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Matt, Engineer - BEng Hons
Category: Porsche
Satisfied Customers: 21616
Experience:  Mechanical Engineer with 20 years experience in the auto industry, 8 yrs in formula 1 engine testing
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2002 boxter good shape. Battery new just checked but every

Customer Question

2002 boxter good shape. Battery new just checked but every third time wont start.mstrNge but after car is off it nakes noises seeming to come from gas tank. Then if ii disconnect black battery fonnector npise stops and starts qgain after recnnect. How to make start each time? New key and security light on dash stays on.mhelp!!!!!
JA: Have you checked the fuses? The dashboard bulbs?
Customer: Ok the overhear bulbs out. All other dash lights and rqdio work perfect. When starts sounds great?
JA: What is the model of your '02 Porsche?
Customer: Boxter
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: Had barrerty checked. No problems last night. Then started starting hen i touched brake to start and depressed clutch. Sounds great otherise. Im confused.
JA: Anything else you want the mechanic to know before I connect you? What confuses you?
Customer: Why does it start great and all other radio heqt works great hen wont start every third time.
Submitted: 6 months ago.
Category: Porsche
Expert:  Matt replied 6 months ago.


This sounds like a lack of fuel and could be a lack of fuel pressure from the electrical pump at the tank.

1st thing to try is to remove the fuel filler cap and then flick the ignition on whilst listening for the brief ‘buzz’ of the pump

If the connections to the pump are corroded or damaged then the pump could stop at any time or could not be running at full speed. Check that its relay switches in and out and the relay contacts are clean and bright – replace the relay if in any doubt and do the same for the fuse,

Ideally measure the pressure at the injector rail (should usually be around 3Bar / 45psi +) and if this is low check the pump as described and also consider changing the fuel filter as if this partially blocked this too will reduce pressure.

And one other thing to try is to loosen off the fuel filler cap, as there’s a 1 way valve built into the cap to let air into the tank and so prevent a vacuum from being created as the fuel leaves the tank to the engine

If this helps then replace the cap with a new item

Expert:  Matt replied 6 months ago.


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