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Well I decided to start a new thread on this issue, a while back I mentioned in a couple threads that my remote mounted oil pressure sender would go to zero on the gauge and DIC at a certain point on the x-way. I have now seen that there is a radio tower there as well as a cellular tower both causing the malfunction at their spots (about 400 yards apart). I have since grounded the sender and as of 6 fly bye’s no more pressure drop (was not really dropping just a interference on the gauge).
Could be some crazy EMI that affects the sender circuit... could also just be that precisely at that point you're driving in a way that causes something to shake juuuuust right.
In any event: weird!
I guess I should have been more explicit in saying that EMI usually gets solved with a better ground, or a grounded cage in the worst case.
I guess I should have been more explicit in saying that EMI usually gets solved with a better ground, or a grounded cage in the worst case.
A friend of mine works on firetrucks and told me how they have to run special grounded harnesses around certain things on a firetruck including the oil sender because of EMI !!!!! I figured mine with a steel braided hose grounded for a while and after a certain number of miles didn't ground the sensor well enough anymore ????
Well I decided to start a new thread on this issue, a while back I mentioned in a couple threads that my remote mounted oil pressure sender would go to zero on the gauge and DIC at a certain point on the x-way. I have now seen that there is a radio tower there as well as a cellular tower both causing the malfunction at their spots (about 400 yards apart). I have since grounded the sender and as of 6 fly bye’s no more pressure drop (was not really dropping just a interference on the gauge).
you might have just solved one of my problems I was having. on a certain stretch of road by my house i would watch my pressure go from 50 to 40 in 2 psi increments at a constant 2000 RPM's. and then when I just got passed it it would rise back to 50. Im going to ground my sensor better and see what happens. Kudos to you.
A friend of mine works on firetrucks and told me how they have to run special grounded harnesses around certain things on a firetruck including the oil sender because of EMI !!!!! I figured mine with a steel braided hose grounded for a while and after a certain number of miles didn't ground the sensor well enough anymore ????
The best answer I can give you without proper analysis is:
Anything not directly intended as a ground should never be relied on as a ground.
A stainless steel hose that crews into your engine block and into your pressure sender _should_ ground the pressure sender. However, you have to remember that often the threads are wrapped in teflon tape, or some form of dielectric grease, or there's oil in there; and the system vibrates; and so on. In other words, just because it's a metal hose doesn't mean it will necessarily ground anything properly. The only way to be sure is to *test* it. You'd need to run a continuity tester / ohmmeter from a well known ground to the sender unit. You'd need to log data as you drive. Remember, a medium-resistance ground will ground the device, but it won't do it well enough in all cases. You really want ~0 ohm resistance to ground at all times, and unless you're sure you have it...
In other words, if you want to ground something, you need to explicitly ground it with something you're sure will work as a ground. Generally that'd be a wire directly to the engine block, which is what you ended up doing!
As an electrical guy, I can tell you that cars are seriously hostile environments. You have huge temperature swings and high operating temperature, terrible weather, crap from the road, weird electrical interference inside the car itself from things like coils firing and current through the ignition wires, weird electrical interference from outside... and oh yeah, since the car doesn't have a grounded metal shell (largely fiberglass etc), you don't get a lot of protection from weird outside crap.
The best answer I can give you without proper analysis is:
Anything not directly intended as a ground should never be relied on as a ground.
A stainless steel hose that crews into your engine block and into your pressure sender _should_ ground the pressure sender. However, you have to remember that often the threads are wrapped in teflon tape, or some form of dielectric grease, or there's oil in there; and the system vibrates; and so on. In other words, just because it's a metal hose doesn't mean it will necessarily ground anything properly. The only way to be sure is to *test* it. You'd need to run a continuity tester / ohmmeter from a well known ground to the sender unit. You'd need to log data as you drive. Remember, a medium-resistance ground will ground the device, but it won't do it well enough in all cases. You really want ~0 ohm resistance to ground at all times, and unless you're sure you have it...
In other words, if you want to ground something, you need to explicitly ground it with something you're sure will work as a ground. Generally that'd be a wire directly to the engine block, which is what you ended up doing!
As an electrical guy, I can tell you that cars are seriously hostile environments. You have huge temperature swings and high operating temperature, terrible weather, crap from the road, weird electrical interference inside the car itself from things like coils firing and current through the ignition wires, weird electrical interference from outside... and oh yeah, since the car doesn't have a grounded metal shell (largely fiberglass etc), you don't get a lot of protection from weird outside crap.
When I remote mounted it I never would think it should be grounded. Then again most mount theirs to the engine somewhere and I mounted mine to the fiberglass firewall.
Six more drive byes and still no oil pressure drop, I think it is fixed, this winter will do a better looking ground set up. Might go on the engine with a gauge ?????
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oil pressure
