I just picked up my first Boxster a few weeks back. Its a 1999 2.5L Manual. When i picked the car up the check engine light was on, i asked the seller about it. I was told it was a bad O2 sensor, no big deal. Well by the time i made the 30 mile drive home the check engine light cleared, car ran great the whole way. The car has 70K miles on it and needs the rear bearing replaced, again not a big deal. Well two days ago i drove it to work, ran fine. When i finished my shift i got in the car, started it up. Right away i had a rough Idle, check engine came one and felt like it wanted to stall. Took it to Autozone and had codes pulled, this is what i got. p0410, p1411, p0300, p0301,p0302, p0303, and p0341. I know what the codes are just want to know if one thing could be causing all the codes to pop up? Could it just me a issue with the camshaft sensor or wiring back to DME? or something more? Thanks in advance...

 

Sorry I have to list them just to get a better idea of what may be going on.

P0410 - Secondary Air Injection System - Signal Implausible (Cylinders 1 - 3)

P1411 - Secondary Air Injection System - Signal Implausible (Cylinders 4 - 6)

P0341 - Camshaft Position Sensor 1 - Signal Implausible, Short to Ground, Short to B+

And the misfire codes...

There are two problems. (Unless there is just one or 3 or more...)

Seriously, I think there are (at least) two problems. The secondary air injection system -- to state the obvious -- and the camshaft position sensor.

Now that all 3 error codes are due to implausible signals that suggests a common failure and one could be the wiring harness or even the DME.

However, the misfires are all on Bank 1 and this bank also has the suspect camshaft position sensor that manifested the P0341 code. This strongly suggests there is real problem with the camshaft position sensor or the camshaft position hardware (the VarioCam system) and the result is misfires on that bank. I know from when my 02 suffered a VarioCam solenoid/actuator failure the DME will try to adjust teh fuel trims of the cylinders of the affected bank to try to get the 02 sensor readings it expects and the techs told me this can lead to misfires as the DME will go too far.

The car is new to you and you do not know its history. Thus wiring harness as I covered above could be the issue. Or someone has been at the engine and disturbed the wiring. Perhaps connectors are not securely connected?

On a related note perhaps the engine was recently cleaned/washed prior to offering the car for sale? If so the issues could arise from moisture in some connectors. So an expedition to find the related connectors, carefully disconnect them and clean them with a proper cleaner, be sure they are dry, then just as carefully reconnect the connector could be the solution.

This could be the solution anyhow as over time the connectors can build up a surface corrosion that affects signal integrity.

You have to check too for the possibility of rodent damage. If the car sat too long unused before sale or I hate to say this but this was the reason for the sale...mice (or rats) could have been at the car and untoward engine behavior and inexplicable DTCs are often the initial things that have the car in the shop.

Of course the secondary air injection system sensor could be bad. If this is not too hard to/expensive to replace you could throw a new part at this. While you are there check the wiring, connections, and hoses and such for any signs of damage or just aging. The car is going on 14 years old and the hoses and such can be failing due to age.

You might consider getting the car to a qualified tech for a pro's diagnosis too. Sometimes an hour's intelligent diagnosis can save you hours online and save you from buying expensive and unnecessary parts.

 

Have an update, as it is a new car to me im giving it a tune up and checking the basic health of the car. I noticed i had some oil just below all 3 coils on cylinder 1,2 and 3. I removed spark plug #3 and oil poured out of the tunnel. Im guessing this would explain the misfiring codes on all 3 on bank 1. Now i guess my question is what would cause oil to find its way there? The spark plug its self looks great, nic even burn, looks to be color consistent with a properly firering plug. No oil found on plug past where it threads in the head. Can i replace tubes as it seems they may have cracked? Thanks again for your quick response. Im new to boxsters,have had a bunch of 944's and a 924's and now a 951. The Boxster seems to be a different animal.

 

Changed out plugs, cleaned out oil but still have misfire issue, look like ill be digging deeper tomorrow..

 

Ok here is the final update. My misfire codes we're caused by my verio cam actuator chain guide being broken. Looks like it over heated, pitted and cracked. Replaced it and im back on the road.

 

Did you take pics of the guide?

The guide can look a bit worse for the wear but still be quite alright. The chain initially wears a groove into the plastic but and takes away the smooth surface as the plastic is porous and the layer of plastic over these holes is thin. As the rollers make contact with the plastic there is a bit more wear at the thin plastic layers fracture exposing the holes (pits). Then there is no more wear barring no oiling/mechanical problems (like a failing tensioner which let the chain slap the guide and possibly fracture the plastic.)

BTW, the pits (porosity) are (is) on purpose to help hold oil to lube the chain as it slides over the plastic.

With around 250K miles on it, here's the old one from my Boxster:



The guide was fine, the actuator was bad.

Here's a new one:

 

No sorry i did not take a pic but that is exactly what it looked like. I did notice when i replaced the IMS bearing the bottom tensioner was stuck in the compressed position. I replaced the tensioner also so hope i wont have anymore issues with it for a while. No i have a ticking sound for about 1-2 sec on cold turnup on the same bank, maybe a stuck lifter? Sound goes right away an car runs great.

 

If the noise goes away right after starting the engine the lifter is not stuck, or collapsed. What you are probably hearing is just the normal noise hydraulic lifters make until they get pressurized oil. If the noise is not too bad and doesn't continue or reappear when the engine is up to temperature and as long as the CEL stays off and the engine doesn't exhibit any untoward behavior I'd offer the noise is really nothing to worry about.

Noises are funny. Upon cold start of my Boxster I was hearing a deep bass knocking noise. I was convinced it was coming from the engine, the crankshaft, probably the crankshaft end play being too great. I decided nothing I could do about it and I'd just continue to drive the car until I was forced to deal with the cause of the noise. With around 280K miles on the engine I figured it was just wearing out. Well, after a failed smog test and having a tech diagnose the buzzing noise I would hear from the car not being from loose heat shields like I thought but instead coming from the converter I finally broke down and bought 2 used converters and had them installed. As expected the new converters eliminated the buzzing noise. And so far the P0430 error code which used to appear once in a while with the original converters has not reappeared (nor have any other converter related error codes) but the knocking noise is gone too. I was talking to the tech about this the other day and he confirmed what I suspected and that is the knocking noise cold was from the converter brick knocking about inside the converter housing.

All I can offer is be sure the oil is reasonably fresh and the level is not too low or too high. Fresh oil, reasonably fresh oil, is important. Even with just 5K miles I've really noticed a difference between the noises the engine makes with 5K mile oil vs. fresh oil both at cold and hot starts. Be sure the engine has an approved oil (my preference, naturally) in it with Mobil 1 0w-40 being the factory fill but there are a number of approved 5w-40 oils available and even one approved 5w-50 oil oil (not a typo for 15w-50!).

Last oil change I had my 02 Boxster filled with Mobil 1 5w-50 and the next time the Turbo is due for an oil/filter service it will get 5w-50 oil too and I might just stay with this oil year 'round, as it doesn't get very cold where I live/drive but it gets plenty hot. (For instance, 105F the other day, and later this week and early next it is forecast to get up to 99F maybe a few degrees hotter.)