 Blowing bubbles |
|
|
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
|
| emerygt350 |
 Apr 29 2026, 04:05 PM
Post
#1
|
|
Advanced Member  Group: Members Posts: 3,536 Joined: 20-July 21 From: Upstate, NY Member No.: 25,740 Region Association: North East States  |
I know it's click bait but whatever. So gradually working through the starting issues on my 73 djet 2.0. is anyone aware of a bubble blowing condition that doesn't require vapor lock? Is there something that can go wrong with a stock 73 fuel pump that would cause it to blow audible bubbles into the tank? This only happens after I have driven it, but doesn't require it to be hot n hot. If I turn the key to the on position and the fuel pump starts I can hear bubbles coming into the tank (even when the tank is full). This is at 40 degrees ambient. This is the real kicker, this will continue after the point at which the fuel pump cuts because the engine is not running. However , when I turn the key off, even after the pump has stopped , the bubbles will stop. ????? When this happens I have a difficult time starting, but it really smells and feels like a rich condition, not what I know from vapor lock. Under true valor lock I can't hear the pump at all.
After I get the engine to catch, normally only a few tries, it stumbles a little then immediately runs great I think there are two separate problems here, but perhaps not. It's the bubbles that gave me stumped. How could I get bubbles without vapor lock? |
   |
 
|
  |
Replies(1 - 5)
| BillC |
Apr 29 2026, 04:09 PM
Post
#2
|
|
Senior Member Group: Members Posts: 711 Joined: 24-April 15 From: Silver Spring, MD Member No.: 18,667 Region Association: MidAtlantic Region 
|
Are you sure they are bubbles?
What is the fuel level in the tank? If it's really low, maybe you are hearing splashing from the fuel being returned to the tank. Maybe you can have someone try cranking the engine while you look down the filler with a flashlight? |
 |
|
| 76-914 |
Apr 29 2026, 04:25 PM
Post
#3
|
|
Repeat Offender & Resident Subaru Antagonist Group: Members Posts: 13,880 Joined: 23-January 09 From: Temecula, CA Member No.: 9,964 Region Association: Southern California
|
Sounds to me like cavitation. See if your intake line is kinked or has an obstruction.
|
|
|
|
| emerygt350 |
Apr 29 2026, 05:01 PM
Post
#4
|
|
Advanced Member Group: Members Posts: 3,536 Joined: 20-July 21 From: Upstate, NY Member No.: 25,740 Region Association: North East States |
QUOTE(BillC @ Apr 29 2026, 04:09 PM)  Are you sure they are bubbles? What is the fuel level in the tank? If it's really low, maybe you are hearing splashing from the fuel being returned to the tank. Maybe you can have someone try cranking the engine while you look down the filler with a flashlight? Yeah, bubbles, full tank. No mistaking it. Nothing has changed in the system but I am going to look through everything as soon as it stops raining. I should mention as well that I had no such problem last year before its long winter sleep but I was noticing what I thought was some pretty poor gas mileage but that turned out to be.a broken thermostat cable. Wrong side of the engine for messing with the fuel lines. |
|
|
|
| emerygt350 |
Apr 29 2026, 05:13 PM
Post
#5
|
|
Advanced Member Group: Members Posts: 3,536 Joined: 20-July 21 From: Upstate, NY Member No.: 25,740 Region Association: North East States |
Dbl post
|
|
|
|
| Literati914 |
Apr 29 2026, 05:34 PM
Post
#6
|
|
Advanced Member Group: Members Posts: 2,312 Joined: 16-November 06 From: Dallas, TX Member No.: 7,222 Region Association: Southwest Region |
I've heard of the internal sock getting clogged and causing similar noises when the fuel is run low, just a thought.
|
|
|
|
|
4 User(s) are reading this topic (4 Guests and 0 Anonymous Users)
0 Members:
|
Lo-Fi Version | Time is now: 29th April 2026 - 06:15 PM |
Invision Power Board
v9.1.4 © 2026 IPS, Inc.