'08 Cayenne Turbo starts normally but dies after 5-10 seconds

[pilhaus]

Hello to all,

 

I was a happy Porsche owner only for couple of days until problems started after buying the car. As the title says, car starts but dies after running a short while. The car has been staying now on a local Porsche mechanic but so far (imo) the original problem has not been found. As the car was attached the first time to Durametric, of course no fault codes were caught. Typical problem (we both thought), fuel pumps in the tank should be changed. So those were replaced with original VDO pumps.

But the problem stayed. Next reasonable action was to change the HPF pump. That was replaced with 1 year guarantee spare part, so it should be okay.

But same sh#t continued. Except the mechanic was able to run the car couple of days ago like 5 kilometers without any problems. Until he tryed to start the car again. This is what I  also experienced when the symptoms started, car needed maybe 2-3 cranks and then it kept running totally fine. So car hasn't stalled even once when driving, only soon after starting.

Lot of writing already (sorry for that, hope someone still keeps on reading) but so far only thing what has been found is that something stops the fuel pumps. Relays for fuel tank pumps have been bypassed, no problem with those. Durametric shows getting fuel pressure until pumps stop so fuel pressure should be okay. Ecu gets the 'running bit' so it doesn't stop the pumps.

 

So finally the question, what next? I'm not willing to spend any more money to change even a single fuse without some guarantee that it will fix the car. I've been digging forums like hell and of course I have found some good guesses of similar cases with bad fuel problem, MAF problem, fuel pressure valve problems, camshaft sensor problems etc. And according to seller, he didn't suffer from this problem. Maybe he lied, maybe not but at least he didn't know anything about cars. Or he was just a freakin' good actor.

 

And final words so far, when I last time drove the car (when it stayed running), it run totally normal. There was no lack of power, it idled smoothly etc.

 

Good ideas are very welcome.

Thanks beforehand.

 

Ps. And whenever the problem is solved (with Your help or not), I'll promise to post the solution here. ;)

Edited August 27, 2016 by pilhaus

[phollero]

I would check your battery terminal connections as well as the ground to the chassis under the driver's seat. They must be tight and clean free of corrosion.  

[lewisweller]

8 hours ago, pilhaus said:

Hello to all,

 

I was a happy Porsche owner only for couple of days until problems started after buying the car. As the title says, car starts but dies after running a short while. The car has been staying now on a local Porsche mechanic but so far (imo) the original problem has not been found. As the car was attached the first time to Durametric, of course no fault codes were caught. Typical problem (we both thought), fuel pumps in the tank should be changed. So those were replaced with original VDO pumps.

But the problem stayed. Next reasonable action was to change the HPF pump. That was replaced with 1 year guarantee spare part, so it should be okay.

But same sh#t continued. Except the mechanic was able to run the car couple of days ago like 5 kilometers without any problems. Until he tryed to start the car again. This is what I  also experienced when the symptoms started, car needed maybe 2-3 cranks and then it kept running totally fine. So car hasn't stalled even once when driving, only soon after starting.

Lot of writing already (sorry for that, hope someone still keeps on reading) but so far only thing what has been found is that something stops the fuel pumps. Relays for fuel tank pumps have been bypassed, no problem with those. Durametric shows getting fuel pressure until pumps stop so fuel pressure should be okay. Ecu gets the 'running bit' so it doesn't stop the pumps.

 

So finally the question, what next? I'm not willing to spend any more money to change even a single fuse without some guarantee that it will fix the car. I've been digging forums like hell and of course I have found some good guesses of similar cases with bad fuel problem, MAF problem, fuel pressure valve problems, camshaft sensor problems etc. And according to seller, he didn't suffer from this problem. Maybe he lied, maybe not but at least he didn't know anything about cars. Or he was just a freakin' good actor.

 

And final words so far, when I last time drove the car (when it stayed running), it run totally normal. There was no lack of power, it idled smoothly etc.

 

Good ideas are very welcome.

Thanks beforehand.

 

Ps. And whenever the problem is solved (with Your help or not), I'll promise to post the solution here. ;)

Hello and welcome to the cayenne club........

Firstly does sound like fuel related, assuming the NEW pump(s) are not faulty there is also a possibility the many fuel pipes in the tank can be split and leaking on the straight or elbows fitting. Also you do not mention the filter and regulator were replaced? Also suspicious of those two components for this problem. Regulator will increase cranking time, filter can be very clogged and intermittently blog up flow. 

On the touareg forum one guy had a bad earth wire between the ECU and the primary fuel pump left side (driver side if left hand drive). The cayenne will run both pumps on start up then switch to the "primary pump" after 5 seconds unless fuel tank is nearly empty then both pumps run all the time. Whats the fuel level?

 

Also possible is evap blockage or tank ventilation problem. Try removing fuel cap and start the car, and try starting the car and then remove the fuel cap and see if make any difference. 

 

Lastly the fuel maybe a total red herring and this is a sensor problem which is not showing any fault codes. Like maf sensor, o2 sensor, crank cam position sensors etc .......the list is long.  

 

Unplug the the maf's and try starting it. 

 

[pilhaus]

Phollero and Lewis, thanks for quick answers. Good points and good ideas.

 

Some more information and answers... When the 'turd started to hit the fan' first time for me, I had to crank maybe 2-3 times until it stayed running. Fuel tank level was showing about 1/4 level (range less than 200km). I drove to the gas station and filled it up full. After that, no problems within next 400 kms, car run perfect. Symptoms started again when fuel level reached around that 1/4 level. Actually it went so bad that when I finally got it running, I drove straight to this mechanic who has Durametric... I had to left the car there because after fault code reading, car didn't want to co-operate any more to drive back to home. After all (and behavior how it worked) the mechanic also was willing to try to fill the tank so now the fuel level is about half tank.

 

Battery connections and ground connections have to be checked, that's definitely the first thing where to continue.

Still my engineer mind wants to rule out some of the ideas... And please correct me if my thinking follows the wrong road...

- blocked fuel filter / regulator --> nope, they either work or not, those are mechanical things anyway. Cranking time hasn't increased and when it runs, idling is totally normal. Those were also not changed with the pumps, maybe need to be changed still...

- evap blockage --> my opinion no, if there's a blockage, it stays and doesn't go away by itself

- tank ventilation --> fuel cap has been removed, didn't affect anything

- MAF problem --> hmmm... after all, big maybe... odometer shows around 131tkms, so maybe the MAF's are coming to their end --> at least cheap and worth to try to start without MAF's

- fuel problem is totally bluff (red herring) --> the fuel problem is actually the way what has been followed so far, maybe it's time to open the mind more and think also some other faulty sensors etc. But as a question; if you have e.g. a faulty camshaft sensor, can it work every now and then? Shouldn't it at least give some fault code at some point related to timing etc.?

 

I'll let you know when things go forward on this.

 

[lewisweller]

11 hours ago, pilhaus said:

Phollero and Lewis, thanks for quick answers. Good points and good ideas.

 

Some more information and answers... When the 'turd started to hit the fan' first time for me, I had to crank maybe 2-3 times until it stayed running. Fuel tank level was showing about 1/4 level (range less than 200km). I drove to the gas station and filled it up full. After that, no problems within next 400 kms, car run perfect. Symptoms started again when fuel level reached around that 1/4 level. Actually it went so bad that when I finally got it running, I drove straight to this mechanic who has Durametric... I had to left the car there because after fault code reading, car didn't want to co-operate any more to drive back to home. After all (and behavior how it worked) the mechanic also was willing to try to fill the tank so now the fuel level is about half tank.

 

Battery connections and ground connections have to be checked, that's definitely the first thing where to continue.

Still my engineer mind wants to rule out some of the ideas... And please correct me if my thinking follows the wrong road...

- blocked fuel filter / regulator --> nope, they either work or not, those are mechanical things anyway. Cranking time hasn't increased and when it runs, idling is totally normal. Those were also not changed with the pumps, maybe need to be changed still...

- evap blockage --> my opinion no, if there's a blockage, it stays and doesn't go away by itself

- tank ventilation --> fuel cap has been removed, didn't affect anything

- MAF problem --> hmmm... after all, big maybe... odometer shows around 131tkms, so maybe the MAF's are coming to their end --> at least cheap and worth to try to start without MAF's

- fuel problem is totally bluff (red herring) --> the fuel problem is actually the way what has been followed so far, maybe it's time to open the mind more and think also some other faulty sensors etc. But as a question; if you have e.g. a faulty camshaft sensor, can it work every now and then? Shouldn't it at least give some fault code at some point related to timing etc.?

 

I'll let you know when things go forward on this.

 

Yes a lot of questions, myself and a few other members have been trying to track down our own separate issues which involved fuel, vacuum and sensors. 

Fuel filter and regulator issue are not necessarily an on or off type of possible failure. Definitely don't rule them out. 

 

This 1/4 tank situation is very interesting and I would definitely open both side and inspect the pipes for twisting, cracks leaks etc. One guy had a cracked pipe which transfers the fuel from right side pump to left side connector before going into the filter. He had similar issues it would run Ok then have issues stall depending on fuel level and which pump(s) was running.  

Another, link below, is for the driver side pump "primary pump", definitely check the new pump is working properly and that all those pesky pipes are not kinked or split. 

http://forums.vwvortex.com/showthread.php?5432546-04-Touareg-runs-for-about-10-secs-and-dies#/topics/5432546?_k=qjgisg

Edited August 28, 2016 by lewisweller
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[pilhaus]

Finally I had time to post a solution to my problem what was fixed like 2 months ago.

Here's a short story how everything went:

- both tank pumps were changed --> car worked normally couple of runs, then same s#¤t started again

- HPF pump was changed, luckily I found a spare part with 1 one year guarantee --> no help at all to original issue.

At this moment I lost me patience and changed the repair shop... Another shop started to investigate the problem.

Soon I got a phone call from the second workshop and I was explained that everything points to the fact that DME (ecu) is broken.

New DME unit at local Porsche dealers costs here in Finland around 3k€ and you need also 1 hour PIWIS time to copy the original sw for it.

Anyhow, I was not willing to pay that money for it especially if the problem is not there, you can't return the DME card to dealer. It's a single-use.

So the original DME unit was sent to some other workshop that fixes the cards. After 2 weeks got the unit back and they didn't basically find anything else

except couple of bad soldered joints... Meanwhile I had had discussions with my friends about the problem and also with the owner of the first repair shop

and solution might be to install some extra relay and take some 'juice' for it behind the ignition. The original problem anyways was that the tank pumps

loose the current. I proposed this to the second workshop and they started to investigate how this could be done...

 

And then the original problem was finally found. Behind the relay/fuse panel in engine room there was found an extra immobilizer with some extra relays.

After removing the relays and immobilizer and fixing the connections, car fired up and stayed  running without any problems. And has worked ever since

'like a buick'. The original idea to put another immobilizer to the car was probably good (try to steel this car you fools) but no one thought what

this might cause in the future.

[lewisweller]

2 hours ago, pilhaus said:

Finally I had time to post a solution to my problem what was fixed like 2 months ago.

Here's a short story how everything went:

- both tank pumps were changed --> car worked normally couple of runs, then same s#¤t started again

- HPF pump was changed, luckily I found a spare part with 1 one year guarantee --> no help at all to original issue.

At this moment I lost me patience and changed the repair shop... Another shop started to investigate the problem.

Soon I got a phone call from the second workshop and I was explained that everything points to the fact that DME (ecu) is broken.

New DME unit at local Porsche dealers costs here in Finland around 3k€ and you need also 1 hour PIWIS time to copy the original sw for it.

Anyhow, I was not willing to pay that money for it especially if the problem is not there, you can't return the DME card to dealer. It's a single-use.

So the original DME unit was sent to some other workshop that fixes the cards. After 2 weeks got the unit back and they didn't basically find anything else

except couple of bad soldered joints... Meanwhile I had had discussions with my friends about the problem and also with the owner of the first repair shop

and solution might be to install some extra relay and take some 'juice' for it behind the ignition. The original problem anyways was that the tank pumps

loose the current. I proposed this to the second workshop and they started to investigate how this could be done...

 

And then the original problem was finally found. Behind the relay/fuse panel in engine room there was found an extra immobilizer with some extra relays.

After removing the relays and immobilizer and fixing the connections, car fired up and stayed  running without any problems. And has worked ever since

'like a buick'. The original idea to put another immobilizer to the car was probably good (try to steel this car you fools) but no one thought what

this might cause in the future.

Well blow me, great find that one. Well done for persevering and updating the forum. 

Normally an immobiliser issue prevents starting but to have it start and run then cut out would throw off even the best auto technician. Big Props.