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

[ekstroemtj]

I fixed the wiring with some special glue but i would prefer to replace this entire connection. Can find it in a parts diagram. Maybe somebody can help please.

[lewisweller]

16 hours ago, ekstroemtj said:

I fixed the wiring with some special glue but i would prefer to replace this entire connection. Can find it in a parts diagram. Maybe somebody can help please.

Hi Thomas

Saw your email.

I think this is the whole Wiring Loom and not a single part you can buy new. See picture either its the Green circle or less likely the red circle hard to tell really from this no descript diagram.

I would try to find the connector with some cable and solder to the existing wires and heat shrink wrap it. Will cost only a few Euro and good as new as long as you solder it well and heat shrink it properly.

 

This Bosch diesel injector connector looks similar to it? Some searching I bet you can find one. 

http://www.ebay.co.uk/itm/1-x-Diesel-Injector-Plug-Electrical-Connector-Pre-Wired-for-Vauxhall-Vivaro-/121347938121

Edited February 27, 2017 by lewisweller

[ekstroemtj]

@ Lewis

 

Thank you very much. Actually if i was a little bit more handy i could fix it but ...

i will see what i can do. The wire is broken and the one end which is inside the connector is so short. Difficult to connect. 

I will check ebay for a similar part . 

[lewisweller]

Bank 2 precat lambda sensor arrived today will be fitting tomorrow but not getting my hopes up this is the final cure. 

I'm also going back to basic of the cayenne engine and looking for leaks again. 

Inlet manifold will be coming off and will cut out those leaking rigid pipes at the back the turbo vent. I know they don't leak a physical amount of measurable air on the grand scheme of things so the chances of it being the cause of hesitation is remotely slim. 

Maybe I find a crack in the manifold or something drastic! What ever it is, it affects both banks and makes it run lean when warm / hot engine temps is all I know for sure. I did a propane test and can see both sensors show rich, then rev and both go lean. If not this, im back to dme or fuel delivery issues which is baffling me. 

Not to mention fuel trim numbers which look to goo to be true maybe? Stft 2.9 0.8 ltft 0.8 1. I think this is because at idle and cruise I have good mixture lambda 1 is showing on both banks but during acceleration or load with Fix throttle position ie going up slope is when you will fell it shudder stutter and hesitation. 

No codes ...............  : (

Edited March 3, 2017 by lewisweller

[lewisweller]

Busy day planned today. 

First will be changing the bank 2 precat  sensor and front differential oil for redline heavy shock to try and quiet down that noisy bearing at some speeds I can hear and hopefully extend its life for many more 1,000's km as I don't want it to break one day. 

Then will have a test to see if the bank 2 sensor replacement has any positive results.

Following that I also have redline D4 atf fluid for the transfer case. The reason I'm going to change this again three reasons:

1. The current fluid is Toyota type iv which may or may not be exactly as per the transfer case spec it's highly debatable, but the D4 is the same spec as the esso 71... fluid spec Porsche recommends. 

2. Noticed the transfer case leaks are worse and maybe could be caused by the fluid change or type can't be sure. 

3. The transfer case on the cayenne and other vehicles ie BMW x3 has been reported for problems related to hesitation or drive related issues so going back to the spec'd fluid is the baseline idea. The random "faulty four wheel drive" warning also showed itself for the first time shortly after all fluids was replaced following head gaskets work but this also was the same time the temperature here increased considerably. So unsure if related or not to fluid type. 

 

Another line of thought is some Porsche and other brands suffer with crankshaft position sensor proximity to the crank Wheel and the Fix was to use a small spacer to give a little extra air gap and thus "clean up" the wave signal and make the dme a lot more happy with the info received and processed for all critical engine functions. 

As the cps is so easy to access and takes 5 mins to put a thin card spacer in, its something I may as well experiment with. 

 

The last thing on my radar is this exhaustive thread ( below) for VARIOCAM "bump" non smooth transition of the cam phasing which is plaguing other Porsche models and the symptoms they have are nearly exactly like what I have. This thread is so long I haven't got to the end yet!

And yes the newer model have "variocam plus" valve lift adjustment and inlet cam adjustment) but they still feature the use of inlet cam advancement just like the cayenne. 

So even though I did test the variocam confirming it is working so to speak, it may not be Switching smoothly or at the correct time to produce a smooth power transition and thus the stutter hesitation and also the feeling of roughness when deaccelerating down to lower speeds and rpm just like the engines in the post experience. Idle dip may or may not be associated I'm not sure. 

Some people think it could be software related as they have nearly brand new cars but on the cayenne it's more likely a oil/mechanical or electrical / mechanical issue like blockages for oil flow/pressure through small orifices in actuator, oil viscosity vs older engine, cam actuator getting hot and malfunctioning, the cam phasing/timing chain stretched/worn. 

Many questions and not so many answers ..........

 

Has anybody had or found any issue with the variocam on their cayenne? 

 

http://www.6speedonline.com/forums/991/300360-engine-stumble-hesitation-around-2500-rpm-8.html

[ekstroemtj]

Busy day Lewis. I hope all this work will improve the handling of your beast. The note you put here to share with us the insight of your technical skills always top. Thank you

[lewisweller]

Transfer case fluid changed from Toyota type iv to redline D4, as of yet not seen the four wheel drive faulty warning but I'm sure it will appear sometime soon as it not related to the fluid by all accounts it the software on 06 models and the stepper motor actuator and software on older cayenne. 

 

The bank 2 precat new lambda sensor also fitted (much more trick than the passenger side accessed from underneath and squeezed my cut and bruised arm passed the pipes and stuff in the way) had to heat up and bend the 22mm spanner about 15degrees I reckon.

 

 Battery disconnected for about 2 hours total. Did a throttle reset and let idle for 10 mins. Driving no real changes stutter is still prevalent. If I was being generous I would say it is marginally smoother around the other rpm's but definitely not the cure to this saga. 

 

Next job except the front differential oil swap which I wait until oil change is due, will be to experiment with crankshaft position sensor spacers! 

Also I may take the manifold off and fix the vent pipe at the rear and recheck for other vac leaks etc. Running out of ideas. 

[ekstroemtj]

If anybody ever going through the same problem. The purge valve wiring/connector failed because the wiring became briggle.  There is a chance not to buy the entire wire. The connector is available from Bosch for 6.50. 

[lewisweller]

Took of the manifold today looking for leaks and found nothing. Tested all the check valves and pipes even replaced the DV pipe from changeover valve just in case it was a bit squashed. I even added a smear of gasket sealer before reinstalling the manifold of course with green gaskets which are still like new from a 8 months ago. Looking inside the valves all look OK no real gunk or build up, can't see any chips or cracked valves from back side . Looked at injector nozzles each one has four little holes and all looked cleaned, each injector tested for 12.5 ohms resistance. 

 

That rigid metal turbo vent lines which are obviously leaking some oily yuk is so difficult to fix, I thought about cutting it out but would need to straddle the engine and I'm not exactly a small guy. So I rechecked the jubilee clamps were tight and cleaned off the muck. When I blow or suck the vent pipe no air passes so it must just be a bit of oily vapors escaping over time and I'm sure it not going to make the car turn into a kangaroo when warm. 

 

I also removed both camshaft potion sensors for a look. Can't see anything obvious, looked inside at the camshaft pick up tab(s) luckily one was in view and both in exactly the same spot on each bank which testifies to the cam timing being pretty much spot on I guess. The tabs are not bent at all either. 

 

Put it all back and it started first time. Check for codes nothing in the engine module but see code 1314 ( Engine control module fault) in the transmission module! Seen this a few times before and cleared it without it coming back for months and months. 

Is this really a fault? A ghost? Is this the transmission module's subtle way of saying all the issues are the dme but it's not going to tell you about it itself? 

 

I got one small pipe connection from intercooler to plastic pipe before intake Y which I can see is leaking a bit although I tighten it some weeks ago I will change the oring as a matter of course. All the while No boost loss or noises runs fine when cold so really doesn't seem this is the issue, a very small leak. 

The crank position sensor spacer I will try for the hell of it but I'm seriously doubting it will have any positive effect more likely negative effects. 

 

Anyone ever had a cayenne dme failure?? 

[Brainz006]

So strange. I have no idea what the issue could be. Your symptoms sound like a vacuum leak - - or are at least remarkably similar to my symptoms with various vacuum leaks. I keep reading and hoping you find a solution, but alas, no joy yet. I'll keep my fingers crossed for you.

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[Ddavidoff]

Same here similar problems. I'm hoping you find something soon.


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[lewisweller]

11 hours ago, Ddavidoff said:

Same here similar problems. I'm hoping you find something soon.


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Would you care to elaborated pls? 

[Ddavidoff]

Mine has a very slight hesitation at low RPM's. I have replaced the ignition coils as well as spark plugs air filter's and have fixed the T vacuum connector at the back of the intake manifold as well as fixed the vacuum line for the brake booster. Also found some air leaks in the intake tube's which I was able to tighten the connectors on to seal up any leaks. Still similar issues, hesitation as well as low idle, it will also hunt for gears. Doesn't matter how much fuel is in it it has done it with low fuel as well as a full tank. Might pull one of the fuses next to try and isolate it to a fuel pump but thinking that might not be the issue. Took apart the AOS recently to make sure that it was functioning properly and no torn membrane so I put it back together.


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[lewisweller]

6 hours ago, Ddavidoff said:

Mine has a very slight hesitation at low RPM's. I have replaced the ignition coils as well as spark plugs air filter's and have fixed the T vacuum connector at the back of the intake manifold as well as fixed the vacuum line for the brake booster. Also found some air leaks in the intake tube's which I was able to tighten the connectors on to seal up any leaks. Still similar issues, hesitation as well as low idle, it will also hunt for gears. Doesn't matter how much fuel is in it it has done it with low fuel as well as a full tank. Might pull one of the fuses next to try and isolate it to a fuel pump but thinking that might not be the issue. Took apart the AOS recently to make sure that it was functioning properly and no torn membrane so I put it back together.


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Would you say the low rpm hesitation sensation is increasingly worse when the boost is coming on strong as well? 

Example 2 gear come of roundabout ......

Accelerated maybe 1/2 to 3/4 throttle 

The stutter stutter stutter bop borp borp borp increases as rpm climb 

Then boost kicks in around 2500-3000rpm and it's worse, heavier stutter more abrupt.  

After 4000rpm it clears and sings pretty well clean to the redline to change gear and if your at 3/4 to wot the next gear pull is above 4000rpm so it doesn't happen. 

How does yours compare to this? 

[Ddavidoff]

Would you say the low rpm hesitation sensation is increasingly worse when the boost is coming on strong as well? 
Example 2 gear come of roundabout ......
Accelerated maybe 1/2 to 3/4 throttle 
The stutter stutter stutter bop borp borp borp increases as rpm climb 
Then boost kicks in around 2500-3000rpm and it's worse, heavier stutter more abrupt.  
After 4000rpm it clears and sings pretty well clean to the redline to change gear and if your at 3/4 to wot the next gear pull is above 4000rpm so it doesn't happen. 
How does yours compare to this? 

That sounds pretty accurate, but mine is very subtle right now. Trying to deal with it before it's a major borp. Right now it just feels like a misfire.


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[lewisweller]

3 minutes ago, Ddavidoff said:

 

That sounds pretty accurate, but mine is very subtle right now. Trying to deal with it before it's a major borp. Right now it just feels like a misfire.


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I Watched more closely today the issue starts at rpm is 2700 to around 3300-3500 and then clears. At that point the boost has kicked in already. 

So I though that maybe it's the boost blowing out the spark for some reason or ignition related misfire stutter due to boost combustion conditions.

So I disconnected the MAP sensor which cuts off all boost and you run on motor alone. The stutter is still there but not as pronounced. So it is not the boost! But is worse with boost! 

So what do I take from this? Not forgetting it runs ok when cold. 

In left with these possibles : 

1. Crankshaft sensor air gap issue flywheel expands when hot air gap reduces? Spacer experiment is planned next week. 

2. The variocam Switch over is not smooth? struggling to find any tangible info about exactly when and how many degrees the intake cam is supposed to advance at that rpm. Could it be oil getting thinner and causing this? Maybe a thicker oil would improve this? It's a long shot. I'm using 10/40 semi synthetic. Could a thicker oil work better for the variocam?  

3. Fuel / ignition problem only showing when warm? Everything is new so find it hard to believe.  

4. Dme getting warm, the eprom for the fueling and ignition map is faulty when warm or someone been playing around and flashed it with some sh*t software tune. Like the "Bluefin" I bought for my 2013 Golf R which made it pink and detonate at light throttle in the midday heat. I quickly removed it and took the Ecu to APR head quarters in uk and had Keith (software Tuning developer and the number 2 man of APR) bench flash my Ecu from his laptop (whilst I picked his brain for 2 hrs) for a killer special tune which had me whipping *** in dubai with any and all takers for 18months and never missed a beat. 

 

 

[lewisweller]

After some more research on fuel pressure and pumps I started to investigate the likely hood that I had a power or ground fault to one or both pumps possibly. 

I was passing my favourite porsche parts guy Hussain and couldnt resist nipping in and buying two new 15amp fuses and 2 new relays 404 for both pumps. I fitted them in a parking spot nearby and reset the DTC codes so as to clear the fuel trims and get a fair Base line if it made any difference. 

Well guess what the idle Dip is gone! And the acceleration seems smoother, the stutter at 2700-3200 rpm has not disappeared but it almost like it trying to behave. I may have stumbled on something here. And I fully intend to dive in to this further and do some amp testing and voltage test and ground volt drop tests to see the extent of the problem. 

I will bench tested the old relays as well and if I found some anomalies I will cut them open to investigate. 

And would you believe it, I ran the journey home with AC on high which felt and blew cooler than its been for a while (34oC outside today) and the "rear check tail light fault" warning I couldn't get to pop up on dash with all lights on and front fogs and music pumping to try and draw some extra power as it voltage related I'm sure. 

 

I don't know, it's all to good to be true at the moment and I've been here before thinking all was good and bang it didn't last long. I've got less than 1/4 so also I'm suspicious of this (hence the title of the post) and will fill up tomorrow and see if the problem return or not. 

 

I need to see some clear wiring diagrams of the power and grounds for the fuel system and the rear comfort control module to see if any common power or grounds are there. And the spec for running amps current of the fuel pumps would be good to know. 

 

Loren if you could be so kind as to PM me anything you have relative to this I would be most great full thank you. 

 

[Ddavidoff]

Wow. This would be an amazing find if it turns out to solve this problem for you. I will try a swap as well.


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[Brainz006]

What's your resting battery voltage? I could swear my CTT runs better when the battery is fully charged. I do a lot of short trips (work is only 3 miles away), so my battery tends to lose power over time. I know it's time to charge the battery when I get the CD changer error. On my 997, a low battery causes a Check 3rd Brake light error. I use a CTEK charger, and it seems to do a good job bringing the charge back.

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[Ddavidoff]

Mine has a brand new battery as I suspected this to be an issue. Tail gate not opening all the time, hard steering, other gremlins. All problems gone with a new battery. Good advice on swapping it out Brainz.


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[lewisweller]

5 minutes ago, Brainz006 said:

What's your resting battery voltage? I could swear my CTT runs better when the battery is fully charged. I do a lot of short trips (work is only 3 miles away), so my battery tends to lose power over time. I know it's time to charge the battery when I get the CD changer error. On my 997, a low battery causes a Check 3rd Brake light error. I use a CTEK charger, and it seems to do a good job bringing the charge back.

Sent from my Nexus 6 using Tapatalk
 

Normally around 12.6volts. I do alot of long journeys and sometimes the whole day im driving, so really in theory it shouldnt need a maintainer although i do have one which i used a few times to experiment with no real differences. Since the new hitachi alternator and 3rd new battery under warranty everything starting and charging wise has been fine knock on wood. 

[Brainz006]

12.6V is quite good, and the new battery should rule out a failing cell. When my 997 battery recently failed, it would charge up to 12.6 (or more), but very quickly lose charge under load. After a few cranks it was sub 12V. Sounds like that's not your issue, although perhaps grounding is. Might be worth confirming voltage at different points on the car just to see - - I'd start with the rear tail lights if you're getting an occasional error.

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[lewisweller]

Didn't last! 

Drove to warehouse this morning and crap as usual. 

I decided to fix a niggling leak in the intercooler to Y pipe connecting pipe with new oring (for some reason it won't let me add more than two pictures?) which was yuck with oil gunk and dirt. I thought maybe fixing this would have some positive effect if not a miracle one but Na who was I kidding. Fyi getting the Allen bolt out from the inside is a complete pita and getting it back in was an absolute ball ache. A telescopic magnet holding the bolt in my left hand, a torch in my mouth and an Allen key in my right hand doing a reach around to impress a contortionist. 

Left warehouse and total pants, needed fuel and put in up to 3/4 full after it ran especially dog rough stuttering, throws hands in the air. Wtf. 

Edited March 13, 2017 by lewisweller

[lewisweller]

Found this interesting case of running issues caused by oil viscosity too thin when engine is hot resulting is incorrect hydraulic tappet lift. 

Make me wonder if my hot engine stutter hesitation could be caused by the 10w40 oil simply not being thick enough? Maybe having an effect on the variocam change as well?

This may in fact point towards a less than optimum oil pressure (tiring pump maybe) which the thicker oil would help I guess as well. 

Anybody have any experience of oil thickness causing running issues? 

 

I'm due oil change in the near future and will try a 10w60 or 10w50 depending on what I can find here. 

 

Edited March 21, 2017 by lewisweller

[Brainz006]

I seem to remember high mileage BMWs suffering such issue with VANOS. You are in a hot part of the world, so a heavier oil could make sense. Remind me: What's your mileage?

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