haz_norway

Hello, first time poster, and sorry to be asking for your help already but I really need some smart thinkers - quick.

I am having misfire on cylinder 1 - 2 -3 and this morning the CEL came on and the car studdered and almost stalled completely.

History:

1: New MAF 4 weeks ago.

2: Two weeks ago it started to "chase" revs when idling, up/down, up/down so I checked and got these error codes:

P1341 Camshaft adjustment bank 1
P0300 Misfire detection
P0302 Misfire cylinder 2
P0303 Misfire cylinder 3


3: So yesterday I replaced all plugs to Beru (previous one were Bosch) and coils for cylinder 2 and 3 --> Same error codes! Now it even says misfiring on cylinder 1!

Then this morning the car almost stalled as described above + CEL.

Could it be that the problem is the left bank, since cylinder 1-2-3 is on the same bank? I'm asking since "Macster" said this could be the issue in this thread:

https://rennlist.com/forums/997-foru...s-4-5-6-a.html

Any tips are greatly appreciated

Macster

The root cause is (my WAG) the VarioCam solenoid/actuator. The misfires arise from the DME attempting to adjust fueling to get the O2 sensor readings back to what they should be.

When the solenoid/actuator failed on my 02 Boxster there were no misfires but I observed with an OBD2 scan tool the fuel trims and they were well, very odd, compared to the other bank's fuel trims.

Later, when I had the car in the shop, and when I talked to the tech about this he said that was confirmation of the VarioCam hardware failure and had the failure gotten worse misfires could have followed.

Before any real wrenching is done though the connections to the solenoid need to be checked.

My advice is you do not delay in getting this looked at and avoid running the engine. If I'm right in the case of your car the failure is more severe, further along, than it was in my car.

In the case of my car, while there was some up and down idle speed variation along with a rough idle there were no misfires, not even a check engine light although a reading of the pending codes found one related to the camshaft adjustment.

Also, be aware that while the solenoid can be tested and replaced if bad the actuator can't be tested other than by replacing the solenoid and buttoning up the engine then driving the car.

Often, I'm told, the actuator is bad and the techs I talk to recommend doing the actuator at the same time. It is more money (more labor approx. 4 more hours) and the actuator is not cheap (nor is the solenoid) but if just the solenoid is replaced and later -- in my car's case the day after I got it back -- the actuator proves to be bad there is a lot of duplication of the work to get to the actuator.

My car's case was an odd one. I was never asked if I wanted to replace both items. Had I been asked I would have gone with the tech's recommendation which I found out later would have been to replace both at the same time.

Only the *solenoid* was replaced. A day later the engine acted up and this time the CEL came on with same error and I took the car back.

The diagnosis was the actuator was bad. (My theory is the failing solenoid causes the actuator to fail, wear out.) The dealer service department agreed to eat the cost of any duplicate work and parts/supplies (the camshaft cover bolts have to be replaced) and all I would have to do would be to pay for any labor that was directly related to the actuator R&R and of course the parts cost for the actuator.

I agreed and the work was done and I have a bad solenoid and an actuator at my desk at work and the engine has been just fine since the work roughly 25K miles ago.

Side note: I asked the tech about the other side. He said he'd wait until it signals it needs attention. I asked him what about the VarioCam chain rails, their wear? Should these be replaced as a preventative measure? He told me let's wait and see what the ones on the bad actuator look like. They looked just fine, with minimal wear so the decision was to leave the other bank's solenoid, actuator, and actuator rails alone.

haz_norway

Congrats on a very helpfull 9400th. post, Macster

Thanks, I think I´ll just flatbed the car to my local PC. I´m afraid this is going to be big $$$

Just did the IMS also... damn these cars can be costly. Has perfect service history even..

Again, thanks.

Macster

I won't sugar coat it. The total cost for my 02 was around $3K. But the engine was sick and it was not going to get any better on its own.

It was either fix the engine or scrap the car, sell it as essentially a non-running car.

The engine had around 250K miles on it at the time but was in otherwise fine shape, as was the rest of the car. I priced some replacement cars -- not even Porsches -- and decided spending $3K was better than spending $30K...

Oh, my car has had excellent service, too. 5K mile oil/filter services and other services on time/schedule. It was not a service issue. The solenoid is an electrical device and somehow it failed electrically. (I think it failed intermittently and this intermittent behavior is what wore out the actuator, which is just a very fancy hydraulic valve body activated by the solenoid.)

Actually good servicing pays off in that because in the case of my car the rest of the car was in good shape and everything worked there were no "little" problems, I knew that underneath the car was still very solid and viable platform and if I fixed the VarioCam hardware I would have a car that would take me perhaps another 250K miles.

haz_norway

Nice info, thx. Mine has 100k miles.

haz_norway

I have made an appointment to have it scanned at Porsche Center for a diagnosis on monday..

haz_norway

Mechanic @ Porsche Center called: it's the cam shaft variator that's gone. He talked about my car having vario cam bla bla. He talked so fast.. he is going to email me an offer, but he did imply a job in the range of $1800-3000.....

If this part http://www.design911.co.uk/fu/prod13...r-99660610602/ is the correct part that he is offering to replace, I'll flatbed the Boxster to my local indy thank you very much..

Macster

You need to get it confirmed what part or parts the mechanic from the Porsche Center was talking about replacing.

The part at the link is the sensor. The error codes do not point to the sensor, but to the either the solenoid or actuator.

As I mentioned in a previous post I had this repair done on my Boxster. The SOP is to replace both the solenoid and the actuator. There is no way to determine which component has failed. If one just replaces the solenoid the risk is the actuator is bad -- which proved to be the case in the case of my car --- and there is a lot of duplication of labor to go back in and replace the actuator. Fortunately for me this duplication of labor was absorbed by the dealer because the tech failed to give me the option to replace both and the dealer management knows me well enough to know I would have gone along with what the tech advised.

'course, the extra cost to replace the actuator is not insignificant. IIRC the labor is another 4 hours and the part cost is high, around $800. (The solenoid was nearly that high.)

You need to talk to a trusted tech and get his input, and pay closer attention. Is it really the sensor he believes needs to be replaced, or is it the solenoid, or the actuator? What about both the solenoid and the actuator?

haz_norway

Thanks Macster.

Got an email from my PC mechanic. He is asking $5000 :barf:

This is the part that needs replaced and a bunch of small stuff like screws and o rings.

http://www.rmeuropean.com/Part-Numbe..._8ADE1731.aspx

+ many other small parts... I don´t know what to say...

90006737201
99914103207
99610421554
99970721540
99970734341
00004320373

Macster

That's the VarioCam actuator. I guess it does not include the solenoid.

My (limited) experience is both should be replaced, but if your trusted tech feels otherwise, that's his call. He is after all the expert.

As for the cost, I knew it would not be pretty. Since I do not know your location I can't offer much in the way of comment on that "$5000" quote for just the actuator other than it seems a mite high to me, to put it mildly.

But different regions charge different amounts for similar repairs and there the issue of the exchange rate if you are not located in a region that uses USA dollars for money.

As I mentioned in an earlier post, the solenoid/actuator job on my Boxster ran to around $3K. This job was done at least a year ago and probably longer...checked some pictures and the job appears to have been done around January of 2011, just about 2 years ago

Both the solenoid and actuator were replaced. About half the cost was in parts, primarily the solenoid (roughly $700) and actuator (roughly $800). (I am a PCA member and my dealer service (and parts) department give me a discount.)

Together the major items cost about $1500. Labor and incidentals accounted for the rest. (Labor was billed at $150/hour.)

haz_norway

That's right.

I'm considering doing the job at a Porsche engine rebuild specialist that did my IMS upgrade this summer. He has a used actuator and gave me a great price (one third of PCO) for the parts and job.

Will keep you posted.

Macster

How would someone end up with a used actuator that was any good?

It is up to you but if it were me paying that money I'd want a new one used, one with a warranty that covered a defective part.

flyingpenguin

Macster,

I have followed your comments on the board with much interest over the past years. Learned a lot from it.

You mentioned this before, that the Variocam actuator (so the hydraulic part, without the solenoid attached to it), can go bad, but that it is difficult, if not impossible to bench test.

I have taken a few apart and wonder WHAT it is that goes bad. It is a simple machined casting with a valve shaft operated by the solenoid, that channels oil into an expanding / contracting piston that is under spring tension.

If the valve shaft can move freely and the spring loaded piston has tension and moves up and down, I figure the actuator is OK.

Am I missing something?

If not, replacing just the solenoid is about a quarter of the cost vs. replacing the whole actuator assembly.

haz_norway, I am travelling to Bergen in February, so could bring (small quantity of) parts if needed. I know how expensive everything is in your neck of the Woods.

Joost

Macster

I do not recall saying the unit is difficult or even impossible to bench test.

However, now that you brought this up I would offer my opinion VarioCam actuator bench testing is while probably not real difficult -- it depends upon the skill level and motivation of the person setting up the test and doing the testing -- the results are likely to be not trustworthy. (More on this below.)

I just looked for my old actuator and I can't find it but working from memory I do not recall seeing any screws/bolts by which to disassemble the thing. I wanted to take it apart and see what was inside it and to get an idea of what it actually did inside, besides the obvious of moving the rail one direction or the other to change the intake valve timing.

What I was told was -- in the case of the Boxster engine at any rate -- is there is no way to know if the actuator is bad without installing the solenoid and buttoning up the engine and driving the car.

The problem is if the actuator is bad quite a bit of the cost of doing the actuator is the duplication of the work to the actuator, which is "below" the solenoid. IOWs, one has to disassemble the engine to the point he's at the solenoid again then go further, IIRC another 4 hours' worth of labor further.

Thus to avoid the risk of a comeback the (Porsche dealer) techs I have spoken to about this tell me that the SOP is to replace both the solenoid and the actuator. Under warranty I believe this is what the factory has them do. Out of warranty the recommendation is to replace both items but it is left to the customer to decide.

As for bench testing, the factory does not bother to require this and it won't pay for the time for the tech to do this and the dealer will not pay for the tech's time to do this. The tech would have to be willing to do this on his own time and in lieu of working on a job for which he gets paid. There is the time/cost involved in putting together a rig as well.

Anyhow, if there are specific error codes, with or without symptoms, and other tests/checks eliminate other causes for the error codes and any symptoms, the repair procedure is to replace both items.

Besides, I dare say no tech would want to bench test the unit and base his decision to replace or reuse based on the test results. For one thing the new parts are warrantied so if he installs a new actuator and it proves bad the factory eats the cost to redo the job.

If the tech oks the unit based on bench test results the dealer eats the cost. I imagine the 1st time the dealer had to pay for a comeback the test rig would end up on the dumpster and tech reassigned to less desirable work.

Also, there is bench testing and there is bench testing. While one might be able to rig up some fixture to route oil to the unit there's the question of all the variables: not only oil but oil pressure, temperature, and the real world forces on the unit from the camshaft chain, how often the actuator gets well, actuated, and so on.

I note in the case of my Boxster the bad actuator didn't act up after the solenoid was replaced and the engine buttoned up and the car road tested. It acted up later after I had picked up the car and drove it around some time and at the engine spend some time operating at its operating temperature then the error code came back along with the symptoms.

The next day the actuator was replaced and the symptoms were gone.

In short I would say if your acceptance criteria for a good actuator is that under some very limited test condition "the valve shaft can move freely and the spring loaded piston has tension and moves up and down" you are likely to be disappointed more often than not once the deemed good actuator is actually put back into service and the truth of its condition is determined in real service conditions.

Only if you do a significant number of these and after the above results you find in actual service the actuators are ok then you will have a bench test you can rely upon to identify bad vs. good actuators.

If you have any real costs associated with this bench test and the results it provides you it could prove costly to you if the success rate is not high. Very costly.

flyingpenguin

Agree with Macster that a professional shop environment puts different economic considerations into the equation then when you are working on your own car, don't keep close track of the hours because you have to make a living out of it, and out of pocket for parts may be a bigger consideration that down time and hours spent on getting the job done.

Having said that, I'd still be interested in additional input on what makes the actuator go bad and how to verify with acceptable (this is subjective..) accuracy if replacement is an absolute must or not.