Ford Focus 2006 1.8 turbo diesel

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Re: Ford Focus 2006 1.8 turbo diesel

Postby Dan » Tue Feb 14, 2012 2:14 pm

GRUSS wrote:Spoke to another tech at ford down the road who informed me that they had no in tank electric pumps.

That is correct - as they are external :-) There's an electric 'lift pump' (low pressure) at the rear and then the injection pump (high pressure) at the front.

GRUSS wrote:My next plan was to scope the injectors but the salesman booked it into ford and i had to come away from it. This afternoon i was told that the fuel filter was replaced as it was blocked??? only time will tell if the fault is fixed and the car runs ok.

What do you think to what i've captured with the scope, am i barking up the wrong tree. It was very interesting to say the least...


A few schools of thought regards the drop - by no means the answer, nor am I saying it is this at all. (I don't have tech info on this model)
- The way you are taking feed from the sensor - the sensor may be grounded rather than powered, so when ignition is cut, there's nothing measurable on the scope. (most likely this is why you get an abrupt cut)
- The filter was restricting enough fuel to not build up the required pressure. Just enough to idle, but starve when driving.
- The sensor may be a pressure switch (unlikely) - so it switches at peak pressure only. However, you'd notice no 'variation' - just 5 or 12v when on or nothing when off. The trap would be seeing 'noise' or interference, but you'll learn to spot that by taking a reference/comparison from another 12v or 5v source and compare. [Note: I can't say anything modern uses such switch on the fuel system, but it's worth making a mental note as anything 'could' appear!]

If you find the signal cuts sharp with ignition off - and it's not because the key is turned too far,
you will need to connect your scope leads to measure between + and the sensor lead, as this will measure resistance.

As the brain is ticking...
- You could get similar issues with the car if the alternator is failing, where the voltage drops below the fuel relay threshold.
Last edited by Dan on Wed Feb 15, 2012 9:45 am, edited 1 time in total.
Knows pre-2000 Fords and R33's better than the back of my own hand.
Anything newer... I'm probably driving it :-(
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Re: Ford Focus 2006 1.8 turbo diesel

Postby GRUSS » Tue Feb 14, 2012 7:22 pm

Hi Dan
Thanks for the reply and your thoughts, as i dont work on fords this is new to me. The pressure sensor on the rail had 3 wires. 12v or 5v (cant remember now) an earth and the signal wire i back probed. I followed the preset in pico to get the waveforms. I wish i could have spent longer with the car but its gone now...

Do you think the pressure sensor was a switch or not? got a little confused with your reply :? :oops:

Everthing i was capturing was matching the preset for fuel prail pressure sensor apart from when i turned the engine off, but i dont think i had enough time on the screen..?

Either way i found it interesting.

Ive got a vw polo 1.4 petrol to look at in the morning thats running rough. No dtcs, check check of the injector waveforms and they look ok. It has 4 wire COP so will try and have a go at testing them. Ive seen alan's thread on how to test COP so i'll follow that. :D
May start another thread if i find anything interesting.
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Re: Ford Focus 2006 1.8 turbo diesel

Postby Robski » Tue Feb 14, 2012 8:10 pm

Everthing i was capturing was matching the preset for fuel prail pressure sensor apart from when i turned the engine off, but i dont think i had enough time on the screen..?

What do you think happened when the ignition was turned off ?
Did you notice if the injectors buzzed for a while when ignition was off ?

Ive got a vw polo 1.4 petrol to look at in the morning thats running rough. No dtcs

What's the MAP reading ?

check of the injector waveforms and they look ok

What was the on time ?

It has 4 wire COP so will try and have a go at testing them. Ive seen alan's thread on how to test COP so i'll follow that.

Why...........are misfires logging in MVB's ?
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Re: Ford Focus 2006 1.8 turbo diesel

Postby Dan » Wed Feb 15, 2012 9:40 am

GRUSS wrote:Hi Dan
Do you think the pressure sensor was a switch or not? got a little confused with your reply :? :oops:

Everthing i was capturing was matching the preset for fuel prail pressure sensor apart from when i turned the engine off, but i dont think i had enough time on the screen..?


I'll correct that - it does read poorly! FYI - The Ford item is a 'sensor'.
If it were a 'switch', you'd only see on or off, no variation.

From what you describe, the sensor takes power (likely 5v) and ground. The signal out will vary across those two depending on pressure - as you expect.
When cutting the ignition, the ECU tends cuts power to the sensor.
As scopes measure voltage and the ECU has removed that power, the scope has nothing to measure - so no signal.

If this happens when cutting ignition, you may simply need to switch the ignition back on.
This presents an issue however, as:
- It will cause a glitch/cut in the readings.
- You need to cut ignition long enough to prevent the engine inertia to restart itself!

You 'could' (only if your well versed with the safety aspect and the engine) get around this by:
- Removing power to the fuel cut-off on a diesel.
- Removing power to the injectors on either diesel or petrol or coils on petrol.
- Unplug the idle control valve.
- Unplug the crank sensor. (Note: Not the cam sensor though [unless it's a CAS type], as Ford in particular only reference this briefly. Others will default or go into 'limp'.)

However, modern cars may throw a fault - so don't do it unless you know the existing faults and can clear them.

It's never an idea to try stall the engine by covering the inlet!

A fair bit of effort to test the pressure sensor curve, but useful for that or similar sensors.
Knows pre-2000 Fords and R33's better than the back of my own hand.
Anything newer... I'm probably driving it :-(
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Re: Ford Focus 2006 1.8 turbo diesel

Postby GRUSS » Wed Feb 15, 2012 1:08 pm

Hi dan
When I turned the engine off I didn't switch it totally off if that makes sense, either way I can't do anymore tests :(
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Re: Ford Focus 2006 1.8 turbo diesel

Postby Robski » Wed Feb 15, 2012 1:12 pm

If this happens when cutting ignition, you may simply need to switch the ignition back on.
This presents an issue however, as:
- It will cause a glitch/cut in the readings.
- You need to cut ignition long enough to prevent the engine inertia to restart itself!


No need, if the correct test procedure was carried out.

You 'could' (only if your well versed with the safety aspect and the engine) get around this by:
- Removing power to the fuel cut-off on a diesel.
- Removing power to the injectors on either diesel or petrol or coils on petrol.
- Unplug the idle control valve. On a TDCI ?
- Unplug the crank sensor. (Note: Not the cam sensor though [unless it's a CAS type], as Ford in particular only reference this briefly. Others will default or go into 'limp'.)


Why ? Again correct test procedure !

A fair bit of effort to test the pressure sensor curve, but useful for that or similar sensors


Isn't it just ?
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Re: Ford Focus 2006 1.8 turbo diesel

Postby Alan » Thu Feb 16, 2012 7:09 am

Sorry to be late to the party...

Interesting waveform. Most 5V powered sensors have working output ranges from 0.5V to 4.5V (above or below is a fault) so when you cut the engine the fact the output fell straight to 0.5V would to me suggest a quick drop to zero pressure (rather than the ignition cutting off the supply).

I do not have a waveform from a similar system so not sure if this fast drop is normal or not. Will ask around.
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Re: Ford Focus 2006 1.8 turbo diesel

Postby GRUSS » Thu Feb 16, 2012 7:22 am

Alan,
That's how I saw it going on the preset notes, it talked about the residual pressure in the rail. I might test a vauxhall in a similar way. I have had a cdti insignia and when the engine is turned off there is still pressure in the rail when checked on live data.
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Re: Ford Focus 2006 1.8 turbo diesel

Postby Alan » Thu Feb 16, 2012 9:07 am

This is from a Mazda 1.6 engine (MZ-CD / Y6, Euro 5, Bosch system). Much longer for the pressure to die away.

crd pressure sensor.jpg


Any diesel experts out there to comment?
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Re: Ford Focus 2006 1.8 turbo diesel

Postby PicoPhil » Thu Feb 16, 2012 3:36 pm

This is taken from a Ford Mondeo 2000 HDI Engine code FBB Year 2004.
Waveform shows Fuel pressure sensor Igniton off, ignition on, Start, Idle, Wide open throttle, idle, ignition off.
Hope this helps
Attachments
fuel pressure sensor tem 3.gif
fuel pressure sensor tem 3.psdata
(441.91 KiB) Downloaded 197 times
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