What Petza said about Durametric, and Vagcom can too if you have that. Watching the misfire count as it happens can be interesting, how many and which cylinders at Idle compared to how many (adjusted for RPM) and how often at above idle (undle load) condtions. I think I mentioned logging misfires at the beginning of this thread as well as 'your inspection camera sucks" x2 . A cheap Amazon camera can be had that is better than the one you used or if you want something better you can find new/used genuine automotove inspection cameras on EBay. I've got a Snapon BK6000 but Snapon makes a few different models and they're all good and all have camera heads that will fit through the Sparkplug holes. I've heard the Milwauke cameras are pretty good too. I think it's coming time that you really need to pull that Intake manifold, as I mentioned earlier in the thread think of it as preventive Mx, brittle vacuum lines under there that will need to be replaced. I'm also not familiar with the Foxwell, Durametric is the most common for Porsche which I have but I love Vagcom so I use it more than Durametric even though it's meant for VAG cars but the Cayenne is more than half Touareg/Q7 anyways.

 

Yes I know, cheap camera reminders. Mine WAS one of the cheap amazon ones btw. It works with my android phone, obviously not well.

I can see misfires guys, I did mention it above, as they happen, and a counter that keeps adding them up, as mentioned cylinders 4 and 8 have about 200 or so right now, all other cylinders have 20-30. Im wondering what could affect the back 2 more that the rest.

What I was asking related to scanners is does PIWIS or Durametric see fault codes pertaining to specific components before a check engine light is set? Not even sure of thats a thing, but for example, if a cam sensors is failing, but not failed, can it be flagged in PIWIS but not result in a check engine light yet? Maybe this doesnt happen, but I thought I read somewhere someone mentioning things along these lines. The foxwell does quite a bit, and works with other cars, the reason I bought it from ECS tuning, plus it was on sale. No computer needed, android based. But yes, it doesnt do everything.

And yes, I got the intake manifold gaskets so will be pulling it when I get time.

 

A new development, over the weekend, after replacing the coils and the driver side valve cover gasket, I finally got some codes,
P0418, P0419, P2257, P2259, secondary air injection low circuit and cicuit open.

Fuse 12 blown, which is connected to the air injection pumps and the auxilary cooling pump, which I never even knew existed or worked, cause I dont hear it. Its tied to the REST function, which does work after shutting down, I hear the blower kick on low speed and feel warm air, but dont hear a pump. Maybe every CTT doesnt have this pump option? Sounds nice to have if it runs to cool down the engine after key off.

I checked the relay 404 for the air injection pumps, its fine and working, searched and found there is another 404 relay for the auxilary coolant pump tied to this #12 circuit, under the dash, can hear it working, but didnt remove it or check it.
Unplugged both the air injection pumps, that seemed to keep the fuse from blowing. I 've already gone through replacing the pumps 6 years ago, foam is fine, pumps are fine, lines to the egr fine, as I checked them, doubted these to be the problems since they where relatively new. Maybe something with the wiring to the pumps?

I then reconnected the pumps, used the foxwell to activate them, no issues. Backed the car out of the driveway, and the fuse blew. Only thing I did was start the car, put in gear, and step on the brakes a couple times.
I put a new fuse in, stepped on the brakes, hear the vac booster pump which sounded weak, then it stopped. Turns out, the vacuum booster pump is also on this #12 circuit. Hooked a test loop/fuse buddy to the #12 fuse, started it, pumped the brakes, and sure enough, amps spiked and I could hear the vacuum booster faintly and then stop. New vac booster pump on order. Ive had it unplugged and no blown #12 fuses anymore (5 amp one).
Interesting thing is with the car running, I had my wife pump the brakes, even with the booster pump connected, and now not working at all, and fuse not blowing just yet, I could hear a sucking sound under or inside the middle to back of the intake manifold. Im guesssing the brake booster series of lines that ends in the one running to the back of the intake manifold is calling for vacuum from the engine and creating the sucking noise, and since the pump isnt working to come on and help, its creating the noise trying to pull more vacuum.
UNLESS, there is a vacuum line under the intake manifold, as you suggest maybe hahnmgh63, but I didnt think there was and, just the coolant breather Y hose and the coolant pipes and started? PLus I smoked the line coming off the booster 3 way hose going to the rear of the intake manifold, and no leaks.
Cylinders 4 and 8 are at the back where the brake booster line comes into the intake, is it then messing with the air flow into those 2 cylinders 1st, pulling too much vac and no booster pump to help causing misfires????

Hear is the other twist. When the #12 5 amp fuse is blown, from what im 99% sure is the failing booster pump, the DME goes into closed loop mode of something, cause I see no fuel trims, all show zero (mean, short term, low load, high load), and it runs crappy.
So, the brake booster was probably failing for a while, and when the fuse is blown, it definitely makes the car run worse since no fuel trims working, but I didnt get this code till a few days ago, and its been running bad for a couple weeks now. At least I finally got a code which I can act on! So related or maybe not entirely, perhaps the plugs and new coils helped one thing, then this problem?

New pump is coming tomorrow, so Ill find out more if this helps with the rear cylinders. Pig is running better now that fuel trims are working with booster unplugged and fuse #12 not blowing (I just ignore and know why the booster error dash warning is on). Maybe now I need more drive time to get the trims all optimized.

 

You can check camshaft deviation numbers. If you see one occasionally got to 0.0000 then recover to an actual value, that's a sensor that's failing but hasn't yet failed. Once it fails it will show that value all the time. The engine doesn't actually use these for about the first 2 minutes of running, so if the car starts and runs ok then after about 2 minutes you get a rough idle and a CEL, that's a good indication of a bad camshaft position sensor.

 

Ok ill follow those in the next few days.

I was still thinking more simple, my low circuit air injection codes, maybe the DME sees this, but diesnt activate the CEL. It sees this low circuit again and again in quick succession, then it says this is a reoccuring problem, turn on the CEL.
can this happen and can a oiwis see these eminent codes prior to the CEL?
maybe it doesn't work that way.

 

As promised, the UOA with the Redline 0W40 at 1200 miles (recall I added a qt a 700, and then again around 1100 in, then I decide to drain it).

Coincidental to my issues, or part of the problem?
The oil is obviously very strong, high moly, high zinc and phos, and I wanted a higher viscosity, as most euro oils, 0W40 and 5W50 are at the low end, this stuff is right at the high end, albiet only 1200 miles.
So no doubt this oil is excellent, BUT, maybe in an engine with consumption, its too good?
Thinking perhaps the higher levels of moly, or calcium, or the ZDDP is harder to burn off, more problems with fouling the plugs? I also read on Bob is the Oil Guy, it makes sense to think a thicker oil would be harder to get past rings and seals, but because its thicker or has better properties to stick to the cylinder walls, it hangs around and doesn drain back into the sump as easily, therefore more consumption, burning, fouling???? There we several members who when to a thicker oil for consumption and when back to a thinner oil cause their consumption actually increased.
Crazy non-sense?

So far I have about 700 miles on the Valvoline 5W40 Euro, and havent had the check oil light come on yet.

Vac booster pump is in from FCP. Just like the OE, same Hella unit, a different sticker and the plate between the top and bottom housing is different. The old pump looked like some fiberglass or pressed and epoxied textile material, the new pump plate/gasekt is all metal.
Pig is running even better now, perhaps because its no longer starving the intake of air when hitting the brakes.
Just trying to log more miles to help everything re-adjust but the poor idle, big cam sound, smoothness in driveability, even the down shifting is now snappy and crisp, with no delay or clunks.

Seems like the failed fused for the pump which forced close loop running with no fuel trim adjustments, and the loss of vacuum from the pump and increased vacuum in the intake, a bad vac pump CAN affect how the engine in addition to the brakes, performs. Honestly, with the vac booster pump totally disconnected and the vac line capped off when I was waiting for the new pump and still driving it, I didnt notice any impact at all on the brakes in normal use! I only noticed the poor running and now the improvement in running with the new pump. Maybe I got used to it over the weeks while the pump was dying.

 

Those iron numbers are kind of high for only that many miles and if the same oil in the previous reports you can see that they kind of consistently go up with each 1,000 miles, then jump up a fair amount when you get close to 4k miles. I'm not sure these oils have been working that well to minimize metal wear. I look for single digit metals in 5k mile change intervals as the judge of a good oil and healthy engine.

 

What would be wearing that's iron? I don't dissagree Petza, that's why Ive been switching oils every 2 or so changes trying to find something better. Ill try the Driven oil next, I know thats what you use Petza.

So I was happy and optimistic about all these things lately, the battery, new coils and plugs, vac booster, but just when I thought everthing was better, its not.
i finally drove it hard today. And as soon as I drive it with some good pulls and max boost, it starts running bad again.
Its,been great the last couple days with the pump fuse not blowing, newcplugs/coils, and with the new vac booster pump, but I was babying it and driving it easy. Soon as I think we are all good and I finally push it starts getting rough and big cam feeling with hesitation immediately after.
im pretty sure it will be ok tomorrow 1st thing if I start off easy, but then get worse if I push it.
Not sure what this means, heat is affecting something, an air leak only presents itself at high boost and then messes things up, but cools and then is better again, crazy cause it was silky smooth this moring alk the way to work, like a new car, while driving normal.

i think im to the point of giving up, 1st time ive been this frustrated with this car, even thought ther have been a lot of things to keep on top of, so is this the Gen of Cayenne, and im all good with that.

Yes, I still have to pull the intake and see what I can find, and Im also going to reflash back to my stock tune just to try something else.

 

Iron can come from camshafts, crankshaft, valve train, timing gears, timing chains and bearings once you get through the coatings. Hard to know for sure.

 

When I had the valve covers off, timing gears still appeared to have the coating on the teeth, I could see the dissimilar finish on the teeth.

 

Coming back with another update..... I have another thread more specifically about the braking vacuum circuit, but wanted to share:

Two days now Ive been driving it with the soft hose disconnected from the hard line (see middle right of image, hard pipe port pointing up) which is by the passenger secondary air pump for the vacuum supply to the brake booster, and connected to the series of pipes (3 headed monster) leading to the vac booster pump) and plugging that port). Also I have the vac booster pump disconnected otherwise it would be running non-stop.
This is the vac line, pulls vac from the Ypipe and from the back of the intake (coincidently from near the #4 cyl which has had the crazy number of misfires and takes vacuum to the booster, see bottom right of picture, the connection pointing down). So I think its affecting cyl #4 the most, but not sure why yet. The port (upper left of image) attaches under the Ypipe, would would starve all the cylinders equally.
Im starting to think the one way valve in the middle of that mess of lines, if that is indeed one, is allowing boost to pass (metered air not getting to the cylinders, particularly #4 since the one line is close), as I can suck out air from the intake, as well as blow into the intake from the middle right connection.


Since being disconnected, its been driving perfectly. Idle is great, no jerkiness, full power with no surging, smoorh, sounds like what I fell in love with from this V8 and my tailpipes are even cleaner.
so i fix one big problem and now have another, lol, stopping is a chore, and boardering on unsafe, but I needed this experiment. Fuel Trims have adjusted to, and no misfires.

With this experiment, the whole brake booster, lines, vac pump, etc and the vacc feeding line to the intake are out of the equation. So there is something here I haven't been able to pinpoint.

I thought about a leak, since my vac pump did die., but haven't found one. And,when I had the new vac pump connected and all lines hooked up as normal, it would only come on if I pumped the brakes 3 times or more, and for about 5 seconds, so don't think i have a leak.
overnite, if i pump the brakes engine off, I get 2 soft pumps indicating vacuum still held in the booster, 3rd pump it gets hard.
can someone check theirs for comparison, don't have to wait overnite.

So I ordered this hose im questioning (94811007003), I replaced it back in 2021, but maybe the one way is bad, these lines do not leak I smoked them. So ill check its operation, to confirm the one way operation, before installing. Hoping I cant suck air through the out port to the vac pump/booster

 

I ordered the 94811007003 hose above, pulled mine and check the operation by blowing and sucking in all ends, mine is working just fine.
So, this is not the problem. And yes, you can suck through it simulating vacuum and blow into it, there is no one way valve in this hose despite the white portion looking like it has one.

After driving for 3 days without this connected to the booster, and everthing running great, I put the new line in anyway and connected everything up as it should, drove 100 miles, the 1st 50 were ok, but then the last 50 return trip after sitting for 3 hours, its back to driving bad.

Im at a loss. I vacuum checked the brake booster over nite, held vacuum fine. Checked all the lines between it and the engine, smoked, pressure, vacuum tested, all fine. I did all the normal brake pedal tests from inside, with and without it running and it all checks out.

Im gonna disconnect the vac to the booster circuit again and see if it corrects itself.

Only thing left to check is fuel pressure under load, which I am not sure how to do, but still puzzled by why its driving perfectly fine with the vac line disconnected from the brake circuit.
Im gonna post some fuel trims in another thread to see what anyone thinks.

 

Well guys, again, thanks for all the ideas and suggestions but I finally resolved my surging.

As many others have said on this forum, it was the fuel pumps (or the filter or regulator).
after seeing some suspiscious behavior with a fuel gauge at idle when blipping the throttle, and while driving (underload), and being 20 years old with 105,000 miles, i replaced both pumps and the fpr/filter and all is well. They werent failed, but not performing at their best.

ill create a separate thread to document the fuel pressure readings, with pics and videos.

Used VDO/Continental ones from FCP. Seemed a bit overwhelming at 1st but its not a bad job (especially due to all the great write ups here).