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Think it is new alternator time...

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Old 05-13-2005, 10:00 PM
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Default Think it is new alternator time...

Mihnea was in town today and tomorrow for custom tuning on several Audi's, including Frank "The Don" Amoroso's new dual program ECU, and we found out while doing a new Rev of software on mine that my alternator is only putting out between 11.5 and 12V. Thus we think causing some lean A/F ratios during our runs.

How much are we looking at a replacement alternator? I "believe" that my brushes and voltage regulator where replaced about 1.5 years ago. If this doesnt fix it, A/F issue, we are looking at a Bosch Motorsport Fuel Pump or Audi 5000 Turbo Fuel Pump.

PS- Had some great fun with a riced out & chopped Honda Civic on the way home. I was doing about 85-90 on the open highway tonight and see and smell a car about 500 yards in bouncing in front of me accelerating. I ended up catching up and passing him with authority. I get about 200 yards in front and slow down...then here he comes again...full bore...I let him get about 20-30 feet behind me..he is easly doing 30+ over me. I punch it..we go door to door for about 2 seconds and I put on 15+ car lengths on him Exited and went home...silly kids
Old 05-13-2005, 10:52 PM
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Foe me too. My bearing is gone (in my 90)
Old 05-14-2005, 07:53 AM
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Default Cody: You are correct: fuel pump voltage is very important to the ....

output of the fuel pump. If you have been following my posts, you will know that I was experiencing lean pinging at WOT with the widely available "370" software. I actually got some flow vs voltage information from VDO and Bosch (but it was generic). Sean Douglas and I checked our fuel flows against the standard Bentley requirements (breaking open the fuel line near the driver's side firewall jumpering the fuel pump via the + post and fuse holder no. 17, a stop watch and a measuring cup (wash afterwards)). Sean did the same thing but also applied artificial "boost" pressure to the fuel pressure regulator. The results were that the fuel pump was not quite putting out the required flow and pressure (for an RS2 set-up). As a result, we devised a scheme to relay the fuel pump and drive it right off the battery. I posted the procedure last July here in AudiWorld. The results were a gain of 1 to 1.5 volts at the fuel pump (well at the connection in the trunk) to about 13.1 V at the pump (vs. 12.5 at idle and 11.9 under load before).

Once you get the alternator so it puts out the required 13.7 V, I recommend that you relay your fuel pump before you go the bigger fuel pump route (if you do, the 60 mm motorsport fuel pump can be made to sit in the fuel tank - you don't need Hap's auxiallary fuel sump in the engine bay).

Dave F.
Old 05-14-2005, 08:24 AM
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Default I have had good luck dropping alternators off at an auto - electric shop...

...in the AM - & picking it up on the way home. New bearings, regulator, slip ring, etc - $100 - and I can talk with the rebuilder & see exactly what was amok.
Old 05-14-2005, 05:44 PM
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Default Link to my Fuel Pump Relay Install post from Aug. 3, 2004 (Search worked - sort of)

<ul><li><a href="https://forums.audiworld.com/s4s6/msgs/31970.phtml">https://forums.audiworld.com/s4s6/msgs/31970.phtml</a</li></ul>
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