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toolbox1211
Joined: 18 Apr 2025 Posts: 3 Location: western mass
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Posted: Sun Aug 24, 2025 2:40 am Post subject: In tank fuel pump desirable? |
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So I have a 1980 924 turbo. The previous owner drained the fuel tank before it was parked in 2000. Point being, I have a tested and fully functional clean origional in tank fuel pump.
I know the pump is often replaced with the screen from the 944.
So my questions are.
Is there any reason to run the in rank fuel pump?
I see the price for the pump is a lot. I assume due to availability and not because people want it?
My thought was to go with the screen and sell the pump for a good price to someone who needed it to help fund my 931 project. Is the pump even somthing people want? _________________ 1980 924 turbo m471 |
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chuck21401

Joined: 20 Feb 2005 Posts: 587 Location: Annapolis, MD
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Posted: Tue Aug 26, 2025 10:22 am Post subject: |
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I don’t think the pump is needed. I’m running a single pump and 944 screen in my 931. I bought my car in 2019 and it was like that when I bought it.
From time to time I’ve seen people looking for the in tank pump; a good one is worth something. _________________ 1981 Porsche 931 w/S1 engine & euro g31 transaxle. Water-cooled intercooler |
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morghen

Joined: 21 Jan 2005 Posts: 9082 Location: Romania
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Posted: Tue Aug 26, 2025 8:00 pm Post subject: |
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I always gut them or change to the 944/928 filter. _________________ Supercharger and EFI kits
https://www.the924.com |
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Beartooth
Joined: 05 Apr 2022 Posts: 305 Location: Roberts, MT
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Posted: Fri Aug 29, 2025 5:05 am Post subject: |
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Mine was trashed when I got it, and I eliminated it without any issues so far as I can tell. The consensus is it's not necessary, but they wouldn't have included it, especially in a lower-price sports car like the 924 if there was no reason for it. I suspect you'd have to crack a fuel line to prime the pump if you ran it out of gas (especially if you were only able to put a couple gallons of gas in); I've done that the couple times I emptied the tank to work on it. I've seen speculation that it make a difference when you're running low on gas; not sure if it's a matter of fuel pressure transients, hard on the main pump, or maybe a mix of the two. The counterpoint to that is that cars like my Mercedes have no in-tank pump. The pump(s) are below the gas tank, but I'd think it's effectively the same if you have more than a couple gallons in the tank of a too-for.
If I had a good one, I'd prefer to run it, but at the price being asked for a new (or even used) one, I'm not buying one unless I come up with a really good reason. I have no idea why replacements are so expensive: even for a Porsche part, it seems excessive, especially when you consider that there's no way there's more than $100 in component cost to build one. If I ever decide there's a good reason to have it, I think I'd find a way to adapt a universal in-tank pump, like this https://deatschwerks.com/products/9-110-1055, rather than spending big money on the "correct" pump. _________________ 1980 931 diamond in the rough |
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toolbox1211
Joined: 18 Apr 2025 Posts: 3 Location: western mass
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Posted: Sun Aug 31, 2025 7:37 am Post subject: |
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you all have been very helpful, thank you. I will buy the pickup screen for a backup and run the pump until it fails _________________ 1980 924 turbo m471 |
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Elektrobank

Joined: 19 Mar 2007 Posts: 146 Location: Pozzuoli,Napoli, Italy
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Posted: Sun Aug 31, 2025 8:54 pm Post subject: Re: In tank fuel pump desirable? |
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| toolbox1211 wrote: | So I have a 1980 924 turbo. The previous owner drained the fuel tank before it was parked in 2000. Point being, I have a tested and fully functional clean origional in tank fuel pump.
I know the pump is often replaced with the screen from the 944.
So my questions are.
Is there any reason to run the in rank fuel pump?
I see the price for the pump is a lot. I assume due to availability and not because people want it?
My thought was to go with the screen and sell the pump for a good price to someone who needed it to help fund my 931 project. Is the pump even somthing people want? |
The pre pump helps the bigger fuel pump tò reach the correct fuel pressure
If you are a normale driver the car can leave without any problem, of you like to drive the car with the pedale on the metal then you can have big problem
Now those spare parts are nla or really crap quality so Will be Always more difficult tò keep the Cis in good working condition
Switching tò EFI Will solve many problem and car Will became a Daily driver
Good luck _________________ 924T Dta inj + sequential LPG
Cosworth
MotoMorini 501
Moto Morini 350 K2
lot of fun but always on foot.... |
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Raize
Joined: 18 Sep 2013 Posts: 403 Location: Scotland
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Posted: Sun Oct 05, 2025 7:44 am Post subject: |
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| Beartooth wrote: | Mine was trashed when I got it, and I eliminated it without any issues so far as I can tell. The consensus is it's not necessary, but they wouldn't have included it, especially in a lower-price sports car like the 924 if there was no reason for it. I suspect you'd have to crack a fuel line to prime the pump if you ran it out of gas (especially if you were only able to put a couple gallons of gas in); I've done that the couple times I emptied the tank to work on it. I've seen speculation that it make a difference when you're running low on gas; not sure if it's a matter of fuel pressure transients, hard on the main pump, or maybe a mix of the two. The counterpoint to that is that cars like my Mercedes have no in-tank pump. The pump(s) are below the gas tank, but I'd think it's effectively the same if you have more than a couple gallons in the tank of a too-for.
If I had a good one, I'd prefer to run it, but at the price being asked for a new (or even used) one, I'm not buying one unless I come up with a really good reason. I have no idea why replacements are so expensive: even for a Porsche part, it seems excessive, especially when you consider that there's no way there's more than $100 in component cost to build one. If I ever decide there's a good reason to have it, I think I'd find a way to adapt a universal in-tank pump, like this https://deatschwerks.com/products/9-110-1055, rather than spending big money on the "correct" pump. |
This micro pump is still too big to fit into the opening. I've looked into it extensively because whoever could find an aftermarket pump that would fit there would be rich given the price of the proper in-tank pump, but there is really nothing. |
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