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924 In-Tank Fuel Pump

 
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larchie  



Joined: 19 Jun 2003
Posts: 297

PostPosted: Tue Jul 30, 2013 2:52 am    Post subject: 924 In-Tank Fuel Pump Reply with quote

The current in-tank "Genuine Porsche" fuel pumps (Part No. 928 608 13 00) for the 1979-1982 924s are about 0.3mm thicker in diameter than those sold some years ago, but in every other respect appear identical. (I did this replacement successfully with no problems about a decade ago.)

But now over the past two weeks I've tried 2 different new replacements from different distributors but neither will fit as both are some 36+ mm in diameter for a 36 mm hole. As I live in the Southern U.S., running just the one external fuel pump in the summer heat seems to lean out on the highway.

Has anyone else run into this issue? Any suggestions for a fix? I just spent about $200 for the 924 Bosch external fuel pump so I'm hoping I can avoid buying a more powerful external pump to compensate for the lack of an in-tank pump.
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peterld  



Joined: 10 Dec 2006
Posts: 773
Location: Noosa Heads QLD Australia

PostPosted: Tue Jul 30, 2013 10:32 am    Post subject: Reply with quote

Oh yeah...so good luck with that

Went through the very same thing a while ago. Porsche and the resellers didn't want to know. Current OEM manufacturer is in Romania and they obviously cocked-up in their dimensions slightly.

By sheer trial and error, I very lightly sanded the outside of the pump body, particularly around the rivets and it became a virtual press fit in. Luckily I had the seal in place when I was trying it, for it wouldn't budge. If I ever have to remove it, I'll have to destroy the pump to get it out!
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larchie  



Joined: 19 Jun 2003
Posts: 297

PostPosted: Tue Jul 30, 2013 12:06 pm    Post subject: Reply with quote

Greatly appreciate your reply to this question peterid -- I was beginning to think I was either losing my mind or getting counterfeit parts from reliable distributors.

My hat's off to you for pressing it in -- there was no way I could succeed with that, even after over three hours of effort. I found the pumps were slightly out-of-round, but even after patiently reshaping the housing of the second in-tank pump to a near perfect cylinder I was unable to insert it more than 3 mm. or so. The housing was scratched so badly I'm not sure the part will be accepted back from the dealer. Had I inserted it any further I recognized it would both be impossible to fully insert or remove without completely destroying the pump.

The first pump was made in Romania, but the second pump had "Hungary" on the plastic wrapping. Markings on the filter ends of both differed from each other and from the pump I was seeking to replace.

I spent last Monday calling knowledgeable Porsche dealers and mechanics all over the U.S. but even those Porsche gurus were unaware of the problem.

I found out that some 924 owners are installing filters at the tank and a higher pressure external fuel pump than the normally recommended Bosch pump.

So it looks like the current in tank "Genuine" Porsche Part No.928 608 13 00 fuel pump being sold won't fit the 924. Even so, I still puzzled since I talked with a 928 mechanic in California this afternoon who says that same in-tank part still fits the old 928s of that era and so "should fit the early 924s too."
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larchie  



Joined: 19 Jun 2003
Posts: 297

PostPosted: Sun Aug 04, 2013 11:32 am    Post subject: Reply with quote

I thought I would post an update on getting an in-tank (pre-pump) fuel pump for a 924 in case anyone else with the Porsches listed below fitted with the same part runs into the same problem in the near future. I would not at all call myself a car mechanic, much less a Porsche 924 mechanic, so what follows is just my present opinion.

After trying three different Porsche recommended "Genuine Porsche" in-tank pumps in my 79 924 part no. 928 608 013 00 which is used in

Porsche 924 above VIN 9247204807 '79-'82
Porsche 924 Turbo and 928 '78-'79

as a pre-pump for the in-line pump, I found the part would not fit in the 924 even after carefully manually re-shaping the aluminium cylinder, which was slightly over 36mm in diameter. I read online that some Porsche parts outsourced out of Germany have been found to vary a bit from Porsche specifications. The in-tank pumps that I tried were manufactured either in Hungary or in Romania and these were thicker in diameter than the original pump.

I found some owners simply run these 924s without the in-tank (pre-pump) with no problems. I doubt that the 924 turbo's could do this and I found my non-turbo ran too lean at higher RPMs with the non-working pump in place.

As far as I can see, there remain four options for other owners of these cars in the same predicament as I am (I don't want to spend for more "re-stocking fees"):

(1) The owner can leave the old in-tank pump in place and rely solely on the inline fuel pump. Since the inline pump is mounted higher than the tank itself, this is less than ideal for a number or reasons. From what I can gather the purpose of the in-tank pump is to get fuel up to the in-line pump at start-up since the fuel itself lubricates keeps that pump from wearing out prematurely. If the inline pump is starved for fuel on start up or upon rapid acceleration, it wears quickly. Another apparent purpose is to help overcome hot start problems on fuel delivery when the engine runs hot. A third factor to consider is that leaving in the dead in-line pump would add additional resistance to fuel flow to the in-line pump. A fourth factor for not doing this is that the in-tank pumps' internal rubber hose degrades and will soon clog the in-line pump. There is some speculation that it's the ethanol in fuel which is causing failure. So even though owners who have posted to various Porsche message boards are doing this option, I don't think it's an ideal solution.

(2) The owner can replace the Bosch in-line pump Part No. 928 608 013 00 with a more powerful pump such as the Bosch 044 as is done for performance cars. If the in-tank pump is repaced also as in option 3 below, there is some controversy as to whether or not the in-tank pump can feed fuel fast enough to the Bosch 044 or equivalent and so tend to starve the in-line pump under performance conditions. Is seems to me that this would be a simple problem to solve in fluid mechanics, but this option did not appeal to me because the 044 seems to be overkill. I don't know how the additional pressure would affect the fuel regulator or whether it might lead to flooding on the normal 924s.

(3) The fuel resistance from the in-tank pump can be reduced by replacing the non-working in-tank pump with an intank fuel strainer Porsche Part No. 928 201 081 04 which supposedly fits these models:

911 1989-1998
924 1977-1982
944 1983-1991
928 1978-1991
969 1991-1995

To my mind such a replacement would be absolutely necessary as the normal in-line Bosch fuel pump does not tolerate contamination well at all. The strainer is not really a filter at all like that in the engine compartment. Presumably, the in-line the fuel screen would be replaced less often than the fuel filter in the engine compartment, but replaced from time-to-time nevertheless.

(4) The owner could install another manufacturer's in-tank fuel pump equivalent to the stock "Genuine Porsche" in-tank pump. I was told there is a Walbro equivalent but I was unable to locate this part. I found only two others: (1) an SWF pump Part No. E3000-24257 which is made in China and (2) an Airtex in-tank pump Part No. E8165H --either one is available from about $150 -200 online.

So, I'm going to try the Airtex and if that won't fit, try to live with the in-line fuel screen and hope that the car's performance doesn't take too big a hit.
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kcoyle  



Joined: 15 Jan 2011
Posts: 712
Location: Long Island, NY

PostPosted: Sun Aug 04, 2013 11:57 am    Post subject: Reply with quote

I think the earlier cars came with only one pump from the factory. Maybe you can get away with the external pump and a 944 type strainer/screen in tank to remove any obstruction in the flow.

I think this is the correct PN 928 201 081 04 ( but I could be wrong) for the strainer.

Also, here is a bit of info on the pumps themselves. Maybe you can mix and match parts to make it all fit.

http://members.rennlist.com/bcookt06394/pump.html
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larchie  



Joined: 19 Jun 2003
Posts: 297

PostPosted: Thu Aug 15, 2013 2:34 am    Post subject: Reply with quote

Two parts suppliers say that the Airtex pre-pump or in-tank fuel pump has been discontinued and so is no longer available.

Thanks kcoyle for the links to the pre-pump images and the suggestion to try a rebuild. It might be possible if I can figure out how to get the aluminum sleeve removed. Maybe cutting the rubber housing to get the pump apart and then improvise the hose somehow on the rebuild would work. I'm told that the newer pre-pumps for the early 924s and 928s don't last more than 3 or so years because the rubber housing degrades -- possibly due to the ethanol in US fuel or possibly due to a change in construction composition.

If rebuilding the pump doesn't work out, I'll try the in-tank strainer. The "Genuine Porsche" in-tank strainer. I just found out it's made of plastic (total weight 54g) and runs about $50. I guess it would be torqued by feel?

In case the plastic strainer doesn't work out, does anyone have experience with the (Chinese manufactured) SWF in-tank pump-- since the newer manufactured Bosch in-tank pumps no longer fit the 924?

Thanks for any help on this.
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escombralls  



Joined: 21 May 2014
Posts: 3
Location: Barcelona

PostPosted: Thu Jan 15, 2015 4:14 am    Post subject: Reply with quote

Hello everybody,

I have a leak on the in-tank fuel pump of my 1979-924-2.0. The leak seems to be on the "Bakelite" connector of the pump, even if it's difficult to be sure about the exact point of leakage. The car is going quite well, I only realized that because of the petrol stain under the car.

Firstly, I would like to know your mind about that. Is that connector a typical point of leak? As I've said, I cannot be sure, but it seems that the leak doesn't come from the hose itself, or the union between the hose and the pump. But, I cannot be sure...

Anyway, supposing that the leak is on that connector, I will look for the cheapest alternative, as the car is... on sale!! Different options :

1. Rebuild the fuel pump. But how? I cannot imagine how to fix the leak on the connector, I suppose that no silicone will work, but I am not an expert on that.

2. Replace the in-take fuel pump by the in-take strainer (928 201 081 04) which is not expensive. But, will I have any issue doing that? I've read that it could be some hot-start issues. My in-line fuel pump is the BOSCH 0 580 254 053 in-line pump, and I live in a temperate/hot city (Barcelona).
Maybe I could try firstly to disconnect the electrical connection of the current in-take pump and see if the fuel goes correctly to the injectors. If no problems, I could then replace the pump by the strainer (it will be even less power loss with the strainer than with the disconnected int-ake pump).

3. Other solutions? I've already read some interesting posts here on 924board :
http://www.924board.org/viewtopic.php?t=38945&start=0&postdays=0&postorder=asc&highlight=
http://www.924board.org/viewtopic.php?t=8565&start=0&postdays=0&postorder=asc&highlight=
http://www.924board.org/viewtopic.php?t=15721&postdays=0&postorder=asc&start=0

Thanks for your help!
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morghen  



Joined: 21 Jan 2005
Posts: 8183
Location: Romania

PostPosted: Thu Jan 15, 2015 4:36 am    Post subject: Reply with quote

I will remove the in tank pump from my 924s and relocate the main pump lower, so that it sits parallel to the ground and at the same level as the internal pump.
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nickthompson  



Joined: 26 Mar 2013
Posts: 873
Location: Central Georgia

PostPosted: Thu Jan 15, 2015 6:42 am    Post subject: Reply with quote

I can say for sure that early cars had only one pump. My 77 had a single external pump.
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KDJones2000  



Joined: 14 Sep 2010
Posts: 321
Location: Phoenix, AZ

PostPosted: Thu Jan 15, 2015 7:42 am    Post subject: Reply with quote

The 944's strainer has a metal threaded fitting on it, but uses a plastic strainer inside the tank.

It is a very robust piece and you should have no issues installing/torquing it.

It sounds like the most reasonable solution for this problem...
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kcoyle  



Joined: 15 Jan 2011
Posts: 712
Location: Long Island, NY

PostPosted: Fri Jan 16, 2015 6:38 am    Post subject: Reply with quote

escombralls wrote:
Hello everybody,

I have a leak on the in-tank fuel pump of my 1979-924-2.0. The leak seems to be on the "Bakelite" connector of the pump, even if it's difficult to be sure about the exact point of leakage. The car is going quite well, I only realized that because of the petrol stain under the car.

Firstly, I would like to know your mind about that. Is that connector a typical point of leak?



It happens. Here is how I "fixed" mine. I only get slight weepage, no drips anymore. Thanks to user McGyver for the tip.

http://www.924board.org/viewtopic.php?t=37680&sid=a5a5cceb7b2456e7918369db8fef8da1
_________________
1982 931- Stock with MBC at 8psi

Relax, all right? My old man is a television repairman, he's got this ultimate set of tools. I can fix it.
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escombralls  



Joined: 21 May 2014
Posts: 3
Location: Barcelona

PostPosted: Mon Mar 09, 2015 6:52 am    Post subject: Reply with quote

Wow, thanks kcoyle for the post, I will try that this week! I was wondering to use some Nural 28 or similar 2 components silicone, any suggestion about that?

I will keep you updated, with some photos if possible !
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bradito  



Joined: 04 Aug 2011
Posts: 62
Location: Iowa

PostPosted: Wed Oct 04, 2017 2:06 pm    Post subject: Ethanol!? NOO! Reply with quote

Dear Gawd I hope noone is using ethanol in their two-four. That is asking for your fuel system to be destroyed. NO car built before the mid to late 90s should EVER see ethanol (unless you've done your research and modded your vehicle appropriately).
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DootToot  



Joined: 31 Oct 2018
Posts: 8
Location: Australia

PostPosted: Thu Jul 04, 2019 11:23 am    Post subject: Reply with quote

Been doing some research to avoid spending $900USD on a new intank pump for my turbo, and I stumbled across these photos, linked to a now dead Canadian amazon page.

https://www.amazon.ca/Porsche-Fuel-Pre-Pump-replacement-12343002001/dp/B01N0ZL7P6

https://imgur.com/8EWtZVj

Seems to be re-using the threaded top from an old in-tank pump and combining it with this Land-Rover diesel fuel pump:

https://www.ebay.com.au/itm/New-In-Tank-Diesel-Fuel-Pump-Land-Rover-Discovery-2-7-TD-V6-Mk3-2004-2009/323844851734?hash=item4b66a84816:g:D6IAAOSwvFZW8Fl2&frcectupt=true

Would this work?
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peterld  



Joined: 10 Dec 2006
Posts: 773
Location: Noosa Heads QLD Australia

PostPosted: Thu Jul 04, 2019 10:58 pm    Post subject: Reply with quote

Providing you have the correct CIS external fuel pump, you can dispense with the in-tank pump, utilising the 944 strainer or simply gutting the old in-tank pump of it's electrical gubbins and just using the screw-in flange (and obviously disconnecting the wiring, and rendering it safe).
Oh, and my case, I wired on some stainless guaze on the tank side to shield the pump from any possible debris. (Would you believe my camping toaster gave up the guaze...lucky find.)
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