Porsche Cayman S catalyst and O2 DTCs.

I have a long story about catalyst efficiency DTCs on the 2006 Cayman S.  It starts back when I bought the car in 2014.  You can see that story here.  It had 60k miles on it when I bought it.  The car had a P0421 DTC which means "Warm Up Catalyst Efficiency Below Threshold (Bank 1)".  On this car that is the passengers side.  I installed an O2 bung on the muffler on that side and moved the downstream sensor there which generally eliminated that DTC, but I would occasionally get a DTC for the front sensor of that back stuck rich.  It would set that DTC randomly but not very often.

It did get annoying to have this DTC trip though, and I wanted to upgrade to better headers so I finally did in 2019.  I put the bank 1 downstream sensor back in the proper position when I installed the headers. The DTCs were finally gone for good, or so I thought.  I went to a track weekend in April just a month after installing the headers and I had no issues.  However, I went back to then same track in October and the car tripped the P0421 and P0431 ("Warm Up Catalyst Efficiency Below Threshold (Bank 2)") after idling for extended periods during warm-up.  Normally I just start the car and drive off but at the track the car sits and gets cold between sessions and I needed to get it fully warmed up before entering the track so I would idle it for much longer than normal.  It appeared the Fabspeed headers, in combination with this cold idle warm-up, was enough to fail the warm-up efficiency test. 

I suspect that these headers with the high-flow catalysts and larger, somewhat longer primary tubed are not as good at heating the catalyst, and that catalysts are enough less efficient that the test is below the threshold at times.  One of the known ways people get around this is by adding a spacer to the downstream O2 sensors.  This simulates catalyst oxygen storage to some degree and can help the test pass.  So, I installed some short straight extensions I bought through Amazon for cheap.

After installing these, I immediately got a DTC P2198 "O2 Sensor Signal Stuck Rich Bank 2 Sensor 1".  Since the car now has 87k miles on it, I replaced both the bank 2 O2 sensors but the P2198 remained.  I noticed the bank 2 upstream O2 sensor was loose when I went to replace it.  I checked and cleaned the MAF sensor, checked for vacuum leaks, re-torqued the headers and checked for exhaust leaks, and all was good.  Finally I removed the bank 2 downstream O2 extension and the P2198 went away and my O2 and catalyst monitors tested and passed (monitors were ready and no DTCs).  

Now, with an O2 extension in bank 1 but not in bank 2, I get these OBD test results (mode $06)

when the P0431 is pending.

Test report:
------------------
TID:$01 CID:$05
- Rich to Lean sensor threshold voltage(constant)
Min: 4,096
Test result value: 15,458
PASS
----
TID:$01 CID:$06
- Rich to Lean sensor threshold voltage(constant)
Min: 4,096
Test result value: 3,639
FAIL

I can't currently find the definitions of these but given that my pending DTC is P0431 I am presuming that CID $05 is bank 1 (which passed) and $06 is bank 2 (which failed and set the DTC pending.  You can see the large difference in test result values here.  The sensor without the extension is 89% of what it needs to be to pass whereas the other bank is 377%.  All other test results in the report passed.

I bought some shorter spacers and installed one in bank 2 only. 

I cleared DTCs and drove the car again, including cold start.  The P0431 sets pending again.  Here are the OBD test results this time:

Test report:

------------------

TID:$01 CID:$05

- Rich to Lean sensor threshold voltage(constant)

Min: 4,096

Test result value: 13,902

PASS

----

TID:$01 CID:$06

- Rich to Lean sensor threshold voltage(constant)

Min: 4,096

Test result value: 803

FAIL 

Strange how it is even worse with the spacer in bank 2.   Also interesting how the medium spacer works well in bank 1 but not in bank 2.  

It seems like my bank 2 catalyst is very weak, at least for the warm-up catalyst test.  

It is strange that I installed the headers March 2019.  I did not mature any DTCs for months of daily driving.  I did not check monitor readiness and did not check for pending DTCs however.  I did a PCA track weekend at Putnam that April and had no issues (that I recall anyway).  I went back to Putnam again October 2019 and that is when the DTCs started tripping pretty often.  Sometimes just one bank, other times both.  It would happen when I warmed up the car and would sit on the grid for long periods.  Since then I have had the P0421 and P0431 keep happening.  Now it is pretty consistent on bank 2..  

I drilled my original longer spacer out to 3/8".  I cleared the DTCs and drove the car.  After about 20 minutes of driving it finally tripped the P2198 again.  I cleared the DTCs, waited a few hours and drove the car again.  This time it completed all the monitors with no DTCs.  Here is my OBD Test results from that drive.

Test report:
------------------
TID:$01 CID:$05
- Rich to Lean sensor threshold voltage(constant)
Min: 4,096
Test result value: 10,503
PASS
----
TID:$01 CID:$06
- Rich to Lean sensor threshold voltage(constant)
Min: 4,096
Test result value: 6,404
PASS

The test result above looks great.  It just seems very inconsistent to get for bank 2.  Bank 1 is now solid and passes every time.  Bank 2 toggles between P0431, P2198, and an occasional pass.  

I took some pictures of Bank 2 catalyst.  Here is the view from the upstream side.

and here is the downstream side.

It looks good physically.  No cracks, chunks missing, melting, or soot buildup.  

I also checked it will then infrared thermometer.  I was in the garage so not much load on the engine.  After running (mostly idle) for a few minutes, it was about 400F both upstream and downstream.  I ran the engine at about 2000rpm for a minute and rechecked.  Now both were around 480F.  Not much temperature change across the catalyst in the garage.  This was the surface temperature of the pipe, not the actual catalyst temperature.  

I finally sent the header that kept failing back to Fabspeed to get the catalyst replaced.  Fabspeed was great to work with throughout this whole ordeal.  I installed the header back and have not had the DTCs ever since.  I also checked to confirm that the catalyst monitors did complete and pass.  I moved the car to my Las Vegas home where I needed a smog check to get registration and it passed the smog check as well.  

Cayman S Water Pump

 I did a dumb thing but it turned out OK.  When I took the Cayman out of winter storage this spring and warmed it up for the first time in a while, I smelled coolant, although none leaked to the ground.  I have seen water pump seals do this before.  On most older cars the water pump has a simple bushing that runs in coolant so a small seep that quits is not necessarily a big deal.  My F250 would do this on severe cold weather but never had a pump failure.  However, the Cayman water pump is not like that.  It has a sealed roller bearing instead, which is far better and should last for life.  However, if you get coolant seeping through the bearing, the bearing will die pretty fast.  The grease will get washed out, the bearing will run dry, and fail.  Well, that is what happened to me.  I had noticed a growling noise from the engine when I started it that morning.  My first thought was far worse than a water pump.  I feared my IMS bearing was going out.  After recalling that I did see dry evidence of coolant from the water pump I sorta convinced myself it could just be some coolant on the belt, which can make all sorts of weird noises.  Honestly I was not that convinced, I was just lazy and in a hurry to meet with some friends.  

On my way back from breakfast where I was meeting with friends I heard a pop and immediately my steering assist was gone and the charging system warning came ON.  Right away I knew I had lost the belt.  I carefully drove the rest of the way home, accelerating moderately up to speed, shutting OFF the engine, and coasting between lights.  By the time I got home the coolant temp was a bit over 200F based on the gauge.  Still safe but I would not want to get it too much hotter.  With no belt, the coolant does not circulate.  You can't go very far like that.  In the video below you can hear the pop right at the beginning.

It is not real loud and I did have the stereo going.  I quickly turned OFF the AC and opened the windows too.  

Once I was home, I removed the panel behind the seats to expose the front of the engine where the belt and water pump are.  I saw the slack belt but upon further inspection I found the water pump shaft had completely sheared off and the pulley was just laying there.

Glad to see it was just a water pump, I quickly ordered parts through the local dealers online website. 

  

Mid-engine cars have a much trickier cooling system since the engine is in the middle, and the radiators are in the front fenders ahead of the wheels.  This makes it an air pocket nightmare.  A vacuum system is needed to pull a vacuum on the cooling system and suck the coolant in.  I found this one on Amazon for $39.99.

Having the engine behind the driver and not even visible without removing bolt-in panels and carpet sounds like jobs like this would be much harder.  However, it is not too bad really.  It takes about 15 minutes to remove the carpet section and both the top engine panel, and the front engine access panel. Once you have these panels off, access is pretty good for most things.  I will say charging the water pump on this car is far easier than most front-wheel-drive cars.  

I positioned the car on a ramp on the drivers side, and jacked up the passengers side as high as my jack stand would allow.  This positioned the coolant reservoir as high as possible relative to the car. I did this to keep the radiators and heater core full of coolant making it easier to ensure all the air was out when I was done.   

I started by clamping the radiator hose and one of the heater hoses.  

I loosened the hose connected to the water pump at the bottom and stuck an Allen wrench in it to allow the coolant to drain in a more controlled fashion.  In this position, and with the clamps in place, about 2 gallons of coolant drained into the pan I had to catch it.  I then removed the water pump.  It is basically just a set of small bolts.  The nice thing is the gasket is metal and does not stick to the block so it left a clean surface.  Here is a photo with the pump removed.

  When installing the new pump, make sure the longer bolts are in the correct holes, with the alignment dowels.  Here you can see the new and old pumps, both showing the alignment dowels.

Here is a photo with the new pump installed.

Before removing the hose clamps, I drew a vacuum on the cooling system and pulled in the coolant.  

I was able to pull in almost 2 gallons right away.  Remember to open the air bleed valve in the top of the reservoir to allow the air to escape the block while doing this.  I then released the clamps, installed the belt, and ran the engine.  With the engine running I could feel more air purging through the air bleed hose that connects from the oil cooler to the reservoir.  I added about a quart more coolant at this point. I ran the engine some more until I could feel the heater hose warm up, indicating I was getting coolant flow.  I ran the engine until the thermostat opened and I could feel the radiator hose at the radiator warm up, indicating flow to the radiators. I did all of this while the car was still raised.  I took it for a good road test, hitting 7,000rpm at times to create high coolant flow and purge any remaining air.  

The whole job took me about 3 hours.  Not too bad.  

2006 Porsche Cayman S Fabspeed Headers

When I bought my Cayman S it had a check engine (MIL) on because of a catalyst efficiency fault, meaning the catalyst was no longer passing a test the OBDII system does to ensure it is working properly.  I was able to trick it by moving the downstream O2 sensor but that would occasionally give another fault.  I researched what options I had for replacing the catalyst.  On this car the catalyst is part of the header assembly.  I started looking into high performance headers.  There are some options out there from a few different manufacturers but the best appeared to be Fabspeed.  They were also the most expensive.  When I started looking in 2014 they were $3500 a set.  Yikes.  That seemed pretty high so I waited.  They finally dropped to $2,895 a few years later.  Then I got a coupon for 10% off through Pelican parts and I was very close to buying.  Then one day in early December 2018 I saw an ad for a Fabspeed sale right at the Fabspeed website.  I figured it would be hats and shirts but my headers were on sale for 15% off.  I immediately added to cart and bought them.

I made a short video to hear the old exhaust as I started the car cold to compare later.

They came in after Christmas and I made an unboxing video.

I was impressed with what I saw.  They were like art, but much more useful.  It was cold and the roads were salty so I waited to install them.  Finally March began to warm up so I put them on.  It took me an afternoon.  I had a few complications as can be expected when working with older exhaust.  I had to cut the bolts for the 3-bolt flange and I had to replace one of the downstream O2 sensors (longer story).  Since I had taken the right side muffler off before, the rusted flange bolts had already been replaced.  I had the right side out in 30 minutes.  The headers fit very well.  I did not upgrade the rest of the exhaust, except the muffler outlets I had done just after buying the car.

While most cars are a big hassle to replace headers, the Cayman is very simple since everything is really under the car with nothing in the way.  You can easily see and access all of the head flange bolts.

The other end has a simple 3-bolt flange which is easy to access after removing the wheel and the small plastic panel.

 The factory nuts rust to the bolts and almost never come out.  Some will break off, others you have to get out the cutting tools.  That is the hardest part of the whole job.

Here are some shots comparing with the factory headers.

Notice the equal length mandrel bent primaries going into a nice 3 into 1 collector on the Fabspeed headers.  The factory has each tube connecting into a single tube into the catalyst.  Also notice how the Fabspeed has a more straight shot through the catalyst whereas the factory hits it at an angle.  I also noticed the inlet side of the factory headers looks very restrictive.

I am surprised how bad the factory headers look for performance.  The Fabspeed design is far better.

Here is what they look like installed.

Here is a video of the very first cold start after the header upgrade. Since I changed only the headers you might expect the sound to be about the same.

It could be my imagination but it seems to rev quicker now.  It does seems to have slightly different sound on acceleration too.  At idle is seems about the same (as expected).  Driving the car after the header install is only slightly different than before.  It seems smoother and it does feel like the power is smoother and a bit higher everywhere.  Some have said they lost a bit down low and gain at the top.  In my case it seems like it gained a bit everywhere.  My case is unique since I left the stock mufflers and downstream cats in place.  As I mentioned before, I had already replaced the very restrictive outlet "T" with mandrel bent tubes back when I got the car.  I also removed the intake sound snorkel and panel and installed a K&N air filter around the same time so both of those mods were done well before.

I plan to install an intake plenum and 82mm GT3 throttle body next.  I am also considering what to do with the mufflers.  Sound is a personal thing.  I don't like a raspy sound or a drone, nor do I like cracks and pops, so I want to be careful to not do that.  I like the sound I have now but would not mind turning the volume of it up a bit.  I am more interested in power than loud.  I also like the induction sound at wide open throttle more than exhaust sound.

Update 3/24/2019: After driving the car a week through several warm-up cycles and some good highway runs I re-torqued the headers per the instructions.  Some bolts were a tad loose so this is a good thing to do and it is very easy (literally a 15 minute job). As expected the headers do change color with use.  Now they look gold (aligning with the price I suppose).

Update 3/29/2019: Now that I have been driving it for a couple weeks I have noticed more about the performance and driveability.  There is a hill on my way home that has a 45mph speed limit.  Before the headers I would have to downshift for that hill, now I don't.  The performance at low RPM is smoother and it has more power there.  Light throttle operation is crisper than before.  The engine is a bit more responsive to throttle input.  The power seems to be a bit more everywhere.  The difference is not huge but it is noticeable. 

Porsche Cayman S Car Stereo Head Unit Upgrade

As I discussed in my Car Stereo Head Unit Wish List post a while back, I wanted to upgrade my stereo to add some features such as navigation and backup camera. I finally did it.  Here is a summary of that installation.

Head Unit Selection

I finally chose the Pumpkin AE0273B-08A. I liked this one because it had:

• A volume knob (a must have)
• Android 8.0
• 4GB RAM (so multiple apps can run smoothly)
• 32GB internal memory (because apps and app data does best here)
• Google Play store (so I can install any apps I want like Waze, Google Maps, etc.)
• Capacitive tough screen (versus resistive or other)
• Backup camera support
• External GPS and WiFi antennas (for better GPS accuracy)

The way I will use this when I am on the road is just hotspot my phone and let the unit connect to it via WiFi (for internet) and Bluetooth (for hands free calling).  This way the head unit does all the heavy lifting for navigation,Waze, etc. I can also run Spotify, Amazon Music, Play Music, etc., right in this unit and control it without having to mess with my phone.

I purchased this from Amazon for $299.  However you can also buy it directly from Pumpkin for that same price.  By the time you read this it will likely be even less as things like this often drop fast.  When I first saw this unit it was $349.

Electronics Integration

My 2006 Cayman S has the Bose system which makes this upgrade much more complicated and expensive.  The Bose system uses a MOST fiber optic network to communicate between the head unit, CD changer, and amplifier.  The car has a 10 speaker system which uses very low impedance speakers as well. There are several paths you can take when making upgrades to this system but here are the most likely:

1. Replace pretty much everything. Since the speakers are non-standard you would really need to replace all of them except the sub woofer.  The Sub woofer has its own amp and you can connect a standard low-level output to it with some modification.  Everything else though would need to go.  
2. Get a MOST gateway to connect into the factory amplifier and retain the amp and speakers. This way you can just replace the head unit and not have to change the rest.

  I chose option 2.  This sounds like the simpler and cheaper way to go until you see the cost of these gateways.  I found some as cheap as $99 and others over $600.  There is another complication: the factory stereo only has battery power and ground.  Pretty much everything else is handled with data link messages over CAN or MOST.  You could work around the CAN stuff by just running wires to the signals you need (key power, park brake, illumination, reverse gear, etc).  I chose a $300 kit that included both the MOST and CAN gateway modules. One of the differences between the lower priced kits and the most expensive ones is the support of fader.  The Axxess kit I chose only has 2 channel (stereo) inputs so you lose the ability to fade front to back.  In the Cayman this is not a big issue as there are only 2 seats and a very small cabin.  In a larger 4-door vehicle you may want to choose differently.

I used a terminal strip to connect the Axxess kit to the Pumpkin wiring as shown in the photos below.

I got the system installed in the car to find that the CAN module (labelled STK760) did not work.  That module is responsible for energizing the key switch input to the system and it was not being energized.  I called Axxess who makes this kit.  They had me measure voltage in the CAN wires.  Both wires were at 2.5V.  They said this means this CAN network is a slow/symmetric network and so the module in the PO904 kit would not work and I needed the PO90052 instead which has a CAN module labelled STK758.  These modules look the same but support the different CAN types.

I received the PO90052 and installed it.  Now the CAN module worked.  The unit would power up and it supplied the park brake and reverse inputs I needed.  Great, except there was still no sound.  The MOST module did not work.  Rats.  I connected my factory stereo to confirm everything else was still working and it was.  I messaged Axxess tech support with my problem.  He had me send a photo of the wire connection at the MOST module.  From that he determined that they had made the wiring incorrectly and that the amp power ON wire (blue/white) needed to be moved over 2 places.

I figured out how to release the terminal and move it over and it worked! Finally. The terminals are released using a small pin from the front (the side that plugs into the module).  I pushed the pin into each side of the terminal carefully bending the retaining tabs in to release the terminal.  Once you get the terminal out, bend the tabs back out so they will catch when the terminal is placed in the correct spot.

One other thing.  The AXXESS adapter did not include the power antenna power wire in the connector for some reason. Since I did not use any of the speaker wires, I just used one of them (green/black) to go into position A5 of the ISO10847 main power connector and wired it to key ON power coming from the AXXESS CAN module.  Without this the radio reception is poor.

These modules don't have mounts so you need to wrap them in foam before placing them in the dash or else they will rattle around. These modules do not produce much heat. I happened to have some Alcantara headliner material from a few weeks ago when I replaced the headliner in this car. It's perfect for this as it has foam and the Alcantara is actually a durable covering.

Fitting all of this into the dash in a way that will not rattle around and where you can also fit the stereo is a challenge. I put the CAN module into a opening on the left (US drivers) side.  I fit snugly and tucked away clear of the head unit.  I put the MOST module directly behind the head unit towards the left.  It's important to not king the MOST fiber optic leads as they sharp bends can cause problems and these can break.  The bulky ISO connectors also need to be wrapped and tucked out of the way of the head unit.  Unfortunately I ended up with 2 ISO connectors: one from the Axxess integration kit that is used for power and ground, and the other from the Pumpkin wiring that has all the speaker level outputs (which I am not currently using).

Installation into dash

Dash Bezel

This was the biggest challenge.  I purchased a American International POR911S kit.  This kit is actually not good.  The plastic side mounts are too thick to fit the Pumpkin head unit.  They have little mounting tabs that won't compress to fit the opening because they hit the stereo.  If you ever did manage to get a head unit installed, removing it again would be a bear.  The only part I used was the dash bezel itself and even that required significant modifications.  The opening was too small to fit the Pumpkin properly so I had to trim it, a bunch. I used a router with a very small bit to carefully trim the opening.

Trimming the bezel with a router

I did the trimming by carefully setting the depth and trimming the back side of the opening.  Then I finished with a file.  I had to trim in many places to make this fit correctly.  I think I spend about 4 hours just on the bezel.

Bezel trimmed and set in place

Now I needed a way to retain the bezel.  The bezel kit was set up to have the side mounts also hold the bezel but this will not work in my installation with custom mounts. I needed to make clips that had some spring to them that would fit into the slots in the bezel and behind the side panels that fit on either side of the center console.  These side panels clip and screw in place well so these clips would hold the bezel firmly in place once the side panels were installed.  I bought some 90 degree speed nuts from the hardware store and began modifying them into retention clips.

These will fit in the bezel slots in the sides and then catch behind the center stack trim panels of the Cayman to retain the bezel.  I also attached felt pads like the ones you use on kitchen cabinets to create for constant pressure to hold the bezel tight.

Head Unit Mounts

Now I needed to fabricate mounts for the Pumpkin since the ones in the kit were not going to work.  I started with raw sheet metal from the hardware store.  I used the plastic mounts from the POR911S kit as patterns.  I used a sheet metal cutting blade on the table saw to carefully cut the metal for the mounts.

Significant drilling, bending, and shaping ensued.  I also had to add screws and nut to fit into the slides to hold the back of the head unit.  Of course this made it too thick to fit so I had to grind them down.  I then set the unit in place in the dash with the bezel in place to find the right depth.

I marked it in the image above.  I then removed the mounts and carefully bent this front edge.  This limits how deep the stereo goes into the dash to meet the bezel properly.  I also had to trim the bent edge to eliminate interference with the bezel.  I trimmed the back of the bezel to also allow proper clearance.  Once I got everything to fit, I cleaned, primed, and painted these new mounts so they would not rust. Obviously I was not going for pretty here.

Next I needed to figure out how to actually retain the radio and the bezel.  The factory mount had a set screw on the passengers side.  I noticed the drivers side also had a spot for a set screw so I installed one.  Now I had set screws on both sides.  I set the head unit in place and ran the screws in until they left marks on the mounts.  I then drilled small holes right where these screws contacted so the screw would not lock into the holes.  

Great, now the head unit mounts firmly in place.  I do track days and solid mounts are very important.

Backup Camera

When I first got the Pumpkin I powered it up on the table and set it up, installing the apps I wanted and configuring it.  I connected an old camcorder to it to test the backup camera and video inputs.  The Pumkin did not recognize the signal.  I also noticed that Pumpkin says to use their backup camera to ensure compatibility.  So fine, I bought their camera for $15.  When it showed up I immediately noticed how huge it was.  

I went ahead and mounted this one in the front for a front facing parking camera.  It fit in the pocket under the front license plate.  Since this and the pocket are all black, it blends right in.

The Pumpkin has a video in you can connect this to.  I put a quick link to this video in on the bottom row of the main UI screen.  Tap that button and the camera pops right up.

Then I started searching for a better place to mount this and route the wires.  It was looking very grim.  There is really not a good place on this car for a camera and even if I could find a spot, how would I route the wires?  It was looking like I would have to remove the whole bumper cover or something to route the wires.  The exhaust system spans the whole back of this car so running wires from underneath was not going to work.  Then I found this thread on Planet 9.  I also found a better and much smaller backup camera on Amazon from TOPTIERPRO.  This had a mounting bracket that went behind the license plate instead of in top and the camera was much smaller.

I removed the taillight assembly on the right side and the right side license plate assembly.  Now you can actually see right through from the taillight opening to the license plate light opening.  Nice.

I used a coat hanger, cut it and bent it straight with a hook on the end and pulled the wires right though.  I used a small round file to make a notch in the back inner corner of the license light opening for the wires and snapped the license light back in place.

I connected the camera power and ground wires to the backup light wire and taillight ground as shown below using a terminal block. Note that this connector is inside the car, protected from weather.

I tucked the camera wires under the taillight seal which is a thick foam.  I also taped the wires in place and tapes the connectors which are outside the interior and not fully protected from weather.

It works very well.  This camera has very bright white LED lights to assist the backup lights.

The backup camera function does not require that Android be booted up to work.  When reverse is selected the unit directly feeds the camera to the screen.  

Parts and Tools Needed

Parts List

• Pumpkin AE0273B-08A Android stereo head unit if found on Amazon.
• American International POR911S dash kit.
• Axxess  PO90052 or PO904 head unit replacement kit. There are other options and this is only needed if you plan to retain the Bose amp (and that you have the Bose sound system).
• Sheet metal stock.  I used 22 gauge steel.  
• 90 degree angle speed nuts to be modified to retain the bezel.
• Screw to retain head unit similar to the one on the right side.
• Small screws and nuts for mounts to slide into opening.
• Terminal strip to connect Pumpkin wiring to the Axxess integration kit.
• Primer and paint to paint the fabricated mounts so they don't rust.
• Antenna adapter for the AM/FM antenna lead. 
• TOPTIERPRO backup camera if found on Amazon. Others will also work.

Tools List

• Screwdrivers.
• Torx drivers.
• 7mm wrench.
• wire cutters and strippers.
• Router with 3/16" straight bit.
• Table saw with sheet metal cutting blade.
• Hammers and chisels to make mounts and bezel clips.
• Plastic prying tool to remove trim.

Using the System

Sound

At low to mid volume the sound seems very similar to before, as expected.  From about 3/4 volume to max it seems like it may not get quite as loud as before.  It still gets plenty loud for me.  I would guess it is maybe 15% less loud at max.  As I mentioned, I can't fade the sound since the Axxess kit has only 2 channels for input.  

I could easily wire the subwoofer output from the Pumpkin to the Bose subwoofer since this has its own amplifier with line inputs.  This would enable the subwoofer control from the Pumkin so you could adjust the subwoofer level.  I did not bother with this as it seems fine running the subwoofer through the factory Bose system. I doubt this would improve sound quality but it would give the user a bit more control.

9/7/2018 update:  I installed an AXXESS AX-LDBK Universal Line Output Converter Power Converter between the head unit and the MOST adapter.  This gives the ability to add some gain to the line level signal going to the MOST box.  I was able to completely restore the sound level and quality to match the factory head unit. This little $35 unit is well worth it. 

UI

The UI is good.  It seems very responsive.  The launcher they provided seems good too.  This has less system apps than most Android devices and this makes sense.  The use cases for a car stereo head unit are of course different. The apps they provided are simple and functional.  You can of course install different launchers, some focused on car stereos like this.  I have VLC Player installed and it gives a bit better experience for navigating a large music and video library than their apps.  The great thing about having Android in the dash is flexibility.

The screen resolution is 1024x600.  Apps with a light theme, such as Google Maps, look a bit washed out.  Dark theme apps look great.  There is no contrast adjustment in the UI either but it can be done by disassembling the unit.  It has a dash illumination input that will dim the dash a predetermined amount (could not find any adjustment for this) when the dash lights are turned ON.  This can also be used to turn ON the button illumination but you can also configure it to illuminate the button with key power too.

The Android 8.0 OS is very bare bones and focused on being a car stereo head unit.  It reports as a Rockchip PX5 tablet.  It lacks several common Android settings such as developer settings.  You can put it in developer mode but still no developer settings are shown.  It seems the only widgets that work are the ones that are pre-installed.  I installed several apps that generally have widgets yet none are available.  Some apps like Google Contacts will load but when you open them and it asks for an account it will not log in to the same account the connected phone has.  After I tried this though I realized there is not really a use case where I want to use the contact app.  If you go to the Phone app in the Pumpkin it does sync your phone contacts there.  I am not able to get any apps to start at boot.  I have Tasker installed and set up to start at boot but it never does.

Unlike many, I really don't like a touchscreen while driving.  I actually really like the Mercedes Benz Command UI where it has buttons to get to things like radio, navigation, etc., and a center console knob as well as dedicated volume knob, next/last buttons and more.  You can feel and control them without taking your eyes off the road.  This Pumpkin can be controlled with Bluetooth or USB input devices such as a mouse, trackball, or media controllers.  I connected a standard PC USB mouse and it worked fine.  I found many simple Bluetooth media controllers that should also work giving physical buttons for play/pause, previous/next, and more.  There is this thread on XDA Developers though which indicates this may not work. Ideally I would like to make a controller that is similar to the Command control and this should be very doable. Besides USB and Bluetooth, I could also set up dedicated buttons using the steering wheel control inputs.  This can be done with simple switches and resistors and the Pumpkin has a mapping utility in it already.

System

Powering up from completely OFF takes about 15s to 20s.  It has a mode where it suspends instead of completely shutting down and waking from that mode is pretty much instant.  The downside of that instant mode is it will use more of your cars battery.  You can set how long the key is OFF before it fully shuts down.  I found that the Axxess MOST module takes several seconds to power up and start delivering sound anyway, something like 8s.

This unit has 32GB on-board which is more than enough space for all the apps and their main data.  It has 2 micro-SD card slots as well as 2 USB ports.  The documentation says "Support SD card/ USB drive up to 128GB".  I presume this means each can have 128GB?  Not sure but it is more than enough anyway.  I have one 8GB and one 16GB micro-SD cards in it now.  I also had a 64GB USB drive connected.  All worked fine.

I set up my phone as a WiFi hotspot that the Pumpkin connects to for a network connection when driving.  I used Tasker to automate this so that when my phone connects to the Pumpkin for hands-free calling, it also enables the WiFi hotspot on my phone.  When my phone Bluetooth disconnects from the Pumpkin at key OFF the hotspot is returned to its previous state (OFF in my case). 

Tasker profile to see the car connected and turn ON hotspot

It is interesting how focused Android is on battery powered mobile devices.  I guess I didn't think about it much until I got this device.  Unlike phones or tablets, this device has infinite power available (the cars charging system).  Things like battery optimization features are not useful here.  

Final Thoughts

This installation was more difficult than I expected but I would do it again.  I just got it done so I have not used it much yet.  I may add a follow-up in a few months.

I noticed deep in the "factory settings" menu that there are CAN (car data link) settings for many manufacturers including Porsche.  I asked on the Pumpkin support site about this and hope to get some info from them.  

Short demonstration after the installation 

(if the video does not play click "YouTube" to open it in YouTube app or separate browser tab)

Update 9-2020

Using a touch screen in a Porsche sports car on Illinois roads does not work well at all.  Even when bracing your hand with your thumb to try a touch gesture, it is too easy for your finger to slide and the OS think you are giving a slide gesture instead of touch.  I much prefer the knob my Mercedes Command systems have.  My Porsche does not have steering wheel controls.  I decided I would add a few switches to allow for some more controls and depend less on the touch screen.  After looked at many options I settled on a membrane switch in the ash tray (which I never use anyway).  I bought the switch on Amazon for under $10.

I used a simple terminal strip and 4, 100 Ohm resistors.

The head unit has the key-mapping tool build in.  You just open the tool, press a button, and then select the short and long press responses you want.