Vauxhall Fault Code P1191-5a Help Needed

#1
My Zafira 2.2 (Z22YH Enginge) 05 plate Petrol went into limp mode and the amber spanner light came on. The RAC diagnosed a code P1191 Low Pressure Fuel input Sensor. My local garage have had it for 13 days now and still have not been able to diagnose the problem. When I called in to check on progress the Exhaust Emission light had come on and the garage told me it is misfiring on cylinder 3. They are not sure what the problem is. They gave me it back saying the problem had cleared and that they had test driven it and it was ok. However when you drive it and take it up to 5000rpm it stutters and goes back into limp mode.

In 2009 a new Siemens Fuel Pump was fitted, which I now understand are the defective pumps and continental have replaced them. Vauxhall have told me that via a silent recall my Zafira had a new fuel pressure regulator fitted in 2010.

Today I have had it on the Od Com diagnostic kit and it is showing error code P1191-5a Fuel Rail Pressure Sensor Low Input. Also the fuel pressure in the Fuel Pressure Rail is 380kpa which I believe is poor it should be 600kpa.

Do I need to replace the fuel pump or is this something like an electrical wiring fault?

Any help is appreciated.

Mike
 

evocarlos

Stupid Bollocks
Staff
#2
hey mike heres some info to help :)
i may have highlighted the valid text

this is how the special kids at vauxhall would determine which part was at fault
(2005.06) - Signum/vectra 2003 To 2004 - Engine Type: Z22YH - High Pressure Pump, Fuel Pressure Regulator - Defective (P1191 set)



Signum/Vectra 2003 To 2005 - Engine Type: Z22YH

High Pressure Pump, Fuel Pressure Regulator - Defective (P1191 set)

The customer complains that the MIL is on. P1191 us set in the ECU.

1. High pressure pump defective, vehicle not driveable

2. Fuel pressure regulator defective, vehicle runs in emergency operating mode

This is caused by a defective high pressure pump or fuel pressure regulator valve. In case of customer complaint proceed as follows to verify the defective part:

1. Check fuel feed pressure at high-pressure pump with manometer (engine running)
Is primary feed pressure less than 3, 4 bar?

Yes: Low pressure fuel feed failure -> check fuse, relay, intank module.(tank pump)
if its not low pressure move on

hp pump
2. Measure fuel pressure in the high pressure rail at idle by using Tech2 Datalist.

Is fuel pressure in the high pressure rail less than 600kPa?


Yes: High pressure pump defect, replace.

pressure regulator
3. Pull off connector (two-core) of the fuel pressure regulator.

Measure the voltage of the fuel pressure sensor at 3000RPM (standing vehicle) with Tech2.

Is Voltage greater than 1, 2V?

Yes: Fuel pressure regulator defect, replace.


4. Defect is not clearly allocable to one component. Proceed according to TIS 2000 service instruction.

made this flow chart to decode it all :)
flow chart.JPG
 
Last edited:
#3
Evocarlos thanks for the info.

Can I assume that from the diagram that as my Zafira goes into Limp Mode and is still driveable then the regulator is defective?

I am confused because this section of info indicates my fuel pump may be defective as the high pressure fuel rail on mine is 380pka way below the 600kpa

2. Measure fuel pressure in the high pressure rail at idle by using Tech2 Datalist.

Is fuel pressure in the high pressure rail less than 600kPa?

Yes: High pressure pump defect, replace.

One confused person.

I have three areas identified:-

Fuel Regulator

Fuel Sensor

Fuel Pump


Helpppppppp.....................
 

evocarlos

Stupid Bollocks
Staff
#4
i would now get op com plugged back in and find out what the voltage is on the pressure sensor with the pressure regulator unplugged
if its higher than 1.2v you can say its the regulator this may also affect hp fuel rail pressure
but listed are the 2 ways to show if either the fuel pump or the regulator is defective
but then its still down to spending money
£90 for the regulator
or
£270 for a new continental hp pump
or
£35 for a fuel pressure sensor
http://www.ebay.co.uk/itm/Vauxhall-...arts_Vehicles_CarParts_SM&hash=item4176ae291b

change the sensor just because its £35 then you know when you test for fuel pressure regulator that its not the sensor then if its gives a reading lower than 1.2v with the regulator unplugged you know its the hp pump :)
 
#7
Evocarlos

Just tested the Zafira on the OP Com and these are some of the readings.

Desired Fuel Pressure - 7000Kpa

Fuel Pressure Feedback - 380Kpa

Fuel Pressure volt at 3000rpm fluctuates between 0.6v and 0.7v

Fuel relay active okay

Fuses ok

I think the Siemens Fuel Pump has gone.
 
#10
Evocarlos

I will let you know and I want to thank you for all your help. The only thing I could not test was the sensor. I did not have a manometer to test the pump pressure manually. But I am going off the desired and actual fuel pressure readings.

Thank you once again.

Mike
 
#11
Received new Continental HP Fuel Pump today from Choice Car Parts (£275.00). Fitted the pump, ran the engine for a while to get pressure back in the engine and I am back on the road.

It feels like a new car, my 2.2 SRI it has its vroom back, it feels like a new car. When I removed the old pump the internal guts were covered in oil. Clearly the seal had blown.

No errors showing on the OP Com and the fuel pressure is back upto 5000Kpa, so hopefully that is it sorted.

Thanks for all the help.
 
Top