The increased leak off is due to how diesel injectors work.

Kinda hard to explain without a pic, but essentially when the injector is commaned to open, a small valve opens, which then allows high pressure diesel through to the main needle (essentially another valve for simplicity!), which in turn lifts the main needle of it’s seat allowing high pressure through the injector nozzle and into the cylinder. However only a small proportion of the fuel that gets past the valves ends up in the cylinder, as the rest leaks up the side of the needle and valve into the leak off port (it’s designed this way, so the valves shut quicker, and everything that moves gets kept lubricated). When either valve fails to shut properly, high pressure fuel continues to leak past the valves, where some will leak out the nozzle giving you white smoke due to poor atomisation/unburnt fuel, and the rest will flow out the leak-off port.

And just realised I never answered the EGR question.
The purpose of Exhaust Gas Recirculation is to reduce the amount of oxygen in the cylinder inorder to lower the combustion temperature below the point at which Nitrogin Oxides are formed. NOx is one of the key elements that was targetted early on in the Euro diesel emmision requirements, as it’s a pretty horrendous thing in large quantities (http://www.belleville.k12.wi.us/bhs/health/environment/nitrogen_oxide.htm has all the key points).
The result of the lowered combustion temperature is a less efficient burn with more soot/carbon/particulates, however those can be dealt with pretty effectively with a cataylist (most euro 3 diesels would have one), particulate filters (requirement at euro 5, but often fitted to euro 4 to improve road/company car tax bands), and some manufacturers are moving to urea injection with a secondary catalyst to tighten emmissions further while improving fuel consumption.
Most truck manufacturers went the Urea injection route for Euro 4 instead of EGR, as they claimed using EGR would involve a ~10% hit to fuel economy, so the cost of adding and running a Urea injection system works out far cheaper. Off course, Euro 6 means trucks are having to use EGR aswell now.

Ah, that’s really interesting on both counts- I always thought the EGR was basically about reburning exhaust gas, no idea where I got that from. Cheers!

(I can drive spanners pretty well but with modern cars it’s so hard to figure out what’s going on… I miss carbs, you know where you are with a carb. Possibly in a puddle of petrol, or running on one cylinder because it’s a bit cold and damp, but still.)

Aargh, FFS… This is a long shot but does anyone know how to release the fuel hose connector at the end of the leakoff hoses? I couldn’t release the hoses from the leakoff connectors to do the test so cut them off, figuring I could just swap the whole lot… So now I have this:

And had assumed it’d be a simple plug and play but I cannot for the life of me get the bottom connector undone. It’s black, with a separate white clip part in it, similiar to (but not the same as) the fuel filter connectors. The access is pretty akward so hard to see what’s going on but I’ve pushed and prodded it every way I can think of and no futher forward. Given up for the night before I kick something.

So annoying, getting the injector out is easy but swapping a bit of ****ing hose has me beat.

I miss carbs, you know where you are with a carb.

I don’t think so.. I know where I am with fuel injection. Engine looks at sensors, injects right amount of fuel in – done. No stupid levers, diaphragms, vacuum advance mechanical crap to guess about.

VW had to stop selling diesels in the US in 1997 due to super strict NOx regulations, and had to develop urea injection before they could sell them again. Hopefully we’ll get those here soon before I need to buy a new car.

I think its a U shaped clip that slides at 90 degrees to the pipe. A bit like the connections to the fuel filter I think. If not will need to check with mr Haynes.

“No stupid levers, diaphragms, vacuum advance mechanical crap to guess about”

Whos guessing …..

I understand the mechanics of it better than smoke in the wiring of an injection car although im getting better i just have no interest in them.

I understand the computerised systems better, but then again I do work in IT so maybe that’s it 🙂

Inbred456 – Member

I think its a U shaped clip that slides at 90 degrees to the pipe. A bit like the connections to the fuel filter I think. If not will need to check with mr Haynes.

Yeah, that’s exactly what it looks like. Except when you look at it closely, it kind of looks like the sliding white part has to go in a direction it can’t. Maybe it’s just putting up a fight and causing me to overthink it. Going to fix it or destroy it tonight 😉

Carbs… You can take a carb to bits, clean it, replace a single part, fingertip diagnose. Change fuelling with a couple of quid’s worth of jets and washers and maybe a drillbit instead of having to pay a dude to do it, depending on design. Sure if you’ve got a bank of 8 then there’s trouble afoot though! Carb’s a living thing, injector’s a boring box.

You can only diagnose faults if you knwo the black magic. No black magic in electronics, just sensors and wires.

Yeah but no… Like this one here, no fault codes, no useful sensors, it was diagnosed with tubes and bottles and the internet. And can’t be fixed without specialist equipment. Electronics are helpful but there’s still an element of car whispering, it’s just harder to do. (when my Focus was playing up, the sensors chose to take a minor fault and turn it into a dangerous fault, and the only code provided was “engine stop”. Inevitably it was a faulty sensor)

Injector leak on this car, costs hundreds of quid, needs a laptop and the right software to recode. Carb leak on my bike? Costs 50p to fix and needs a #2 philips screwdriver.

Or perhaps I’m just being grumpy because I had to unchain my wallet

Even purely mechanical diesels need some specialist equippment.

I have engaged in combat with my dread enemy, the high pressure fuel connector, and I have emerged bloodied but victorious! You may throw flowers in my path, if you wish.

Or alternatively, I moved some bits and squished it around and cut off a bit of the old hose, and that meant I could see into the connector and realise that it pushes from the other side- it looks just like all the other fuel connectors on the car but operates in exactly the reverse way. Re-hosed, primed and…

Ah ya bastart, injector still hasn’t arrived!

FFFUUUUUUUUUUUUUU

So, new hoses in, new filter in, bled/primed as much as possible. “New” injector in (recon from a recommended supplier), recode… Misfire every few seconds. Checked my working, decided to refit the original injector, recode… Smoke again but no misfire. Repeated process back to new injector, smoke goes away, misfire comes back.

So… Bad “new” injector, right? Leakoff test fine, same part number, something else wrong with it, rebuilt but not recoded or something? I can’t think of anything else, sure you could have some crazy random collection of faults…

Misfire.. regular or random? You have a fault code reader?

Semi-regular, it sounds slightly off all the time with a big shake every 4 or 5 seconds. Ran off the fault codes, it has a persistant gauge cluster related one but then it has that regardless of which injector is in it (and has had it for about 20000 miles). Nothing helpful though

Take it to a garage. Ask them to fix it. Drive away. Easy.

Lol. Take to a garage, ask them to fix it, watch as they empty your wallet throwing random parts at it, then take it home again still not running properly.

NW – when there’s a shudder, is there a puff of white from the exhaust?

iolo – Member

Take it to a garage. Ask them to fix it. Drive away. Easy.

Average price for an injector fix on a mondeo is quite a lot. Very tempted to nip into the local delphi place and get the old injector rebuilt though, you can never have too many injectors! Pending better ideas I’m reasonably sure it’s the injector, the fact that changing it changes the symptoms…

molgrips, not that I can see- it is smoking thinly but nothing like with the known-leaky injector, pretty much consistent with normal poor running but no obvious peaks. (bearing in mind that the exhaust may very well be full of crap right now)

PS, mmm, beer.

Wiring, I was thinking.

Can you take it for a thrash up the road?

Mmm. I’m inclined to say not electrical- main reason being that the failure changes so perfectly with the injector, but also, I know that running it with an injector disconnected throws an error code so I’d assume that’d be the same with a bad connection or similiar. Lets say there’s more things leading me to other conclusions.

Haven’t driven it…Kind of wary of it. Might not be a bad idea tbh.

What do you do to code it?

Googling throw anything up?

Is the new injector the spec as the 2.0 and 2.2 Injectors are different although they look the sane. Check the numbers.

molgrips, got a usb connector and a bit of software called Formiddable that can read codes, live-feed the sensors etc and code injectors. Nice bit of kit.

@Craig, yeah, same part number on the side. (and sold as an ST part, though obviously you can’t take it as read that it’s right)

Where did you get the recon injector?

Also, have you tried the old code with the new injector?
You won’t break anything by doing it, just either make the rough running worse or possibly better.

To properly generate the code for reconditioned injectors involves some very expensive machinery, and I know several places don’t bother. Lots just rely on the fact the ECU will adapt, and hope that it doesn’t have to adapt that far it triggers a fault.

FYI the code isn’t programmed into the injector. It’s a code generated from measuring the injector flow at specific pressures to allow for manufacturing tolerances, as it’s pretty much impossible to manufacture two common rail injectors with identical flow rates at all pressures.

Just fb’d ya…

In theory the injector should have been coded, this is a company that sells bucketfulls of mondeo injectors and have a good rep. Course, that may or may not be true, and it’s always possible they’ve just screwed up…

Did consider popping in the old code, I’ll give that a pop. Could try copying the other ones just to see, feels bodgy mind!

Yah, was using “recoded injectors” as shorthand, it’s recoding the car to the injector, rather programming the injector I know.

An intermittent misfire though? If the flow was just wrong, you would expect rough running as one cylinder was down on power, not an intermittent hiccup, suurely?

Call the company back.

ECUs can appear to do strange things when trying to compensate for running issues. It could be it’s unable to balance the engine by correcting the injection values, so it’s reaching some programmed internal limit, and then trying to adjust something else until it hits another limit or just resetting to original values at which point it tries again and ends up stuck in a loop.

These kind of things don’t always trigger a fault code, and it’s up to the person fixing it to identify the problem.

I had the symtoms you describe turned out to be the turbo. if the car was left idling its like it would build up with oil then when you took off lots of white smoke. it was fine when it was getting driven normally as it would just burn it slowly and not noticeable. worth a look?

I was advised by a mate not to put reconned injectors in. When they tried to put them in a customers car they never worked he’s a jag mechanic, same engine as the mondeo. One of the cars leaked a load of diesel into the cylinder so much in fact that it hydro locked and wrote the engine off. The life of a Delphi injector is about 80 to 120k, depends I suppose on use ie urban or motorway miles. Bite the bullet and put a new one in. I think you need to code it because each cylinder has a different firing characteristic because of the exhaust manifold and inlet but also because of the heating and cooling of the engine block. The codes are normally on the rocker cover. Sounds to me like a faulty injector. I exhausted all my options with my mondeo, loved that car but I had to let it go, just to expensive to put right, and the new ones have crappy dpf’s and additive fluid tanks and cambelts!

worth a look?

He categorically identified a bad injector, and the smoke’s now gone with the new unit.

Yeah, definitely a bad injector. Doesn’t rule out another simultaneous fault but if the turbo’s also gone, I’m going to be watching out for lightning strikes too… I don’t feel like the company are cowboys, I think it’s possible they’ve screwed up somehow though. They’ve not come straight out with a refund offer but say they’ll retest it if need be so we’ll cross that bridge maybe.

Didn’t get the chance to look at it today, biek racin! And, er, tonight race biek fixin (mc, you’re never going to guess what I broke…)

What USB to obd device have you got?

F-super, one of these:

http://i00.i.aliimg.com/wsphoto/v0/612338074/SUPER-SELLING-Ford-Scanner-USB-Scan-Tool-obd2-code-font-b-reader-b-font-VIA-FREESHIPPING.jpg

So, today was more biek racin. But spent a little time on the car tonight. Fun fact number one: The new injector runs better with the old injector’s code than it does with its own. Still idles like a sack of hammers but pulls better. So that’s interesting.

Roadtest, well, first of all it reminded me after 2 days of driving my dad’s focus that the clutch on my car is ridiculously heavy, but also that no matter how knackered my car is, it’s still ridiculously more powerful than a 1.6 petrol focus.

But besides that… It feels better under load than at idle and better at high revs than low, with either code. Little bit noisy. Otherwise, nothing too interesting. Oh and still no fault codes.

So I think that’s more evidence against the injector. Or perhaps the code on the injector. I’ll see what the supplier says.

And, er, tonight race biek fixin (mc, you’re never going to guess what I broke…)

Little dangly bit at the back?
Any chance you could grab a pic of one, just to check I’ve got all the necessary bits to machine them?

Northwind I thought the code was to match the injector to the car, ie all the injectors are the same and the code is to suit the individual car/cylinder characteristics which would bear out the fact that it runs better with the original code. The injector may just be out of spec a bit.

I think you will only get a fault code if the exhaust oxygen sensor picks up the mixture leaning off to much or it senses a pressure fluctuation in the common rail.

Inbred456 – Member

Northwind I thought the code was to match the injector to the car, ie all the injectors are the same and the code is to suit the individual car/cylinder characteristics which would bear out the fact that it runs better with the original code.

Nah, the code belongs to the injector (one of the likely suspects was that they might have done a cowboy refurb and not bothered to recode it, but that doesn’t seem to be the case)

I’m going to go out on a limb and bet 10 scottish pence that there’s something innocently wrong with the injector or its code- it’s going back to the suppliers for a retest and we’ll take it from there. They give reassuring vibes.

@MC: looks like a mirror image of this:

I can’t blame it for breaking this time – I’m not used to having to take the wheels out of the bike to put it in the car, so I absentmindedly took the wheels out, noticed the dropper post was still up, and decided to push it down while it was resting on the mech. 😳

Actually not quite like that hanger now I look at it again, but very similiar in design/shape. 2 holes not 3.

Hands up everyone who said “It’s still the injector”- replacement replacement arrived today, popped it in, recoded- sorted. Well. Not quite, still a small amount of smoke, going to give it a proper run to let it settle and burn off any crap that’s ended up in the pipework as a result of all this, but it’s a massive improvement.

Injector hasn’t been given a new code which is not inspiring. And no explanation of what was wrong with the last one. Still some ground to cover with the supplier.

Keep us informed how it goes. Still deciding if I am going to go diesel or petrol. Might go for an old knacker and keep something back for repairs. Thinking cheap lexus sportback 3.0 Auto. Will look into coding of injectors. Still not convinced about code for injector rather than car. Why would the codes be on the rocker cover ie each cylinder. Have you used the code supplied with the injector or the original one?