None Rover - Ford OBD related.
 

Hi folks.

Been a while since i have been on here but i would like your help please.

Ford Fiesta MK6 2006. 1.25.

Had a miss fire...Sorted that after removing the ORIGINAL 14 year old spark plugs.!

Engine light was flashing before - then went to just being on, after putting new plugs in. (Engine runs fine now.)

My local mechanic plugged in his OBD and turned off the light.

All good and well but the light has now come back on again.

Iv'e checked everything that i can think of...Coil Pack, Various sensors etc...All seem okay.

I'm thinking of buying an OBD scanner to turn off the MIL...?

But what would cause it to keep coming back on?

Thanks fellas...:)

Many years ago my son's 2007 Focus 1.6 kept cutting out. He tried new plugs/leads but it was still cutting out. He fitted a new coil pack but it was still cutting out. I noticed that the three LT leads going into the coil pack were under tension and the way they were clipped resulted in fatigue where they entered the coil pack connector. With the engine running I pulled and pushed on the wires and the problem came and went as I did so. The fatigue had severed the copper strands in one or two of the LT wires but the plastic insulation was intact. I cut the connector off, opened it up and extended each of the wires by a few inches so I could form a strain relieving loop at the connector. The car was perfect after this repair and never gave any more trouble. I think the 1.6 Focus engine is a larger capacity version of the 1.25 Fiesta engine. I am not saying you have this problem but it is worth a quick look.

I have a fiesta 1.25 . For my driving school .

Missfire and light on .
If you haven't already checked .
Pull each lead off the coil . ( Engine switched off obviously)
Look inside the coil for corrosion . absolutely notorious .
New coil from local factors £25 cured.
Light went out by it's self after fitting.
Have a look anyway

A learned friend tells me you should investigate the core plugs in the head, these can rot through letting water onto the leads and plugs.

I would have a look there first..

Maybe the misfire has caused a problem with the Catalyst or a Lambda. Unburnt fuel can cause havoc to these sensors.

Thanks for all the messages. The OBD scan reported that there was a miss-fire on cylinder 3, but that was cured after fitting the new spark plugs.

Good shout about the Core plugs. There was slight evidence of the top core plugs leaking so i replaced them both and it's now bone dry inside the spark plug wells.

I replace the air filter and changed the oil and filter.

The car runs extremely smoothly now but i will take a closer inspection of the coil pack and leads and the catalyst and lambda sensors. ( I'm now thinking this is where the problem lies.)

I know it's an old car but it's been very well looked after at some point, just not in the last year or so and i want to bring it back to it's former glory so to speak.

One thing iv'e noticed about these MK6 fiesta's is you hardly ever see one with any rust. Iv'e crawled all over and underneath this one and i can't find any corrosion anywhere.!

Thanks again great advice as usual. I did have a nosey on the various Ford forums but the advice was woeful at best and they don't seem a very friendly lot, unlike here.

I will update as soon iv'e got it sorted.

There was an issue with some older Fords with the washer jets leaking, which incidentally is just above the spark plugs.

Quick update folks.

The problem was definitely the front 02 sensor. (Pre Cat.)

I went to 3 of my local car spares shops and they quoted me between £50-75 for an aftermarket sensor.

I had a look on ebay and found them to be a lot cheaper at £12.00 with a 3 year warranty.

Iv'e also had to buy the special removal tool (£5.99) to get the bluddy thing out.! (all it is, is a 22mm socket with a grove cut out down one side to acomodate the wires. (Nifty little tool though.)

The sensor was a nasty little thing to get out, took some real effort to loosen it and access isn't great as it's right at the back of the engine.(Again... it's probably never been changed in 14 years )

The engine warning light has gone out now so i'm confident that was the problem.

Sworks. Thank you, iv'e read about that problem with the washer jets but mine are sealed with a rubber grommet and don't appear to leak. But agreed, that is a bad design with the air box situated like it is. Any leaks will go directly into the spark plug wells. I will keep an eye on it.

All great advice that steered me in the right direction. Thank you to all.