Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
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.
 

Welcome Guest ( Log In | Register )

 
Reply to this topicStart new topic
> Everything I know is wrong, Fuel Filters
NARP74
post Jul 6 2026, 10:32 AM
Post #1


Senior Member
***

Group: Members
Posts: 1,451
Joined: 29-July 20
From: Colorado, USA, Earth
Member No.: 24,549
Region Association: Rocky Mountains



Around the beginning of the year, there were a few threads about fuel filters. Do you need them, what size, location, the tank sock etc. I pondered the info. I decided to start my thread instead of hijacking theirs. I just waited too long to do it, better late than never.

Car 1, 74, 2.0 4 cylinder Purchased a pump filter combo from an online retailer. Many people sell the same one at various prices. In the notes it says, do not remove the filter or the warranty is void. Stock location, sock in the tank, should the filter be there before the pump or somewhere else or not at all?

Car 2, 74 3.2 6 cylinder I was redoing the pump location and while the pump sat around dry it must have gone bad. Seals dried up or something maybe. When I put it back in and filled the tank, all the gas ran out of the pump. So i bought a new one, Bosch 580 464 200, but there are several numbers on the box. It is replacing an older Bosch pump. I am putting it under the steering rack and I decided to run a pre-filter. I have a new sock in the tank, then to a Earls 100 micron filter, then the pump, then through the lines to the engine. The engine has a stock Porsche fuel filter on it before the injectors.

The problem I am having is that with all of the different connections and sizes and adapters and hose splices, I am having trouble fitting everything in line without hose kinks in a very tight space. There was one thought in those earlier threads that said you don't really need a filter before the pump and it would actually reduce performance of the pump. If that is correct, removing the filter before the pump on car 2 would solve all of my problems. But i don't want to add more by note having one.

Maybe some of the other commenters from those older threads will chime in and set me straight on filters, size, location etc.

Poor visualization skills are not an excuse to request pics! Haha

User is online!Profile CardPM
Go to the top of the page
+Quote Post
Superhawk996
post Jul 6 2026, 03:17 PM
Post #2


914 Guru
*****

Group: Members
Posts: 7,936
Joined: 25-August 18
From: Woods of N. Idaho
Member No.: 22,428
Region Association: Galt's Gulch



Look to modern OEM fuel systems that are engineered for performance & reliability.

The layout is:
Tank pre-filter (100-300 micron)
Pump
Filter

User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Ninja
post Jul 6 2026, 04:16 PM
Post #3


Member
**

Group: Members
Posts: 234
Joined: 25-September 25
From: Granbury Texas
Member No.: 29,004
Region Association: Southwest Region



The OEM world has eliminated the post pump fuel filter starting about 15 years ago.

The only thing they have is the pre-pump fuel sock now.

About 35 years back we had a horrendous fuel contamination problem, and a bunch of new fuel storage/transfer laws went into effect.

They appear to have been effective.

Today's fuel is pretty clean (except for the ethanol content which DOES eliminate any water).

On an old 914 I'd go clean tank, new strainer in tank, pump, then filter.

Only reason for pre pump filter would be nasty tank in my book.

I'd change that one two maybe three times a year and plan cleaning or replacing the tank soon.
User is online!Profile CardPM
Go to the top of the page
+Quote Post
NARP74
post Jul 6 2026, 04:38 PM
Post #4


Senior Member
***

Group: Members
Posts: 1,451
Joined: 29-July 20
From: Colorado, USA, Earth
Member No.: 24,549
Region Association: Rocky Mountains



I am most concerned with #2. The tank is clean. There was some small dry debris in the bottom when I drained it, gone now.

Haven't looked in #1 for a while, not injected, carbs, less concerned.

I have seen it mentioned here but forgot and search might be futile, what is the equivalent filtering size of the in tank fuel sock?
User is online!Profile CardPM
Go to the top of the page
+Quote Post
Cairo94507
post Jul 6 2026, 04:48 PM
Post #5


Michael
**********

Group: Members
Posts: 10,691
Joined: 1-November 08
From: Auburn, CA
Member No.: 9,712
Region Association: Northern California



And here I thought this was about being married... (IMG:style_emoticons/default/beerchug.gif)
User is online!Profile CardPM
Go to the top of the page
+Quote Post
NARP74
post Jul 6 2026, 04:53 PM
Post #6


Senior Member
***

Group: Members
Posts: 1,451
Joined: 29-July 20
From: Colorado, USA, Earth
Member No.: 24,549
Region Association: Rocky Mountains



QUOTE(Cairo94507 @ Jul 6 2026, 03:48 PM) *

And here I thought this was about being married... (IMG:style_emoticons/default/beerchug.gif)


It could be... I am not anymore!
User is online!Profile CardPM
Go to the top of the page
+Quote Post
Jamie
post Jul 6 2026, 05:41 PM
Post #7


Senior Member
***

Group: Members
Posts: 1,215
Joined: 13-October 04
From: Georgetown,KY
Member No.: 2,939
Region Association: South East States



QUOTE(NARP74 @ Jul 6 2026, 02:38 PM) *

I am most concerned with #2. The tank is clean. There was some small dry debris in the bottom when I drained it, gone now.

Haven't looked in #1 for a while, not injected, carbs, less concerned.

I have seen it mentioned here but forgot and search might be futile, what is the equivalent filtering size of the in tank fuel sock?

For practical reasons I suggest in tank sock filters are useless, I've damaged several while attempting inserting into the tank, whether in or out of the car. An inline filter before front mounted pump is accessible and easily replaced, and I also run a filter post pump to keep stuff out of my injectors.
User is online!Profile CardPM
Go to the top of the page
+Quote Post

Reply to this topicStart new topic
4 User(s) are reading this topic (2 Guests and 0 Anonymous Users)

 



- Lo-Fi Version Time is now: 6th July 2026 - 05:47 PM
...