Crank No Start
 

Good afternoon,

I own a 2000 Porsche Boxster 2.7L that will crank but will not start.
I have verified that junctions 85 and 86 on the fuel pump relay are not getting the signal to turn on; but I don't know why.
So far I have done the following:
- Replaced the fuel pump
- Replaced the Crankshaft Position Sensor
- Replaced the coils and spark plugs
- Purchased a fuel pump relay bypass relay
- Verified the immobilizer isn't corroded
- Verified the fuel pump fuse isn't blown
- Changed the battery in the key fob
- Did a bunch of various different reset procedures:
- Hold the button on the key
- Manually lock and unlock the car while holding the button
- Put the key in the ignition, turn to on position and hold button on key
- Put the key in the ignition, turn to on position, turn to off position, remove key then press button
- Put key in door, hold button then lock and unlock the car various amount of times while holding button
- Etc. Etc. Etc.

The fob buttons do not function for my car; the buttons do not lock nor unlock any part of my car.

Is there any way to actually know that my immobilizer is the issue without having to take it to a mechanic and spend tons of $?

You might actually do some basic trubleshooting... instead of throwing a bunch of money and parts at it. You mention the relay pins not properly functioning (bad relay), and then you post that laundry list.

It may be cheaper to have the problem diagnosed. Best wshes. :cheers:

Ok, so you've verified that the fuel pump relay is not getting energized to command the pump on. That's a good start. Stop throwing parts at it until you can narrow down the reason for the fuel pump not getting commanded to energize. Do you have a scan tool? First I'd want to scan for any codes, report back if there's any active codes.

I haven't scanned it in a while, but I will order an OBD2 scanner and get back to you with more information.

Is there a technical diagram of the immobilizer?

Basically I'm assuming that if the logic strings don't match up between the immobilizer and the key then the immobilizer sends a signal to various parts of the car preventing them from operating. I would like to take my multimeter and test if I'm getting an electrical signal from my immobilizer, (or perhaps even a lack of signal that SHOULD be there) thus preventing the car from starting. The immobilizer is complex, but it's not magic; I should be able to test it myself with a multimeter, I just don't know what or where I need to test on it.

Thank you.

You're going to spend a shot ton of money if you don't embrace the KISS philosophy. I'd be checking (troubleshooting) the simple... easy things first. You wanting to dive headfirst into the DME... brain... whatever is a little lofty.

Since the car isn't starting... I'm hoping, for you, a code is resident and you'll pull it. Keep us apprised.

Check ignition switch?