P0106

[Winco]

2014 Fiesta 1.0 Ecoboost.

Engine was running fine but I was fighting, what I thought was, air in the clutch system, and was constantly bleeding the system.  Turns out the new 3 piece Sachs clutch had a leaky slave cylinder, where the the pipe from the car plugs into the slave cylinder.  Where I wanted the gearbox to remain in situ so the clutch hydraulic was complete, I decided to pull the engine out to get to the slave cylinder.

I fixed the leaky cylinder by adding an o-ring to bulk out the rubber seal deep inside the port of the slave cylinder.

Engine goes back in, but doesn't want to start.  The car will crank for a second or so then stop. FORScan gives a P0106 code.

Errors like can be caused by air leaks, so I performed a smoke test into the air pipe that connects to the air filter. No leaks could be seen.

FRP is at 640kpa, but there is a FUELSYS error.  I partially cracked open the pipe from the fuel pump to the injector rail and fuel spurted out.

I'm stumped.  Anyone any ideas?

[Tizer]

Have you had a look at the Live Data for the MAP, Boost Pressure and Barometric Pressure with the Ignition on to see if they are all reading Atmospheric Pressure.

[Winco]

Good point, thank you.  I will check and report.

[Winco]

[Tizer]

That fault code has me stumped as well, all the readings are the same.

Regarding the Fuel, there are a couple of things that you can do.

Have a look in service Procedures and there should be a Key On Engine Off test that may throw some light on things.

I would have expected that there are Fuel Pressure readings for both the high and low side and separate Desired and Actual ones. The Desired ones should be high during cranking and the Actual ones will catch up when started, if it ever does.

[Winco]

The Key On Engine Off On Demand Self Test resulted in no errors.

In the service Procedures I have performed the PCM Reset All Adaptations.  This has made no difference.

 

The only Fuel related tests I can find are shown.  At the point of first cranking the FP% Fuel Pump will momentarily go to 100% then back to 0%. All the other numbers stay the same.

The FUELSYS error remains.

 

[Tizer]

That is a strange one and I can't help thinking something must have become damaged or corrupted during the engine removal and refitting. I'm surprised there are not more PID's for the Fuel System.

You have probably already done this, if not it would be worth checking every fuse in both boxes. I don't have a wiring diagram for that car but there will be one for the Fuel Pump and maybe another for the Fuel Pump Module. The Relays are probably built in ones rather than replaceable.

There will be a Fuel Cut Off arrangement either a physical switch or electronically controlled that maybe has tripped.

Other than that I'm all out of ideas.

[Ecosport2019]

I know it sounds basic but have you checked you have bolted the gearbox earths back on fully? Upper front of bell housing if i remember 

[Winco]

Don't worry about asking about basic questions.  The gearbox earth is back on and also the awkward earth that bolts to the back of the head that is always the last to be disconnected as you are in the middle of hauling the engine out and something is snagging......

The fuses and fuel cut off is also a good suggestion.  

I will check.  I suspect it will be something simple once found.....

[Ecosport2019]

I couldn't tell you where it is but you could bypass the Starter Inhibitor Relay to get it cranking, or bump start the car just so if you get it running you maybe able to pull out some more codes.

[Winco]

Earlier in this thread I showed a Forscan screenshot of fuel related PIDs. The FP% (pump) was zero but momentarily jumps to 100% on initial crank and the FRP was about 640kpa. FUELSYS was error.

I took the same readings from another working 1.0l ecoboost car. On that the FP% is 18 with ign on rising to 50+ when the engine runs. With just ign on  the FRP is 10x greater at 8000kpa+. FUELSYS is also error until the engine starts and changed to open.

On the no start car, the fuel pump runs briefly at time when the door opens or ign on. I hotwired the pump to run continuous and attempted to start the car; no start.

I have found the start inhibit relay and can hotwire the start motor to continuously crank the engine. Ivtried this with ign on but no start

The 10x difference in FRP is my next course of investigation.  I could not find any fuel cut off switch anywhere  but,  there again, the fuel pump does run.

[Tizer]

A few general thoughts based on your findings, I don't have full details of the exact system used on your car so don't take them as gospel.

I'm sure your car will have a Returnless Fuel System, the only way that pressure can be reduced is when the Injectors open. If a car has been run then the pressure will be at nearly full running pressure even a long time after switching off, hence the high readings that you are getting from the good car.

When the Ignition is on then the Low Pressure Pump in the tank will run and I would expect the maximum output of that to be no more the pressure in the Fuel Rail that you are seeing in the bad car.

When cranking the High Pressure Pumps Duty Cycle should go quite high until the engine starts and the Fuel Rail Pressure increases considerably, then I would expect it to drop to around 20% under light load, your one goes to 0.

I think there is a problem with your High Pressure Pump or the commands it is getting from the PCM. It could be a physical problem or an Electrical one, maybe its Regulator. I don't understand why you are not getting any codes though.

I don't know what FRP_LRS,V is, but it is showing 5V. Generally 5V is the reference value and the output normally max's out at 4.5 or 4.8 Volts if they are operating within their normal range.

Did the P0106 code clear?.

 

[Winco]

Just to add; I swapped the maf and map sensors with the good car, no difference. The good car runs fine with the bad cars sensors.

I disconnected the pipe from the HP pump to fuel rail.  On cranking, only a spurt of fuel would come out of the HP pump as per the brief  FP 100% I would see as a PID.  When I hotwired the low pressure pump, fuel flowed from the HP pump.  But as we know, if I hotwire the low pressure pump, the car still does not start.

If I disconnect the plug to the fuel rail sensor, I get the expected error

If I disconnect the plug from the HP pump, I get no extra error or no change in the non start (just the same P0106) and no change in the PID readings.

What I will do is do the same test on the good car.

 

[unofix]

From all the work you have done and all the information you have from FORScan my conclusion would be that the high pressure fuel pump is faulty.

 

[Winco]

I removed the HP pump.  All present an correct with the cam bucket in place and the cam turning when the engine turns. I have checked all fuses in the engine bay fuse box.

As has been alluded to earlier, the FRP_LRS (V) is a solid 5V.  On the good car, this around 2.5V.

FRP_LRS is Fuel Rail Pressure - Low Range Sensor. Does anyone know what and where this is located? 

[Winco]

I downloaded a local copy of the 2014 Fiesta wiring etc from https://cardiagn.com/2014-ford-fiesta-offline-service-repair-manual-wiring-diagrams/, although I think this may refer to the USA model.

Nice hyperlinks to the diagrams with sensors and wiring at different colours.  I have yet to find a sensor called Fuel Rail Pressure - Low Range Sensor.

I used Forscan on the good car and called up the ign on live data.  I unplugged the fuel rail sensor, and the FRP reading went to a solid 5V.  Plugging it back in and it went back to 1.5V or so.  This had no effect on FRP_LRS.  However, where FRP_LRS is a solid 5V it does indicate something is unplugged.

Whilst at it I went through a vain attempt of unplugging the majority of the sensors to see if any of them had any effect on FRP_LRS.  Non did.

Assuming the PCM cannot get a reading from the FRP_LRS, even after pulsing the fuel pump 100%, I guess that is why it wont then start. I am also wondering the P0106 fault is a red herring where it is a down the line result of something wrong, and not the fault itself.  The fault is upstream but outside of the fault code software.

Thoughts and investigation continues.

 

 

[Ecosport2019]

Have you got your registration,  i will look at my software of all data and autodata to see if i can find anything

[Ecosport2019]

Also i know sometimes stuff just goes wrong and its just coincidence, but i cant help thinking that it was all ok before you removed the the engine, now it doesnt run.

I know youve probably been round the engine until you blue in the face by now!

Maybe check live data and then physically check each sensor listed is definitely present and plugged in. Live data can still read a base reading even though its not plugged in.

 

[Ecosport2019]

Just had a look at a general fiesta 2014 1L ecoboost wiring diagram and the only other i can see there, is component Y194 fuel flow control valve, again maybe double check the actuator is plugged in🤔.

Also is the crankshaft sensor plugged in?

[Winco]

All the obvious sensors around the engine are plugged in. including crank.  The fuel flow control valve - if that is the 2 pin sensor on the HP pump, then disconnecting this does not show up as an error.  However, it may well be it wont throw up an error until later on in the starting phase?

 

 

[Ecosport2019]

Did you unbolt the high pressure pump ontop of the engine to remove the engine or did you manage to undo that pain in the ***** pipe connection?

Im just finishing replacing one of these engines today ( still waiting for new fuel injectors as even with the special tool they didnt move and snapped 2 of them in half! ).

Just wondering if you removed it completely whether something hasnt met up just right going back on

[Ecosport2019]

Ignor that, i just read you have already removed it😬

[Tizer]

3 hours ago, Winco said:

All the obvious sensors around the engine are plugged in. including crank.  The fuel flow control valve - if that is the 2 pin sensor on the HP pump, then disconnecting this does not show up as an error.  However, it may well be it wont throw up an error until later on in the starting phase?

 

 

That is a Solenoid controlled valve. Either it is faulty or it is not getting a the correct signal from the PCM or the wiring is faulty. The FP % that is showing as 0  must be the Duty Cycle for the Solenoid.

It may have burned out naturally or because of another fault keeping it fully open all the time.

I don't know if it can be replaced on its own. 

[Winco]

For the record, I unplugged the solenoid valve plug on the HP pump on the good car. The car started but was suttery when revving. The fault code was delayed but it finally appeared for the HP pump fuel metering solenoid.  In other words, the fault is not checked or detected until after the engine has started. Therefore unplugging this on the bad car has no effect because the engine hasn't started yet.

[Winco]

On 9/25/2022 at 8:23 PM, Ecosport2019 said:

Have you got your registration,  i will look at my software of all data and autodata to see if i can find anything

RX64SGO