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I wouldn't say the car won't start, because actually it will or at least it did (This is a 2000 S).

When I turn the key to the first click, the car makes all the typical buzzing and clicking noises. When I turn it over the car turns over just fine and starts right up, but then right away very gently dies. It runs less than a second. This is repeatable: it always catches and never runs any longer.

I disconnected the battery and grounded the positive cable to remove any charge in any effort to reset the computer. After that didn't work I also briefly disconnected all 5 cables from the ECU.

I opened up the engine compartment and primed the engine by adding a teaspoon of fuel to what seems to be the fuel collector... see attached photo. The car started right up and ran with what I consider normal after having the battery disconnected (some idle surging). The pedal was dead. The rod is indeed connected to the gas pedal, but pushing on it does absolutely nothing.

I suspect it is something electrical... a computer foul up, something disconnected, an immobilizer. The car had some work done a week ago in Los Angeles including replacement of the clutch, , battery, O2 sensors, and shift tower. When I picked the car up it ran fine and I drove it to San Felipe. Since then, about a week ago, I have taken the car for 2 short drives, about 20 minutes each. Yesterday morning the car refused to run. The nearest Porsche dealer is a long way away... any diagnostic suggestions?

fuelcoll.jpg

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Any P-codes?

Did you check the fuel pump for output?

Sounds to me like it *could be* a fuel pump issue too... It primes the fuel rail, starts up, then the fuel pump shuts off and the car dies... I've seen fuel pumps behave very erratically before - sometimes working, sometimes not...

Could be a fault with:

- ECU (no signal on fuel pump control)

- Fuel pump (dying pump)

- Debris in your fuel tank (is your fuel level low? If so, fill up a petrol container with fuel and put it in the car)

If you know what you're doing electrically you can monitor the fuel pump output line on the ECU for activity. Checking engine codes might help too...

Thanks!

Shash

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Hi Loren,

Thanks for your reply. To read the P-codes I must take the car to a dealer or someone with a PST2?

Is there any value to the OBDII readers that can be purchased for a couple hundred dollars?

The car is in San Felipe and if I can't resolve it, then I will tow it to San Diego which I expect will be about a 6 hour drive pulling it on a trailer.

Can run fine for 5+ minutes after priming, so I don't think it is the fuel pump. Would really like to be able to check the p codes.

If you have the same problem then the same question applies...

Do you have any P-codes?

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Loren, the Durametric software looks great. My question is how quickly can I get one to San Felipe? The donkey express will add 2 weeks just to get it from point of delivery in CA to down here. Until you posted this product, I was considering an Equus code reader because I found a few posts where people are happy with the product and I can have someone pick one up for me in San Diego on Thursday and bring it down to San Felipe. I do not really have an understanding of the differences between the various products. If you tell me the Durametric software has more functions and that it may be more useful, then I will find a way to get it here. If you think the Equus is sufficient, then I will get it this week. Thanks so much for your help.

Here I posted pics and links to the Equus products... http://www.babblers.org/forums/showthread....36739#post36739

Hi Loren,

Thanks for your reply. To read the P-codes I must take the car to a dealer or someone with a PST2?

Is there any value to the OBDII readers that can be purchased for a couple hundred dollars?

The car is in San Felipe and if I can't resolve it, then I will tow it to San Diego which I expect will be about a 6 hour drive pulling it on a trailer.

Can run fine for 5+ minutes after priming, so I don't think it is the fuel pump. Would really like to be able to check the p codes.

If you have the same problem then the same question applies...

Do you have any P-codes?

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  • Admin

No other reader than the Durametric (and of course a PST2) can turn off the air bag light AND read the fault codes for alarm, airbag, ABS, seat memory and heating & A/C. I think the Durametric Software is a good investment.

They are in Oregon so call or email them - they can likely expidite the able to you. And, I think they can email you the software.

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Ok I ordered the software and cable from www.durametric.com

No other reader than the Durametric (and of course a PST2) can turn off the air bag light AND read the fault codes for alarm, airbag, ABS, seat memory and heating & A/C. I think the Durametric Software is a good investment.

They are in Oregon so call or email them - they can likely expidite the able to you. And, I think they can email you the software.

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Codes! Thanks Loren for the recommendationt o Duramteric.com. It immediately showed me a list of codes from the motronic. Here is a link the pdf file I created to show the codes. Any help guessing why the car won't run. BTW O2 sensors are all new. I do have a new MAF in storage (old style which is what I have now) I can get here in a few weeks.

http://www.catalogguy.com/ecu20060401.pdf

Tell us the codes when you get them...

ecu20060401.pdf

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This appears to be a harness problem, there is no way that all of these sensors have failed at once.

This looks very similar to when we are developing a DME without the vehicle and no sensors hooked up.

I would look for a portion of the harness that has been severed or disconnected, you might start with a portion of the harness that is easy to reach like the airflow meter and work backwords until you reach the ECU.

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Update and more info attempting to diagnose.....

2000 S that starts but does not run. Pcodes posted separately.

We spent some time last night looking for and not finding a disconnected or severed cable. Here are some notes on what we did and at the end is a list of 4 possible causes we have identified based on information so far.

-Pedal cable intact and moving the arm of the potentiometer

-Wires from potentiometer to connector seem ok and connections on both sides of connector for potentiometer wires seem ok.

-Wires from mass air flow sensor seem well connected.

-Wires to throttle position sensor seem connected.

-Wires to ECM seem connected.

-When throttle butterfly valve was slightly opened, the idle speed increased significantly but was surging more and engine died from fuel starvation, i.e. extremely lean mixture when throttle valve pushed open more than a few degrees, probably because air flow sensor not reading need for more fuel.

-When fuel pump relay was unplugged, engine ran for less than a minute. Engine restarted and idled when fuel pump relay was reinstalled.

1. ECM

2. Mass air flow sensor not working

3. Throttle position sensor?

4. Potentiometer to which pedal attaches

http://www.catalogguy.com/ecu20060401.pdf

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  • Admin

Since you have both P1121 and P1122 that would seem to signify that the throttle position sensor is not getting any signal.

Here is the wiring connection from the DME to the throttle position sensor.

post-2-1144080675.png

The P1219/P1578 would seem to signify that the accelerator pedal sensor is also open.

Here is the wiring diagram from the DME to the pedal sensor.

post-2-1144080770.png

This would suggest that the possible faults are the pedal sensor, the throttle position sensor, the wiring to these from the DME, or the DME itself.

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  • 2 months later...

The car finally made it to a dealer in SoCal. They think that the wiring harness has been damaged and is causing a short which blew the DME. They have not found the exact location of the damage, but think that a small animal may have gotten in there and chewed on something. Hopefully will have more information soon.

Since you have both P1121 and P1122 that would seem to signify that the throttle position sensor is not getting any signal.

Here is the wiring connection from the DME to the throttle position sensor.

post-2-1144080675.png

The P1219/P1578 would seem to signify that the accelerator pedal sensor is also open.

Here is the wiring diagram from the DME to the pedal sensor.

post-2-1144080770.png

This would suggest that the possible faults are the pedal sensor, the throttle position sensor, the wiring to these from the DME, or the DME itself.

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You've not had the car running for 3 months?? It would have driven me crazy not to have the car running for 3 days! ;)

Good luck on the diagnosis - hopefully it doesn't cost too much to repair!

Thanks!

Shash

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  • 1 year later...

This just happened on my track car, but it wasn't due to an animal - my throttle pedal came off at turn 3 at Buttonwillow, thanks to the uber-durable engineering marvel that is the thin plastic piece serving as the hinge. I got the pedal back on with some jimmy-rigging, and ran another 15 minute session, but when I got back, the throttle stopped working, and I found the same codes on my read.

What did your dealer do? I tried to reset the codes, but they come right back...

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  • 2 months later...

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