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Hi there, my cayenne won't drive as long i have the relay placed at 1/6 (the 404 relais) functioning. Once I take it out the car runs perfectly on one pump but once I put it back in the car stops working although I hear both fuel pumps working.  What to do?

Thanks for your response.

relay post-1-090362600%201285002042.png

relais phpy9MS4FAM.jpg

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2 hours ago, ralphro said:

Hi there, my cayenne won't drive as long i have the relay placed at 1/6 (the 404 relais) functioning. Once I take it out the car runs perfectly on one pump but once I put it back in the car stops working although I hear both fuel pumps working.  What to do?

Thanks for your response.

relay post-1-090362600%201285002042.png

relais phpy9MS4FAM.jpg

404 is one of the fuel pump relays I guess the one you pulled was the left primary. FYI fuse 13 is left pump and fuse 14 is right side pump both 15 amp. 

The system uses the left driver side pump as the "primary pump" this pump is likely dead or a fuel line is broke between the pump and the fuel filter or something else strange is going on. Anyone been in there for any work? Previous related service history, model and mileage is helpful.  

 

Removing the fuse and/or relay automatically makes the other pump run on the right passenger side (assuming left hand drive). 

I bet if you had a low fuel level it would run with the both fuses and relays connected this is because below a certain fuel level both pumps run. Somewhere below 1/4 tank and the fuel light coming on both pumps will be running. 

 

So verdict is either a pump problem or associated component of the pump is the problem. One guy replaced his pumps and got some fuel pipes squashed, another connected the pipes wrong somehow, another guy had cracked pipes which only broke when he installed new pumps and that threw him off until he stripped it all out again. 

 

Of course do your Diagnostics to confirm this before spending out. 

Might be an opportune time to do some other service items like full filter and regulator as a dead pump would mean it done some service life already I'm guessing. 

Don't forget 2 new rubber Seals or you will regret it. 

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On 5 December 2016 at 5:56 PM, ralphro said:

Thanks Lewis, this is helpful!

Any update on this? 

 

Thomas is going to be wondering as well, he seems to have a dead primary pump judging by his email to me. 

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This afternoon i checked the fuses because i dont here this grinding noise when i open the drivers side door.

i pull out fuse 13 and the car started and run

i pull out fuse 14 and the car died after some seconds

 

fuel level about 3/4 full

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On 12/5/2016 at 9:48 AM, lewisweller said:

404 is one of the fuel pump relays I guess the one you pulled was the left primary. FYI fuse 13 is left pump and fuse 14 is right side pump both 15 amp. 

The system uses the left driver side pump as the "primary pump" this pump is likely dead or a fuel line is broke between the pump and the fuel filter or something else strange is going on. Anyone been in there for any work? Previous related service history, model and mileage is helpful.  

 

Removing the fuse and/or relay automatically makes the other pump run on the right passenger side (assuming left hand drive). 

I bet if you had a low fuel level it would run with the both fuses and relays connected this is because below a certain fuel level both pumps run. Somewhere below 1/4 tank and the fuel light coming on both pumps will be running. 

 

So verdict is either a pump problem or associated component of the pump is the problem. One guy replaced his pumps and got some fuel pipes squashed, another connected the pipes wrong somehow, another guy had cracked pipes which only broke when he installed new pumps and that threw him off until he stripped it all out again. 

 

Of course do your Diagnostics to confirm this before spending out. 

Might be an opportune time to do some other service items like full filter and regulator as a dead pump would mean it done some service life already I'm guessing. 

Don't forget 2 new rubber Seals or you will regret it. 

 

Are you sure you don't have fuses mixed up? I'm currently on 1 pump in my CS with fuse 14 pulled and can hear the right side pump running/whinning when the car is on. I think Fuse #14 is for the driver side pump and #13 is the right pass side pump, but feel free to correct me If I'm wrong USA

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12 hours ago, ybe said:

 

Are you sure you don't have fuses mixed up? I'm currently on 1 pump in my CS with fuse 14 pulled and can hear the right side pump running/whinning when the car is on. I think Fuse #14 is for the driver side pump and #13 is the right pass side pump, but feel free to correct me If I'm wrong USA

Sorry my bad. You are correct 14 is left pump primary, 13 is right pump secondary. 

IMG_20161222_083312.png

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Just been for drive after removing and disassembling my throttle body and doing a full internal clean of the motor and sweeping variable resistor tracks and contacts.  I couldn't find anything wrong with the throttle body. 

 

Put all back together and went for drive after doing a reset. All OK but stutter still there no different to before, didn't hear that whine noise though so maybe it fixed something? 

 

So I thought OK back to the possibility of a faulty fuel pump (still no codes fyi). I pulled in a layby and pulled out fuse 14 left pump and the car died which is not right. It should have kicked in the rightside pump automatically. 

So I'm left with the prognosis that either the relay is faulty, there is a cabling problem or the right side pump is dead!!!

I have removed the fuse before and the car ran on either pump I'm sure a few months ago. Maybe the pump was failing but still worked so hence I wasn't any the wiser. 

Note the filter and regulator are new and the fuse 13 is OK for right side pump. 

 

I think tomorrow I will be buying the vdo right side pump and fitting it if swapping the relay of left pump to the right pump doesn't make it work. 

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Scrap the above. I missed a key piece of info which I found on another forum, the fuel pump will not auto switch from left to right or visa versa. You have to cycle the ignition off and on with one of fuses out to get the other pump to run. Duh brain. 

Anyway did the test again today and been running on the right pump only, no change to running stutter symptoms. 

So I'm Barking up the wrong tree. To be sure that my pump are working correctly I still need to make up a pressure test kit. 

 

Sherlock Holmes said ilminate everything possible and what your left with must be the cause. 

This could take some time ...............

Edited by lewisweller

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If you pulled fuse 14 and your vehicle died then your left/Driver side fuel pump is dead. I'm in the same boat. I use to have cut out on acceleration and stuttering problems all kinds of issues than read up on it and discovered my driver side fuel pump was dead after pulling fuse. Even Porsche dealer did not figure it out and told me it was the MAF and tried to charge me 2800 to fix! There is no telling how long I had been driving on 1 pump with the main pump either partially running or dead but I'd say it's been at least 6 months to a year. Plan to fix it next week.

 

The thing that had me fooled was my PIG would drive fine for about an hour until the pump warmed up then it was start acting crazy upon accel cutting in and out and such so it can appear as If your pump is running correctly when it's not 

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7 hours ago, ybe said:

If you pulled fuse 14 and your vehicle died then your left/Driver side fuel pump is dead. I'm in the same boat. I use to have cut out on acceleration and stuttering problems all kinds of issues than read up on it and discovered my driver side fuel pump was dead after pulling fuse. Even Porsche dealer did not figure it out and told me it was the MAF and tried to charge me 2800 to fix! There is no telling how long I had been driving on 1 pump with the main pump either partially running or dead but I'd say it's been at least 6 months to a year. Plan to fix it next week.

 

The thing that had me fooled was my PIG would drive fine for about an hour until the pump warmed up then it was start acting crazy upon accel cutting in and out and such so it can appear as If your pump is running correctly when it's not 

YBE essentially I'm on the same possible prognosis that the pump actually seems to work when the engine is cold has some enrichment to cover up the lower fuel pressure delivery. But depending on your ambient temperature this quickly warms up and the stutter is felt. As I'm here in the middle east all summer the car basic never got less than 40oc temp even over night so cold starts are virtually none, the winter comes now and 20oc is lowest so I do get some small window of warm up 5 mins max to drive the car and feel it does pull almost clean and perfect, but before I get out of my community it already misfiring for the rest of the day. 

 

My issue is slightly different to yours in the fact both the pumps work. But both the pumps don't deliver enough pressure when warm. Fuel heating is one of the things Porsche tried to mitigate against by having two pump which don't always run togther but only when required like in high prolonged flow and or low fuel level to ensure both side of tank drain equally to empty. 

I'm still to do the fuel pressure and flow test. 

Flow I belive is OK because you would have the stutter at high rpm wot. Pressure related issues highlight at pick up, acceleration and dripping back to idle after injectors are shut and then open to hold the idle after lift off. 

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Two days I Searched this whole useless town for M16 or Schrader valve adaptor fittings to make a fuel pressure testing kit and totally frustrated to find nothing will work. Should have ordered a kit online I guess but wtf this isn't even any complicated fittings. 

I'm tired of this s**t now and the car is running terrible (i mean like a total dog , so lean I'm thinking it might melt a piston) and still no codes at all, unbelievable, OBD11 where are you now #*;/*+-==+*/!*(+--=    ?????

 

F**k it, New Vdo left side primary pump is in the boot ready to fit tomorrow. Paying 200 dollars for my sanity was cheap. 

 

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On 9.1.2017 at 9:16 PM, ybe said:

 

The thing that had me fooled was my PIG would drive fine for about an hour until the pump warmed up then it was start acting crazy upon accel cutting in and out and such so it can appear as If your pump is running correctly when it's not 

 

Thats why experts say we have to avoid driving on high RPM with a low fuel level. Fuel is cooling the pumps. Low fuel level, higher temps and stress for the pumps.

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Lewis how much you pay for your pump? AS i remember the Touareg is using the same. Its about 85 Eur.

 

By the way, somebody knew how much pressure / bar they deliver and how much Liter per hour? Thank you

Edited by ekstroemtj
Mistake

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27 minutes ago, ekstroemtj said:

Lewis how much you pay for your pump? AS i remember the Touareg is using the same. Its about 85 Eur.

 

By the way, somebody knew how much pressure / bar they deliver and how much Liter per hour? Thank you

The pump is from vdo they are the oem manufacturer without the Porsche or vw price tag for the same pump inside the box. I paid 740 dhs which is 144 euros. 

It's so hot here I think both my pumps are just knackered and don't deliver the correct pressure and maybe volume too. 

 

The specification says each pump individually 58psi or 4bar pressure at idle and flow of 800ml after 15seconds equivalent to 3.2 litres per minute. 

 

I wish I could test the pump to really prove if the pressure is down but I lost patients with trying to find the fittings and the cost of special fittings here is half the pump cost anyway, so pointless to fight it any longer. 

 

Tomorrow we shall know all about the left pump if bad or not. 

 

FYI both pumps work but the car runs crappie on either or both which ever way meaning neither are in spec anymore. But as the left pump is only required to provide the pressure and flow and the right is to transfer fuel from the right side and for a back up then for now I just need one pump the left to fix the problem.

 

Remember my other post I started saying the car ran on sometimes on less than 1/4 tank?? Well maybe I wasn't going crazy as the right pump was kicking in to cover the lack of pressure from the left pump and just enough to cover the poor running. That was 3 months ago and now I think pumps are finally f**ked. 

 

If the right pump was not working then I would be replacing both pumps for sure (may do it in the near future anyway for peace of mind) or you can't run under 1/4 tank without running out of fuel unexpectedly). 

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47 minutes ago, ekstroemtj said:

Lewis how much you pay for your pump? AS i remember the Touareg is using the same. Its about 85 Eur.

 

By the way, somebody knew how much pressure / bar they deliver and how much Liter per hour? Thank you

The pump is from vdo they are the oem manufacturer without the Porsche or vw price tag for the same pump inside the box. I paid 740 dhs which is 144 euros. 

It's so hot here I think both my pumps are just knackered and don't deliver the correct pressure and maybe volume too. 

 

The specification says each pump individually 58psi or 4bar pressure at idle and flow of 800ml after 15seconds equivalent to 3.2 litres per minute. 

 

I wish I could test the pump to really prove if the pressure is down but I lost patients with trying to find the fittings and the cost of special fittings here is half the pump cost anyway, so pointless to fight it any longer. 

 

Tomorrow we shall know all about the left pump if bad or not. 

 

FYI both pumps work but the car runs crappie on either or both which ever way meaning neither are in spec anymore. But as the left pump is only required to provide the pressure and flow and the right is to transfer fuel from the right side and for a back up then for now I just need one pump the left to fix the problem.

 

Remember my other post I started saying the car ran good sometimes on less than 1/4 tank?? Well maybe I wasn't going crazy as the right pump was kicking in to cover the lack of pressure from the left pump and just enough to cover the poor running. That was 3 months ago and now I think pumps are finally f**ked. 

 

If the right pump was not working then I would be replacing both pumps for sure (may do it in the near future anyway for peace of mind) or you can't run under 1/4 tank without running out of fuel unexpectedly). 

Edited by lewisweller

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I did the regulator and fuel filter replacement already, also vdo brand I used which had the vw toureg part numbers "erased" from the top Covers and the invoiced used the porsche part numbers. Lol some dealer service type parts are a real scam to the unwitting owner. 

 

6psi ? Not sure where that info came from but thats not enough pressure to wash your hands well under a tap. 

 

58psi or 4 bar came from the workshop manual. And also 3 bar after 10 mins and 2 bar after 1 hour it should hold in the line after the ignition is switched off (this checks that the non-return valve is working to stop the fuel draining back to the tank causing longer cranking times in certain circumstances). 

 

Screenshot_20170113-094537.png

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3 hours ago, ekstroemtj said:

I mean 6 bar. Sorry

IMG_5839.PNG

I think that is a pump max pressure as opposed to the operational pressure. 

Would be good if someone can post the measure pressure of a tested good condition system?? Pls 

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i am just a bit confused because my general understanding is the Cayenne and Touareg pumps are the same.

now when searching for parts a read the Touareg pumps have 4 bar and the Cayennne have 6 bar

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1 hour ago, ekstroemtj said:

 

It fixed ......almost :)

 

This is my old and new left side pump. Both are vdo but the new pump part numbers and vw audi logo are scratched off. This is not the original pump either as it dated 21/10/10! So this is the third pump at least. 

 

The car runs soooo much better I would say 85-90% Fixed the bad running. Hooray. :)

Still have some small roughness and the idle Dip is still there. 

I'm trying to research the actual true function and sequence for the pumps running to determine if the right side pump could affect the fuel delivery even if not running when the tank level is above 1/2 tank for example and the left primary pump is solely running. 

Does anyone know the answer to this conundrum? Ie if under hard acceleration does the second pump cut in quickly or is it possible it is faulty and allowing the pressure and flow from the left pump to bleed / leak off??

 

Another theory I have is the possibility the injectors are blocked a small amount, this was maybe exacerbated by the low fuel pressure previously. I have run a few bottles of cleaner through before some months ago with no change. 

 

I think if someone drove the car they might not notice anything is wrong and maybe for a 11 year old twin turbo car I am expecting too much and too smoother power delivery and running. I don't know as I have never driven a cayenne turbo before to compare it to. 

 

IMG_20170113_1204264.jpg

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IMG_20170113_1203569.jpg

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