2003 Boxster Fuel pump fuse is blowing

[172rgpilot]

My boxster blows its fuel pump fuse after start and warm up. Its been at the dealer for 2 weeks..they have put 10 hours into it.....and nothing ....anyone ever had this issue....or thoughts of what could be causing this?

thanks

[rsfeller]

My boxster blows its fuel pump fuse after start and warm up. Its been at the dealer for 2 weeks..they have put 10 hours into it.....and nothing ....anyone ever had this issue....or thoughts of what could be causing this?

thanks

I'll be Dr. Obvious then...has anyone though of swapping the fuel pump?

I'm not electrical genius but I do know from my job that electric (AC) motors tend to start blowing fuses before they go bad.

Now in defense of the mechanics I have replaced 4 fuel pumps in my Saabs in about 10 years. Not once did they ever toss a fuse before the pump go. They just tend to work one day and not the next with no warning.

Just what did they rule out in 10 hours of testing/troubleshooting!??!!

[172rgpilot]

I will ask them tommorow...i would hope a porsche tech would think of this....and i havent a clue of what has been ruled out....all i know is the car is torn apart...driver seat out, back left wheel off, all types of wiring in the trunk out.....im starting to get concerned what this fiasco will cost me. would the pump make any type of whining noise if it were going bad? there is a slight whining noise...which I thought was power steering fluid level a little low.

it has 63 k miles on it

[Loren]

Sorry, but step 1 should have been to measure the fuel pump output volume.

[rsfeller]

I will ask them tommorow...i would hope a porsche tech would think of this....and i havent a clue of what has been ruled out....all i know is the car is torn apart...driver seat out, back left wheel off, all types of wiring in the trunk out.....im starting to get concerned what this fiasco will cost me. would the pump make any type of whining noise if it were going bad? there is a slight whining noise...which I thought was power steering fluid level a little low.

it has 63 k miles on it

Fuel pump is up front and in the tank. They always have a slight whine if you are close enough to hear them but I think most of us cannot hear ours unless we try to put an error to it. They seldom make any sounds prior to failure beyound normal operation.

Often when an electric motor goes bad (or has an issue) the amperage goes up and that what blows a fuse. When cars (and more common in boats due to long wire runs) get old they often suffer from what is known as voltage drop which is a decay of power quality due to old connections and such. This causes issues with amperage going up and blowing fuses to. Your Porsche is newer and small so voltage drop is not an issue but I mention it for the theory. Vw (IMHO) suffer from voltage issues due to small wire gauge, long runs and bad connectors.

I am no means an electric expert and many on this board are engineers that can explain better theory. I just know from 20 years of wrenching cars and boats what common failure trends can occur for all vehicles. I don't think we see an abnormal failure trend in fuel pump fuses on the Boxster so more common troubleshoot can prevail. When fuses go bad it's either due to poor connections, poor wiring (cuts and shorts can show their head when humidity and moisture are present) and bad motors.

Maybe someone on this board can read the wiring schematic for your model year and determine what else may be on that circuit to consider.

A good mechanic should have isolated this concern in a couple hours.

Edited September 9, 2008 by rsfeller

[rsfeller]

I agree with Loren...this would have told you how effectively the pump is working. If these guys didn't try this first get that car out of there and tell them to stuff the bill up their butt. They are bilking or incompetent.

Edited September 9, 2008 by rsfeller

[172rgpilot]

great duelly noted......I will head down tommorow and have some intelligent questions to ask...its my first porsche...guess i just trusted the dealership would be my best repair option.....i'll now come here for advice before i get it towed in...thanks guys :)

on a lighter note.....when its working, it puts quiet the grin on a guys face!

[rsfeller]

great duelly noted......I will head down tomorrow and have some intelligent questions to ask...its my first porsche...guess i just trusted the dealership would be my best repair option.....i'll now come here for advice before i get it towed in...thanks guys :)

on a lighter note.....when its working, it puts quiet the grin on a guys face!

Always hate to see a guys first visit to this site be due to a problem and not just general education! I think I was on this site for a month before I took delivery of my used 986 just getting as much pre-info possible. I am a DIY'r but many on this board are not and it can still allow you to make confident informed decisions. Regrettably we all make the mistake of taking cars and approving work before getting opinions from other experts. You expect them to be the expert, but it's not always true.

One think that is ALWAYS true is they charge ridiculous amounts and their prices for parts will be silly too. Even if you find a good indie mechanic some will allow you bring in your own discount parts or find them for you cheaper through many great suppliers.

I tell all newbies on this site that plan to do some of their own wrenching to go get the Bentley Repair Manual and invest in the Durametric Software (google it) that will allow you pull error codes and reset many common CEL (check engine light) issue. These can help you with minor needs or get good information from this site before you take it to your favorite mechanic.

They call them "Porsche Stealer" around here not Dealers! There are great dealers out there but for most who don't have money to burn they are not always the best choice. My local shop (MAG in Columbus Ohio) was rude the first time I walked in and the tone was set for me. I was going to matain everything on this car short of pulling the engine myself.

Lastly if you get anything good from this site ( and you will) please make a donation to this site to become a contributing member to help Loren (site owner) keep it going. You will find this and few other sites a wealth of knowledge. The different sites have their strong points but this one gets my vote for best due to quick answers, no drama, good technology and plenty of good photos and documentation.

I almost forgot. Let us know where you live and find the PCA chapter in your area to recommend good independent shops who have the proper tools to save you money.

Edited September 9, 2008 by rsfeller

[172rgpilot]

thanks for the advice....im in the louisville ky area

[rsfeller]

thanks for the advice....im in the louisville ky area

I'm in Ohio so not to far away!

PCA is by regions: http://www.pca.org/regions/ to find out who is in charge to recommend anyone in the area. I cannot recall if their site has a indie listing. Loren has a forum here for recommendations but it really hasn't been populated by members with indie shops. I may be missing another posting area though. I would start a new thread specifically asking for any recommendations in your area.

[wvicary]

This should be an easy problem to sort. As already suggested test the fuel pump volume and amp draw of the fuel pump. Both tests only take a matter of minutes each to perform and the problem narrowed down in about an hour of labour.

[172rgpilot]

update....after 1600 bucks of searching ...dealership thinks its a short in the engine wiring harness....they say they might be able to repair it....if not, wiring harness runs 1500 bucks.......where can I get parts for less then retail?

[rsfeller]

update....after 1600 bucks of searching ...dealership thinks its a short in the engine wiring harness....they say they might be able to repair it....if not, wiring harness runs 1500 bucks.......where can I get parts for less then retail?

They could have hardwired a single line for that much.

There are several dismantlers that specialize in Porsches but they will most likly not have a whole harness, but it's worth a try. Check out Mike Focke's site, I think he lists the common ones. Otherwise try the site sponsor (sunset imports). First get the part number you need, and check the retail price check on the site her to make sure they are not hosing you...then get the quote from Sunset. Since it's at the P-Dealer they won't allow you your own parts though, usually.

If you got the money go for it, but the DIY car builder in me says get an expert to run their own wire.

they should be ashamed it took that much money and time to figure this out and it's not a sure thing still. But that is what dealers do best.

Did they do a flow test?

Did they check the amperage of the circuit?

What answers have they given you?

Are they just guessing at this point because they don't know?

[172rgpilot]

im not sure the answers.......i should find out tommorow...gut says they are guessing....im at the point where i just want my car back fixed. lesson learned, ive found a good indie.