Hello and welcome to Packard Motor Car Information! If you're new here, please register for a free account.  
Login
Username:

Password:

Remember me



Lost Password?

Register now!
FAQ's
Main Menu
Recent Forum Topics
Who is Online
126 user(s) are online (82 user(s) are browsing Forums)

Members: 2
Guests: 124

Pgh Ultramatic, Braden , more...
Helping out...
PackardInfo is a free resource for Packard Owners that is completely supported by user donations. If you can help out, that would be great!

Donate via PayPal
Video Content
Visit PackardInfo.com YouTube Playlist

Donate via PayPal




1936 Packard 320 ci fuel issue
#1
Home away from home
Home away from home

series014
See User information
I have 1936 Packard 320 ci that goes from 4.5 Psi to 0 fuel pressure at the carburetor after the engine runs for 10 minutes (engine dies at 0). I have had the pump professionally rebuilt. I used an auxiliary tank at the inlet to the fuel pump to eliminate any tank/line problem. I also run ethenyl free gas.
Has anyone had a problem with the pump push rod?
Any other ideas? Thanks

Dean

Posted on: Yesterday 10:16
 Top  Print   
 


Re: 1936 Packard 320 ci fuel issue
#2
Home away from home
Home away from home

56Clippers
See User information
Is the pressure drop a slow decrease over the ten minutes or is it a step function that suddenly goes from 4.5 to 0?

How long do you have to wait until you can start it again and get 4.5psi?

Have you tried isolating the fuel pump and measuring the output?.

Posted on: Yesterday 11:02
 Top  Print   
 


Re: 1936 Packard 320 ci fuel issue
#3
Home away from home
Home away from home

TxGoat
See User information
Be sure the air vent in your gas cap is not plugged. If you have a replacement gas cap, it's possible it doesn't have a vent.

Posted on: Yesterday 11:21
 Top  Print   
Like (1)
 


Re: 1936 Packard 320 ci fuel issue
#4
Home away from home
Home away from home

Pgh Ultramatic
See User information
I vote gas cap as TXgoat said.

Posted on: Yesterday 11:43
1955 400 | Registry | Project Blog
1955 Clipper Deluxe | Registry | Project Blog
1955 Clipper Super Panama | Registry
Email (Parts/service inquiries only, please. Post all questions on the forum.)
service@ultramatic.info
 Top  Print   
 


Re: 1936 Packard 320 ci fuel issue
#5
Home away from home
Home away from home

series014
See User information
It can't be the gas cap since I am running for the test, on a 5-gal fuel can with the cap off. The pressure drops incrementally in 10 minutes. It will restart in about 20 minutes with 2.5 psi. completely cold engine then goes back to 4.5 psi, but repeats to 0 psi in about 10 minutes. I don't think I can isolate it any more without making a rig with a cam to operate the pump lever. Any another idea are appreciated! Thanks

Posted on: Yesterday 15:36
 Top  Print   
 


Re: 1936 Packard 320 ci fuel issue
#6
Home away from home
Home away from home

56Clippers
See User information
Quote:

series014 wrote:
It can't be the gas cap since I am running for the test, on a 5-gal fuel can with the cap off. The pressure drops incrementally in 10 minutes. It will restart in about 20 minutes with 2.5 psi. completely cold engine then goes back to 4.5 psi, but repeats to 0 psi in about 10 minutes. I don't think I can isolate it any more without making a rig with a cam to operate the pump lever. Any another idea are appreciated! Thanks


I was thinking of a rig with a gravity feed gas tank connected to the line from the pump to the carburetor and an output line connected to the pump output going into another tank. This would allow you to observe the pump output directly for changes in stroke volume and pressure versus time.

Is your pump the combined fuel and vacuum pump?

Posted on: Yesterday 16:16
 Top  Print   
 


Re: 1936 Packard 320 ci fuel issue
#7
Home away from home
Home away from home

Pgh Ultramatic
See User information
Did you check the pump flow rate by disconnecting the exit line from the carb?

My other thought is that maybe a check valve is sticking somehow? 🤔

Posted on: Yesterday 16:17
1955 400 | Registry | Project Blog
1955 Clipper Deluxe | Registry | Project Blog
1955 Clipper Super Panama | Registry
Email (Parts/service inquiries only, please. Post all questions on the forum.)
service@ultramatic.info
 Top  Print   
 


Re: 1936 Packard 320 ci fuel issue
#8
Home away from home
Home away from home

series014
See User information
Fuel flow goes to a drip if I disconnect the line at the carb. I checked the hardline to the carb. it is clean and flows freely. Since the tank is normally lower than the fuel pump, I thought it would be best to put the test gas can at the same level as the tank to mimic the tank.

Posted on: Today 3:42
 Top  Print   
 








- Logged-in users will not see the following Adverts. Please Join (it's free) and Donate to help support the website -


- This above Google Ad-Sense Advert helps fund the cost of providing this free resource -
Search
Photo of the Day
1952 Packard touring sedan, s…
Recent Photos
1946-47 Packard in ... (04/23/2025)
1946-47 Packard in ...
Torsion Level WITHO... (03/30/2025)
Torsion Level WITHO...
56 Trunk Lining Set... (03/15/2025)
56 Trunk Lining Set...
Brantford Coach Ad (01/25/2025)
Brantford Coach Ad
Recent Registry
Upcoming Events
AACA Fall Meet (Hershey)
10/06/2025 - 10/10/2025
South Pacific Packard Club 2026 Rally
03/22/2026 - 03/28/2026
Website Comments or Questions?? Click Here Copyright 2006-2025, PackardInfo.com All Rights Reserved