Anatomy of a fuel pump failure
04-03-2013, 06:02 PM
#31
Rennlist Member
Thread Starter
Here's the filter... I am not sure what color it is supposed to be, but it is the same on both sides and looks pretty clean...
So wherever the brush and commutator material went, it must have been some time ago-- the last filter change was about 15K miles ago, in 2008. Or it was fine enough that the filter didn't catch it-- which seems unlikely. Weird...
So wherever the brush and commutator material went, it must have been some time ago-- the last filter change was about 15K miles ago, in 2008. Or it was fine enough that the filter didn't catch it-- which seems unlikely. Weird...
04-04-2013, 01:51 AM
#32
Chronic Tool Dropper
Lifetime Rennlist
Member
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At this price, I'd have to worry about what corners were cut to get the cost so low. 'Course I can buy four or five for the cost of a new Bosch part. It's a slippery slope though. If I wanted a car that was not guaranteed to get me to charch, the liquor store and home again, I could spend a lot less and just take the Rollerblades.
"And at $200-250 a pop it's kind of painful to just add a fuel pump to the every-60K-mile"
Jim
I am using this.
http://www.ebay.ca/itm/390476309080?...84.m1423.l2649
The volume is 228L/Hour
At this price I can keep a spare. If anyone is concerned about volume this puts out 228L/hour or 60 gal/hour.More than any 928 requires we hope.
From the WSM
1979 1360 CC/30 SEC
FOR K-JETRONIC
(1981/1982 Models)
Engine M 28.09 and M 28.10 1120 CC/ 30 SEC
(1980/1981/1982/1983 Models) L JETRONIC
at least 1150 cc/30 sec.
Beginning with 1984 Models
Engine Type M 28.21/22 1350 CC/30 SEC
85 on 1350 CC/30 SEC. M28 43 44 45 46
As from Model 87
Englne type M 28. 41/42/47/49/50
87 on 1250 CC/30 SEC
At 6300 rpm the fuel pump is turned off at the relay
228 L/ hour or 1900cc/ 30 sec so we are well covered. If you need more pressure put a restrictor in the return line to the tank but more than likely the pressure regulators will take care of that.
Jim
I am using this.
http://www.ebay.ca/itm/390476309080?...84.m1423.l2649
The volume is 228L/Hour
At this price I can keep a spare. If anyone is concerned about volume this puts out 228L/hour or 60 gal/hour.More than any 928 requires we hope.
From the WSM
1979 1360 CC/30 SEC
FOR K-JETRONIC
(1981/1982 Models)
Engine M 28.09 and M 28.10 1120 CC/ 30 SEC
(1980/1981/1982/1983 Models) L JETRONIC
at least 1150 cc/30 sec.
Beginning with 1984 Models
Engine Type M 28.21/22 1350 CC/30 SEC
85 on 1350 CC/30 SEC. M28 43 44 45 46
As from Model 87
Englne type M 28. 41/42/47/49/50
87 on 1250 CC/30 SEC
At 6300 rpm the fuel pump is turned off at the relay
228 L/ hour or 1900cc/ 30 sec so we are well covered. If you need more pressure put a restrictor in the return line to the tank but more than likely the pressure regulators will take care of that.
04-04-2013, 01:33 PM
#33
Shameful Thread Killer
Rennlist Member
Rennlist Member
At this price, I'd have to worry about what corners were cut to get the cost so low. 'Course I can buy four or five for the cost of a new Bosch part. It's a slippery slope though. If I wanted a car that was not guaranteed to get me to charch, the liquor store and home again, I could spend a lot less and just take the Rollerblades.
05-04-2018, 12:47 PM
#35
Three Wheelin'
Old thread revival. Cars now much older since last post.
I just bought one as a spare to carry with me on the road. My car has a new Bosch pump in it, but the quality of Bosch pumps isn't exactly sterling anymore. If I'm on the road, and the two options are putting in my $50 pump, and a $300 tow, plus a new pump, plus garage charges this starts to make sense.
05-05-2018, 12:15 AM
#36
Rennlist Member
Depending on the parking area's acoustics, I would have thought a running pump (when It shouldnt be) would become audible sometimes. Has the current draw of the new pump been measured to see if the wiring is in good order? My CIS pump pulls 7A, now that the fuse and relays are good - having burned 2 relays out due to poor fuse contact.
jp 83 Euro S AT 57k
jp 83 Euro S AT 57k
05-05-2018, 12:50 AM
#37
Three Wheelin'
Join Date: Feb 2004
Location: Jacksonville and sometimes St. Aug Beach, FL
Posts: 1,727
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I found a lower cost alternative for the Bosch Fuel Pump and posted it here...
https://rennlist.com/forums/928-foru...rt-thread.html
Currently the S4 crowd could pick up a pump for $133 from Amazon.
https://rennlist.com/forums/928-foru...rt-thread.html
Currently the S4 crowd could pick up a pump for $133 from Amazon.
05-06-2018, 09:51 PM
#38
Chronic Tool Dropper
Lifetime Rennlist
Member
Lifetime Rennlist
Member
It's a circulating system with a return line. Running a pump long enough to explain the wear Jim shows would have been noisy and would have drained the battery more than a few times on the way. For those who feel more comfortable with a ride-along spare, install the new one now and keep the old one as the spare. Much easier to change it in the comfort and convenience of the workshop, vs that unscheduled stop on the side of the lonely desert highway in 100º+ conditions.
06-25-2021, 07:35 PM
#39
I've had his page on a browser tab for a few years, until I finally got around to registering on rennlist so I could post a reply.
I'm not a part of the Porsche world, although I do some occasional brake and d-jet Fi work for 914 owners. I work almost exclusively on VW Type 3s, especially the late d-jet FI ones. I rebuild a LOT of the d-jet FI electric fuel pumps. The commutator wear seen in this thread is what I take to be typical of gas that has abrasive dust in it. VW Type 3s have a filter ahead of the pump, so this kind of wear is not normally a problem on Type 3s, but I gather that there is no prefilter in these Porsches. I would recommend a good prefilter for your cars, especially if you live in a dusty area. Not all dust is abrasive, so you may know if your area is known for abrasive dust.
In the process of rebuilding VW Type 3 d-jet fuel pumps, I occasionally see this amount of wear, but it's rare. In the Type 3 case, there is a rubber hose that ages and cracks, letting dirt into the gas tank. If this is bad, enough dirt may get past the prefilter to damage the pump. You will know better than me whether this is a potential problem on your Porsches.
I have looked to see if there's any way I can replace just the commutators in these pumps, and the answer appears to be NO. You'll need a new pump. I recommend a prefilter when you do this. A large prefilter that has very low resistance to flow would be recommended. The filter for my '96 Taurus had 8 mm (5/16") inlet and outlets and worked nicely for me when I had a dirty gas tank. If you need different size inlet or outlet, check your FLAPS to see what they have at reasonable a reasonable price.
That said, the pump in this thread appears to be very much like that in later VWs with L-jet FI. I can sometimes rebuild those, as long as the problems are something i can fix. Clearly, I can't fix commutators like this one, but i have fixed ones where the connections to the commutator became bad. That may have been the problem for the poster whose pump started drawing more and more current.
I'm not a part of the Porsche world, although I do some occasional brake and d-jet Fi work for 914 owners. I work almost exclusively on VW Type 3s, especially the late d-jet FI ones. I rebuild a LOT of the d-jet FI electric fuel pumps. The commutator wear seen in this thread is what I take to be typical of gas that has abrasive dust in it. VW Type 3s have a filter ahead of the pump, so this kind of wear is not normally a problem on Type 3s, but I gather that there is no prefilter in these Porsches. I would recommend a good prefilter for your cars, especially if you live in a dusty area. Not all dust is abrasive, so you may know if your area is known for abrasive dust.
In the process of rebuilding VW Type 3 d-jet fuel pumps, I occasionally see this amount of wear, but it's rare. In the Type 3 case, there is a rubber hose that ages and cracks, letting dirt into the gas tank. If this is bad, enough dirt may get past the prefilter to damage the pump. You will know better than me whether this is a potential problem on your Porsches.
I have looked to see if there's any way I can replace just the commutators in these pumps, and the answer appears to be NO. You'll need a new pump. I recommend a prefilter when you do this. A large prefilter that has very low resistance to flow would be recommended. The filter for my '96 Taurus had 8 mm (5/16") inlet and outlets and worked nicely for me when I had a dirty gas tank. If you need different size inlet or outlet, check your FLAPS to see what they have at reasonable a reasonable price.
That said, the pump in this thread appears to be very much like that in later VWs with L-jet FI. I can sometimes rebuild those, as long as the problems are something i can fix. Clearly, I can't fix commutators like this one, but i have fixed ones where the connections to the commutator became bad. That may have been the problem for the poster whose pump started drawing more and more current.
Last edited by jadney; 06-25-2021 at 07:38 PM.
06-26-2021, 07:26 PM
#40
Jim, thanks for this post, very interesting.
A little off-topic, but if you don't mind...
what type of camera did you use for the photographs in your initial post ?
Outstanding picture quality. Thanks
Dan
A little off-topic, but if you don't mind...
what type of camera did you use for the photographs in your initial post ?
Outstanding picture quality. Thanks
Dan
06-27-2021, 10:31 PM
#41
Rennlist Member
Thread Starter
I've had his page on a browser tab for a few years, until I finally got around to registering on rennlist so I could post a reply.
I'm not a part of the Porsche world, although I do some occasional brake and d-jet Fi work for 914 owners. I work almost exclusively on VW Type 3s, especially the late d-jet FI ones. I rebuild a LOT of the d-jet FI electric fuel pumps. The commutator wear seen in this thread is what I take to be typical of gas that has abrasive dust in it. VW Type 3s have a filter ahead of the pump, so this kind of wear is not normally a problem on Type 3s, but I gather that there is no prefilter in these Porsches. I would recommend a good prefilter for your cars, especially if you live in a dusty area. Not all dust is abrasive, so you may know if your area is known for abrasive dust.
In the process of rebuilding VW Type 3 d-jet fuel pumps, I occasionally see this amount of wear, but it's rare. In the Type 3 case, there is a rubber hose that ages and cracks, letting dirt into the gas tank. If this is bad, enough dirt may get past the prefilter to damage the pump. You will know better than me whether this is a potential problem on your Porsches.
I have looked to see if there's any way I can replace just the commutators in these pumps, and the answer appears to be NO. You'll need a new pump. I recommend a prefilter when you do this. A large prefilter that has very low resistance to flow would be recommended. The filter for my '96 Taurus had 8 mm (5/16") inlet and outlets and worked nicely for me when I had a dirty gas tank. If you need different size inlet or outlet, check your FLAPS to see what they have at reasonable a reasonable price.
That said, the pump in this thread appears to be very much like that in later VWs with L-jet FI. I can sometimes rebuild those, as long as the problems are something i can fix. Clearly, I can't fix commutators like this one, but i have fixed ones where the connections to the commutator became bad. That may have been the problem for the poster whose pump started drawing more and more current.
I'm not a part of the Porsche world, although I do some occasional brake and d-jet Fi work for 914 owners. I work almost exclusively on VW Type 3s, especially the late d-jet FI ones. I rebuild a LOT of the d-jet FI electric fuel pumps. The commutator wear seen in this thread is what I take to be typical of gas that has abrasive dust in it. VW Type 3s have a filter ahead of the pump, so this kind of wear is not normally a problem on Type 3s, but I gather that there is no prefilter in these Porsches. I would recommend a good prefilter for your cars, especially if you live in a dusty area. Not all dust is abrasive, so you may know if your area is known for abrasive dust.
In the process of rebuilding VW Type 3 d-jet fuel pumps, I occasionally see this amount of wear, but it's rare. In the Type 3 case, there is a rubber hose that ages and cracks, letting dirt into the gas tank. If this is bad, enough dirt may get past the prefilter to damage the pump. You will know better than me whether this is a potential problem on your Porsches.
I have looked to see if there's any way I can replace just the commutators in these pumps, and the answer appears to be NO. You'll need a new pump. I recommend a prefilter when you do this. A large prefilter that has very low resistance to flow would be recommended. The filter for my '96 Taurus had 8 mm (5/16") inlet and outlets and worked nicely for me when I had a dirty gas tank. If you need different size inlet or outlet, check your FLAPS to see what they have at reasonable a reasonable price.
That said, the pump in this thread appears to be very much like that in later VWs with L-jet FI. I can sometimes rebuild those, as long as the problems are something i can fix. Clearly, I can't fix commutators like this one, but i have fixed ones where the connections to the commutator became bad. That may have been the problem for the poster whose pump started drawing more and more current.
Cheers,
06-27-2021, 10:34 PM
#42
Rennlist Member
Thread Starter
Cheers,
06-28-2021, 12:57 AM
#43
Former Sponsor
My dad, a professional mechanic his entire life, taught me more things than I can possibly remember, but he always carried a box with spare parts in all his vehicles.
He would say: "if you carry a spare, you are virtually guaranteed you will never need it or use it. Something else will fail, which you don't have."
Although he was a fanatic about vehicle maintenance, we had a few "car vacations" (it was all my parents could afford) with car problems. However, we never needed anything out of that box!
"Murphy's Law" stuff.
He would say: "if you carry a spare, you are virtually guaranteed you will never need it or use it. Something else will fail, which you don't have."
Although he was a fanatic about vehicle maintenance, we had a few "car vacations" (it was all my parents could afford) with car problems. However, we never needed anything out of that box!
"Murphy's Law" stuff.
Last edited by GregBBRD; 06-28-2021 at 01:07 AM.
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928FIXER (07-16-2021)
07-16-2021, 10:43 AM
#44
07-16-2021, 01:36 PM
#45
My dad, a professional mechanic his entire life, taught me more things than I can possibly remember, but he always carried a box with spare parts in all his vehicles.
He would say: "if you carry a spare, you are virtually guaranteed you will never need it or use it. Something else will fail, which you don't have."
Although he was a fanatic about vehicle maintenance, we had a few "car vacations" (it was all my parents could afford) with car problems. However, we never needed anything out of that box!
"Murphy's Law" stuff.
He would say: "if you carry a spare, you are virtually guaranteed you will never need it or use it. Something else will fail, which you don't have."
Although he was a fanatic about vehicle maintenance, we had a few "car vacations" (it was all my parents could afford) with car problems. However, we never needed anything out of that box!
"Murphy's Law" stuff.
