Unusual 986 intermittent cutting out problem

[Evo]

Hi,

I need some help / advice with an intermittent problem.

We have a 99 2.5 tip and it intermittently cuts out but restarts no problem. When the car cuts out the interior light comes on and the hazards flash quickly but no siren. It can cut out when on the move or when stationary, i did notice when it cut out whilst parked that doesn't just stall it's as if the fuel pump has stopped and it lets the fuel run though until it stops. It's as if a an alarm tilt switch is intermittently failing that cuts the fuel pump or it thinks it's had an accident and cut the fuel pump???

Can anyone shed any light of what might be causing this?

Thank-you in advance

[hueyhoolihan]

if the engine has one, and i think it might, it could be a bad fuel pressure sensor.

just a not-very-educated guess...

[Heaveho]

I'd agree that it sounds like a fuel pressure problem, but the flashing of the hazards etc, is like something electrical is briefly being cut and then restored. It's the kind of thing you get when you turn off the alarm and open the door. I'd be looking at the battery terminals, the strength of the battery itself, and for a bad earth, then checking fuel pressure.

Porsches are notorious for doing weird things if the battery is starting to go.

Edited to add, I'm not dismissing the post by the previous poster, he well be more accurate with his theory than me.

[gwsinc]

Is your key hard to turn in the ignition? Faulty ignition switch or worn ignition mechanism can give rise to weird electrical gremlins.

I proactively replaced mine yesterday - £150 part from OPC and about 3 hours work to get it swapped out - only basic tools needed to diy but also some patience.

Details of problem/symptoms here: https://www.pelicanparts.com/techarticles/Boxster_...

[Evo]

Thankyou for the replies,

I think the list will be tilt switch replacement, check battery and connections/grounds, replace the ignition switch and the alarm module under the passenger seat.

[tr7v8]

Are the carpets dry

[austin]

tr7v8 said:

Are the carpets dry

This.

Central locking started going mad on mine while driving along...

Check passenger one under the seat, it's where all the electronics are.

If it's wet get the seat out and carpet out with sound proofing, (a massive sponge at this point.)

Then remove the black box and dry out / clean etc etc.