Quote:
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.
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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.