Packard Forum Index » Post-War (1946-54)

I have recently received as a present a 1952 Packard 300 sedan. There seems to be a loud hum from the fuel pump, beginning as soon as a turn the ignition key ad continuing while I am driving the car. Do I need to get a new fuel pump or is there a simple fix?

It sounds like somebody installed an electric fuel pump. With the key turned ON and engine not running follow your fuel line from the tank and see if you can find an electric fuel pump.
Wes

Yes- It is definitely an electric fuel pump. Am I stuck with this noise unless I change it out?

Ron Levine

Not knowing your setup it's hard to say whether the sound is normal or not. Most electric pumps are "pulsers" which have a throbbing or clicking noise when working. Humming might mean a rotary type. Whether you would get rid of the noise completely with a new pump is unknown.

Many have added that pulser type electric pump near the gas tank to push fluid to and thru the regular pump. The electric is controlled by a switch so it's only on for a few seconds to prime the carb when the car has sat for long periods. Once the car has started, the electric is turned off and the regular pump takes over pulling gas thru the electric and all works as normal -- and quietly. NOTE: The pulsing type will usually allow gas to pass thru if off but the rotary type generally does not without extra plumbing.

One other nice thing with that arrangement is if the car acts like it is getting vapor lock with todays more volatile fuels, it could be turned on and with the fuel being pushed under pressure usually alleviates the vapor lock symptom.

If I were going to do something I would get the proper mechanical pump operational and do the electric as described as a backup. Your car also depends on a working mechanical pump for the secondary or vacuum section. That part provides supplemental vacuum for the wipers when the engine is under load and can't provide much.

That response was very helpful. I have printed it off and will take it with me to a mechanic that has been recommended to me. Not being too mechanically sophisticated, this is exactly what I need and I appreciate it. Which brings me to the problem with this car that plagues me the most.

After driving for a while and heating up that big straight 8 engine, I have had difficulty re-starting the engine after shutting it off. It seems like the the heat from the engine interferes with the starter, which is right next to the engine and, only if I wait a while until the engine cools down will it start up again. Someone told me they heard of folks putting some kind of heat baffle between the engine and the starter. Any solution to this problem? The car ordinarily starts up nicely, in spite of the 6 volt battery and runs nicely but it's no fun to get stuck somewhere, reading a book until the engine cools down.

Ron

As to the fuel pump, I'd install the correct mechanical fuel pump and discard the electric pump, or get a new electric back at the tank as an emergency pusher if your car is prone to vapor lock or you live in a very hot climate. But I'd rely on the original mechanical pump under normal circumstances.

As to hard hot starting, it's possible that your starter motor needs service, but more likely if your problem is that the engine has a problem cranking smoothly when hot, you should check your ignition timing, a balky starter motor on a hot engine is a classic symptom of excesively advanced ignition timing.

One other thing, is that with an electric pump running all the time with the key ON. If you were in an accident and with the engine stopped, your electric pump could still be pumping gas and if a fuel line breaks, you would be pumping gas out.
I know this is a lot of if's but that's what causes accidents.
Wes

Regarding your trouble re-starting when hot, recommend you check out the excellent thread below written by one of our friendly forum ambassadors, BH. I have often experienced the hot start problem in my 23rd series if it has been shut down for longer than 10 minutes or so, but I have always been able to easily re-start the car under these conditions if I floor the accelerator to open up the choke (i.e. I'm dealing with a flooded engine following a "hot soak" as decribed in the below thread). Recognize that this may not be your problem, but it's certainly very possible and easy enough to test. Until I learned this technique, I had significant difficulty getting it re-started. Haven't had any problem since that little discovery 5 years ago.

https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?topic_id=8144&forum=14&post_id=87720#forumpost87720

theres supposed to be a heat baffle between the exhaust header and the fuel pump ,it bolts on one of the manifold bolts with a little l shaped bracket it looks like a 1/2 of a pingpong paddle sort of , its in the manual ,i put reflective heat tape on both side s and also wrapped the fuel line in a heat reflective cover where it goes near the exhaust ,it looks a little stupid but what the heck ,i got ths from the racing doo dad section at the auto parts store
also having a phenolic block under the carb helps ,but the biggest cure for the hot start issue is a big battery the original speck is 1000 cch ,the 6 v jobs fron the auto supply are 600;s the closest thing around I found is a napa forklift battery with 900 ccw ,you have to mod the battery tray just a hair ,makes a huge difference and the car will laugh its way through a hot start from then on slao you need fat battery cables if your 6 v

If the fuel system does have an electric fuel pump that can be switched to always on, I would strongly recommend installing an inertial fuel pump cut-off, like this one.

Fire sucks, and it sucks fuel even more.

Tom