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sean, Ford Technician
Category: Ford
Satisfied Customers: 3105
Experience:  Ford Master Technician.
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I am trying to help someone sort out a running problem with

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I am trying to help someone sort out a running problem with a 2007 Ford Mondeo. OBD reported that fuel pressure was low (sorry, I can't find the exact fault code at the moment, I can look again if needed.) The injectors were suspected, especially as one of them is "noisy".

Anyway, he has obtained a set of 4 replacement (second hand) injectors from an older (2003) model, but they are the longer nozzle "402Z" injectors as opposed to the 504Z fitted.

He is short on money, and while I appreciate it is better to have his originals refurbished or replaced, is it possible for the 504Zs to be swapped for the 402Zs?

Some extra info from ETIS:
Build Date: 22.02.2007
Vehicle Line: Mondeo 2001-2007
Body Style: 4 Door Estate
Version: Series 40
Engine: 2.0L Duratorq DI HPCR (115PS)
Transmission: 5-Speed Manual Trans - MTX75
Drive: RHD FWD
Axle Ratio: 3.41
Emission: Stage IV Emissions

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Hello, do you still require advise with regard to this concern?
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Thank you.
Customer: replied 4 years ago.

If you could, thanks

Hello again,

the simple answer is no the different injectors are not interchangeable.

The cylinder heads are different to suit the 2 different injectors, with the earlier 29.805mm tip injector the cylinder head is manufactured for the end of the injector nozzle to sit in the correct position in the combustion chamber, this injector also has 6 holes where as the later 22.155mm tip injector has 7 holes to improve atomisation of the fuel for emission purposes. Obviously the approximate 7mm difference from the sealing washer to the tip of the injector between the 2 injectors would make a huge difference to the injector tip position in the combustion chamber.

One quick point is with any fuel pressure concern on this engine if the fuel filter hasn't been replaced recently then before replacing expensive parts replace this especially if the codes were P0251 and P1211.

I hope this is the information you require but if I can assist further let me know and I'll reply as soon as I'm able to.

Best wishes,


Customer: replied 4 years ago.



It is as I expected, then, and why I never tried fitting them.


The fuel filter was one of the first things changed.


If I recall, the P0251 error code did come up, but I don't have access to my notes or the car right now. I suspected the injectors as two of them are noisy (you can hear a "squeak" as they are actuated, if that makes sense, and not just the normal ticking). Unfortunately I've not been able to do a leak test on them. There is also a light amount of white diesel smoke from the exhaust.


It is a high mileage car at 197k miles, so knackered injectors are a definite possibility, along with the diesel pump, etc.



Let me know if I can assist any further.
Best wishes,
sean, Ford Technician
Category: Ford
Satisfied Customers: 3105
Experience: Ford Master Technician.
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