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

[lewisweller]

3 minutes ago, Brainz006 said:

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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127,000km. 

m3 bimmers use 10w60 castrol oil. 

[Ddavidoff]

Oddly enough my issues have somewhat disappeared after drying out my foot wells. I found a substantial amount of water, cleaned the drains and soldered and shrink wrapped the two crimped and taped wires that are in the left side harness in the puddle. I have only driven it once since completing the dry out and it was cold out today -4 Celsius. Will post again if my issues return or something changes. Maybe these two wires were shorting out in the moisture....

 

Maybe someone knows what the two wires that are crimped and taped from the factory are for? Other post mention unable to start when they corrode and become disconnected.

 

 

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[lewisweller]

3 minutes ago, Ddavidoff said:

Oddly enough my issues have somewhat disappeared after drying out my foot wells. I found a substantial amount of water, cleaned the drains and soldered and shrink wrapped the two crimped and taped wires that are in the left side harness in the puddle. I have only driven it once since completing the dry out and it was cold out today -4 Celsius. Will post again if my issues return or something changes. Maybe these two wires were shorting out in the moisture....

 

Maybe someone knows what the two wires that are crimped and taped from the factory are for? Other post mention unable to start when they corrode and become disconnected.

 

 

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Got any pics? 

I remember I had some red with black strip wire which looked a bit suspect and thick black wires with the factory crimp exposed but nothing was wet or corroded or broken and I did a neat wrap and didn't think about it again really. Considering its a hot running issue it's not concurrent with a wiring problem on a loom inside the car. 

[Brainz006]

I would think that 125k km would still be too new for variocam wear - - there's plenty of Cayennes running around with way more miles without this issue.

Random anecdote per Ddavidoffs post: My brother had a rock crawler that was giving him fits. It had a Chevy LS engine in it with a Painless Wiring harness. Started fine and ran great when cold, but as it warmed up it would intermittently stutter and lose power. I seemed to remember it throwing a code or doing something that made us suspect a failing crank sensor and O2s - - replaced those and some other bits, still no joy. While testing it one day, we notice that the ECU voltage was dipping when the issues were happening (note that it would also hesitate and stutter at idle when hot, which made troubleshooting easier than your situation). We wondered if maybe the ECU was failing, but wanted to check all the wiring first before throwing more dollars at parts. So as I wiggled all the wires on the various harnesses and suddenly the engine stutter would coincide with the wire wiggle. It turned out there was a bad/weak crimp in a major (positive, I think) lead to the fuse panel that fed the ECU amongst other circuits. And as the amperage heated up the wire crimp, the connection got slightly intermittent - - not enough to cause an obvious electrical issue, but enough to sag the ECU and make it hiccup. New crimp - - No more issues. Lesson: electrical gremlins are a b*tch. We got lucky to find that wire.

Consider logging ECU voltage, cleaning ECU harness plug with contact cleaner, checking any suspect connections, and maybe wiggling wires.

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[Ddavidoff]

There are a few pics in this thread, but I didn't take any as this issue was well documented.

http://www.6speedonline.com/forums/cayenne-955-957/316151-09-brake-proportioning-ignition-lock-fault-issue.html

Thanks for the ECU idea. I will start cleaning connectors and checking wiring. It ran better even when warm this afternoon, so I think this may have helped. Not sure I'm 100 cured yet.


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[lewisweller]

5 hours ago, Brainz006 said:

I would think that 125k km would still be too new for variocam wear - - there's plenty of Cayennes running around with way more miles without this issue.

Random anecdote per Ddavidoffs post: My brother had a rock crawler that was giving him fits. It had a Chevy LS engine in it with a Painless Wiring harness. Started fine and ran great when cold, but as it warmed up it would intermittently stutter and lose power. I seemed to remember it throwing a code or doing something that made us suspect a failing crank sensor and O2s - - replaced those and some other bits, still no joy. While testing it one day, we notice that the ECU voltage was dipping when the issues were happening (note that it would also hesitate and stutter at idle when hot, which made troubleshooting easier than your situation). We wondered if maybe the ECU was failing, but wanted to check all the wiring first before throwing more dollars at parts. So as I wiggled all the wires on the various harnesses and suddenly the engine stutter would coincide with the wire wiggle. It turned out there was a bad/weak crimp in a major (positive, I think) lead to the fuse panel that fed the ECU amongst other circuits. And as the amperage heated up the wire crimp, the connection got slightly intermittent - - not enough to cause an obvious electrical issue, but enough to sag the ECU and make it hiccup. New crimp - - No more issues. Lesson: electrical gremlins are a b*tch. We got lucky to find that wire.

Consider logging ECU voltage, cleaning ECU harness plug with contact cleaner, checking any suspect connections, and maybe wiggling wires.

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I have suspected an ECU or related wiring issue but as you said very hard to find a bad connector. 

I've had the Ecu out and open. Nothing obvious and connector and plug looked in decent shape. 

Whats the ideal ecu voltage (straight 5v?) and does anyone know where to look for the specific ECU voltage group? I'm using the ......ahem...... Vcds vagcom so label files not available to tell me all the group names I'm looking at. Need to buy duremetrics I know, would make life easier in these situations but that don't work on the Audi.  I Will invest soon. 

[lewisweller]

After watching my injection pulse width milliseconds in relation to my rpm and load it seems apparent what the dme is instructing is looking correct and logical according to the fuel map. So this begs the question are my injectors partially blocked? Could this be why once warm and any warm up enrichment is reduced their is simply not enough fuel flow to get a decent burn and results in the stutters, hesitations and idle Dip ? As computer Diagnostics aren't going to help much here I guess there is only one thing for it. 

This is my next little project in the continued search. 

 

Edited March 24, 2017 by lewisweller

[lewisweller]

Well I took out the injector rail today and stripped off each injector. 

Using a 9v battery I energised the injectors and cleaned them all with crc solvent degreaser cleaner. The injectors all were crap, and no amount of solvent would get a nice clean 4 spray pattern. Only 1 would remotely be acceptable I would think. 

I reinstalled everything and it started up fine. I ran it on each pump just to see if any difference between the left and right but none I could detect. 

Went for a drive (bare in mind I'm at just under the magic 1/4 tank) and it seems initially to be a bit cleaner to accelerate. So I put it through some mixed driving and the hesitation has not gone which is no surprise as I achieved nothing by cleaning the injectors, as they aren't clean. 

I put some techron fuel system cleaner in the less than 1/4 tank of fuel and went for some more driving, still seems a bit more lively bit not fixed by any means. 

Went through the auto car wash and vaccum bay engine was idling a long time and then shut off and then restart (loads of heat soak cycles I'm trying to accomplish here). 

Then I went and filled the tank to 3/4 full, this was on purpose because I didn't want a full tank incase the issue is some how to do with the evap canister getting saturated with full tank topped off etc. Restarted after fill up just fine but when I drove off the acceleration is terrible and hesitation is felt on way more places in the rpm range not just around 3k. 

I did some driving and acceleration testing, even stopped the engine, let it sit for 5 mins and restarted but was the same. 

So my conclusion is my injectors are wank. The picture is difficult to see the holes. But they look clear sometimes and sometimes blocked with something inside the pintle area.

The reason why below 1/4 it not as bad is  maybe simply because this is the time both pumps are running, this extra boost of pressure and flow capability possibly is enough to cover a little the blocked injectors, once I filled up its back to the left pump only and its dog rough again. 

 

Why are my fuel trims so good ???!!!

Why don't I get lean codes ???!!!!

Wtf????!

 

New injectors are extremely expensive. Will proper injector cleaning work or are these just pass serviceable? 

Answers on a postcard. .......

Edited April 1, 2017 by lewisweller

[Ddavidoff]

Sounds like you should just replace them....but I know your costs are adding up.


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[lewisweller]

Wow can't believe how expensive a Bosch injector is new! Multiply by 8 equals .... Broke ***. 

Some I see selling are remanufactured. Erm had one bad experience of remanufactured part already (alternator) and not confident about another. 

Any one got any insight as to whether injectors online remanufactured are any good? Or maybe I should try and find a local place to do it here, and they can demonstrate the working injectors before I had over my cash. 

 

[lewisweller]

Just to keep this thread updated, will be taking my injectors to a local garage here in dubai to be professionally cleaned for about 140 dollars. 

Wish me luck this is the end to the story........

 

Edited April 2, 2017 by lewisweller

[Brainz006]

Good luck!

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[ekstroemtj]

maybe Lewis you can transfer the video you posted in the other conversation to this one here?

[ekstroemtj]

Maybe this is the right place to put my question in. 

My fuel Pump was already complaining One time Last year.

Now i believe again something wrong. 

Cant hear the Pump Prime when i am opening the drivers door. 

 

I found a interesting report in a Touareg Forum.

Is the System in my Cayenne the Same?

 

 

 

 

[ekstroemtj]

http://www.clubtouareg.com/forums/f92/fuel-pump-doesnt-prime-when-i-open-the-door-219762.html#/topics/219762?page=2

 

 

[ekstroemtj]

Just to be shure.

I pulled the Fuses 13 and 14.

When i pulled 14 the Car dies after a few seconds. Fuße 14 is the passenger side pump? This means the System is changing to the Pump on Driver side. If it dies means the Pump on drivers side is Toast!?
 

Is it a difference in pulling the fuses or pulling the Relais? 

[lewisweller]

12 minutes ago, ekstroemtj said:

Just to be shure.

I pulled the Fuses 13 and 14.

When i pulled 14 the Car dies after a few seconds. Fuße 14 is the passenger side pump? This means the System is changing to the Pump on Driver side. If it dies means the Pump on drivers side is Toast!?
 

Is it a difference in pulling the fuses or pulling the Relais? 

Fuse 14 is the left pump. It should die when pulled assuming you don't have a low fuel level, which would leave the right pump running anyway.

 

Try pulling fuse 14 and then cycle the ignition and start and run car on right pump.  Both pump should be able to run independently. 

 

[ekstroemtj]

@lewis

 

Nothing happens. If Fuse 14 is Out the Car doesnt Start at All. Inside the Tank now maybe 25 liters

 

[lewisweller]

13 minutes ago, ekstroemtj said:

@lewis

 

Nothing happens. If Fuse 14 is Out the Car doesnt Start at All. Inside the Tank now maybe 25 liters

 

If fuse 13 is OK and the relay is also ok then perhaps the right side pump has a problem! You should check the connector as well under the seat to the regulator unit which of course passes the power to the right pump and level sensor. 

 

A garage can use power probe to activate the pump and bypass the relay and controller to verify if the pump will run or not. 

 

Edited April 29, 2017 by lewisweller

[Ddavidoff]

You can pull the relay and jumper it yourself to see if it will run.



You can also test pressure at the fuel rail using the jumper and can disconnect the fuel line and spray the fuel into a container to check fuel delivery quantity.


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[ekstroemtj]

Thanks guys. Any easy way to test the relais? I am little bit affraid with overjumping. Maybe i can damage something

[ekstroemtj]

I am really confused.

 

Here some other thread:

 

There our member noted that if Fuse 14 is out and the car is struggling the DRIVER side pump is gone. 

 

Can somebody clarify please

 

 

 

[lewisweller]

5 hours ago, ekstroemtj said:

I am really confused.

 

Here some other thread:

 

There our member noted that if Fuse 14 is out and the car is struggling the DRIVER side pump is gone. 

 

Can somebody clarify please

 

 

 

This info is incorrect, as per the porsche diagram the fuse 14 is the driver side left side pump. 

[lewisweller]

So as not to leave this long thread open (that is the most annoying thread ending ever Init?) 

I have sent the car to auction due to convertor seal leak and never got to do the injector professional cleaning, I'm sure it is the real reason for the lean hesitation but I guess I will never know now for sure. Bye bye cayenne it's been an expensive ride ..........

[ekstroemtj]

@ Lewis

 

Sad Story Lewis.  At least i hope you will get a reasonable offer for your car.