2001 Boxster Camshaft issues

[blue62]

Originally Posted by maytag

Start with the easy stuff first.
Lumpy idle can very frequently be traced to the MAF. ESPECIALLY when, as you describe, it's fine when cold. But when the motor warms and it kicks out of the pre-programmed cold start settings and starts using sensors to determine settings then it gets rough..... yeah.... in my world that points to MAF all day long.

AND it's easy to check. When your idle gets rough, unplug your MAF and see if it smooths back out.

Always easy stuff first.

Sent from my SM-G970U using Tapatalk

Unplugging your MAF senor to check MAF sensor condition is not a very reliable test of the MAF sensor.
Yes it seems to work if your sensor is bad.
But by unplugging it your not really testing it.

What if you have a vacuum leak?
A vacuum leak can cause lumpy idle, it is a lean condition due to the unmetered air.
When you unplug the MAF the DME reverts to a default fueling strategy based mostly on engine load and RPM.
That default fueling strategy is biased on the rich side which tends to compensate for the lean condition so the car idles and runs rather well with a vacuum leak and the MAF unplugged.
Plug the MAF back in or replace it now the car again idles lumpy because in this case it was a vacuum leak.
So now in this case you have spent what? over $200.00 on a new MAF sensor and not fixed the lumpy idle.

Much more reliable ways to test the MAF.
Fuel trims and comparing Throttle Position Sensor signal to MAF sensor signal are two means.

[maytag]

Originally Posted by blue62

Unplugging your MAF senor to check MAF sensor condition is not a very reliable test of the MAF sensor.
Yes it seems to work if your sensor is bad.
But by unplugging it your not really testing it.

What if you have a vacuum leak?
A vacuum leak can cause lumpy idle, it is a lean condition due to the unmetered air.
When you unplug the MAF the DME reverts to a default fueling strategy based mostly on engine load and RPM.
That default fueling strategy is biased on the rich side which compensates for the lean condition, so the car idles and runs rather well with a vacuum leak and the MAF unplugged.
Plug the MAF back in or replaces it the car again idles lumpy because in this case it was a vacuum leak.
So now in this case you have spent what over $200.00 on a new MAF sensor and not fixed the lumpy idle.

Much more reliable ways to test the MAF.
Fuel trims and comparing Throttle Position Sensor signal to MAF sensor signal are two means.

you're not wrong on any of that, Blue, but I feel like you're barking up a tree which doesn't get much attention because it's so uncommon.

As you say; there are ABSOLUTELY more reliable ways to positively-test a MAF, but none as easy to narrow-down what's going on. Basic Troubleshooting 101 says see if you can produce a change in the symptoms. If unplugging the MAF produces a change in symptoms, then you are one step closer to understanding what's REALLY going on.

We're chasing cam solenoids and timing, without (seemingly) to have checked some of the (honestly more likely) easy and cheap items.

Vacuum leaks are VERY common, of course; but how many of them will show up only during closed-loop, or open-loop? Most of them will be causing the same issue regardless.

Again; y'all can chase whichever squirrels you like, but the OP asked for some suggestions. I'm simply suggesting that the easiest and cheapest things shouldn't be overlooked in favor of something more complex, for no apparent reason. Especially when the more complex things have been checked and seem to be correct.

[blue62]

Originally Posted by maytag

you're not wrong on any of that, Blue, but I feel like you're barking up a tree which doesn't get much attention because it's so uncommon.

As you say; there are ABSOLUTELY more reliable ways to positively-test a MAF, but none as easy to narrow-down what's going on. Basic Troubleshooting 101 says see if you can produce a change in the symptoms. If unplugging the MAF produces a change in symptoms, then you are one step closer to understanding what's REALLY going on.

We're chasing cam solenoids and timing, without (seemingly) to have checked some of the (honestly more likely) easy and cheap items.

Vacuum leaks are VERY common, of course; but how many of them will show up only during closed-loop, or open-loop? Most of them will be causing the same issue regardless.

Again; y'all can chase whichever squirrels you like, but the OP asked for some suggestions. I'm simply suggesting that the easiest and cheapest things shouldn't be overlooked in favor of something more complex, for no apparent reason. Especially when the more complex things have been checked and seem to be correct.

Maytag,
I agree with some of what your saying.
If you have ever read any of my previous posts I very often suggest that a person check and prove good or bad the simplest things first and work their way up the diagnostic ladder step by step from simplest to most complex.

I first started trying to help Kbod in another thread that addressed the same issue he is describing in this thread.
In both threads he has stated that he gets a reoccurring P1341 code. Bank 1
Lumpy idle after warmup and stalling at stops.
He also has excessive Cam deviation on Bank 1

Vacuum leaks are very simple and basic and can cause lumpy idle and stalling.
That is why I mentioned Vacuum leaks to Kbod.
Many time they only cause lumpy idle and stalling after warmup. Why?
Because on cold start open loop the DME is providing a very rich mixture with no feedback from the O2 sensors. Tends to compensate for the unmetered air from the vacuum leak, so the car may idle just fine.. Once the system warms up and goes into closed loop the mixture leans out and becomes too lean at idle because of the vacuum leak. So you may get lumpy idle warmed up but not on cold start.

What I first suggested to Kbod was to check for any wiring issues related to the Cam position sensor on bank 1
Why? The P1341 code.
Checking the wiring and testing the Cam position sensor would be my starting point.
I don't know how to go about testing a Cam position sensor. So I suggested replacing it.
Seemed the simplest, most basic most logical and cheapest to me.
I mentioned Cam timing because Kbod had replaced the Actuator on bank 1.
and still has the issue.
Not sure how I am barking up the wrong tree.The P1341 code gives a good tree to bark up
As for the MAF sensor and vacuum leaks, which either could cause the lumpy idle.
I told Kbod I can tell him how to test both the MAF and possibly for vacuum leaks with his Durametric after we see what affect changing the Cam position sensor has.
Although I don't think the MAF or vacuum leaks are the issue.

Not sure what squirrels I am chasing. But I could be, very hard to diagnose an issue via the internet.

[Homeoboxter]

Originally Posted by blue62

Maytag,

I don't know how to go about testing a Cam position sensor. So I suggested replacing it.

To test out the camshaft position sensor he could just swap it with the other bank`s and see if the error code moves. As far as I can recall they are interchangable.

[maytag]

Originally Posted by blue62

Maytag,
I agree with some of what your saying.
If you have ever read any of my previous posts I very often suggest that a person check and prove good or bad the simplest things first and work their way up the diagnostic ladder step by step from simplest to most complex.

I first started trying to help Kbod in another thread that addressed the same issue he is describing in this thread.
In both threads he has stated that he gets a reoccurring P1341 code. Bank 1
Lumpy idle after warmup and stalling at stops.
He also has excessive Cam deviation on Bank 1

Vacuum leaks are very simple and basic and can cause lumpy idle and stalling.
That is why I mentioned Vacuum leaks to Kbod.
Many time they only cause lumpy idle and stalling after warmup. Why?
Because on cold start open loop the DME is providing a very rich mixture with no feedback from the O2 sensors. Tends to compensate for the unmetered air from the vacuum leak, so the car may idle just fine.. Once the system warms up and goes into closed loop the mixture leans out and becomes too lean at idle because of the vacuum leak. So you may get lumpy idle warmed up but not on cold start.

What I first suggested to Kbod was to check for any wiring issues related to the Cam position sensor on bank 1
Why? The P1341 code.
Checking the wiring and testing the Cam position sensor would be my starting point.
I don't know how to go about testing a Cam position sensor. So I suggested replacing it.
Seemed the simplest, most basic most logical and cheapest to me.
I mentioned Cam timing because Kbod had replaced the Actuator on bank 1.
and still has the issue.
Not sure how I am barking up the wrong tree.The P1341 code gives a good tree to bark up
As for the MAF sensor and vacuum leaks, which either could cause the lumpy idle.
I told Kbod I can tell him how to test both the MAF and possibly for vacuum leaks with his Durametric after we see what affect changing the Cam position sensor has.
Although I don't think the MAF or vacuum leaks are the issue.

Not sure what squirrels I am chasing. But I could be, very hard to diagnose an issue via the internet.

Honestly., Blue, you're kinda my hero right now. I look at how much time you're spending trying to help and I think to myself "now there's a guy trying to get into Car-Heaven" or wherever car-saints go to.

The amount of effort you've put in here is MUCH greater than my own "dive bomb" effort to spread too little too late. haha.

I'll bow immediately to your logic and reasoning, 'cuz it's right on target, near as I can tell.

And you're so right: diagnosing over the internet is iffy at best.

Happy New Year!!

[blue62]

Originally Posted by maytag

Honestly., Blue, you're kinda my hero right now. I look at how much time you're spending trying to help and I think to myself "now there's a guy trying to get into Car-Heaven" or wherever car-saints go to.

The amount of effort you've put in here is MUCH greater than my own "dive bomb" effort to spread too little too late. haha.

I'll bow immediately to your logic and reasoning, 'cuz it's right on target, near as I can tell.

And you're so right: diagnosing over the internet is iffy at best.

Happy New Year!!

Being old, single, retired, and a car nut I have time to try to help others.
I have always had an interest in things mechanical.
When the computer age came along it changed automobiles in many ways.
The DME/ECU and the OBDI and OBDII systems came along and I was lost.

What do you mean I can't adjust the timing Multiport fuel injection
Check engine light???? P-Codes????WTF?????
So I have had to try and learn what I could about those things.
It's car stuff right

Part of learning is trying to help others and getting their feedback on results.
Another part of learning is having people like you question or comment on my advice to others. Makes me go back and think about my approach.

Yes diagnosing via the net is hard.
I don't have the car before me.
I can't see it, touch it, feel it, smell it, hear it, taste it, talk to it, and it can't talk to me. So ya it's hard
Take care.

[kbod]

Originally Posted by blue62

Being old, single, retired, and a car nut I have time to try to help others.
I have always had an interest in things mechanical.
When the computer age came along it changed automobiles in many ways.
The DME/ECU and the OBDI and OBDII systems came along and I was lost.

What do you mean I can't adjust the timing Multiport fuel injection
Check engine light???? P-Codes????WTF?????
So I have had to try and learn what I could about those things.
It's car stuff right

Part of learning is trying to help others and getting their feedback on results.
Another part of learning is having people like you question or comment on my advice to others. Makes me go back and think about my approach.

Yes diagnosing via the net is hard.
I don't have the car before me.
I can't see it, touch it, feel it, smell it, hear it, taste it, talk to it, and it can't talk to me. So ya it's hard
Take care.

Words can not describe how grateful I am for all the help blue has given me thus far . honestly. Today I brought the car in and Replaced the factory stereo with a nice apple carplay unit (I know fix the engine then do upgrades...oopsie) and I also unplugged the mass air flow sensor and Wow it ran like extra crap. extra lumpy, extra rich, extra terrible. It's safe to say I don't think the car has a vacuum leak or a broken mass airflow sensor. My new camshaft position sensor came in but i'm waiting on my air oil separator to also come in since the cam position sensor is below the oil separator and mine is shot. Ill post a quick update when I get it replaced on if it fixes the car and if it doesn't fix the car what my deviations/actual angles are.

When I do the camshaft position sensor Ill also remove the lower camshaft rubber plug and check/repeat the timing process just incase.

[blue62]

Originally Posted by kbod

Words can not describe how grateful I am for all the help blue has given me thus far . honestly. Today I brought the car in and Replaced the factory stereo with a nice apple carplay unit (I know fix the engine then do upgrades...oopsie) and I also unplugged the mass air flow sensor and Wow it ran like extra crap. extra lumpy, extra rich, extra terrible. It's safe to say I don't think the car has a vacuum leak or a broken mass airflow sensor. My new camshaft position sensor came in but i'm waiting on my air oil separator to also come in since the cam position sensor is below the oil separator and mine is shot. Ill post a quick update when I get it replaced on if it fixes the car and if it doesn't fix the car what my deviations/actual angles are.

When I do the camshaft position sensor Ill also remove the lower camshaft rubber plug and check/repeat the timing process just incase.

Glad to try and help just hope I have in some small way
Hoping the Cam position sensor is the issue
Keep us posted I always like to hear results.