S4 NA types: What's 1atm show for voltage on your SAFC?
I'm pretty sure my pressure sensor is going out, but I want to confirm this.
At full atmospheric pressure, my pressure sensor (S4 NA, read via SAFC-II sensor check) is only putting out ~3.3v. This seems low, I haven't been hitting 100% "throttle" opening on the SAFC, and it seems to be outside the range of the FSM test, but I don't actually have a vaccum pump to apply the proper test with. I seem to recall on the NAs, full atmospheric pressure should be around 4.5v or so. Is this correct? Other than a bad sensor, are there any other common causes for low voltage here? I'm planning to get the DMM out & probe things later today (if I brought it with me) to make sure I've got the full 5v source & such. I don't have any of the standard signs of grounding issues, just the low voltage (and I think last time I had diagnostic lights on, it was complaining about the pressure sensor at high RPM)... ... and anyone have a spare S4 sensor laying around they'd sell? -=Russ=- |
The book says, with the engine idling and the vacuum hose pulled off and the hose plugged to prevent vacuum leaks, the sensor, the reading will be 3.5vdc to 4.0vdc.
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Thanks. I'll look for a new sensor,then.
-=Russ=- |
just wondering, what is the range? and is it linear?
sounds like 4.0 V is around upper range for NA operating condition, but what is lower limit (full vac)? FSM says 100mmHg is 2.8-3.2V, although i forget exactly how this compares to full vac on an NA... |
Russ, did a new sensor actually fix this??
because i am getting 3.37v with the engine off. however the S5 FSM says that at atmosphere the pressure sensor should be 3.4-3.6v (although i do believe an S4 pressure sensor is different), so i guess this isn't too far off...i haven't datalogged vacuum yet... |
good thing a pressure sensor will be like $10 used
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