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Guys - I’m have a hellova time getting gas to the carburetor. I have a 70’ cutlass convertible. When I bought the car, the seller said he thought there was a clog in the gas tank so rigged a gas can upfront under the hood. That worked.
Since then, I’ve replaced the gas tank and sending unit. I’ve replaced the rubber hose between tank and hard lines at the rear of the car. I replaced the mechanical fuel pump last night. I had someone blow through the line to check to see if anything was in there. Air flow seems strong.
With All of this either changed or checked, I still have no fuel getting to the carburetor. WTF can be the problem? Is there a camshaft pushrod? I didn’t see one when I replaced the fuel pump, but I’m also a newbie so........
PLEASE HELP.......FEELING HOPELESS AS HELL RIGHT NOW.
Rosco, if you remove the fuel IN to the mechanical pump and put it in a jerry can you should get fuel OUT of the pump if it is working. Try this agian but feed the fuel OUT into a coffee can. If you don't have positive flow you know the pump is bad.
I bought a new gas cap, but for what it’s worth, I left one of the vent lines open because I needed to get another rubber hose. I’d assume this isn’t the problem because the car should be able to run while the fuel cap is off or pumping gas. Correct me if I’m wrong though.
not a camshaft pushrod like chevy has, but oldsmobile uses a camshaft driven eccentric wheel that drives the fuel pump arm. also check the fuel flow after the pump and at the carb intake port to verify just how far the fuel gets before stopping.
Rosco, if you remove the fuel IN to the mechanical pump and put it in a jerry can you should get fuel OUT of the pump if it is working. Try this agian but feed the fuel OUT into a coffee can. If you don't have positive flow you know the pump is bad.
I’ll try this tonight. One question, can the cam be bad? I’d assume that maybe the lobe is worn or broken where it’s not hitting the arm enough? I haven’t opened the motor yet, but seller says everything is stock.
I suppose the eccentric on the front of the cam could be damaged. I doubt it though. You should be able to see the eccentric with a light and inspection mirror with the fuel pump removed.
back to your original post. when you had the gas can under the hood to get the engine running, was the gas fed to the carb by gravity or were you using the stock fuel pump?
not a camshaft pushrod like chevy has, but oldsmobile uses a camshaft driven eccentric wheel that drives the fuel pump arm. also check the fuel flow after the pump and at the carb intake port to verify just how far the fuel gets before stopping.
Thanks for replying. There isn’t any gas flowing to the pump. I pulled the tube to the IN port on the pump. It looked bone dry. Let me ask you this.
My tube in between the fuel sender and gas line is curled (Not kinked). Could this be the issue? Should this be as straight as possible? I figured the vacuum/sucking from the pump should have sucked it regardless since there weren’t any kinks.
interesting.
depending on the bend or curl, that could be your problem. fuel pumps like easy pulls. check to see if you can manually siphon fuel thru the fuel line. if you can then the curl is probably your problem.
assuming your fuel pump has checked out good? will your fuel pump draw gas from a gas can? will your engine run when hooked up thru the fuel pump and gas can?
if yes, then you've isolated the issue to the fuel line from tank to pump.
Sorry guys, I am green when it comes to older cars w/ carburetors.
When I first starting the car, I poured fuel into the carb. It starts right up then dies (obviously from lack of fuel). Should keep pouring fuel in the carb to prime the system? If so, I'll do that. I stopped after a couple times.
The only reason you would need to pour fuel into the catrburetor/intake is if you're trying to start a car that's been sitting in a field for 10 years. Cranking the engine should spin the eccentric on the end of the cam which will activate the fuel pump.
The only reason you would need to pour fuel into the catrburetor/intake is if you're trying to start a car that's been sitting in a field for 10 years. Cranking the engine should spin the eccentric on the end of the cam which will activate the fuel pump.
Ok. Gotcha! I believe this car has been sitting for a while. The previous owner used to start it here and there, but using the little gas can upfront. All There isn't any fuel in the lines. When I swapped the tanks last weekend, no fuel came out the lines.
Sometimes there's a check valve inside the fuel pump that fails. If this happens you could see hard starting in the morning if you're driving the car regularly. Also, if the rubber hoses between the fuel tank and fuel line are deteriorated (i.e. 30+ years old) then your fuel pump will suck air through the holes in the hose and cause hard starting.
Both things I learned on ClassicOldsmobile. Although I learned the fuel hose in a coffee can trick from some old fat guy (my father, Oldsguy).
Well gents, I have fuel coming to the pump now. It seems to be flowing correctly. I guess I probably had to try a few times to prime the system. I also made the hose between the tank and hard line more straight.
Now I have to figure out why the damn thing won’t stay running. It runs and then dies out. Now I have another issue to troubleshoot :-)
I guess this is all one big learning experience!
Last edited by Olds64; March 22nd, 2018 at 06:27 AM.
Reason: No cussing please!
If your getting fuel now, then check dwell (if applicable), timing, choke position, idle speed, and idle air/ fuel mixture. Also look for vacuum leaks.
If your getting fuel now, then check dwell (if applicable), timing, choke position, idle speed, and idle air/ fuel mixture. Also look for vacuum leaks.
Noted! Thanks man. You guys are very helpful. Appreciate it
Before you drop the tank, disconnect the rubber hose that connects to the tank. Then do the same at the front, disconnect the front rubber hose that connects to the fuel pump. Using your air compressor, blow some air pressure through the metal pipe, and see if there is any restrictions. The metal pipe might be rusted shut on the inside. If you are getting a steady stream of air through the metal pipe, then check the metal pipe for leaks, by brushing it with a solution of 25% dishwashing liquid diluted with 75% water. Use a cheap half inch paint brush to brush the metal pipe. and while someone is pressurizing the hose, look for bubbles. It might have some pin hole leaks in it, so when the fuel pump tries to pull fuel through it, it can't develop a vacuum.
The next thing that I would do is to put a long rubber hose onto the fuel pump inlet, and put the other end into a small container filled with gasoline. Then crank the engine, and see if the carburetor is getting gas. If it is, then you know that the problem is in the metal fuel line, and the fuel pump is good.
The last thing to check, is the sock at the end of the pick up tube on the tank level sender. If you didn't get a new one with the new sender, then that also might be your problem. I have seen them clog shut, and visually, they don't show any indication of being clogged.
Once you get the fuel issue resolved, you can then deal with why the engine doesn't stay running.
Before you drop the tank, disconnect the rubber hose that connects to the tank. Then do the same at the front, disconnect the front rubber hose that connects to the fuel pump. Using your air compressor, blow some air pressure through the metal pipe, and see if there is any restrictions. The metal pipe might be rusted shut on the inside. If you are getting a steady stream of air through the metal pipe, then check the metal pipe for leaks, by brushing it with a solution of 25% dishwashing liquid diluted with 75% water. Use a cheap half inch paint brush to brush the metal pipe. and while someone is pressurizing the hose, look for bubbles. It might have some pin hole leaks in it, so when the fuel pump tries to pull fuel through it, it can't develop a vacuum.
The next thing that I would do is to put a long rubber hose onto the fuel pump inlet, and put the other end into a small container filled with gasoline. Then crank the engine, and see if the carburetor is getting gas. If it is, then you know that the problem is in the metal fuel line, and the fuel pump is good.
The last thing to check, is the sock at the end of the pick up tube on the tank level sender. If you didn't get a new one with the new sender, then that also might be your problem. I have seen them clog shut, and visually, they don't show any indication of being clogged.
Once you get the fuel issue resolved, you can then deal with why the engine doesn't stay running.
how important is the return line being hooked up? I have it open atm because I need to get another hose.
On your car, the return line doesn't know if it is hooked up or not, since it just takes excess fuel back to the tank. If it isn't hooked up, then the excess fuel will spill out where ever it is unhooked to.
Now, since you brought this up, is there a possibility that you have the fuel pump hooked up to the return line by mistake? If so, that would account for the no fuel condition. The return line usually drops the fuel into the top of the tank, and doesn't require a dip tube. Some return lines also are teed into the main fuel line, and in that case, it has to be hooked up to maintain the closed loop for the fuel pump to work.
The advise that I am giving in this and the last post is generic to all cars, and any peculiarities that might exist in your particular car are excluded, since I am not well versed in your model.
Here's an issue!. There are 3 lines mounted in the center under the floor. Looks like this:
/|\
There are also 2 lines that run on the passenger side of the frame. One should be the main gas line and the other is either return or vapor and I think it connects to the radiator.
I rolled under the car and followed the 2 lines with eye and hands. The line that should be the fuel line disappears AFTER it crossed past the spring mount. The other line drops down by the tank. I hooked the line from the tank to the line that's hanging. Nothing happens. I also had someone blow down the line from the front of the car and air flow seemed good.
I also still never got fuel from originally stated. I was mistaken when I said that I have fuel and it keeps shutting off. I have a can rigged to the front of the car and the fuel from this tank was left overs still in the pump.
I'm starting to think the issue may be the eccentric. There is one in there obviously because I had to crank the motor to move it so that I can properly sear the fuel pump.
Something that should be so simple and causing a pain in my a$$.
use your mouth and try to suck/siphon gas out of the line you have connected to the tank.
doubt the eccentric now, because you had to crank the engine over to get the fuel pump seated. eccentric is fine and should operate the fuel pump.
the two lines on the passenger side you describe. you say one is connected to the radiator?? this should be a transmission line. the transmission has two steel lines connected to the radiator.
FYI...1970 cutlass has a single feed gas line only, unless your car is originally air condition equipped. A/C cars had a vapor return line. both lines for fuel and transmission are on the passenger side. be sure your connecting the fuel pump to the fuel line. fuel line is the one with the 12" long, braided rubber hose from fuel pump to steel fuel line mounted on the frame. tranny lines will be smaller diameter and close to the motor mount.
This shows the two steel tranny lines on a 70 cutlass running to and from the radiator.
The 12" rubber line and fuel filter mounted to the fuel pump and connected to the steel fuel line on the frame rail.
March 21st, 2018, 04:43 AM
