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2007 XC-70 rough starting V70-XC70

I did some digging in VIDA, and located where the crank and cam sensors are located. Should not be a big deal to access.

Trying to understand how electrical interference can impact the signals from the crank and cam sensors as suggested by VIDA. Especially only during starting. Trolling around a few forums, I found references to electrical noise coming off the starter and the cabling leading to the starter during cranking. I can see the logic to this as the starter is a high current device which can emit nasty EMI. However, if the crank and cam position sensors are sensitive to EMI, then why doesn't the the problem occur on more cars since they are all manufactured pretty much the same. Also, since it sounds like this problem can occur as the car get some age on it, what is changing to cause the problem?

I am theorizing that with miles on the engine, perhaps the sensors are aging, and producing weaker signals. During starting, the EMI from the starter is interfering with the sensor signals enough to muddy the pulses and confusing the computer. If the computer does not have a good fix on crank or cam positions, it can't fire the plugs correctly. Once the engine starts, the EMI from the starter goes away, and the pulses from the sensors are less noisy, enabling the computer to know the crank and cam positions, even if the signals are a bit weak. Solution would be to replace the sensors with the anticipation of stronger pulses.

Does this logic make sense???

Thoughts from others on my thought process are welcome.


Gary
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Gary D






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New 2007 XC-70 rough starting [V70-XC70]
posted by  Gary D  on Thu Nov 7 15:09 CST 2019 >


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