Waterlogged 99 Boxster

[ARModen]

I don't know Landrovered. I considered that and haven't found any mention of one. But it can't be that because they would turn off the fuel pump via the relay, and I've already tried to run the car with the relay jumpered out to no effect.

This might be my problem...

[landrovered]

Well the immobilizer error code may be more important than you are currently ranking it in your troubleshooting.

Start sequence (not porsche specific) is pretty simple.

Power, ignition switch, inertia switch, immobilizer, fuel pump fuse, fuel pump relay, fuel pump, MAF reading, fuel temperature sensor, coolant temp sensor, throttle position sensor, crank postion sensor, cam position sensor, energize coil packs, starter motor, start.

I have seen where folks suggest starting without the MAF connected, I for one don't think this is a great idea or that it proves anything other than the fact that the ECU has a "limp home mode" fuel curve and will in fact run without a MAF although it runs badly.

The devil is in the details, I suggest you re-examine every one of your "givens" and reconfirm your current assumptions before proceeding further to other systems.

I think I saw that car in the pic for sale on eBay!

[ARModen]

I highlighted what I've verified to work, or doesn't seem to exist.

Originally Posted by landrovered

Well the immobilizer error code may be more important than you are currently ranking it in your troubleshooting.

Start sequence (not porsche specific) is pretty simple.

Power, ignition switch, inertia switch, immobilizer, fuel pump fuse, fuel pump relay, fuel pump, MAF reading, fuel temperature sensor, coolant temp sensor, throttle position sensor, crank position sensor, cam position sensor, energize coil packs, starter motor, start.

No one seems to be sure what the immobiliser signal does, but the consensus thinks it diables the fuel pump, ignition, and injectors. I can't help but think the immobiliser code would disable the starter. The immobiliser is part of the alarm module, and the alarm module disables so much of the car. When it's removed you lose interior lights, starter, window control, and of course both remote and local locks. Removing the alarm module disables the starter so why wouldn't that be part of the immobiliser? Since all of those other alarm module functions work and the module is in pristine condition, I find it unlikely that this is the source of the error. In addition, the car ran, very poorly, but continued to run for several minutes after I started losing power. I think if it was something on the alarm module it would have died hard and not even cranked.

This all happened after I filled the tank from almost empty in the rain. It's not water in the gas, and it doesn't appear to be water in the alarm module, so I'm back to it being a fuel delivery problem. I sucked up a frog or something.

[landrovered]

I don't know about Porsche but in Land Rover the immobilizer does not disable the starter just the fuel pump as does the inertia switch. That being said I feel for you chasing this gremlin around.

Have you verified with a test light or multimeter that you are getting electricity to the fuel pump?

Have you checked the fuel pressure sensor? It shuts off the fuel pump when sufficient pressure is built up in the fuel rail. If it is faulty then the pump may think that it has pressure and not turn on.

When the vehicle ran poorly before konking out, it could have been using the fuel in the rail until it ran out of pressure to the injectors.

let me know what you find.

[ARModen]

yeah, I'm an electronics tech so I have all sorts of toys. The fuel pump runs fine when the relay is closed, but that doesn't fix the problem. I think it was using up the fuel in the rails and what little was getting by the filter before it died. When I get home i'm going to jumper the relay back out and check pressure at the rail. There is supposed to be a 13mm brass cap covering a shraeder valve that is used to test fuel rail pressure. I'm going to jumpered it out and try to cover myself in gas. If I don't get sprayed it's the filter.

[landrovered]

Yes, I use those schrader valves all the time, handy little buggers. If it makes you feel any better I have a friend who ran his LR out of gas and burned up his fuel pump, I have been helping him, I had two fuel pumps of different sytles in my truck and wouldn't you know that his is neither of the ones I had. I had to flat strap his truck to his office which is always a joy. He only ran over the tow strap once.

I used the term fuel pressure sensor but actually meant regulator in the last post.

If you have fuel in the rail and still don't get any joy, I had a recent situation where a bosch controlled motor was dying and would not restart, it turned out to be a bad crank position sensor.

[ARModen]

Originally Posted by landrovered

I used the term fuel pressure sensor but actually meant regulator in the last post.

If you have fuel in the rail and still don't get any joy, I had a recent situation where a bosch controlled motor was dying and would not restart, it turned out to be a bad crank position sensor.

Both of those are definite possibilities. The car makes the usual beautiful vroom when I start it up, but instead of settling down to a nice gurgle, it dies. would the crank sensor give me an error code though?

[yimmy149]

I'm not sure if it's already been mentioned in this thread, but the ignition switches go bad on these cars very frequently. It's a $20 part from VW, and an straight-forward DIY if you have small hands. It's probably worth changing just to rule it out, lots of strange things happen when it starts to fail.

-james