Alex Crow
Senior Member
- Joined
- Jul 9, 2009
- Messages
- 10,677
- Reaction score
- 48
- Location
- Super Suffolk
- Your Mercedes
- W169, W124, w202, W203, KTM 250 EXC, VW T25 camper and a Polo in a pear tree
OK, this works on a W211 with CDI3 electronic EGR valve and 648 (IL6 320 cdi) engine.
It satisfies EGR monitoring function over various driving conditions, and also prevents EGR valve open circuit/short circuit etc fault codes.
On road test the car performed very well, with no black smoke but plenty of acceleration on demand, as said, no codes are being logged during mixed road test and period of idling.
What does it do?
R3 gives a path to ground to 'drag down' maf signal voltage as per earlier CDI2 mod. The diode again is also as per the other mod, and prevents the circuit from raising the maf voltage above its natural value.
R1 satisfies the monitoring of the EGR valve, to avoid open circuit codes.
R2 is a balancing resistor, and has a value chosen with the gain of the transistor in mind, to ensure the transistor is fully saturated when on.
The transistor is used as an inverter, to reverse the PWM signal.
The mod should cause no damage to any electronic components on the car, the max current that can flow is through R3, limited to 18ma or so.
It satisfies EGR monitoring function over various driving conditions, and also prevents EGR valve open circuit/short circuit etc fault codes.
On road test the car performed very well, with no black smoke but plenty of acceleration on demand, as said, no codes are being logged during mixed road test and period of idling.
What does it do?
R3 gives a path to ground to 'drag down' maf signal voltage as per earlier CDI2 mod. The diode again is also as per the other mod, and prevents the circuit from raising the maf voltage above its natural value.
R1 satisfies the monitoring of the EGR valve, to avoid open circuit codes.
R2 is a balancing resistor, and has a value chosen with the gain of the transistor in mind, to ensure the transistor is fully saturated when on.
The transistor is used as an inverter, to reverse the PWM signal.
The mod should cause no damage to any electronic components on the car, the max current that can flow is through R3, limited to 18ma or so.