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Matt, Mechanical Engineer
Category: UK Car
Satisfied Customers: 21707
Experience:  BEng hons Mech engineering, in auto industry 22 years
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I have a early 2011 Mondeo Mk 4 Auto Sport. When cold it has

Customer Question

I have a early 2011 Mondeo Mk 4 Auto Sport. When cold it has a tendency to temporarily miss or occasionally stall when setting off from a junction. Starts and idles fine. No issues when run for a few miles. Petrol.
Submitted: 1 year ago.
Category: UK Car
Expert:  Matt replied 1 year ago.


This could be an airleak after the airflow meter, any air dragged in here isn't 'seen' by the ECU and so not compensated for and can lean the engine out causing rough running.

As its a mechanical fault it tends not to turn on the fault light and you can sometimes hear a 'hissing' noise with the engine running.

Check the hoseclips for tightness and inspect the trunking for any cracks or splits and also all the vacuum system, the small bore pipes and fittings for cracks and missing parts.

The best way to locate a leak is to have the engine running and warm and then spray lighter gas/propane around each joint in turn. If the engine rev's up you've found yourleak.

Now you mightthink that spraying lighter gas around a hot engine isn’t wise, however theflash /ignition point of gas is about 400°C so you need a naked flame or sparkto set it off and I’ve used this method for many years without incident.

Work your waythrough each possible joint one at a time and you should find it. I use aslightly flattened piece of brake pipe and some rubber hose from the can oflighter gas to provide a spraying 'wand' and allow a direct blast of gas intoeach area, especially those difficult to reach with large implements.

It’s also worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a poorly pump will all result in insufficient fuel being delivered to the engine

Might also be worth checking the wiring and connector to the airflow meter for any signs of corrosion or damage. you can do a quick fault find if you unplug the meter and run the engine without it.

if the engine condition is the same then chances are the meter or the connection to it is faulty

Air leaks are very temperature dependent as gaps can open or close up as things expand with heat,so the weather and engine temperature can effect them.

This leads them to be quite intermittent in the case of mild leaks

its also worth cleaning the airflow meter by removing it from the car and spraying the exposed sensor wires inside the tube with a brake or switch cleaner - ensure that the cleaner is one of the old fashioned, non Eco type that does not leave a residue

On no account touch the sensor wires with anything physical as they are extremely fragile

Customer: replied 1 year ago.
The idle is very smooth, whether cold or hot. There is never an issue from first pulling away from standstill, only on the 1st couple of junctions, within the 1st mile or so - usually ok after 1st 1/2 mile, after that it appears fine. It does not do it every time. The ambient temperature - winter / summer / rain / dry does not seem to affect whether it will do it or not. The car is kept in a garage over-night. If it was an air-flow meter I would have thought this would have an noticeable affect at other times, rather than just within the 1st half mile or so. The air-flow connector is in very good condition with no signs of corrosion.
If a fuel-pump fault surely this would cause issues at other times, not just within the 1st half mile or so?
Customer: replied 1 year ago.
When cold - more accurately is if the car has not been running for the last 8 hours or so rather than ambient temperature.
Expert:  Matt replied 1 year ago.


thanks for the extra information

in that case its soundsing more like an intermittant electrical conneciton

This could be a wiring issue as things tend to expand when hot and its possible a poor orpartial electrical connection is being pushed apart on one of the major sensors so check the connection plug and wiring to the following;

Airflow meter

Crank positionsensor

Cam positionsensor

O2 sensor

Throttle positionsensor

unplug each in turn and use some switch / contact cleaner spray on the pins to ensure its all grease / dirt free

Also worth checking the connections to the fuel pump for the same reason - unplug each in turn and give them a good squirt of switch / contact cleaner - Not WD40

and also unplug and inspect the main power relays and fuses for signs of overheating orcorroded terminals - so the ones for the ECU and the fuel pump

And also unplug the wiring loom connections in the engine bay one at time and inspect for corroded or recessed pins.

Customer: replied 1 year ago.
Surely an intermittent electrical connection would show up at other times rather than under specific operating conditions. Whenever there is a problem, it is only when starting from standstill for the 1st 1 mile if the car has been standing ie normally over-night. I have inspected all sensor connections that I can find and they are in a practically as new condition. This includes the O2 sensors - since I have a pit in the garage and thus can get access to them. I have not checked loom connections since they are not in exposed conditions and thus not exposed to the environment - and as indicate, the sensor connections themselves are such good condition that I would be surprised that loom connections, that would be considerably less prone to movement and thus connection issues could be the cause. As indicated previously, if a fuel pump / connection issue surely this would be evident under other conditions and not just under the specific operating conditions as indicated above.
Expert:  Matt replied 1 year ago.


thanks for the extra information

OK in that case I'd suggest investigating for a faulty watertemp sensor. If this is the problem then the ECU will be leaving the car constantly ' on choke' and not reducing the fuelling as the engine warms - so unplug the sensor and clean the contacts on both sides with some switch / electrical cleaner (not WD40) and inspect thewiring for any signs of damage to the insulation especially where it runs over other components and through the bulkhead- if this doesn't help consider replacing the sensor as they're not expensive

Customer: replied 1 year ago.
As indicated previously all sensors contacts have been checked and are still in a 'as new' condition.
Monitoring the data via the diagnostic port indicates the water temperature increasing as expected and not doing anything different during the 1st half mile or so or there after. The engine temporarily faltered, at the 1st junction but did not stall during the above monitoring period.
Expert:  Matt replied 1 year ago.

Ok in that case the try checking for exhaustleaks before the O2 sensor as if this has been experiencing an exhaust leak then it will have been running very rich as the sensor will see the extra air pulled in as fresh / lean fuelling and be adding fuel to compensate.

this can lead to catalyst failure as the extra fuel can re-light inside and melt the catalyst

The best way to find an exhaust leak is to run the engine from cold and feel around the exhaust joints with your bare hands - you'll have about 30 seconds before it all gets too hot and you should feel any escaping gas blowing over your fingers

Customer: replied 1 year ago.
When I was underneath checking the connections to both of the O2 sensors, there was no evidence of leaks. The car is very quite - petrol - no noticeable change in exhaust note before / after the fault occurred, and leaks are more easily identifiable via carbon deposits at any point there is a leak (or was a leak before sealed via the the carbon deposits) - saves risking burning the fingers. The guy on wheel-dealers showed putting your hand over the end of the exhaust was a good way of detecting exhaust leaks - also reduces the risk of burnt fingers.
The Diagnostics indicate the 02 sensor 1 varies between 0 and 0.9v from the start, whereas 02 sensor 2 remains at about 0.55v for the first 45s before varying between 0 to 0.7V.
Expert:  Matt replied 1 year ago.


thanks for the extra information, the switching of the 2nd O2 sensor sounds a bit low as ther should be closer to 1V, the smae as the 0.9 from the 1st sensor - however the 2nd sensor doesn't really do much as its just used to monitor cataylst performance

what happens when you seal up the end of the exhaust with a running engine? Does the engine try and stall or at least slow down?

if it does then the exhaust is sealing well, if not then you have a leak

Customer: replied 1 year ago.
Slows down - similar response as shown on Wheeler Dealers.
The O2 voltage output is continually changing - the 'average' voltage output will be dependent on the measurement technique used by the meter.
Expert:  Matt replied 1 year ago.

Ok thats good

so to recap

the car struggles to accelerate from low speed

there are no fault lights

there's no air / vacuum leak

there's no exhaust leak

all sensors are OK

Fuel pressure 'may' be OK

based on the above I'd say fuel pressure needs measuring with a gauge on a running engine as this seems the only avenue left unxeplored

Customer: replied 1 year ago.
A more comprehensive recap should include:
The car is effectively 'cutting-out' when starting from standstill at the first two junctions within 1/2 mile of so from setting off. There are no noticeable issues when initially setting off from standstill - reversing out of the garage and then forward on my journey.
When the car cuts in / out, the power is still there when it cuts back in - on most occasions it is as though the ignition is being switched on / off at a random high rate - with a rarer occasion where it will actually stall.
The problem appears to only occur when the car has been standing for a period - ie over-night. If I stop for a period - ie while getting groceries - there is no noticeable problem when starting from standstill at the junctions getting out of the super-market car-park.
The attached is a graph of the fuel-rail pressure - this trace was done a while ago, so can't tell whether the car 'cut-out' when this trace was taken.
However it it may be sufficient to gauge whether the pressures are ok. Also I have the issue I cannot drive and watch the screen at the same time to tally up when at a junction and what the pressure is doing - though I would assume the low pressure is while at idle at a junction - usually just for a few seconds. The update period for each point on the graph is about 1sec.
Expert:  Matt replied 1 year ago.


I have to say that the units on the fuel pressure grpah don't make sense unless the engine is actually a diesel ? as it should run at a constant pressure of about 44 to 50 psi if its a petrol

whereas the pressure trace shown varies by over a 1000psi which is how diesel power is moderated?

Customer: replied 1 year ago.
The car is definitely petrol.
There are various fuel pressure values given by the diagnostic tool, OBDwiz, which as a generic tool will cover both petrol and diesel.
Looking at any fuel pressure related values gives:
PID SAE 0x0A Fuel rail pressure (gauge) - sits at '0', no units.
PID SAE 0x22 Fuel rail pressure, relative to manifold vacuum - sits at '0', no units.
PID SAE 0x23 Fuel rail pressure - shown in the previously attached image.
PID SAE 0x59 Fuel rail pressure absolute, sits at '0', no units.The significance of each of them and the relevance of them with respect to a petrol engine I don't know.
Expert:  Matt replied 1 year ago.


OK well ignoring the units the trace is still very noisy

as its should run to a fixed pressure and vary less than 5% so I'd say its well worth getting a mechanical gauge onto the engine to confirm where the pressure is sitting

Customer: replied 1 year ago.
But as indicated previously I cannot see how a faulty fuel pump could only give a fault during the 1st half mile or so, from standstill at the first couple of junctions, not on initial start-up, not miss a beat on all other occasions - high speed, low speed or at any other speed.
Expert:  Matt replied 1 year ago.

I understand and do agree with what you're saying but there seems to be nothing else that fits and I've known electric parts to sometimes show odd faults like this which are heavily influenced by temperature

Customer: replied 1 year ago.
The fault has been occurring on / off for some time and it is clear it is not temperature / humidity dependent. The frequency of the fault occurring is not more prevalent in winter, summer, rain / sunshine.
Expert:  Matt replied 1 year ago.


Ok lets try something else

as the car is an automatic, when was the fluid last replaced? as old , dark fluid will give a lack of internal oil pressure causing the shift solenoids to stick and shifts to be slow

Customer: replied 1 year ago.
The automatic transmission fluid was replaced as per the service schedule at 3 years old, at a Ford dealership - though the car had only done 11,400 miles. There is no obvious discolouration in the transmission fluid - and the fluid remains at the correct level - check while the car is running and on the level. The car is now just over 4.5 years old and just over 20,000 miles on the clock.
Whether cold or hot or in between, there is no evidence of any gear- change issues - normally you struggle to detect when a gear change has been occurred. Only on hard acceleration can you normally detect a gear change and normally just the 1st couple of gear changes.
With it being a wet double-clutch system it provides a much smoother gear change compare to my previous car - Mondeo Mk2 Ghia X automatic.
Expert:  Matt replied 1 year ago.


OK if its the power shift then 1st thing to consider is getting the latest software loaded into the TCM as there were a lot of updates for these

this guy also has a useful tip you might want to try

Customer: replied 1 year ago.
As indicated the car is a wet shift clutch, whereas the guy in the video takes about the earlier dry clutch system. The dry clutch has a chequered history - one that is best avoided.
Previously when I have looked as ETIS it seems impossible to be able to check when updates have been done and be able to compare with the version I have on mine. It seems as though you have to pay Ford to check if you software is up to date.ETIS indicates there was a PCM update but no information on what the PCM update(s) were and thus whether relevant to my issue.
From various forums a PCM software update was issued in December 2010 - but this should have been done on mine, hopefully, when the 1st owner picked it up in Jan 2011. Can't see any references to any updates after that - and thus whether relevant to my issues.I don't fancy paying Ford £75 /hour to check / do PCM updates, if the updates don't relate to issues I have.
Expert:  Matt replied 1 year ago.


your dealer shouldn't be charging for checking to see if there's a TSB update for your vehicle

as it can be done over the phone, all thats required is your VIN number and they should be able to tell if the car has had all its updates applied

also there was a powershift software update created in august 2012 so its quite possible this would apply to your car

Customer: replied 1 year ago.
Hi Matt, sorry for delay in responding. I have been trying to find out from the Ford dealer that I bought the car from, whether there are any outstanding firmware updates, in particular with the PCM. They have finally just replied and said that I would have to book my car in so that they could do the check - which seems to contradict the information from yourself and from other forums. Garage probably keen to charge me £75+ an hour just for the privilege !!
Using my own OBDwiz it shows the PCM level as: BG91-14C204-ABA - though shown as ID Calibration - see attached. I'll probably have to try another Ford dealership to see if I can the information from them, but that won't be until Friday at the earliest.
Expert:  Matt replied 1 year ago.


if you can let me know your whereabouts I'll try and locate someone for you

Customer: replied 1 year ago.
Loughborough area, Leicestershire.
Expert:  Matt replied 1 year ago.


OK try this firm

Customer: replied 1 year ago.
I'll try and email them to see if I can get a reply. Hopefully they won't want me to take the car to them. Kinghursts is based in Solihull, which is a 103 mile round trip. They use the Ford training centre in Loughborough but that is not available to Joe public.
The problem only appears if the car has been left standing- ie over-night and therefore would have to leave it with them the night before for testing the following day - and thus I would have to make my way by train after leaving the car and when to pick it up - certainly far from ideal.
Customer: replied 1 year ago.
No email address for them so I'll have to try an phone them which won't be until the end of the week.
Expert:  Matt replied 1 year ago.

good lord

Sorry this is turning into a scene


Customer: replied 1 year ago.
Graham Goode have emailed back indicating that they do not have the equipment for checking or programming the software on a Mondeo and only a Ford Dealer can do this.We are getting nowhere fast.
Expert:  Matt replied 1 year ago.

OK have you tried the 2 other ford dealers listed in leicester?

Evans Halshaw Ford Leicester

  • Ravensbridge Drive
  • Leicester
  • Leicestershire
  • LE4 0BX
  • Dealer Principal:
  • Joe Hewkin
  • Tel 0116(###) ###-####/li>
  • Fax 0116(###) ###-####/li>

Ford Dealer Leicester

*****br />Leicester
Call: 0330(###) ###-####br />Sandicliffe Leicester
Customer: replied 1 year ago.
The problem is they won't tell you - similar to the Ford dealer I bought the car off, they want you to book it in so they can investigate the fault , and therefore charge you £75 /hr+ for the privilege before they will even consider checking if any software upgrades are available. If there are they will charge you £75 /hr + for doing that.
Expert:  Matt replied 1 year ago.


that's a bit poor on their part, not the way VW, BMW etc behave either

so what you need is an independent Ford specialist with access to the Ford update system

this one looks hopeful

© R&T Auto Centre 2015

R&T Auto Centre,***** Leicester Road Industrial Estate, Melton Mowbray, Leicestershire LE13 0RQ

01664 568569***@******.***


Customer: replied 1 year ago.
I've emailed them, but no reply yet. I suspect they won't be able to do anything since there website suggests they are only a small outfit doing MOT's and servicing so I doubt they will have the equipment for reprogramming the vehicle software.
Expert:  Matt replied 1 year ago.


what might be of use is going up the tree a bit and contacting Ford customer services

Customer: replied 1 year ago.
Already tried them - sent an email on Wed. evening, no reply yet.
Customer: replied 1 year ago.
I have noticed from my credit-card statement that I have been billed by you, even though you have yet to provide a solution to the intermittent problem I have with my Mondeo. I was under the impression you only pay when you provide a solution?.As previously indicated I had contacted Ford Customer service myself - but they just want to hold you to ransom in the guise of saying I would have to book it into a Ford dealer for an 'investigation'; before the Ford dealer would even discuss whether an update was available.
Expert:  Matt replied 1 year ago.


the way the site works is you pay a deposit up front and then if you like my answer / s then you rate me and I receive a portion of the deposit

if you don't like the answers then you can request a refund of the original deposit

sorry to say its looking like a bit of brick wall on the Ford diagnostic front

if you would prefer I can opt out to get another expert involved? Whom may have some further insight

Customer: replied 1 year ago.
Sorry for delay in responding but had email issues.
At the moment I still have a car that hesitates / cuts-out, intermittently, which you have been unable to solve. If there is someone else who can bypass Fords method of holding you to ransom by getting to book the car in for an expensive investigation rather than tell you if there are updates outstanding on the car and what those updates are. Or if they know what the fault could be then I am willing to let them have a go.
Expert:  Matt replied 1 year ago.


I'll opt out to get another expert involved

don't reply to this post other wise it'll lock back to me