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Old 11-10-2016, 11:01 AM   #1
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Accellerator sensor

Has anyone changed a accelerator sensor? I saw a write up how to clean one but this is not my problem. Would you buy a used one from a dismantler or only a new one? Getting a reoccurring fault that I can rest but it comes right back 10 to 15 miles. Power cycles give a better result but it returns in a week or 2.

At this point I have no power loss but it can not blip the throttle downshifting on the brake. I had this in the summer and thought I had a loose connection or heat issue but I can't get it to go away now. I added a fan that got rid of the heat problem. The connection on throttle body and MAF Check out OK and show good on Durametrics.

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2003 Black 986. modified for Advanced level HPDE and open track days.
* 3.6L LN block, 06 heads, Carrillo H rods, IDP with 987 intake, Oil mods, LN IMS. * Spec II Clutch, 3.2L S Spec P-P FW. * D2 shocks, GT3 arms & and links, Spacers front and rear * Weight reduced, No carpet, AC deleted, Remote PS pump, PS pump deleted. Recaro Pole position seats, Brey crouse ext. 5 point harness, NHP sport exhaust

Last edited by jsceash; 11-10-2016 at 11:09 AM.
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Old 11-10-2016, 06:24 PM   #2
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Several times, not too hard especially if you remove the heater duct that is in the way.

I've had good luck with used ones purchased from other members on this board.

Before doing that, check for the lack of resistance and for continuity on all 6 wires from the pedal sensor connector to the corresponding sockets on DME plug 4. I can provide the pin outs if you need them.
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Last edited by Paul; 11-10-2016 at 06:33 PM.
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Old 11-12-2016, 10:43 AM   #3
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Thank you Paul. Purchased a sensor out of a 2004 base that had 22K on it. Let you know how it goes when replaced.
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2003 Black 986. modified for Advanced level HPDE and open track days.
* 3.6L LN block, 06 heads, Carrillo H rods, IDP with 987 intake, Oil mods, LN IMS. * Spec II Clutch, 3.2L S Spec P-P FW. * D2 shocks, GT3 arms & and links, Spacers front and rear * Weight reduced, No carpet, AC deleted, Remote PS pump, PS pump deleted. Recaro Pole position seats, Brey crouse ext. 5 point harness, NHP sport exhaust
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Old 11-13-2016, 02:54 PM   #4
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In case you don't know this already....

This system is very sensitive to wiring issues. It contains 2 internal potentiometers that the DME compares. What codes have you been getting? Note this type of issue does not light the check engine light.

In my case issues have usually been caused by a bad connection on one of the 6 wires.
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1998 Boxster with 7.8 DME, 2005 3.6 liter/325 hp, Variocam Plus, 996 Instrument panel
2001 Boxster original owner. I installed used motor at 89k.
1987 924S. 2002 996TT. PST-2
Owned and repaired Porsches since 1974. Porsche: It's not driving, it's therapy.

Last edited by Paul; 11-13-2016 at 07:58 PM.
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Old 11-13-2016, 06:39 PM   #5
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P2135 p0121 Plugs cleaned several times.
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2003 Black 986. modified for Advanced level HPDE and open track days.
* 3.6L LN block, 06 heads, Carrillo H rods, IDP with 987 intake, Oil mods, LN IMS. * Spec II Clutch, 3.2L S Spec P-P FW. * D2 shocks, GT3 arms & and links, Spacers front and rear * Weight reduced, No carpet, AC deleted, Remote PS pump, PS pump deleted. Recaro Pole position seats, Brey crouse ext. 5 point harness, NHP sport exhaust
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Old 11-13-2016, 07:46 PM   #6
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Those codes can be thrown when pedal encoder 1's voltage is not 2X of pedal encoder 2.

I always check the wiring from end to end with a ohm meter for each of the 6 wires before replacing anything. All 6 wires must have similar resistance for the system to work properly.

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1998 Boxster with 7.8 DME, 2005 3.6 liter/325 hp, Variocam Plus, 996 Instrument panel
2001 Boxster original owner. I installed used motor at 89k.
1987 924S. 2002 996TT. PST-2
Owned and repaired Porsches since 1974. Porsche: It's not driving, it's therapy.

Last edited by Paul; 11-13-2016 at 08:03 PM. Reason: Added PST-2 Display
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Old 11-14-2016, 09:58 AM   #7
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Pinouts:

Pin 1 at pedal sensor to connection 12 on DME plug IV (ground sensor 2)
pin 2 to 8 (signal sensor 1)
pin 3 to 14 (5V supply sensor 2)
pin 4 to 9 (5V supply sensor 1)
pin 5 to 7 (ground sensor 1)
pin 6 to 13 (signal sensor 2)
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1998 Boxster with 7.8 DME, 2005 3.6 liter/325 hp, Variocam Plus, 996 Instrument panel
2001 Boxster original owner. I installed used motor at 89k.
1987 924S. 2002 996TT. PST-2
Owned and repaired Porsches since 1974. Porsche: It's not driving, it's therapy.
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Old 11-14-2016, 12:28 PM   #8
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Are you looking at an e-gas system gas pedal assembly or the Throttle body.

I have spares of both from my 01 'S' that turned out OK when I found it was my ECM had malfunctioned.

I'd sell them to a forum member for a good price.

Sounds like its the pedal components you want.
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Old 11-14-2016, 03:24 PM   #9
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Been through the connection. The output on pot 1 skips. I can see it on a VOM. Durametrics shown a voltage drop in roughly the same spot. A replacement will be here tomorrow we'll see.
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2003 Black 986. modified for Advanced level HPDE and open track days.
* 3.6L LN block, 06 heads, Carrillo H rods, IDP with 987 intake, Oil mods, LN IMS. * Spec II Clutch, 3.2L S Spec P-P FW. * D2 shocks, GT3 arms & and links, Spacers front and rear * Weight reduced, No carpet, AC deleted, Remote PS pump, PS pump deleted. Recaro Pole position seats, Brey crouse ext. 5 point harness, NHP sport exhaust
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Old 11-14-2016, 06:20 PM   #10
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Based on your testing the pedal sensor is most likely the issue.
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1998 Boxster with 7.8 DME, 2005 3.6 liter/325 hp, Variocam Plus, 996 Instrument panel
2001 Boxster original owner. I installed used motor at 89k.
1987 924S. 2002 996TT. PST-2
Owned and repaired Porsches since 1974. Porsche: It's not driving, it's therapy.
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Old 11-20-2016, 06:19 AM   #11
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Problem resolved?
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1998 Boxster with 7.8 DME, 2005 3.6 liter/325 hp, Variocam Plus, 996 Instrument panel
2001 Boxster original owner. I installed used motor at 89k.
1987 924S. 2002 996TT. PST-2
Owned and repaired Porsches since 1974. Porsche: It's not driving, it's therapy.
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Old 11-20-2016, 01:24 PM   #12
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Sorry problem resolve replace the sensor. As a side note Recently having an issue with the AC and inside fan. I notice I could easily see the sensor with the Radio and heater control out. So I remove them to get a better "hands on" the sensor. I believe it made the job easier but I had not attempted the replacement from under the dash.

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2003 Black 986. modified for Advanced level HPDE and open track days.
* 3.6L LN block, 06 heads, Carrillo H rods, IDP with 987 intake, Oil mods, LN IMS. * Spec II Clutch, 3.2L S Spec P-P FW. * D2 shocks, GT3 arms & and links, Spacers front and rear * Weight reduced, No carpet, AC deleted, Remote PS pump, PS pump deleted. Recaro Pole position seats, Brey crouse ext. 5 point harness, NHP sport exhaust
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