1G Electronic Boost Data Logging

[leet]

Originally Posted by cbatters

EGRT = Exhaust Gas Recirculator Temperature

And yes it is a easy/slick mod!


Clint

ok I thought it had something to do with EGR, which is good since I don't have that anymore

[leet]

I found where to order the 2.5bar digikey sensor online, no icky PDF files

http://www.digikey.com/scripts/DkSea...0AP-ND&Site=US

total cost is 18.19 + shipping

[Jomojr]

Im using a scanmaster three, and MMCD. I have the MAP sensor installed to show boost on the scanmaster3. It is working correctly. I have gone into the setting in MMCD and set it to 3.0 BAR. When looking at mmcd while logging it reads correctly as boost. But when I use the MMCD tool to create an excel file, the boost is only displayed as a temperature.

Im all new to this, and have been searching for three days 8(
Please help this noob out 8)

[skunkworks]

You have to do it manually off of the raw egrt sensor data.

This is from clint (cbatters)

3 BAR
BAR = (ADC * 0.0117647) + .1
PSI = (ADC * 0.170632588) - 13.0534

2.5 BAR
BAR = (ADC * 0.0098039) +.1
PSI = (ADC * 0.142193511) - 13.0534

2.0 BAR
BAR = (ADC * 0.0078431) +.1
PSI = (ADC * 0.113755059) - 13.0534

Wideband (0-255 counts = 10-20 AF)
AF = (ADC * .03921569) + 10

[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

[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

[Blue94VR4]

Clint,

I realized I did the measurement wrong. New number are

w/ engine off - 2.2V
w/ engine idling - 0.6V

This looks like 2.5 bar sensor to me. Am I correct?

Thanks,
Sergey

[cbatters]

Originally Posted by Blue94VR4

Clint,

I realized I did the measurement wrong. New number are

w/ engine off - 2.2V
w/ engine idling - 0.6V

This looks like 2.5 bar sensor to me. Am I correct?

Thanks,
Sergey

Saw the other numbers and could not hazard a guess. Those numbers look like the 2.5 bar sensor (you just happen to have the probes reversed.)

Assuming your boost gage was wired using the ECU signal ground for Ground, all you need to do is run a single wire over to the EGRT connector and remove the resistor to give it a whirl.


Clint

[Blue94VR4]

Thanks Clint,

I'll remove 10 ohm resistor and I'll give it a try. I did not use ECU ground for my gauge, just regular one. Where can I connect it to ECU ground? Any particular location? What is ECU ground anyway? Is not ECU connected to the car body as well? When I installed my gauge, there was no mention of ECU ground in Autometer's instructions.

Sergey

[cbatters]

Originally Posted by Blue94VR4

Thanks Clint,

I'll remove 10 ohm resistor and I'll give it a try. I did not use ECU ground for my gauge, just regular one. Where can I connect it to ECU ground? Any particular location? What is ECU ground anyway. Is not ECU connected to the car body as well?

Sergey

I believe there is a discssiion about "grounds" in the boost logging thread. All of the ECU ininputs are single ended inputs referenced to ECU ground. Gages and other onboard instrumentation should use the ECU signal ground.

(There can easily be 10-100 mV of difference between the various "grounds" on the car that would show up as an error in the boost signal. Ground-loops are formed when you attempt to connect two "grounds" together that are at different potentials causing current o flow.

Quick / fun step is to remove resistor and connect a single wire between MAP signal and EGRT input. Very initerestinig to learn if MAP signal is low enough to satisfy the EGRT and keep it from throwing a CEL.



Clint