Help...... misfire ?

[Jban557]

Help needed please ?

Ford Focus 2.0 tdci 2007

We had a misfire and heavy smoking and suspected the injectors so removed and had tested and all over fuelling.

Bought 4 new injectors ££££££ fitted and had coded and set up and all running perfect on diagnostics. (no more smoking)

Problem gone ? No 

Car now struggles to start and still has a misfire when revving up or trying to drive.....

No OBD faults what so ever so guessing it is something 'mechanical'. have looked over checked & cleaned just about everything i can think of and running out of ideas :( 

Any help or suggestions with this would be greatly appreciated.

Many thanks

John

[Dee_82]

diesels don't misfire. the  injectors can be miss timed or not work correctly, but there is no spark, its all down to compression, unless there is nothing in their to ignite, or there is no compression, it should work  did they definitely code them correctly?. 

To work right you need air, you need fuel (which needs to be timed correctly) and you need compression.  Sadly diesels are so computer controlled these days it could also be dodgy sensors making it not work.

When you say you suspected the injectors what made you thnk that? seems odd that all 4 go at once.

 

 

[Jban557]

I know diesels 'technically' don't misfire but that's what it feels like with juddering when accelerating so thought that was the best way of describing it !

Injectors have been correctly coded and all angle setting etc reading well within tolerances

As stated in original post, NO fault codes whatsoever so surely not an electrical fault ?

suspected the injector due to all the smoke, saw them on the test bench and all over fuelling significantly. No smoke now with new injectors.

[JONATHAN_11_80]

Personally I would go back to basics and check the engine compression before going any further. 

[Jban557]

sounds like a plan. do you have to test the compression through the glow plugs holes ? as surely cant use the injector holes because of the fuel pipes ? 

[stef123]

You could also do a ‘relative compression test’. It doesn’t give exact figure like doing it with a gauge but measuring the current draw and using a signal from the injectors you can see on a graph if there are differences between cylinders where the starter motor is turning them through each cycle.

you would need to find someone with the kit to do so as it’s not something the average guy would have the kit for.