[cbatters]

Originally Posted by Blue94VR4

Hi,

I've studied this thread and one question was left unanswered for me. Can anyone help me out?

I have 94 VR4 (hybrid ECU) Cali spec. My car came stock with EGR valve and sensor. I also have Autometer electronic boost gauge, just like Black94TT.

I did vacuum reduction mod and I removed EGR valve and EGRT sensor. However, in order to avoid CEL I had to install 10 Ohm resistor in place of EGRT. This tricks ECU into thinking that EGR system is working.

Questions

1. Clint, you've mentioned earlier that output of Autometer Map sensor is low. I measured 18 KOhms. Does it sound right to you?

2. Can I still connect output signal of Autometer Map sensor to the signal wire of EGRT? I am worried about 10 Ohm resister that's already there. Will it introduce errors for Autometer gauge or data logger?

3. What is the voltage range I can expect from Autometer Map sensor? Is it 0 - 5v?

Thanks,
Sergey

1. You can't directly measure output resistance. Instead, you add a load to the output and measure the attenuation in the signal due to the load. For example, if you connected a 1K resistor and the output voltage went down by 50%, it would mean that the output has a 1K impedance.

2. You cannot use the EGRT input with the 10 ohm resistor attached. The 10 ohm resistor simulates a fairly high EGR temp (low voltage) to keep the CEL light from coming on.

However, the output of the MAP sensor is a fairly low voltage when the engine is under vacuum and may suffice to keep the CEL from coming on. (I have no idea of the logic used to trigger the EGRT CEL)

3. Most MAP sensors put out a 0 - 4.85 V signal. I am not 100% sure but I believe the Autometer is actually a 3.5 bar or 4.0 bar sensor.

If you post voltage/pressure with engine off and with engine on, we can calculate the scale.

Note: MMCd includes the option for displaying EGRT signal as a voltage .



Clint