WJ 2.7 CRD lack of acceleration and power

[giacomo.m]

Hi all,
update for the problem
I replaced the intake manifold with the swirl flap motor, and 0281002942 Bosch fuel pressure solenoid despite the one being removed is 0281002700.
can it still work or do I need to replace it ?
after a test drive, the jeep still has the same symptom: poor acceleration and poor power, no mil light
now the P1270 is no longer there but the P0190 remains
who can help me ?
thank you
Giacomo

[Adrian D]

There are two designs for the fuel pressure regulator, not interchangeable as far as I know. So you need the correct one.


P0190 FUEL PRESS SENSOR CIRCUIT MALF SIGNAL VOLTAGE TOO HIGH
P0190 FUEL PRESS SENSOR CIRCUIT MALF SIGNAL VOLTAGE TOO LOW
P0190 FUEL PRESS SENSOR CIRCUIT MALF SIGNAL VOLTAGE TOO HIGH OR LOW

You can find the factory service manual here:

https://www.colorado4wheel.com/manuals/Jeep/WJ/

In the manual you can find the diagnostics procedure for each error code, what to measure, where etc etc. That's your best option for diagnosing this.

Out of curiosity, you can start the logging in WJDiagPro and log the fuel pressure values. It sounds like the sensor has high readings and forces the fuel pressure regulator to open and keep the real pressure low.

This might be a wiring issue, not a sensor issue.
If there would be problems with the fuel pressure regulator, I assume you would get P1130 because the actual fuel pressure would deviate from the requested fuel pressure.

[giacomo.m]

Thank you AdrianD
but my problem seems to be related to the fuel pressure solenoid and not to the fuel pressure regulator.....
In your opinion, can you read the fuel pressure values with the DRBIII ?
Giacomo

[JeanLuke]

The DRBIII tools are difficult to get, and expensive. A better option is WJ Diag Pro on an Android phone. It can read fuel pressure. I highly recommend it for diagnostics. (I have no skin in the game other than gratitude to the author for his help.)

[giacomo.m]

Thank you JeanLuke,
do you think it could be a problem with the low pressure pump ?
what are the correct low pressure and high pressure values in the fuel rail ?
Giacomo

[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.

[JeanLuke]

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]

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