Help with MAFS/TPS

[jj7]

I was checking on the voltage of the car,it was stone cold.Opened the hood and tested the voltage from the (+) post and ground,it read 12.45v.Then i disconnected the throttle position switch and here are my findings:

1-TPS/ the voltage read 4.96 from the connector,terminal 3 and ground.
2-MAFS/ the voltage on pin 3 and ground read 12.14v.

since those are crucial for the ECU,and any change in voltage could mean change in the mixture, do you think that it can be overlooked,or better carry out more testing? at least what i have in mind is to check them from the ECU for ohm reading.Any other suggestion is appreciated.

BTW/ i suspect that my car has a low voltage problem, i messed with all the ground points possible

jj

[bill g]

Many of the sensors use a 5 volt signal, not 12 volts. Bentley manual and BMW Electrical Troubleshooting Manual on CD give the test procedures. On a 1993 325i, which I think is similar to 525i, I measured 5V at the TPS connector pin 3 to earth, which according to the ETM is correct. Your reading of 4.96V seems to be close enough.

bill g

[jj7]

Many of the sensors use a 5 volt signal, not 12 volts. Bentley manual and BMW Electrical Troubleshooting Manual on CD give the test procedures. On a 1993 325i, which I think is similar to 525i, I measured 5V at the TPS connector pin 3 to earth, which according to the ETM is correct. Your reading of 4.96V seems to be close enough.

bill g
thanks bill for the input,the TPS sounds close enough for 5v, the thing is the car running like crap lately,i can hear the valves pinging the more i press the gas,idle is not that good,hesitation,lean missfire...so i am going through the basics here and want to make sure the major sensors are alright.The mass air flow gave less voltage than the standard voltage present in the system, if i am not mistaken it has the 12v....trying to put reason into this crappy runing.

jj