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JFP in PA

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Posts posted by JFP in PA

  1. If the battery is draining but otherwise good, and there are no undo parasitic drains on the system, you probably have a problematic alternator. Check for electrical drains by putting a digital voltmeter set to current (mA) between the positive battery cable and the positive battery terminal. You should see something around 60 mA or less (normal current draw). If it is higher, something is pulling current out while the car is parked. You can locate the circuit by pulling the fuses one at a time until you see the draw drop into its nominal value; the fuse you just pulled is the problem circuit.

    As for the alternator, you can use the same meter to check the voltage output at idle, should be 14.3V or so. If it is below 14V, you probably need a new voltage regulator for the alternator (same regulator is used in Audi, Mercedes, and VW cars, so you should be able to locate one).

  2. I would say yes, and not just because we do PPI's. When spending an amount that one of these is going to set you back, you want to know as much as possible about the car, even if it carries a CPO. Percentage wise, it is a small investment in peace of mind. If nothing else, an independant PPI may provide "tie breaker" facts between two similar cars, such as a DME read out of how many times the car has been to the rev limiter. PPI's have also proven to be handy negotiation tools when it comes to price...... If there is nothing to hide, no dealer should be hesitant about a PPI.

  3. The mixture codes may simply be "ghost" codes caused by a lack of adaption values in the DME. I would clear the codes using something like the Durametric, or any OBDII scanner, and drive the car for a bit before doing anything else. The mixture codes may come back again, so be prepeared for one more "reset" before taking them seriously.

  4. Let me guess: your mechanic cleared the codes by disconnecting the battery.......

    P1602 is the code for memory loss of the DME adaption values. Usual suspects: Wiring issues at terminal 30, battery was disconnected, DME was unplugged.

    P1123 and 1125 are the codes for both banks being so rich that the DME cannot compensate. Usually this is caused by high fuel pressure or leaking injectors; but as it seems to have happened just after the AOS was changed out, it may just be the lack of adaptation values (running time) on the DME.

    If your mechanic did clear the codes by using the battery, first you need a new mechanic. That is not how you clear codes. Take the car to a shop with either a Durametric system or a PST II/PIWIS unit, re-read the codes and then have them cleared. If there really is a fuel issue, the 1123/25 codes will return without the 1602 code after the DME has relearned the adaptation values, which will require you to drive the car for a bit.

    • Upvote 1
  5. The fans are controlled by an algorithm in the DME and work in unison. The fans have two speeds, one for just cooling, and another faster speed for cooling/air conditioning. Regardless of which speed they are running at, both fans should be turning at the same speed. The DME triggers them for cooling by monitoring the coolant temps, the AC speed is triggered by the AC system engaging the compressor.

  6. A PIWIS is the Porsche diagnostic computer system, mandatory for many types of work on these cars. When the fuel level sensor is replaced, they are supposed to run the level calibration diagnostic, otherwise the fuel gauge will not read correctly. Even a prolonged disconnect of the battery can require this calibration. I would suggest you get the car checked out by someone with the correct equipement.

  7. When your fuel gauge was replaced, did they perform the fuel system level calibration with a PIWIS? This requires totally draining the tank, installing and checking the new gauge, and then putting measured amounts of fuel in the tank to test and set its calibration......................... If they did not, there may be nothing wrong with the gauge itself.

  8. One point often overlooked on header pipe and collector sizes is the fact that you can go too big, which tends to move the torque curve up in the RPM curve, reducing the car's drivability. When the tubes get too big, the velocity of the exhaust gases actually begin to slow down, reducing the lower RPM cylinder scavenging effect, causing the perceived loss of low end response. Don't go nuts, as "size really does matter", and there is a "too big"................ dry.gif

  9. Think of the torque converter as being like a squat bottle lying on it side, with the neck of the bottle protruding into the transmission. The fluid level below the neck, nearly ½ the total volume of the rather large diameter converter, is not going to drain by gravity while the trans is in the car. This is why you have to pump oil into the converter, or pull the trans out and turn the converter upside down to fully drain it. Either way, the water contaminated fluid has to come out………

    • Upvote 1
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