Monday, April 30, 2012

W124 Fuel Pressure Regulator

The Fuel Pressure Regulator (FPR) in any modern car is quite a critical component of the fuel delivery system.

The purpose of the FPR is to ensure a constant fuel pressure that is higher than the intake manifold pressure. In most natural aspirated (NA) engines, the intake manifold maximum possible pressure is 1 bar, which is the atmospheric pressure of almost all places on earth. To ensure proper operations of the injectors, the fuel pressure must be higher than 1 bar, else air will enter the injectors instead of fuel exiting the injectors.
Bosch's stock Fuel Pressure Regulator for W124

Wednesday, April 18, 2012

Leaky Oil Filler Cap?

Do you have the problem of oil stains around your oil filler cap?

It may not just be a leaky cap that is the problem.

Many have tried replacing the cap without any resolution to the leaking oil through the filler cap.

The problem may be built up pressure within the engine due to a blocked engine breather (crankcase ventilation) air passage.

Leaky filler cap? Or other issues?
The engine releases built up pressure from the evaporated fumes via the crankcase ventilation hole.
This is connected to the engine breather hose that routes these fumes back to the air filter box for combustion again in the engine.

If the engine breather outlet is blocked, pressure built up is unable to escape and thus the only other outlet will be via the oil filler hole, causing the oil to stain the area around the cap.

Thursday, April 5, 2012

Idle Air Control Valve aka IACV

The idle air control valve is located between the 3 and 4 air intake header [ further away from front bumper ].

IAC Valve in engine bay [ Pic courtesy of Benzworld forums ]
W124 original Bosch IAC valve outside engine bay

Tuesday, April 3, 2012

CO and AFR relationship

Relation between CO and AFR

The maximum allowed %CO in Singapore LTA smog testing during inspection is as high as 4% for non-catalytic converter vehicles.

Tuning Results Table

Rolling Results of tuning sessions
The aim is to get to 14.1 - 14.2 for most leanest condition.