WJ 2.7 CRD lack of acceleration and power

[JeanLuke]

Originally Posted by giacomo.m

Thank you all for the replies,
the connecting rod of the swirl flaps does not move when you press the accelerator pedal, so this problem could be the cause of the lack of acceleration and lack of power (no mil light) or it could be attributed to the fuel pressure solenoid.... ?
Giacomo

The swirl flaps do not move with the throttle position. They are controlled by the ECU based mostly on TPS, manifold pressure and RPM. With WJ Diag you can manually actuate them with the engine "on" but not running, as a test.

[giacomo.m]

Originally Posted by JeanLuke

If you are not getting errors, I doubt it is a fuel pressure problem. They always light the MIL when the measures pressure does not match the required. Personally, I would be looking at the throttle position sensor. Again, with WJ Diag you can see what the TPS is reading.

Currently I still have the P0190 which does not clear, but no MIL light.....
where is the TPS ?
and what value should I read with WJ Diag ?
thank you
Giacomo

[JeanLuke]

The TPS hangs off a bracket on the left side firewall, above the intake manifold. Using the diag software, it should read between 0 and 100% depending on throttle position.

[giacomo.m]

Thank you,
but I meant the pressures (low and high in the fuel rail) of the fuel.....
Giacomo
​

[JeanLuke]

There's no sensor on the LP rail, but the LP fuel pump is very reliable. It rarely is the problem. The HP rail varies depending on engine load and RPM. What matters is the difference between the required pressure and the measured pressure remains relatively low. The engine will not even start (i.e. the injectors will not fire) until the rail is over around 220bar. Under full load it can reach over 1000bar.

[Adrian D]

I'm keeping my theory, the fuel pressure sensor has incorrect readings due to wiring issues: shows a higher value than real, forcing the fuel pressure regulator (fuel pressure solenoid) to reduce the pressure to match the target.
Your real pressure will actually be lower than the target, which means low power.

[JeanLuke]

Originally Posted by Adrian D

I'm keeping my theory, the fuel pressure sensor has incorrect readings due to wiring issues: shows a higher value than real, forcing the fuel pressure regulator (fuel pressure solenoid) to reduce the pressure to match the target.
Your real pressure will actually be lower than the target, which means low power.

Sounds both plausible and probable.