MAP sensor problem showing up at 35k miles? Plus some interesting data
#11
Community Organizer
Excuse me but who started this thead? Is it the infamous UL himself? My god he can diagnose a car having burned up a roller bearing by a half assed explination by Joe Schmoe with no mechanical background. Though on his car he isn't sure!
What's this world coming to.
I bet you it was your MAP sensor. 65K and never had that big of an issue but in times where it doesn't run right or temps are changing I give a whack or 2 on it. Keeps things "loose".
To quote Space Cowboys: "This is how we fix on Russian space station" As he whacks away at some valve!
What's this world coming to.
I bet you it was your MAP sensor. 65K and never had that big of an issue but in times where it doesn't run right or temps are changing I give a whack or 2 on it. Keeps things "loose".
To quote Space Cowboys: "This is how we fix on Russian space station" As he whacks away at some valve!
#14
What does "whacking" the MAP sensor actually do? Does it knock off some contaminant? Does it make the wiring connection better? Is there a mechanical reason why this works?
Also, UL, has anyone (you maybe) looked into finding another MAP sensor that is less susceptable to this sort of decay in performance over time?
Also, UL, has anyone (you maybe) looked into finding another MAP sensor that is less susceptable to this sort of decay in performance over time?
#18
Registered User
"Whacking" is an age-old technique applied to repair aged contacting potentiometers (the guts of most position sensors, like our TPS). Another method is repeated rapid end-to-end motion of the wiper.
I don't know squat about our MAP sensor design but whacking does a few things (I do help design sensors). It shakes loose debris off the moving contacts and possibly out of the wear track. It can also redistribute bearing debris thereby making the motion smoother. It can clear the oxides or fretting corrosion off any pressure contacts (non-soldered electrical connections).
It can also reset the radial and angular position of the contacts (one of the best benefits). Some sensors allow you to manually reposition the resting angles (ends of travel and/or a midpoint)
That is a big deal for contacting sensors that live much of their life at a few positions (e.g. TPS at idle and WOT). Normal engine vibration causes contacts to 'drill' into the surface ("dither" is the industry term). A contact tracking difference measured in microns can make a night-and-day difference in sensor performance.
There are plenty of non-contacting sensor designs but they tend to be more expensive and can have other issues (drift, sensitivity to electric fields, etc.). Our electric power steering (EPS) torque sensor is a non-contacting design (inductive I believe) but I expect the helical sleeve that drives it will wear eventually.
I don't know squat about our MAP sensor design but whacking does a few things (I do help design sensors). It shakes loose debris off the moving contacts and possibly out of the wear track. It can also redistribute bearing debris thereby making the motion smoother. It can clear the oxides or fretting corrosion off any pressure contacts (non-soldered electrical connections).
It can also reset the radial and angular position of the contacts (one of the best benefits). Some sensors allow you to manually reposition the resting angles (ends of travel and/or a midpoint)
That is a big deal for contacting sensors that live much of their life at a few positions (e.g. TPS at idle and WOT). Normal engine vibration causes contacts to 'drill' into the surface ("dither" is the industry term). A contact tracking difference measured in microns can make a night-and-day difference in sensor performance.
There are plenty of non-contacting sensor designs but they tend to be more expensive and can have other issues (drift, sensitivity to electric fields, etc.). Our electric power steering (EPS) torque sensor is a non-contacting design (inductive I believe) but I expect the helical sleeve that drives it will wear eventually.
#20
Originally posted by Tedster
A whack a day keeps the doctor away.
A whack a day keeps the doctor away.