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Old 08-13-2008, 08:15 AM
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KarTek KarTek is offline
<- Ryuko of Kill La Kill
Join Date: Jun 2007
Location: Bahama/Eno Twp, NC
Posts: 3,249
Originally Posted by scott19_68 View Post
After looking at the schematics I'm not sure it is going to be easier. Mapping the relationship between the EGR transducer signal and the MAF voltage should not be too bad.

I did learn more about the EGR mapping:
The exhaust gases are recirculated in line with the map stored in the IFI control module (N3/7) as soon as the following criteria are met:

* Coolant temperature between 60 C and 110 C
* Battery voltage 11 - 14 V
* Engine speed < 3000 rpm
* Fuel rack travel < 9 mm
I had it backwards - your posted circuit makes sense now.
I did some investigating on this last night and I found a couple things:

1. I located the wires in the box and I'll post a picture tonight or tomorrow night.

2. While monitoring the vacuum signal to the EGR, I noticed that it went away after the car warmed up and never activated again. This seems to represent a very small portion of time when the EGR is actually active.

3. The voltage drop/rise seems to be about 4/10 of a volt depending on where it's measured to. It was getting dark when I was doing this so I'll have to come up with better numbers later.

I think I'm going to pursue the use of a relay that puts the diode inline with the signal wire every time it gets energized by power from the EGR actuator/modulator.

If no one has a firm reason why this won't work, I may try it.

Last edited by KarTek; 08-13-2008 at 10:07 PM.
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