1940 Buick Special Series 40 difficulty starting/running

[M. Derr]

Hey all, this is a re-post in the more dedicated forum than my earlier general post.

 

At any rate, I'm having an awful time getting my Buick started and running. I can only get it running for 3 - 4 seconds and that's with the fuel I'm dumping directly into the carb with a syringe (~10 ml or so).

 

She's sat for a good 5 or 6 years, but has always been hard starting and it seems like it's always been a fuel problem. I've rebuilt the pump 2x now in the 12 years that I've had it, with the last rebuild only a couple of months ago.

 

Now that I've had a bit more time and money on my hands, I've become more serious about getting her back on the road. I've totally rebuilt the carb now as well and have put in fresh gas. Earlier this week I pulled the pump and the lower bowl was full of gas, so that seems to be working. I'm highly suspicious of getting fuel from the pump to the carb though.

 

Shy of pulling the pump and having it sent out for professional refurb, I just don't know what else to do. When I had the pump off earlier this week, I blew compressed air through all the lines thinking that perhaps I had a clog. After re-installing the pump, it made no difference.

 

Lastly, the tank has been cleaned, etched and sealed so that's not an issue.

 

Any help is appreciated. For any Chandler, Az enthusiasts (or other nearby) I'm open to someone coming over and help troubleshoot.

[Matt Harwood]

Fuel getting to the carb? Fuel pumps are cheap, and if it runs with gas being poured down the carb throat and the lines are clean, then your answer is that the pump isn't moving any fuel. Disconnect the fuel line at the carb, put on a short length of hose into a container, and crank it. You should get a few squirts of fuel as it cranks. If not, well, now you know where the problem lies.

 

 

 

[M. Derr]

8 minutes ago, Matt Harwood said:

Fuel getting to the carb? Fuel pumps are cheap, and if it runs with gas being poured down the carb throat and the lines are clean, then your answer is that the pump isn't moving any fuel. Disconnect the fuel line at the carb, put on a short length of hose into a container, and crank it. You should get a few squirts of fuel as it cranks. If not, well, now you know where the problem lies.

 

 

 

Yep, I tried that a bit ago and no dice. 100% not getting any fuel from the pump to the carb. Your thought then is to pull the pump and send it out for refurb? This pump isn't quite dime a dozen, it's a mechanical pump with a vacuum attachment (not sure what the vacuum lines are actually doing for me though).

 

Thanks in advance Matt.

[Matt Harwood]

Bob's Automobilia sells fuel pumps on an exchange basis, as well as rebuild kits. They're not difficult to rebuild but an exchange means you have a new one ready to go right away and send your old one back for core charge. It sounds like the fuel pump is your problem.

[Rock10]

Does that pump have a push rod and is it installed properly?

[1937 Buick 66C]

Good Afternoon Matt et al,

 

Since this appears to be a persistent / recurring problem, it sounds like it's time to verify that the entire.fuel system is intact and operational.  I have been dealing with several collector cars from the collection of my late father-in-law.  In every case, fuel more than a couple of years old caused exactly the symptoms you are encountering.  Fuel that is several years old is a major problem;  It is most likely becoming varnish and is no longer usable. 

 

I would recommend taking a day and performing a full fuel system diagnostic; none of this is is particularly difficult to do.  I strongly recommend acquiring a hand-operated vacuum pump (like a Mity-Vac or similar) where you can safely draw a vacuum on lines that carry flammable liquids.  First, remove any old fuel in the fuel tank with fresh fuel.  Put a couple of gallons of fresh E0 (non-ethanol) regular grade fuel is ideal, however regular fuel with a stabilizer can be used.  You can drain old fuel from the tank using the Mity-Vac (at step #2, you can use thethe MityVac to establish a siphon to drain the tank from under the car, from the rubber line between the tank and steel fuel line secured to the frame)

 

Fuel System Diagnostic:

1. Crawl under the car and trace the fuel line from the tank to the input side of the mechanical fuel pump. 
2. Working from the back of the car forward, verify that all rubber fuel lines are intact, and have not swollen shut due to use of ethanol fuels.  If uncertain about the lines you encounter, replace them.  Using a Mity-Vac or similar tool, apply suction to each line and verify fuel flow.
3. Check for any evidence of leakage from the steel fuel lines that run along the frame.  They are steel, and are subject to rust-through.  Any evidence of leakage from the steel fuel lines must be addressed;  It is both a safety issue, and a point where air will be sucked into the fuel line during fuel pump operation.  The mechanical fuel pump can only pump fuel, not air.
4. As you trace the fuel lines forward, do you encounter a fuel filter and/or electric fuel pump installed between the tank and the mechanical fuel pump on the engine?  These can obstructing fuel flow into the fuel pump if they have old fuel in them.
   1. Remove and bench test any electric fuel pump you encounter.  Replace the electric pump if it does not test successfully  (Older electric fuel pumps have rubber and plastic components that are not compatible with modern fuels, and the internals of the pump turn into goo.  Note here that I am an advocate for installing a low-pressure electric fuel pump along the frame rail between the tank and mechanical fuel pump, therefore if bench testing the pump is unsuccessful, I recommend replacing it with another electric fuel pump).
   2. Replace any filters you encounter.
   3. If the electric fuel pump tests OK, return it to the car and verify that it is receiving power and pumps fuel when reinstalled.
5. Remove the input fuel line at the mechanical fuel pump;  Apply vacuum and verify good fuel flow.  If you have an electric fuel pump in the line, you should still be able to draw fuel through the line to the mechanical pump.
6. Reattach the input fuel line at the mechanical fuel pump, and detach the output line between the mechanical pump and carburetor.  Again, apply vacuum and confirm fuel flow.  (Note: When drawing a vacuum on the fuel line to the carburetor, it will take longer as the fuel will need to fill the mechanical pump, including the glass sediment bowl, before you will see fuel at the carburetor). 
7. If you are unable to draw any fuel to the carburetor, but you know from testing step #9 that you have fuel at the input side of the mechanical fuel pump, it is possible that one of the valves in the mechanical fuel pump is stuck shut.  You may be able to get it unstuck by tapping on the fuel pump lightly with a hammer while drawing a vacuum on the fuel line at the carburetor.  These valves can get stuck when old fuel turns into varnish and "glues" the valves shut.  If tapping on the pump does not result in fuel flowing up the line to the carburetor, you will need to remove, disassemble and clean up the valves in the fuel pump. 
8. Once you have confirmed that you have fuel flow at the carburetor, you can verify that fuel is getting into the carburetor by operating the throttle while looking down the throat of the carburetor while opening and closing the throttle.  You should observe a squirt of fuel each time you operate the throttle.  If you do not observe any fuel, the needle valve inside the carburetor is likely to be stuck shut, again from accumulation of varnish.  You may be able to free it by tapping on the top of the carburetor near the fuel line connection, otherwise you will need to remove the carburetor cover and clean the needle valve. 

I hope this helps.  Please feel free to contact me directly if you have additional questions or concerns.

 

 

 

 

 

 

[critterpainter]

13 minutes ago, Rock10 said:

Does that pump have a push rod and is it installed properly?

No push rods on the Buick straight 8 after 34 or so.

[critterpainter]

One of the most common reasons for fuel pump failure (or the appearance of it) can be the flex line in the fuel line from the tank to the fuel pump.   The flex hose is located between the frame and the engine near the starter motor.   The original is covered with a steel braid.   It can either be cracked and cause a vacuum leak OR swell and plug or restrict fuel.

   By the way I sent you a private message as I live about an hour from you.

[Morgan Wright]

If your 1940 has the fuel pump that sends vacuum boost to the windshield wiper motor, check to make sure it's not losing vacuum in the line to the wipers. But then I thought about it, and I would forget about that and get an electric wiper motor, and a basic fuel pump without that wiper business. Bob's has them.

[neil morse]

You are getting some good advice here, particularly the procedures recommended by "1937 Buick 66C."  He mentions the possible presence of an electric pump in your fuel line.  I know the first priority here is to get your system running properly using the mechanical pump.  However, I just wanted to chime in here to say that if your car does not have an electric pump in the line, I would highly recommend that you install one going forward.  If you put an electric pump back near the fuel tank, it will be a big help in getting the system primed when you haven't driven your car in a few weeks.  It will also work as a back up system if your mechanical pump goes out for any reason.  The best set up is to have the electric pump on a switch so you only need to turn it on when you need it.