ekstroemtj

Mcbit500

Thank you, your advice really makes sence but battery under the seat is almost new.

voltage on my gauge is showing arround 14 volt.

Piwis showing usual numbers too.

What you mean with bad ground?

Should i get the battery tested?

Is there a way to find out if alternator is in bad condition?

Thank you

Hello mudman

Its a early one 2004 cayenne S

Hello !

Maybe someone could help me with this problem.

I know there are a lot if comments about this subject in the forum but i havent found anything which describes my behaviour of my cayenne S.

I have random problems with PSM failure. From time to time its showing up on my display. Sometimes during driving, sometimes when i start the car after parking.

There are no codes showing in PIWIS

I try to give some samples when and what happens.

Driving to office in the morning.

After 10 minutes of driving i had to stop because of traffic jam. PSM warning light coming up but still possible to drive.

Starting the car in the morning. PSM light coming up. Engine starts very very hard. Shaking and stottering. Very bulky start. Not possible to drive.

Driving home at evening from office. Same story. Bulky start. Not possible to drive.

Driving in the city. Stop on a red light. PSM light coming up but possible to continue driving.

Between all this time the car runs without problems. Even a trip to italy.

10 days with 2000 km in total. Not even one time a problem with PSM.

What i did to solve the problem at the moment it appears: i switch on ignigation for one minute without starting the car. It helped.

I reset the DME by using the method with key inside, pushing the gas pedal 5 seconds. Etc. I guess everybody knew this.

Porsche mechanics are frustrated. Me too.

Maybe here someone has a idea what is going on there?!

Thank you in advance

Tom

I had problems wirh fuel pump weeks ago but they replaced just one. Nobody there told me that i have to replace both.

Didnt found out so far. I have to take it to porsche next days. Low octane is not the reason. I use 102 octane and still coming arround 3000 rpm.

Its in some way frustrating . Porsche mechanic told me it cant be related to coils or plugs. This kind of problems would be causing trouble in any rpm range. I keep you informed

Update.....

Yesterday i wanted to open the car by using remote key. Not working. I opend the car by turning in the key and open door manual.

On the display " start engine" in red letters ... Which i never saw before.

I started the truck without problems. I stay in the car, engine running, park position. Checking the display and guess what.... The option "comfort settings" appeared on the display.

I dont know what to say. More and more this car is like a miracle. Doing wyrd things which i cant explain.

But for the moment this display story looks solved. I believe it has something to do with the memory settings of my drivers seat. Because i remember the display story started when i used the memory function of my seat first time last week.

Thank you for all your input.

By the way.... Batterie i guess isnt the problem. I changed it 6 month ago for a new one

I know. Car in parking. But the option "comfort settings" doesnt even appear on the display. Mysterious :-(

How it can be.... There was always an option where i could change the values .

For mirror , for doors etc. The english name is comfort settings i guess.

From one day to next this option dissapeared.

Some idea what could happen?

Thank you

Thank you for this idea.

You mean really during DRIVING or would it be possible to notice in the shop just when they bring it up to this RPM range?!

Thank you for answering. Oil could be but in my case i dont believe. I change oil after 5000 km and use mobil 1 or shell helix. Happens with both.

Regards

There was one code: oxygen sensor. They cleared it and it didnt come back.

Nothing else which is visible at PIWIS.

Wow I would have said the things you already fixed. I would recheck the coils first, just a visual inspection

Dear forum members, i try to find out what could cause this issue and maybe someone has an idea what to look for.

Cayenne is driving fine. At low speed no problems. Kick down getting speed very easy. High speed no problems. Just between i feel its behavior is not normal. I have this problem allready some weeks. Porsche cant find anything. No codes so far.

Last week i drive 1000 km non stop and specially focused on the issue.

My impression, better to say what i learned from this trip. The car acts just strange in the range between 3000 and 4000 rpm. In any other situations no complain.

Strange means its not running smooth, accelaration feels like there are very short moments when the engine isnt getting enough gas. Some kind of very short stottering but you can really feel it. If i pass the 3800 / 4000 rpm its fine again.

Maybe somebody has a clue what it could be.

The car has new coils and short time ago got new throttle body and new fuel pumps. Cayenne S , 2004

Thank you

You should feel it. When starting the car or when driving very hard. Why , because just in this situations BOTH fuel pumps are running

Is there a way to tell if a particular pump is going bad?

Wow! Great info. This i was looking for. Thank you very much !

Thank you very much. I was asking because i got new pumps some weeks before. In the beginning car was running like a rocket. After some hundred km now i had a strange behaviour again. Driving in the city or cruising outside without problems. Highway driving and hard acceleration makes me feel the truck sometimes get no fuel or to much fuel. A kind of very short interruption during accelaration. I guess i have to bring it back to porsche for a checking. Even fuel consumtion changed. Before the car tool arround 20-22 liters per 100 km. Now i even hit 24 - 25.

Thank you again

I know i know its already discussed many times the subject arround fuel pumps. I just would like to learn how exactly these parts are working.

As i know they just work TOGETHER under full load.

Can anybody tell me please if they are starting at a specific RPM or Speed or whatever. What means full load in this way?

Thank you very much

Think about the engine mounts please. How you describe the problem this could be the reason. After some years they get spoiled. Its a hydro system mount . You should even feel a difference of vibration in cold times like now or at summer times

By the way... What is the check valve line?

Strange, this really is sound of scored cylinder wall. Try to get better scope, to make picture with better quality. It's possibly, that we don't see scoring in your pictures. Did you do a compression test?

Thank you. Looks like this is the way how many miracle mistakes of this car can be found. Just by accident

RLHornbeck

...... Glad you found out . But how?

Thank you. If i get you right it doesnt have any impact to fuel pressure and driving behaviour of the car.

Many thankx again for your detailled information.

Great and thanks a lot.

One question left please. What is going to happen if you dont do this procedure after full pump replacement? I had a replacement of all parts at the shop some weeks ago.

Thank you