To remove or not to remove

[doli3415]

That is the question...

MY 1998 Boxster 2.5L manual transmission with 114k, is having a few issues. Out of the blue a couple of weeks ago it started to misfire as soon as I put it into 1st or reverser. Ran the codes came up with 300, 301, 302, 303, and 341. Started researching and of course it could be this and it could be that. Replaced the spark plugs, checked the coils and replaced the fuel and air filters. Started the car,same result, and ran the codes and same ones as above along with 1313,1314,1315, and 1319. still misfire codes with emission relevant codes. Replaced the O2 sensors(all of them) Same result again. More research, could be a camshaft position sensor on bank 1. replaced sensor, No help but it kick off more codes. All of the aforementioned plus 1340, 1397 and 0150.

Now I'm beginning to think is a variocam actuator problem, which for me would mean that I need to pull the engine and replace. So back to my question...TO REMOVE OR NOT TO REMOVE? I'm I being too premature or is this where my problem is headed?

Any advise is welcome.

[Topless]

Get a clear diagnosis first, pull the motor last. It's a process of elimination. I would get a PST2 on there and dig deeper into the problem. If you are getting a bunch of random error codes in might be damaged DME wiring by rodents or maybe it got wet or overheated. Little car computers don't like water or excess heat.

Any oil/coolant intermix?

Make a list of possible causes and check them off starting with the easiest one first. Don't swap any more parts until you are sure you found a bad one.

[doli3415]

No oil or coolant contamination. However it does have power loss when I put in gear along with a "rattle" noise.

[JFP in PA]

Originally Posted by doli3415

No oil or coolant contamination. However it does have power loss when I put in gear along with a "rattle" noise.

What tool are you using to read the codes? If it is the Durametric, look at your cam deviation values to see where the cams are at idle.

[doli3415]

I'm beginning to think that I need to upgrade my diagnostic equipment. I'm using a Actron to read the codes (and there are a lot of them) but I need something that looks a little deeper.

[RandallNeighbour]

The durametric is designed specifically for our cars and will be head and shoulders better than an Actron code reading unit.

[JFP in PA]

Originally Posted by doli3415

I'm beginning to think that I need to upgrade my diagnostic equipment. I'm using a Actron to read the codes (and there are a lot of them) but I need something that looks a little deeper.

Actron is fine for general purpose use, but it will not read cam deviation values like the Durametric system, and cannot activate the VarioCam system to test it, which the Durametric also does.

[doli3415]

Just ordered the Durametric. What should I be looking for when I initially hook it up?

[doli3415]

Ok hooked up the durametric, lot of interesting information. I read the codes and same codes as before. 300,301,302,303, 341,1313,1314,1315,1319. Plus I checked the camshaft deviation #1 is .25% and # 2 is -.4% is that normal?

the car has a misfire/rough idle around 1000-1200rpm with an associated noise like a rattle or a chain flapping.

I've checked the wiring, checked the coils, and the plugs, the AOS has oil in the tube going to the TB. I've cleaned the TB and the MAF sensor. replaced the air filter and fuel filter. No Help. I need HELP!!! please.

[thstone]

Per JHP:

Does the camshaft deviation vary at idle or is it constant?

Try activating the VarioCam.

[jb92563]

Originally Posted by doli3415

Ok hooked up the durametric, lot of interesting information. I read the codes and same codes as before. 300,301,302,303, 341,1313,1314,1315,1319. Plus I checked the camshaft deviation #1 is .25% and # 2 is -.4% is that normal?

Seems good. The acceptable range I've read is between 0 and -6 degrees.

The key is that these numbers are steady and don't fluctuate rapidly.

If they are bouncing around then there is a problem with the timing system, likely the chain/tensioners/variocam.

[doli3415]

I ran the camshaft deviation test again. # 1 is 25.0 and # 2 is -4.0. in addition I activated the variocam on both sides (separately of course). When activating the # 2 bank the idle increased and decreased slightly. # 1 bank however almost stalled the car. I believe it's working but with the misfire on that bank the engine couldn't handle it.

Any Thoughts

[JFP in PA]

Originally Posted by doli3415

I ran the camshaft deviation test again. # 1 is 25.0 and # 2 is -4.0. in addition I activated the variocam on both sides (separately of course). When activating the # 2 bank the idle increased and decreased slightly. # 1 bank however almost stalled the car. I believe it's working but with the misfire on that bank the engine couldn't handle it.

Any Thoughts

Cam deviation value limits are +/- 6 degrees; if you are really reading +25 degrees on bank number one (at idle, VarioCam not activated), you have a problem as the cam seems stuck in the advanced position.

[doli3415]

The # 1 bank camshaft deviation is +25.0, and when I activate the variocam it seems to be actuating due to the idle fluctuates up and down. Which almost stalls the engine. If the camshaft is stuck in the advance position how do I correct that?

Could the camshaft position sensor cause this? How can I test that?

[thom4782]

JFP: could a stuck or broken variocam solenoid cause the large deviation?

[doli3415]

OK I've eliminated the cam position sensors by swapping them, still getting a deviation of 25.0. It seems to run good until the engine warms up. Its looking more like the variocam solenoid, which if that's the case I'm going to pull the engine and take care of a few other upgrades. One last question; Could the AOS cause this issue? there is oil present in the J-tube when I removed it.

[thom4782]

My guess is that your variocam actuator itself or its solenoid is the problem. I can't think of how a failing AOS would affect the cam especially on one side only. BTW: I did not need to pull the engine to replace the solenoid on the bank where it failed on my car.

[BYprodriver]

Originally Posted by doli3415

OK I've eliminated the cam position sensors by swapping them, still getting a deviation of 25.0. It seems to run good until the engine warms up. Its looking more like the variocam solenoid, which if that's the case I'm going to pull the engine and take care of a few other upgrades. One last question; Could the AOS cause this issue? there is oil present in the J-tube when I removed it.

AOS won't affect the cam timing. When AOS goes bad it just allows more vacum to the crankcase which sucks more air & oil into the intake.

[jb92563]

I wonder if you actuate the variocam with the engine off, perhaps you could actually hear if its trying to activate.

Listen to the good side to compare.

If you hear nothing either the solenoid is dead, stuck or the wiring/connector are at fault.

The misfires will probably stop once its working again and the timing is right.

Here is a good discussion on Camshaft Deviation. http://www.renntech.org/forums/topic/32942-camshaft-timingdurametric-readingerrors/?p=175209&fromsearch=1#entry175209

Thread #12 at the link discusses variocam function and the deviation...interesting and enlightening reading.

It just so happens to be that with the vario cam ON, the deviation is supposed to be 25 degrees, so perhaps yours is stuck or jammed up some how.


a detailed explanation of the VarioCam here http://www.renntech.org/forums/topic/32274-variocam-vs-variocamplus-a-primer/?p=171252&fromsearch=1#entry171252

[doli3415]

Tried to activate bank 1 variocam with the car not running, I could not hear anything. Does that mean its stuck? Now when the car is running and I activate it the car almost stalls out.

I guess I know what needs to be done but I looking for direction. What direction am I headed????