Waterlogged 99 Boxster - Page 2 - 986 Forum - The Community for Porsche Boxster & Cayman Owners

ARModen · 01-24-2010, 01:20 PM

Quote:

Originally Posted by Paul

Have you checked the alarm computer under the seat to see if it got wet?

Nope I'm back to square one now. I charged the battery and tried to start it with the fuel pump relay jumped out and it still doesn't run. The fuel pump definitely works and I don't see any water in the gas.

If it was a relay control problem the jumper would have fixed it. So now it's a bad spark issue or back to the fuel filter being clogged. Anyone know where I can check fuel pressure at the engine? Or atleast downstream of the filter? The filter is in a bad location to access with only jacks.

Paul · 01-24-2010, 01:34 PM

If the alarm computer got wet it will cause this issue, stop and check it.

ARModen · 01-24-2010, 01:56 PM

The underside of the seat is dry and dusty. There are some cobwebs, so I don't think that's the issue.

Paul · 01-24-2010, 03:08 PM

Just checking: Does your remote work the locks and trunks?

Dragonwind · 01-25-2010, 02:26 AM

YOu mentioned the fuel filter. Did you remove it and check if gas was flowing through or that you can get air through it? It very well may be blocked.
Chris

landrovered · 01-25-2010, 04:11 AM

Fuel
Air
Spark

Keep looking.

Paul · 01-25-2010, 04:43 PM

Time to read the codes on the alarm system and DME with a PST-2 or better.

ARModen · 01-25-2010, 08:17 PM

Codes:

I've read the codes on all the modules with he durametrics. The alarm module has a fault 21 (immobiliser w-lead) stored, but no active faults. I have no idea if that immobiliser code is recent or ancient. v6 (beta) of the durametrics reported no active faults, and I told it to reset all faults just in case. I also grounded the positive and negative battery cables to discharge capacitors in the memory. The remote works.

Fuel Filter:

I can't get to the fuel filter. While Pedro's description isn't bad, it is not a safe job to be doing without a lift. I would like to check the fuel line at the engine to see if I'm getting flow through the filter. Does anyone know the quickest way to get to the fuel rails to check fuel pressure downstream of the filter? It can't hurt too much to check that.

However if it was the fuel filter I would think the fuel pump would be on continuously attempting to get fuel to the engine. The fuel pump relay works, but it is not turning the fuel pump on.

Air:

I disconnected the MAF as someone suggested but I didn't get any change in the conditions. Not ot over simplify things, but there really isn't much more to a modern cars air system than the MAF and throttle. If the throttle were bad it should still idle, even if it's rough. When the car first died and I could still get it to start and idle roughly it would respond to the throttle a bit. It's possible that a nearly complete blockage of the intake would cause the problems, assuming that it would result in the DME shutting off the fuel pump.

Spark:

I don't know the condition of the ignition. I'd hope that I'd get a CEL or fault in the DME if there was an issue with the spark to all the cylinders. If it was just 1 or 2 it would still run just poorly and throw error codes.

ARModen · 01-25-2010, 08:35 PM

The entire fuel pump thing and alarm module might be a dead end I think. A guy a Pelican says that the pump is only going to come on when the engine is cranking or running. If thats the case then the filter is back on top of most likely faults. My 911 fuel pump runs when the key is placed in the on position and turns off when the carbs are ready and the rails are pressurized. So I was assuming the fact that the pump was off whenever I checked it was a problem. Now i'm going to have to go back out and recheck the pump. I don't know if I checked the pump when the car was cranking or just with the ignition in the ON position. I'm assuming the latter.

I need to find a place downstream of the filter that I can check the fuel flow. Then, I can check flow and bypass the filter entirely to see if the car will run.

I probably have to put the seats back in now hahah.

Dragonwind · 01-26-2010, 02:57 AM

Quote:

Originally Posted by ARModen

Codes:

Fuel Filter:

I can't get to the fuel filter. While Pedro's description isn't bad, it is not a safe job to be doing without a lift. I would like to check the fuel line at the engine to see if I'm getting flow through the filter. Does anyone know the quickest way to get to the fuel rails to check fuel pressure downstream of the filter? It can't hurt too much to check that.

However if it was the fuel filter I would think the fuel pump would be on continuously attempting to get fuel to the engine. The fuel pump relay works, but it is not turning the fuel pump on.

Not true on the lift part. Get a set of ramps and you can get easy and safe access to it. This was one of the easy DIY's and won't take long.

amondc · 01-26-2010, 02:59 AM

You can pull a fuel line on the passenger side of the motor. Its near the back of the motor and either a 16 or 17mm fitting. Also you need to check for fuel volume, I forget what the spec is but can find it for you.

Try that and see what happens.

Chris

landrovered · 01-26-2010, 04:25 AM

Does the car have an inertia switch to cut fuel supply in case of an accident? It might be worth checking to see if it is tripped.

ARModen · 01-26-2010, 05:34 AM

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 · 01-26-2010, 05:57 AM

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 · 01-26-2010, 09:58 AM

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

Quote:

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 · 01-26-2010, 10:25 AM

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 · 01-26-2010, 10:41 AM

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 · 01-26-2010, 10:49 AM

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 · 01-26-2010, 11:32 AM

Quote:

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 · 01-26-2010, 11:33 AM

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