Technical 2.3jtd with P0190 Fuel Pressure Fault

[xad388]

2003 2.3jtd Ducato motorhome, 42k miles.

After a trip of 40 miles with no problems the Yellow Engine light came on and the engine lost power and stopped. Would not restart immediately. It did restart after 5 minutes wait or less - no engine light.. but under any form of load the problem repeated. I had a multiscan code reader and laptop on board so could read the codes - just P0190 found.

Cleared the codes, but problem still happening. Now 200miles from home, the AA were called. They too diagnosed Fuel Pressure Sensor fault in the common rail and measured (with the engine running at idle) the sensor's 3 pins where <0.01v on the centre pin, 12v and 5v on the outer pins. Increasing revs made hardly any difference to the centre pin voltage. So an AA Relay back home! I have a new (bosch) sensor on order - hopefully it will fix the problem.

Does anyone have any other thoughts, advice or recommended checks?

 

[corcai]

Should be 5v 0v and about 1.3v at idle if you have 12v that not coming from the sensor.

 

[xad388]

The original Bosch FP sensor has part number 0281002398
This has a length 17mm (from face of nut to end of threaded "tip", where a flat steel washer appears to be bonded on)

A Fiat recommended supplier has sold me Bosch 0281002964, apparantly this replaces the original. However I observe a shorter length of 14mm. I am concerned this will not hit the bottom of the tapped hole in the common rail and potentially not make a seal against the high pressure diesel.

Should I reject the part?
Or fit the part dry?
Or fit it with loctite?
The latter two choices fill me with some dread - in case of a leak under high pressure.

 

[xad388]

The Bosch 0281002964 fuel pressure sensor has been fitted - actually the original was quite proud of the fuel rail and the replacement is less. So fears of of fitting were allayed.

With new sensor fitted, the multiscan software plots a graph of fuel pressure required against fuel pressure achieved and both follow each other with different revs/load applied. Thus establishing the new FP sensor is sound. Sadly, during a road test of perfect operation for about 5 miles, the engine light came on with immediate engine cut out. Getting code P0191 this time. Cleared the fault and restarted the engine. Same again within a mile.

Clearly it's a fuel pressure problem, but with only codes P0191 (or P0190) pointing to FP sensor failure (now replaced), where shall I start to look?

 

[corcai]

It its easily repeatable like that plot the required vs actual pressure and the regulator duty cycle vs rpm see what happening when it faults

 

[xad388]

Thanks for advice.

The engine stop fault was most repeatable on inclines, where fuel demand would be greatest, so quite likely that insufficient fuel to the high pressure pump was the cause. Changed the diesel filter (although not full of grits or water). Still no improvement.

Discovered only a 3 amp draw by the fuel lift pump in the tank and irregular peaks on an oscilloscope. Presume the lift pump has lost some of the armature segments - resulting in a "slow" pump.

Without low pressure fuel pump or fuel flow sensors, there are no ECU codes to directly identify a lift pump issue. Replacing the Fuel Pressure sensor was akin to shooting the messenger, not fixing the cause. On reflection, the lift pump was noisy and after an engine fault stop the van would not restart until the pump had performed it's 15 second start cycle.

Upon removing the old lift pump to replace with new, it's "sock" filter was very dirty from a lot of cr*p in the tank with scabby rust on the inner surface. Tank exterior OK. Now waiting for a new tank to mate with the new pump and I expect (hope) that will fix it.

I guess previous owners had left the fuel tank near empty for long periods - hence the tank rust. Note to self: keep the tank topped up!

 

[xad388]

Just to confirm, the new fuel lift pump has for sure fixed the problem (in it's new tank with fresh fuel).

 

[MAERSK]

URGENT HELP required please as i need to drive 250 miles to Donington Race Circuit on Weds

I have the same issue, the engine temporarily stalls, black smoke and then carries on.

Engine management light comes on and when tested, the issue is Fuel Pressure Regulator, so following your scenario, I am going straight to the Fuel Lift Pump.

Having searched online for fuel lift pump, the following options are given. Please advise as non say lift pump



FUEL FEED UNIT

FUEL PUMP

FUEL SUPPLY MODULE

see link autodoc.co.uk/car-parts/fuel-pump-10817/fiat/ducato/ducato-box-250/30326-130-multijet-2-3-d?

Which part is it that you replaced and suggest that I replace.

Many thanks for your help.

MAERSK

 

[xad388]

You should be able to get to the lift pump in the fuel tank, from an inspection hatch in the nearside cabin floor. The pump and it's filter are mounted in in a circular hole at the top of the tank - about 8 studs hold the assembly in place. Otherwise, you will need to drop the fuel tank from underneath to gain access. Very heavy if full of diesel!

 

[jackwhoo]

The fuel pressure regulator is usually screwed into the "common rail"
the diesel in the fuel rail is potentially under very high pressure even with engine off- be very very careful you dont end up blind or having things amputated.