ford focus over fueling

Alternators and fuel pump problems are very common on these. The fuel pump leaks into the alternator and then that fails too.

Certainly the alternator is the first thing to do. There is a common fault with the egr valve that makes them smoke, ask about the TSB on it at a ford dealer. about 60 quid or so (if that is what your problem is)

Usually the EGR valve just needs to be taken off and thoroughly cleaned out. I did the inlet manifold on mine as well as that was sludged up too. Whole job took an hour.

I'll do as Conor and strip egr, the inlet and clean the intercooler.

I've just had the on board diagnostic read (20 quid) and only the alternator fault shows. The garage suggests it's the voltage fluctuations of the alternator that's screwing up the ecu. I find this a bit hard to believe as I would expect the ecu to have some sort of voltage stabilisation of its own.

With this alternator is there anyway I can run the car without the alternator charge lead connected? I say this because at least then the Voltage would be fairly constant to see if there is still a problem.

I still don't really understand how the air mass meter voltage is used in a diesel but I can see that poor turbo pressure would cause over fueling. Is there a simple boost pressure meter that I can have in the cab so that I can see boost, my old subaru 1800 turbo had one but I've not seen one on a diesel.

AJH

That won't necessarily cope with noise though

Should work but whinge

It shouldn't, fuelling is controlled by the boost pressure

Any boost guage will work, boosts is boost on anything.

Thanks Duncan

So the erratic voltage might induce the ecu to produce overfuelling.

Which side of the intercooler is the boost pressure read from?

What function has the air mass meter?

AJH

It can do all sorts of things, it's not a particularly obvious failure though

Cold side

It tells the ECU what the maximum fueling should be. If it's duff you can easily get overfuelling at 1/2 boost, although underfuelling's more common.

Unplug it & see how much difference it makes.

Err on the TDDI's the ECU doesnt read boost pressure directly. Turbo is controlled by regular wastegate an a N46 style valve.

There is only a Charge temp sensor post-intercooler.

Boost pressure is calculated from the MAF reading, and charge temp sensor. Likewise so is EGR flow rate.

Tim.

I guess this is a TDDI, it's a 1.8 endura engine. I assume the wastgate and n46 style valve just dump the exhaust once max boost pressure is reached? What should boost be and at what revs, I'll try and buy a gauge at the weekend.

So knowing the revs and maf reading and allowing for temperature you can deduce boost but you don't need to know it because air mass and revs should detremine the fueling alone...

Under what conditions should the egr operate?

I took it half way around the M25 and back today, with a volmeter connected, The charge light came on after 20 minutes but I reset it by switching ignition off and on. Voltage was all over the place, up to 18 at times and with or without headlights on. Then it fell below 12 and I could only stabilise it at 13V by keeping the revs at 1750-2000. Even with the charge warning light on the Voltage stayed the same and it was clear the alternator was keeping the Voltage up because reving the engine above 2000 noticeably dimmed the lights yet they were fine at tickover. I'm loathe to change the alternator again because if the ecu controls the alternator output and the alternator is charging at tickover then mightn't it be a problem with the ecu?

AJH

If the voltage made it to 18V at the dashboard then there's a loose wire between the alternator & the battery or a verk buggered battery.

You're right Duncan. The alternator mounting bolts were both loose, probably causing an intermittent earth fault. Further the intercooler seems to have fretted on the fuel pump pipes, two intercooler pipes holed. This has exacerbated the problem as the air leakage has carried oil over the alternator. Obviously this air leak has also fooled the MAF, now I need to find a replacement intercooler.

BTW how does the alternator come out of this focus?

AJH

This is from Haynes, so apologies for any inaccuracies :-)

1. Remove undershield
2. If aircon, undo 4 bolts and move compressor to one side
3. Remove plastic cover and disconnect wiring
4. Undo 2 pulley bracket bolts, then loosen 3 generator coupling bolts and remove the coupling.
5. Unscrew the mounting bolts and lift from engine

HTH

Chris

Thanks a lot Chris, I'm just waiting to see if I can find a replacement intercooler and then I'll test drive it, with a bit of luck I won't need to remove it but it's good to know how.

AJH

Ford have a smart chargeing system which can up the voltage to 16V quite regualry - it's a real PITA and blows headlamps.

There is a pipe from the side of the EGR valve - a small black one that is made of plastic that goes brittle and cracks. This goes to the manifold pressure sensor. If that cracks or if get's filled with black gunge the system cannot know the boost and so it goes into limp home mode and you end up down on power and often overfuelling - this can also be a problem.

Thanks Chris, I should have reported back, this pipe was fractured and fell apart just as you say. I replaced it with a nylon one, I also repaired some chafe holes in the intercooler with araldite. I doubt my brother looks under the bonnet between services (prof at uni) and I think the garage had left the intercooler loose so it rested on the engine. When he took it to them with charging and over fueling problems they must have refitted it because I can see no way the intercooler could have been damaged otherwise.

I also fixed the egr valve and am waiting to fit a replacement intercooler from ebay.

The car drives fine no, I can provoke over fueling at high boost and 3000+ rpm but not an exceptional amount, at 230k miles I don't think it's worth looking further but I did buy a boost gauge, though I didn't fit it as I couldn't find an easy way through the bulk head.

Once I cleaned the alternator and tightened the bolts charging was rock steady at 14.5V dropping to 13.5V with all lights on.

AJH