I found an electric fuel pump on the frame rail installed (and functioning) on my '71 Cutlass 350 4bbl. Why would someone put this in there with a fully functional fuel pump in place? I have an Edelbrock replacement on top, but it does have that 1/4 or so insulation adapter between the carb and the intake manifold (stock Olds). I can't imagine vapor lock would be a huge deal, as I have not heard of really anyone that has a classic, of any kind really, that is running into this as an issue. I know I never have with my carbureted cars running todays gas in the middle of summer....

 

Because they wanted to fix what ain't broken?

 

Double check that mechanical fuel pump. Does it pump fuel into the crankcase?

 

Ya, she was running just fine. It's a recent purchase, and I don't have documentation for anything recently done, so I'm draining/flushing the coolant system, new water pump, etc. Noticed it then.

 

This was likely put there as a crutch to cover another problem. For instance, if the engine regularly ran hot, the fuel in the mechanical pump could boil, which would have stopped fuel delivery.

Absent information from the previous owner, the way to determine the underlying problem is to remove the electric pump and correctly diagnose and solve the problem that appears.

 

I guess I missed something - did the OP state an underlying problem?

 

No problems were stated, documented or observed. Previous owner is not reachable.

 

The pump could have been put there to help prime the carb after the car has sat for some period of time. Fuel evaporation and Q-Jet leakdown can cause a long period of cranking after the car has not been started for a while. Did you find a switch for the pump? It could also be a backup if the mechanical pump failed.

 

I've seen a bunch of rather stock type cars that were raced add an additional electric fuel pump to help the mechanical.

I even thought that it was allowed in the "stock" classes.

 

Bob - I was actually referring to your post. Is there some problem you're experiencing?

 

Because RACECAR, that's why 😁

 

The electric pump can also help prevent vapor lock in hot weather or high altitude.

 

Does it turn on automatically or do you have to turn it on?

 

Back in the day it was common to simply run the electric pump in series with the mechanical. If the electric pump is higher pressure, it will simply push fuel through the mechanical pump. Also, for today's cars that are not driven that often, the electric pump can be used to prime the carb before starting. Don't lose a lot of sleep over this.

 

I'm curious. Which of "today's" cars HAVE a carburetor?

 

Today's collector cars that are not used as daily drivers. C'mon, how many posts have we had over the years about "why does my car take so long to start?"

 

Oh. Today's COLLECTOR cars. Not a 2025 Buick or something like that. I get it now!

 

Quite a few, for sure, but how many of these people had a problem because their engine wasn't properly tuned or had some other problem?

We're so prone to fixing things on old cars that were never a problem back in the day. How many times do we see people installing electric fans to help keep their engine cool because their newly installed temperature gauge reads 191 degrees and they think it should be 190?

I'm sure that manufacturers in 1966 or 1974 realized that not every car sold was going to be driven every day and that sometimes a car might sit for a while between starts because that was simply the way the person who bought it intended to use it. I'm sure that manufacturers realized that cars treated like this still had to be easy to start without their owners taking extraordinary measures. Just look at the proverbial little old lady who only drove her car to church on Sundays. As I recall, the little old ladies of the world didn't need electric fuel pumps to make this happen.

We used to take family vacations when I was a kid back in the 60s and 70s. We'd be gone for a week at least and one time for almost four weeks. Our other car just in the garage for the entire time, and I don't recall my father ever having a problem starting those cars when we returned. We didn't need an extra fuel pump or anything.

We're just coming out of winter here in Michigan. We had a few warm days about two weeks ago, and I went out to start up my three old Oldsmobiles, all with carbureted engines, that had been sitting unstarted and undriven since late October. Maybe three or four pumps of the pedal and a turn of the key, and all three started pretty much like they would have if I had just driven them yesterday. None of them have an electric fuel pump.

Properly tuned with components working as they should, a 1971 Cutlass or whatever didn't need an added fuel pump in 1971, and it doesn't need one now.

 

It's fine until it's not, like if the diaphragm fails and the electric pump fills the crankcase with fuel. Pick one, and do it right.

 

Apparently nobody on this site can tune a car and a Q-Jet as good as you can.

 

Those "little ol ladies" lived in Pasadena and drove brand new Super Stock Dodge's, according to Jan & Dean.

Gasoline has changed, I went out to start my '66 Toronado last week. and pumped it several times before hitting the starter, No start. So, I got a gas can and trickled some fuel into the Quadrajet primaries. I got in and turned the key....it started right away. I closed the hood and took it for a drive to circulate all the fluids. I do this every spring. If it sits 2 or 3 weeks, I may have to "prime" it again.

 

No problems. Starts, idles, and runs just fine. So wondering if I should pull it out or not. It's not a numbers matching 1-of-a-kind car or anything. Just a nice "mostly" stock olds with all the things that happen over 50 years -- new gas tank, accessory items (alternator, carb,...), rebuilt trans, and I think a color change. So I don't really care one way or another on this tiny item other than it's another thing to break and bother me going forward.

 

MN, The downsides are it may have been installed as a crutch to fix a problem that may become evident once it is eliminated. If that occurs the newly appearing problem would need to be corrected if it exists.

The other downside is that if it is left in place and the mechanical pump fails the car will probably still run but the electric pump may push raw gasoline through a failed mechanical pump diaphragm straight into the crankcase causing diluted oil and potential bearing failure.

If it were mine I'd eliminate the electric pump...my $0.02¢. Good luck and many happy miles and smiles.

 

AURRRGHHH!

That was Jan and Dean. Yeah, Brian Wilson wrote a lot of their songs and the Beach Boys frequently sang backup for them.

 

Not being good at tuning carburetors, I prefer the Tri-Carbs. It is three times as likely that at least one of them will work. I can't tune musical instruments either.

 

"Elec Fuel Pump Assist?" Yes that's exactly why it's there.

Yes, part of the "Pure Stock" trickery playbook.

I would not pull it, unless...

It's very likely starting, idling, and running, fine because of it. The unless part is regarding whether or not you want to open up a possible can of worms... My longtime mechanic going back 30 years who is now a senior citizen. And made his bones working on cars like ours. Has been prodding me to go electric fuel pump since I bought the 69 back in 2014. He told me all my complaints will go bye bye. Because of all the benefits to having one that Joe P points out in post #14 and #16.

I am naturally resistant to change and overall prefer what was. So I have not gone this route as of yet. Instead, just trying to get what's there to run better, as it did when new. Another long time mechanic of mine assisted in getting the carb to be more responsive. And overall there has been a lot of tweaking that has taken place over the years just to get it to do what the electric assist would resolve instantly ... Started her yesterday, after sitting overnight and untouched for 25 hours. 2 pumps crank running by 5 seconds, literally timed it. Warmed up in a good mood she will sink you into the seat and incinerate the tire for a half block on a dead punch. Just cracked 140,000 miles the other day.

 

Dayum Joe P, you caught me again. You are correct as usual, I corrected it, Thank you.

 

Yes, NHRA did allow electric fuel pumps in "Stock" classes. NHRA "Pure Stock" classes had rules that tried to keep cars configured as they came off the showroom floor or dealer lot. "Stock" and "Pure Stock" were not the same rules.

The biggest problem in "Pure Stock" classes was traction. The "Stock" classes were different because slicks, headers, lower gears, blueprinted engines produced higher acceleration and "G forces". A greater demand on fuel flow was helped with electric fuel pumps.

A/S (manual trans), A/SA (automatic trans) to about V/S were the designations on the cars in "Stock" classes. A/PS (manual trans), A/PSA (automatic trans) to V/PS were the designations for "Pure Stock".

 

I own 5 carbureted cars and I think all of them would start after sitting months on the mechanical fuel pump only. I do put some gas down the carb of the project car. The Ford 2 barrel starts its v8 faster than the quadrajets do, but it's about 5 to 7 seconds on those of cranking and then a solid roar coming to life to about 2000 then back to idle. I don't think any GM quadrajetted car needs extra help starting other than there being something wrong.

 

The main thing I find with my ‘66’s when they sit is that the gas in the qjet will evaporate over a week or so of not driving. Or maybe it leaks down into the intake and evaporates there.

Either way I find that a stout battery & thick battery/starter cables (2 or 1 gauge) really help consistent starting for classics that are irregularly driven.

If I haven’t driven ‘em in a while I sit there imagining fuel being drawn all the way front the gas tank in back up to 5-7 PSI. So I wait 15-30 seconds before stabbing the gas pedal to engage the cold start choke.

My cars generally start consistently, but I can’t say this is skill. I think I’ve just made most every error along the way and got past ‘em.

Cheers
Chris

 

That was quite the assortment of options. Since the pump is easily accessible, I think I'll pull it out and test the vehicle without the pump to see if other issues appear. Since it is early spring here, meaning only 6" of snow on the ground, I can afford to wait a week or two between starts and see if that is an issue.

Cheers

 

Quick update.

I pulled the pump out this weekend and she runs like a top. I'll see if I have a difficult start after a week or so of just sitting in the garage. But all signs look good.

 

DOH!

Good deal, I'm glad she runs like a top! 👍