I was taught to get a clear 2 liter bottle and a rubber hose,tie the hose to the fuel line and put the hose inside the top of the bottle and crank for 15 seconds, a stock pump will give you about a pint of fuel in the bottle. a helper to hold the bottle is always good. This will tell you if the pump isn't working.
The eccentric can be felt through the fuel pump opening. but if you were running before than it seems to be working because if it was loose you'd hear it scrapping and scratching the timing cover. My 2 cents, becasue I went through this last year. It was the fuel pressure regulator.
You guys are not going to believe this (I can't believe it myself) Finished work and was going to (test) the pump by pulling the rubber fuel line off the hard line going into the pump, and do the bottle test
Went into the garage...Figured what the hell and tried to start it The [censored] thing fired right up! Drove it around for awhile an it was still bucking under WOT A buddy of mine who has been a mechanic for 30+ years stops by Pulled the plugs...They were fine Checked the choke...Functioning properly Checked all electrical connections because it almost seemed ignition based Everything was tight Double checked the fuel filter and it was clean
BUT....My buddy looks at the fuel filter (and yes, it was properly installed) It has a rubber "roll over plug" on the front...He rolled his eyes, pulled it off and I reinstalled it...and guess what The [censored] thing ran great! Drove it for 10 miles...On and off the highway, WOT, bumper to bumper Not even a hiccup
I am still shocked....My buddy told me the "roll over plug" was in case the car rolls over...It stops the flow of fuel to the carb...He has been peeling those off fuel filters since the 70's
I'm going to go buy a lottery ticket.... Thanks for all of your advice! Mucho appreciated!!
