tomwilley

I have a 1999 Boxster which has been very reliable. Mileage is only about
19k.

Today I tried to start the car but it wouldn't fire up. The starter motor
turns. However it turns whether the clutch is depressed or not.

It's been suggested to me that I may have an alarm/imobilzer problem.

Anyone have any suggestions?

deliriousga

It could be a ground problem. Freaky things happen when your ground points start to corrode and it's an easy thing to do before replacing parts (should be done annually).

If you have a set of FSMs, see if there's a layout of the ground points. You can go around with some very light sandpaper (say 220 or higher), pull all of your ground points and clean them or sand them to shiny copper. Clean the wire end connector, the spot that sits on and the bolt that holds it in. Also clean your battery terminals and the inside of the cable connector to bright, shiny silver with no gray at all.

If that doesn't take care of it and you don't want to take it to a mechanic for diagnostics, start by testing relays and move on to switches from there. Get ready though, if you DIY it can take you a long time to find it and if a mechanic does the diagnostics it can take him awhile too translating into big $$$.

Jeremy Cottrell

Check out this thread.https://rennlist.com/forums/boxster-and-boxster-s-986-forum/208051-starting-problems.html Good luck!

tomwilley

Hi Guys,
OK ... an update. Checked fuses and relays ... didn't seem to make any difference.
Went out of town for about a week and when I came back, tried to start it and it started up just fine.

Car has been working perfectly for about three weeks then on Sunday ... it happened again. Same symptoms as before. Starter motor turns even when I don't depress the clutch.

I'm wondering if it's something to do with the alarm system. After 5 days the alarm system reverts to key only operation.

As before any thoughts would be appreciated.

Jeremy Cottrell

This may be a job for the dealer. Alarm/Immob. problems usually are. They can connect to the PST2 and see if there are any fault codes in the alarm system. Unfortunately intermittent problems are a real PITA to diagnose. It depends on how patient and diligent your local dealer is. Sometimes they will simply use the old caveat, "Could not duplicate client complaint."

smshirk

have you tried disconnecting negative battery terminal for a while (30 min or so) when it won't start, then putting it back and trying to start?

GreigM

Could be flooding. When were the spark plug last replaced?

Pyroproblem

Ive seen immobilizer modules do weird stuff like this, but that doesnt explain the clutch switch. I believe that switch is an input to the DME, not the immobilizer...
Is the floor behind your driver seat wet at all? If it is I bet your immobilizer is the cause of your problem. If it is, find your remote transmitter ID tags. They have a bar code and a 16+ digit # that will let your dealer reprogram your existing remotes. Without the ID tags, you may be forced to buy new remotes. Sometimes a malfunctioning immobilizer wont let you retrieve the remotes to "write in" to the new module...Sometimes it does. Those immobilizers are funny sometimes.

My best advice to any boxster owner is to CLEAR your body drains, front + rear. This will prevent standing water when it rains which will eventually get inside the cabin and ruin the immobilizer unit( which is strategically placed under the drivers seat). Compressed air works great.

Pre MY 2000 boxsters do not need plugs until 30k miles.

Rotten Robby

According to Excellence, Boxster spark plugs are wearing out sooner due to poor fuel or additives I believe they said.

Rob

Boxster88

I have the same problem with my 99 Boxster. Sometimes it starts, sometime it doesn't. I was ready to replace the starter until I decided to replace the battery first. After I replace the battery, the car started and I drove around then stopped by friend's house. He then noticed that my floor mat was way up under the crutch paddle.

So we figure the floor mat might be the problem, it stops the crutch from contacting the switch for the car to start. It fixed the problem. My car starts every time. No more problem.

My floor mat's velcro does not work too well so the floor mat keep sliding up under the crutch, I just pull it down every time.

CHECK YOUR FLOOR MAT IF YOUR CAR DOES NOT START, this might be one of the problem.

San Rensho

Sounds like the clutch switch is intermittent. Try unplugging the two leads and then plugging them together, by passing the switch and ruling out or confirming the switch is the problem.