02-02-2017, 04:33 PM
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#21
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Registered User
Join Date: May 2014
Location: S.California
Posts: 2,027
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Thank you Marcus !
I am hoping to have more diagnosis and tracking done this evening.I suspect a break in continuity deep in the wiring harness.
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02-03-2017, 05:26 PM
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#22
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Registered User
Join Date: May 2014
Location: S.California
Posts: 2,027
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Thank you Chuck W for the SAI Pump
A few more hints for those who follow.
HOW TO FIX A NOISY SAI PUMP.
To test an SAI Pump you need to run it for 2 minutes continuously. In normal operation it runs for 60 -90 seconds. Chuck's pump was quiet for 2 minutes after I tweaked it .Mine was not.I had only tested mine for 10 seconds and presumed that was enough.
After you do the Krazy K rebuild of the pump it may run perfectly for 30 + seconds . Then it may start screeching. STOP ! If you are quick, you can save it.
Remove the discs and run just the motor.If it still screeches, you need to replace the bearings - as described in previous links.
If the motor is quiet ,it must be the discs rubbing. The prime suspect is the last disk to fit.The center lip in the middle of the disc rubs against the fixed disc in the final part of the housing. Look carefully and you should see the rub marks. Note the raised lip in the center ? Use a Dremel tool to grind away part of that lip. Make it perfectly smooth. add a little grease to the suspect area, try again.Yes, it is dentistry. RInse and repeat as necessary until the pump runs quietly. Test for 2 minutes.
Feel the blind end of the motor - is it hot or just warm? Hot = need new bearing.
Feel the volume of air being blown .It should be powerful and the air should be not much above ambient. If the flow is weak, check the air filter.in the end cap. Be very careful removing the tiny push nuts. I used a set of picks from HF. More dentistry ! If you loose one of the push nuts - they spring out wildly - you may be able to substitute an internally serrated washer of the right/tight i.d.
I mention this noise issue because I suspect a noisy pump is often condemned as having defective bearings when actually ir was the center of the last disc rubbing. I hope this helps others.
Last edited by Gelbster; 02-05-2017 at 08:57 AM.
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02-03-2017, 06:02 PM
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#23
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inveniam viam aut faciam
Join Date: Mar 2014
Location: Arvada, CO
Posts: 440
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I do repairs like this almost weekly. My guess is that you either forgot to hook up the power wire to the 40 Amp fuse from the alternator when you did the rebuild, or you have a break or bad connection at the connections from the engine harness to rear harness. Wires pretty much never break in the middle unless they get pinched, etc., and generally you will have multiple issues and shorts and often smoke... That doesn't match your failure descriptions. That wire has no splices, so the likelihood of having a break in the middle of the run is virtually nil (barely a physically damaged harness of course).
Personally, I would first inspection the connection from the engine harness to the rear harness. If there is no power there, then I would disconnect the battery, and get to the back of the alternator and inspect. If you have to pull the alternator to get to it, so be it. My guess is that your problem lies there.
As for the SAI pump, if it is at all noisy, it must be disassembled, the bearings should be replaced, and the commutator turned and polished. Use the best quality bearings with good seals, not just skate board bearings. They don't last long.
One of the big issues with those pumps is that the carbon from the brushes gets into the bearings, first causing noise, then they seize and finally windings burn. If the motor has stopped or doesn't run full speed or has trouble starting, check continuity and shorting of the windings (I do on all of them). Most that have seized have damaged windings IME. If you don't polish the commutator (and brushes for that matter) and remove ALL the carbon dust, the carbon will get into the bearings (especially the one on the fan side) and cause the same problem again. These pumps are not a very good design, and they don't last particularly long. There are a couple of other issues, like exhaust getting into the pump, that is common on Audis that use the same pump, but I haven't seen it on the Porsches.
__________________
'03 S, manual, 18" Carrera wheels, PSM, PSE, Litronic, 996 Cluster, +
Last edited by Qmulus; 02-03-2017 at 06:05 PM.
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02-03-2017, 06:30 PM
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#24
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Registered User
Join Date: May 2014
Location: S.California
Posts: 2,027
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Thank you for the suggestions.
The fuse is fine. No power to the fuse holder terminals.
There is no power to the relay tray in the rear of the vehicle where the 40A fuse is located.
I removed the alternator and there is power there.I have started to trace for break between the back of the alternator and the rear relay tray.
Odd thing is the trunk light is still working .
Just plodding through the circuits with the help of Bentley.
Interesting comments about the pump motor- mus be a lot of them that are just thrown away when they could be repaired.
Interesting comment about the inferior quality bearings inadvertently used for the motor refurb. Do you have a spec & part number to suggest for others who do this diy ?
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02-03-2017, 08:27 PM
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#25
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inveniam viam aut faciam
Join Date: Mar 2014
Location: Arvada, CO
Posts: 440
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While you had power to the alternator, did you have the 2.5mm red wire along with the large cable that goes to the connecting point, and was it intact? You should check continuity between there and X59 (white connector) pin 14. On the other side of the connector it goes to a 4mm wire (because the Maxi fuse terminals are only available for that size) to the fuse holder. Like I said, in most cases you will find the breaks at the ends. That said, also check for chafed or pinched spots in the harness, or melted spots. I still will bet on the ends, either at the alternator, large multi-pin white connector in the back (check both sides of the connectors). or fuse holder (check from behind).
The ONLY thing that wire powers is the secondary air pump, so it is no surprise that everything else works.
Honestly, I haven't bothered to rebuild these pumps in a couple of years. If you want a core, I have a big box of them. For a while you could get new ones for less than $100, so it didn't make sense to rebuild them. That and people were throwing pumps at cars with leaking combi valves that killed pumps in a matter of weeks by filling them with exhaust vapors and expected warranties for that. I had made a prototype replacement with a brushless motor that eliminated the issues, but I lost interest in that project.
__________________
'03 S, manual, 18" Carrera wheels, PSM, PSE, Litronic, 996 Cluster, +
Last edited by Qmulus; 02-03-2017 at 08:32 PM.
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02-04-2017, 07:33 AM
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#26
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Registered User
Join Date: May 2014
Location: S.California
Posts: 2,027
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Thank you Qmulus ,Miles and others who Pm'd me. In the middle of the night I realized what the cause was and wrote myself a note in case I forgot . Yes, I know !
In Post 1 "...(alternator) Terminal B1. So this is where the problem must be ??"
Correct but why?
Qmulus must have been dreaming about this also because he also got the right answer. There are 3 conductors that connect on the back of the alternator : 1 blue that goes to the instrument cluster(IIRC) -it has it's own connector.
The other large terminal with the 14(??) mm nut has the starter wire and one red conductor. This red conductor with a ring terminal was not connected.Exactly what Qmulus predicted. Thank you ! I can still see the i.d. tag "ALT"I made for it dangling.
Qmulus made another good point about carbon contamination of the bearings and the need to clean out the carbon from the motor to prevent the fan discs sucking it into the front bearing of the SAI pump motor.
But how to free the stakes on the face plate of the motor.?? I used a Dremel with a grinding wheel but it was a tedious process and lots of abrasive debris.Maybe Qmulus has a better way to dismantle the motor?
Thank you ALL who helped me !
Last edited by Gelbster; 02-04-2017 at 07:35 AM.
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02-04-2017, 08:16 AM
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#27
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inveniam viam aut faciam
Join Date: Mar 2014
Location: Arvada, CO
Posts: 440
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No problem.
For disassembling the pump motor, I squeeze the "ears" that were peened over back up, then use a flat chisel to work the end plate off of the motor housing. Doing it this way you can then peen the ears back down when you are done with another sharp chisel and it looks like no one was even there. If you grind away the ears, you have no material to keep the end plate on.
The actual process of rebuilding these pumps correctly is an involved and messy process. First you disassemble and clean everything (an industrial washer and or ultrasonic cleaner is ideal), then test the armature windings, turn and properly finish the commutator and brushes, replace bearings, reassemble and test for some amount of time (note current and airflow) . There are also some other steps that I consider "proprietary" that I learned from experience on these, but that is basics. This all assumes the motors are in good shape, when in reality about 50% have damaged windings and/or are badly corroded from exhaust gases. I don't bother with those, but they could be repaired. Luckily the orientation of the pumps in the Porsches (horiontal) is more favorable to these pumps than the vertical orientation used in other cars as the carbon from the brushes is not as likely to settle on the bearings. A brushless motor in this application would be ideal.
Anyway, glad to hear that you found your issue.
__________________
'03 S, manual, 18" Carrera wheels, PSM, PSE, Litronic, 996 Cluster, +
Last edited by Qmulus; 02-04-2017 at 07:13 PM.
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02-04-2017, 08:21 AM
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#28
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Registered User
Join Date: May 2014
Location: S.California
Posts: 2,027
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No, YOU found it- thanks very much .
I hope other Forum Members note you have a stash of cores that they may contact you about buying if you are interested.
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02-04-2017, 08:33 AM
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#29
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Registered User
Join Date: Dec 2014
Location: Pasadena
Posts: 261
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Glad you got it figured out. I'll be up on the Crest or GMR waiting fer ya. See ya on the road.
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02-04-2017, 08:58 AM
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#30
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Registered User
Join Date: May 2014
Location: S.California
Posts: 2,027
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Thanks guys !
So what did I learn and why did I make the mistake? I'll confess in the hope it spares others similar problems.
1. Durametric is an invaluable tool for diy ! It eliminates a lot of speculation.
2. I need to print a good copy of all the electrical component locations that 78F350 posted Is it from PET ?
3. When you do a rebuild, take and annotate lots of photos and organize them. In addition label the components and mark their orientation. You may have a great memory but if life hits you in the middle of a rebuild project (my unexpected 2 year hiatus problem), you will forget the details and the writing on the labels fades,the labels fall off . The best ones are the flag type with the wire tag on them and permanent marker. Zip lock bags all marked too. This was my downfall !
4. Read everything ,bookmark and organize it. This makes it easier to help others. I have almost 1500 posts here and on R'list that are almost all answers using links I culled for my own projects - a few clicks and you can share the wisdom and experience of others . Unlike Qmuluus , I have little proprietary content to offer. Thanks Q.
5. Access - unless you have "keyboard fingers" ,skinny arms and Kevlar-arm gloves this car is hard to see/access. A powerful ,skinny Maglight is invaluable.I just wish they had a "gummy"version you can bite on. Yes, sometimes you need 2 hands and a light so the flashlight is held by your teeth! (Ignition switch r&r for example) I also used a Kobalt flex-neck flashlight with a tiny ,powerful LED bulb. For under car inspection I use a home-made Miners helmet with a powerful light on it.
An oddball suggestion I gleaned from an unrelated post by Member San Renso - remove the trunk lid and the top cover, kneel in the trunk to work on the the engine from above. It isn't as mad as it sounds if you have a lot to do there and maybe the lift struts need replacing anyway.
Hope this helps others who may follow and thank you for all the help given.
Last edited by Gelbster; 02-05-2017 at 08:59 AM.
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02-04-2017, 09:41 AM
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#31
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Motorist & Coffee Drinker
Join Date: Jul 2014
Location: Oklahoma
Posts: 3,665
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Quote:
Originally Posted by Gelbster
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2. I need to print a good copy of all the electrical component locations that 78F350 posted Is it from PET ?
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Glad it is useful. The component locations are in the back sheets of the wiring diagrams. The one I posted from was 'Sheet 19 - Connectors and abbreviations'.
__________________
I am not an attorney, mechanic, or member of the clergy. Following any advice given in my posts is done at your own peril.
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02-04-2017, 06:59 PM
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#32
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Motorist & Coffee Drinker
Join Date: Jul 2014
Location: Oklahoma
Posts: 3,665
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Correction/update:
The component locations I posted were from a PDF I have that is a partial copy of the Porsche Service manual. It only contains the wiring diagrams from 1997 - 1999. The link I downloaded it from is dead now, but I'm sure it's out there on the net still. The actual page was:'Model 1999, Sheet 19 - Connectors and abbreviations'.
I just checked through my hard copy manual (15 binders 2 of which are pull-out wiring diagrams) and saw that it's laid out a little different each year: Sheet 18 for the 1997, Sheet 19 for 98-99, Later model years it's called "Plug Connections, abbreviations" and ranges between sheets 21 - 23.
I Just looked through the Bentley. It has the information, but it is presented differently. It has the X-connectors and their locations stated on "EWD-8", on the page before the actual wiring diagrams start. There's some more useful info on how to read the wire diagrams in the pages before that, "EWD-3", "EWD-4", etc....
__________________
I am not an attorney, mechanic, or member of the clergy. Following any advice given in my posts is done at your own peril.
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02-04-2017, 07:32 PM
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#33
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Registered User
Join Date: May 2014
Location: S.California
Posts: 2,027
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Thank you for finding it. Bentley certainly did hide it well.
I have been trying to get a CD version of the FM with the Supplements/updates but the best I can find is a 1997 manual with updates as far as #16 .There is no date for any of the updates so am clueless as to if it would be useful.
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02-05-2017, 09:35 AM
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#34
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Registered User
Join Date: May 2014
Location: S.California
Posts: 2,027
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A few notes to others who may try this .
I found it very difficult to remove the motor faceplate gently.I did squeeze the stakes as Qmulus kindly suggests below. It went easier when I ground back the obstructing 'ears' and edges. Remove only as much as is necessary. There are 2 Torx screws that help secure the front plate so I was not worried about reassembly with slimmed down stakes.
I was worried about damaging the carbon brushes so removed the springs- that was fun replacing them !I used an Exacto blade to hold them compressed in position while bending back the 4 retaining tabs.
The bearings are(?) 608 2RS .2RS Not ZZ ! I measured the o.d. as 22mm, the i.d. as 8mm and the thickness as 7mm.As Qmulus suggests, this is a popular size for skateboards but better quality are available- even ceramic on Amazon!
The bigger problem is the stakes around the mid point of the circumference of the body of the motor. They are very thick.I had no way of bending them without risking damage & debris inside the motor. Perhaps they could be weakened with a Dremel wheel and then bent out of the way? Q was right ,there was carbon debris so I removed what I could with a powerful shop vac.
My suggestion is that if the motor is noisy - find a replacement motor - but where? It has no part number or manufacturer name on it. Must be available because the same motor is used on many other vehicles.
WRITEUP: 2.7T Secondary Air Injection SAI Pump rebuild - AudiWorld Forums
Maybe the VW/Audi?Mercedes Forums have solved this issue??
Reassembly - you may need pushnuts - the 3 that retain the filter housing? Here is a possible source Aaronspushnuts. FYI ,they are approx. 12mm o.d. and 2mm i.d.:
** PUSHNUTS, push on nuts for bolts or unthreaded rods **
There is also an External circlip 15mm i.d. I do not know what function it has other than to make a scraping noise. Chucks Pump was missing this part but worked fine w/o it.
Quote:
Originally Posted by Qmulus
"For disassembling the pump motor, I squeeze the "ears" that were peened over back up, then use a flat chisel to work the end plate off of the motor housing. Doing it this way you can then peen the ears back down when you are done with another sharp chisel and it looks like no one was even there. If you grind away the ears, you have no material to keep the end plate on.
The actual process of rebuilding these pumps correctly is an involved and messy process. First you disassemble and clean everything (an industrial washer and or ultrasonic cleaner is ideal), then test the armature windings, turn and properly finish the commutator and brushes, replace bearings, reassemble and test for some amount of time (note current and airflow) . There are also some other steps that I consider "proprietary" that I learned from experience on these, but that is basics. This all assumes the motors are in good shape, when in reality about 50% have damaged windings and/or are badly corroded from exhaust gases. I don't bother with those, but they could be repaired. Luckily the orientation of the pumps in the Porsches (horiontal) is more favorable to these pumps than the vertical orientation used in other cars as the carbon from the brushes is not as likely to settle on the bearings. A brushless motor in this application would be ideal.
Anyway, glad to hear that you found your issue.
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Last edited by Gelbster; 02-05-2017 at 09:37 AM.
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02-06-2017, 07:24 AM
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#35
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Registered User
Join Date: Sep 2008
Location: Agoura Hills (LA) So.Cal.
Posts: 1,574
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Great write up Tony. Nicely done. The pump I sent you had about 28,000 miles on it. It was making a whining sound for a couple months before I replaced it. I had read the various threads regarding rebuilding it and some of the rebuild failures. Audi uses the same pump and they had posted some rebuilds too.
Bosch sells them new in the $300 range while the Porsche dealer sells them for $1700.
Then I looked at qualityporscheparts on eBay. They had (have) over 50 pumps for sale (Porsche Part No. 99660510400). Their prices vary depending on the mileage of the Porsche they came out of. I paid $65 for one with 49,000 miles on it. For me, it was worth the gamble of buying a used one for $65 verse trying a rebuild.
One thing I noted is the top comes off very easily by removing three compression nuts. Once removed you can see and remove the air filter. Both, mine with 28,000 miles on it and the donor one with 48,000 miles were filthy with fine black soot. When I cleaned the original one it ripped it. They are very fragile. When I cleaned the donor one I used Dawn dish-washing soap I was very careful and it came out well.
__________________
1995 Porsche C4 Cab
2016 BMW M2, 6 Speed LBB - ED 7/2016
1997 993 Cab - Sold; 1997 993 Turbo - Sold
2001 Boxster S - Original Owner - 30K Miles -SOLD
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02-06-2017, 08:34 AM
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#36
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Registered User
Join Date: May 2014
Location: S.California
Posts: 2,027
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I agree with Chuck's recommendations . Half the battle is knowing how far to go "down the rabbit hole" with these diy projects.
Until we find a source of new or rebuilt electric motors for the Secondary Air Pump, our options are very limited.
Someone in The Audi and VW world must have a source for these little electric motors?
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