stutter and hesitation if fuel level above 1/4 tank!

[ybe]

25 minutes ago, lewisweller said:

Bad news in fact the better running lasted for two days only and then it all came back like some bad nightmare. 

I don't know what happened but I have some theories that the right side pump non return valve inside the pump is leaking the pressure off from the left pump or I got a pipe somewhere in there split or I'm totally wrong and it's nothing to do with the fuel. 

 

For the sake of ruling out all fuel related issues now and for the foreseeable future I own the car I have already bought a new right side pump which I will install on Wednesday as I'm trying to run the tank back down to empty nearly. 

 

I have new filter and regulator with flange gaskets a few months back. 

 

I found a great diagram from someone else's post about fuel pump issues. 

Notice the red line from each pump that joins before going to the filter, my theory is if the right side pump is not running (ie usual part load driving and not too low fuel level) and the check valve built inside is leaking, the pressure and flow from the left pump is bleeding off and doesn't deliver correctly to the engine. 

Possibly when I did the left pump swap I inadvertently mad ethereal check valve work for a little while and then it started leaking again. 

It's a far fetched but possible theory I have to eliminate now. 

 

The only other thing I can think of is the turbo breather pipe at the rear is leaking for sure but that little bit of air can't do all this sporadic running problems and an ok idle and high rpm rev with a stumble at around 1000 and 2000 rpm when stationary parked holding the rpm is just not making any sense. 

 

My mind has run through so many possibilities and I've probably read over 2000 posts and technical informations about everything A-Z. I'm so sick of reading a long thread which ends with.... "and then I read the very helpful DTC code and replaced the coils and all was fixed" ahhhhhhggg if only it was that simple for me. 

 

 

Often times when you replace the left fuel pump and drive around a few days and then symptoms return. It's usually because somewhere a long the line of the install something was hooked up incorrectly. Or maybe the right pump finally gave out altogether. Given your symptoms It is generally 5 things it could be. Fuel Pump/Valve related, MAF related, TPS, Camshaft/sensor related, Coils....

 

1st course of action should be making sure your right fuel pump is still functioning and before replacing make sure the left pump hoses are hooked up 100% correctly. As a matter of fact test your left fuel pump is functioning as well some aftermarket pumps have gave out 48 hours after installation.

Edited January 16, 2017 by ybe

[ekstroemtj]

Lewis as you remember i wrote about my fuel pump problems with my old CS.

the same here. Left side pump replaced because that was the diagnostic of my shop. Working not well. After some days i bring back the car. They replaced right side too and voila. Problems gone

[lewisweller]

2 hours ago, ybe said:

 

Often times when you replace the left fuel pump and drive around a few days and then symptoms return. It's usually because somewhere a long the line of the install something was hooked up incorrectly. Or maybe the right pump finally gave out altogether. Given your symptoms It is generally 5 things it could be. Fuel Pump/Valve related, MAF related, TPS, Camshaft/sensor related, Coils....

 

1st course of action should be making sure your right fuel pump is still functioning and before replacing make sure the left pump hoses are hooked up 100% correctly. As a matter of fact test your left fuel pump is functioning as well some aftermarket pumps have gave out 48 hours after installation.

I just went down to the car to check if it is actually running the left side pump (half tank of fuel still) just in case it failed but nope I pulled the fuse and it does die. Then cycled the ignition and started on right pump engine run the same ok idle as was on the left pump. 

I then replaced the left pump fuse and switched off again. 

Did the throttle reset sequence as this sometimes has by fluke or not made the car run better for a short time at least. But after restart its the same idle and has the same stumbling rpm at 1000 and around 2-2200 rpm. Its like at that particular rpm it vibrating more and doesn't sound happy or clean revving, I didnt go for a drive though. 

 

What I do notice is I have a lot more ticky almost direct injection diesel type rattle and tap, feeling the injectors rail there is what feels like more vibration than I would expect or can remember feeling before. Testament to low pressure quite possibly?

 

Also that tappy ticky noise is what I here at low rpm acceleration when it stumbling up through the rev range, pinking sound "pre detination" perhaps cause of the lean mixture. 

 

Anyway until I get the right pump replaced on wednesday and recheck all piping, I won't be able to rule out that as the cause. 

 

On hinds sight I should have gone to a garage a long time back and done a pressure test before going down this road. I'm pis*ed off I could not find the simple fittings here to make my own kit and could only find a whole kit that was the same cost as the two pumps anyway. Lesson learned! 

[lewisweller]

2 minutes ago, ekstroemtj said:

Lewis as you remember i wrote about my fuel pump problems with my old CS.

the same here. Left side pump replaced because that was the diagnostic of my shop. Working not well. After some days i bring back the car. They replaced right side too and voila. Problems gone

I hope so Thomas, I really do. 

[ybe]

1 hour ago, lewisweller said:

I just went down to the car to check if it is actually running the left side pump (half tank of fuel still) just in case it failed but nope I pulled the fuse and it does die. Then cycled the ignition and started on right pump engine run the same ok idle as was on the left pump. 

I then replaced the left pump fuse and switched off again. 

Did the throttle reset sequence as this sometimes has by fluke or not made the car run better for a short time at least. But after restart its the same idle and has the same stumbling rpm at 1000 and around 2-2200 rpm. Its like at that particular rpm it vibrating more and doesn't sound happy or clean revving, I didnt go for a drive though. 

 

What I do notice is I have a lot more ticky almost direct injection diesel type rattle and tap, feeling the injectors rail there is what feels like more vibration than I would expect or can remember feeling before. Testament to low pressure quite possibly?

 

Also that tappy ticky noise is what I here at low rpm acceleration when it stumbling up through the rev range, pinking sound "pre detination" perhaps cause of the lean mixture. 

 

Anyway until I get the right pump replaced on wednesday and recheck all piping, I won't be able to rule out that as the cause. 

 

On hinds sight I should have gone to a garage a long time back and done a pressure test before going down this road. I'm pis*ed off I could not find the simple fittings here to make my own kit and could only find a whole kit that was the same cost as the two pumps anyway. Lesson learned! 

 

I feel your pain man I'm going through the same. Mine runs on right side fuel pump fine. It seems like from what you are saying that your left fuel pump is not running at all so it is either a dud or something has been hooked up wrong. Make sure u recheck the work. A Hose(s) or ground may have came lose, hose may have been hooked up incorrectly or may have leak in right side hose as u indicate.  Don't forget there is a fuel check valve in the front of the engine as well that can cause similar issues. I think my issue is left fuel pump only since it will run almost normal with fuse 14 pulled. 

 

At this point sounds like process of elimination like with similar to mine recheck hoses replace right pump, replace check valve, replace MAF(s) in that order keep in mind I had these issues and Porsche dealer told me my car was fine then told me it was the MAF when it clearly wasn't other small indy shops couldn't figure it out either clueless techs

Edited January 16, 2017 by ybe

[lewisweller]

1 hour ago, ybe said:

 

I feel your pain man I'm going through the same. Mine runs on right side fuel pump fine. It seems like from what you are saying that your left fuel pump is not running at all so it is either a dud or something has been hooked up wrong. Make sure u recheck the work. A Hose(s) or ground may have came lose, hose may have been hooked up incorrectly or may have leak in right side hose as u indicate.  Don't forget there is a fuel check valve in the front of the engine as well that can cause similar issues. I think my issue is left fuel pump only since it will run almost normal with fuse 14 pulled. 

 

At this point sounds like process of elimination like with similar to mine recheck hoses replace right pump, replace check valve, replace MAF(s) in that order keep in mind I had these issues and Porsche dealer told me my car was fine then told me it was the MAF when it clearly wasn't other small indy shops couldn't figure it out either clueless techs

No my test means both pumps are running but not sure how well. 

Where is this check valve in the engine bay? I can't see anything there and nothing on any diagrams or parts mentioning this, I thought the only check valve is in the fuel filter and or the regulator? 

Edited January 16, 2017 by lewisweller

[ybe]

18 hours ago, lewisweller said:

12 hours ago, lewisweller said:

No my test means both pumps are running but not sure how well. 

Where is this check valve in the engine bay? I can't see anything there and nothing on any diagrams or parts mentioning this, I thought the only check valve is in the fuel filter and or the regulator? 

 

Oh ok I thought you said it does die when you pull fuse 14. It's not a check valve I think its a fuel purge valve something like that I'd have to find it but if you say your 2 fuel pumps seem to be working then yea check hoses replace the right side and if no solution it's probably your MAF which can cause the RPM fluctuation and other weird issues you are describing.

 

I'm no expert but after Fuel pumps/purge valve and MAF the only other things that I can think of over the years of everything I've read on Cayennes that can cause these symptoms would be the TPS/crankshaft position sensor or the camshaft pos sensor, or Battery either that or something is hooked up wrong or a new part is not functioning I know some Porsche techs recommend against using VDO also something to do with having to replace same part over and over

[lewisweller]

Right side pump installed and also inspected the tank, all pipes and all connection for any damage or mistakes. Fuel was quite warm and the rightside punp was hot. I really thought this was going to be golden.

Everything done properly started her up and........ It's the same!! Arrrgggghhb 

 

I don't know what else to look at now or what diagnostic to do without any direction to search. 

 

Just to list the ticked boxes for either service item, repair item found broke or just a waste of money maybe ....... in no particular order:

1. New mafs, air filters and oil changes every 7k km

2. New oem Divertor valves Bosch 710p

3. New fuel pumps, filter and regulator 

4. New 3 way check pcv valve 

5. New purge valve and gas cap

6. New n75 and change over valve with all pipes checked and some replaced.

7. Plenty of gaskets throttle body, intake/exhaust, turbo to IC, injector seals etc when both head gaskets was repalaced

8. New coils and plugs beru oem gapped at spec 0.8mm and 0.7mm with no improvement and now ngk iridium BRK7EIX with standard gap from factory 0.75mm

9. New Temperature sensor and oem Bosch bank 1 pre cat wide band lambda o2 sensor. 

10. New seals in valve covers around camshaft actuators 

11. New battery and alternator 

12. Engine earth and under seat battery and power distribution connections all cleaned and tight. 

13. Smoke tested intake for leaks many times. Checked all little vacuum check valves,  Cleaned map sensor, leak checked wastegates and other pipes. 

 

Only actual leak I can find is the turbo breather pipes at the back of engine. Seen in the image below and zoomed image. This leak is so small and would add minimal amount of air into the pc system I can belive it is the cause. Also why would the car sometime drive ok for a short time then back to usual rough stutter? 

 

It's something electrical it temperamental but don't know where to look? 

 

YBE you said crankshaft sensor and that's the first place I intend to investigate now. I am ruling out the camshaft sensors for now as it's effect is on both banks and not just one bank runs rough. Also the rpm roughness at 1000 and 2-2200 rpm is weirdly related to rotation speed but so is a lot of engine stuff. 

 

 Again no codes ever!

 

 

 

Edited January 17, 2017 by lewisweller

[ybe]

Yea next up would be the crankshaft sensor if u search around the forums u can probably find the guys posts went through much of what u did then finally changed the crankshaft sensor and solved it. He had similar symptoms.

 

I've also heard people throw around ignition switch causes wacky issues like this but not sure how wouldnt be my first place to look

 

Also keep in mind 1 of the aftermarket parts u installed just may not be functioning its happened before it's why some techs rule against 

[lewisweller]

4 hours ago, ybe said:

Yea next up would be the crankshaft sensor if u search around the forums u can probably find the guys posts went through much of what u did then finally changed the crankshaft sensor and solved it. He had similar symptoms.

 

I've also heard people throw around ignition switch causes wacky issues like this but not sure how wouldnt be my first place to look

 

Also keep in mind 1 of the aftermarket parts u installed just may not be functioning its happened before it's why some techs rule against 

Just had a look at the wire connection of the crankshaft sensor and it was cable tied together as the lock clip is broke. 

When I unplugged it it looks like the female side pump are looking wet or have some oil/wd40 in there (didn't show up on the picture though). I tried to blow it out and also warmed it with a lighter to try drying it but its not going, didnt have any electrical cleaner with me in the car park to spray it clean. 

 

Tomorrow will pull out the sensor and check it for dirt cracks loose magnet and resistance and go from there. 

[lewisweller]

Removed and tested th crankshaft position sensor. 

 

Pin 1&2 921 ohms.

Pin 1&3 open circuit 

Pin 1&2 when passing a spanner past the magnets produces a voltage varying random numbers. 

Don't have a scope to see the wave form unfortunately. 

 

Sensor no damage, a bit of dirt but nothing I can say is wrong with it. I gave it a little rub with soft scotch brite pad. Cleaner concnector and examined cable length for damage,......nothing. 

 

Loren please confirm if the ohms is correct? Also the voltage to the sensor I measured is 4.2vdc is this correct? I thought they use 5 vdc. 

 

If anything the car runs like crap more than previous days, I did a quick throttle reset when picking up my son and it was dog rough on the short drive home. Also the start up was laboured I hope not another battery failure. 

 

FYI every morning for just 5 mins it will run its best, once warm it's a turd the whole day. So frustrating I swear, I have so much patience but this is trying me hard . 

[ybe]

Man..... now I'm wondering If it's something that's simply being overlooked like those 'BERU' coils what brand are your MAFS?

[lewisweller]

8 minutes ago, ybe said:

Man..... now I'm wondering If it's something that's simply being overlooked like those 'BERU' coils what brand are your MAFS?

I'm thinking dme! 

Whats the chances? 

[ybe]

Yea I was going to mention it's possible but I know people have messed around with the dme/ecu to no avail or it was temporary fix worth a try I guess pretty much loss without code that's the hardest thing about Porsches the no code faults leaves you with nothing but a process of elimination.. it's why a lot of people get rid of them 

[lewisweller]

Ive been bashing the net all night and i remembered i had a code twice maybe thrice in the transmission module

dtc code 1314 dme control unit 

It cleared and didnt come back i thought maybe a sympton of the bad batterylies ive had and alternator. 

Reading more about this could mean infact dispite no dme codes there is an unlying issue not so apparent. 

I also read how conveniently the "crankshaft position sensor" could  throw this code. 

A guy with another porshe had a cps going bad only when hot, never when engine cold which is mine exactly. 

 

More conjecture, more throwing parts a philosophy i hate and more money maybe. At this stage how easy it is to remove it i may buy one off ebay for 50 bucks and do it. What i got to lose.....yeah i know 50 bucks and alittle more pride. 

 

Related or unrelated i have fluid leak from the transfer case ends i think. Also note shifts have become occasionally rough but could be the crap running engine doing that. 

[ybe]

Yea I'd go ahead and replace that next since it's one of the cheapest and seems like u accessed it pretty quickly one thing about the cps is that it will work intermittently when it goes bad. kinda like the fuel pumps. 

 

Another thing that comes to mind would be to check the AOS brain. And I also recall reading a rough running Cayenne story were the guy replaced a lot of parts and said something about it being the control arm bar the rubber gaskets they were brittle and eroded he replaced so check the rubber on your control arms for cracks, erosion you could probably find the post search around

[lewisweller]

51 minutes ago, ybe said:

Yea I'd go ahead and replace that next since it's one of the cheapest and seems like u accessed it pretty quickly one thing about the cps is that it will work intermittently when it goes bad. kinda like the fuel pumps. 

 

Another thing that comes to mind would be to check the AOS brain. And I also recall reading a rough running Cayenne story were the guy replaced a lot of parts and said something about it being the control arm bar the rubber gaskets they were brittle and eroded he replaced so check the rubber on your control arms for cracks, erosion you could probably find the post search around

Yep I already order one from us 52 dollars. 

 

I don't follow your email maybe some typos there? AOS yes I've had it out twice it isn't leaking or damaged. What was the other one? Control arm bars? 

[ekstroemtj]

Guys....

 

I had a interesting talk with a Cayenne driver whom i met by accident in the porsche shop when i picked up some parts. I try to explain our Problem as good as possible. His answer was: the behaviour oft the engine is 90% a Problem with the vario cam system. Solenoids or other parts which adjusting valve train working

 

[ekstroemtj]

.... as my camshaft sensors on the back of engine are new it has to be / must be the part which is sitting in front of the engine st the valve cover. Whats the name in english? Camshaft actuator? Camshaft solenoid? He told me there is one on each bank including a small filter. He bet if i change this parts my problems are gone.  

[ybe]

4 hours ago, lewisweller said:

Yep I already order one from us 52 dollars. 

 

I don't follow your email maybe some typos there? AOS yes I've had it out twice it isn't leaking or damaged. What was the other one? Control arm bars? 

 

Email?? Yes I believe it was the rubber seal/gasket peice that attaches the control arm bar to the engine it can crack basically loosening and can cause vibrations roughness and such but don't know If this is related to your problem but I'd check also since u been in doing 1000 other things anyway 

[lewisweller]

5 hours ago, ybe said:

 

Email?? Yes I believe it was the rubber seal/gasket peice that attaches the control arm bar to the engine it can crack basically loosening and can cause vibrations roughness and such but don't know If this is related to your problem but I'd check also since u been in doing 1000 other things anyway 

Sorry email was my typo lol. Fat finger and small keyboard on mobile great combo, not. 

 

The control arm is the engine torque arm bolted to the left valve cover and the inner wing. Its new as well. 

 

Thomas this filter is an interesting one. Anybody have a picture or any info on this blocking up and the symptoms of this? 

[ekstroemtj]

I was told the changing of the solenoid alone is not enough. It should be done with the filter. 

I will check the net for pics

 

[lewisweller]

Transfer case fluid drained only 550ml came out, should have been close to 1000ml. I refilled with new fluid. Seems to be working just fine except the leaking end seals. Cleaned it up for now. Note to self drain and change fluid every 6 months before it all leaks out. 

Also put the battery charger on as I'm paranoid about having a dead battery again especially as the Audi is still being repair in the body shop. 

The voltage was 12.57 before charging so battery seems OK for now anyway. But a quick charge couldn't hurt 

Edited January 19, 2017 by lewisweller

[lewisweller]

On 18/01/2017 at 5:21 PM, ybe said:

Man..... now I'm wondering If it's something that's simply being overlooked like those 'BERU' coils what brand are your MAFS?

All parts are oem or original brands Beru Bosch ngk etc 

[lewisweller]

Today I removed the TCU module and the DME module to check for bad connections corrosion and anything out of the ordinary. I also opened the dme to see if I had any dry joints or obviously failed components and if someone had put in a piggy back chip in there or something strange cos you never know! Also checked the wiring under the passenger seat and the foot well.

I found nothing that would suggest any issues. 

Whilst putting the dme back I cleaned the two earth point just behind it just for the hell of it as I was already there. 

Car started and drove Normal (by normal that's stutter for me). 

 

Been reading a lot recently maybe even a little obsessively........ But I came across some info on symptoms of the evap canister being fuel saturated and it got me thinking back to when I bought the car. 

(p0441 or something) purge valve faulty was the only code and the car ran ok except it needed some tlc plugs coils and air filter change regular stuff for 110,000km. It was down on power a bit but it didn't buck and stutter really. 

 

Now some background info which I need to give big prop to some guys on another forum who explained how and more importantly when the purge valve opens! 

After approx 55oC (warming engine, not cold take note, this is where I'm getting excited) the purge valve is opened allowing vapors from the evap canister to mix and burn during engine conditions when there is vaccum. So that's idle and part throttle to the point vaccum changes to virtually nothing and positive pressure comes in as boost on a turbo car for example.  

So given all that, if and this is the big if, the evap canister is for some reason some how fuel saturated the purge valve is allowing an abnormally rich mix of vapors in to the engine creating a overly rich mix and stutter that I feel at low rpm until boost has arrived and it clears to higher rpm just great.  

 

Now if the purge valve is broken it won't open so it can't add the rich vapors as it is normally closed without a power signal to tell it to open. 

 

So getting to the theory which I will test tomorrow by diconencting the purge valve. My hypothesis is the previously failed purge valve and possibly the frequent habit off topping the tank after the first click which here in dubai the pump attendants do all the time to reach a higher whole number, has saturated the evap canister maybe?? 

 

This may also explain the intermittent issue it runs ok when hot occasionally and some weird times when the tank is low it seems to be running ok but never has it ran well after filling the tank or with a relatively high fuel level half way or above. 

 

Experience of this on the Web is very minimal but if anyone has some info or first hand experience of this please reply. 

 

Tomorrow I will run the morning from cold start with the purge valve power plug disconnected. I have less than 1/4 tank so I will also be filling it up to see what happens after filling all the time the purge valve will be disconnected. 

 

Crankshaft position sensor is still waiting despatch from US so I got some days to kill until that job. 

 

Pray to the automotive gods this is going somewhere.........