1.6HDi coming our way - Please Help!

[Welly]

See going back to the subject of this 'EGS' electronic gear roulette system....

It hesitates every single time you set off from a standstill, Citroen dealer couldn't be arsed to sort it properly so we've lived with it. "Sunshine" and higher temps arrive and the car switches on the a/c itself even though I've told it not to do that

Anyway, I left the a/c on thinking it'd give the system a nice workout and would you believe it - the hesitation went away, as in a completely normal drive and totally smooth

Predictably it's now hesitating a little with the a/c on but it's MUCH MUCH improved.

Scratching my head for ideas I can only loosely assume that when Citroen had the car in for "reprogramming" the gearbox then they did so with the a/c running? perhaps there's some compensation effect in the system for having a/c on or off? I don't know it's bizarre but kinda 'fixed' if you like.

We did 550 miles in it this weekend with 4 adults aboard and it didn't miss a beat, happily cruising at 70 plus 15 and civilised enough to be a comfy mile eater.

[OllieNZ]

Modern cars are getting too smart by half........ It may well have a different idle setting for when the A/C is on or it could be that as the motor is under extra load from the compressor that what ever is causing the hesitation (could be engine rather than gear box related) is unstuck already so no hesitation is apparent.

[steve_earwig]

The compressor will put a big drag on the engine, so the ecu will give it a bit more fuel to compensate. Even on the XUD I noticed that, if I used the throttle to hold it a bit above idle and then engaged/disengaged the a/c there was a noticeable difference. So, fuel delivery issue? Do these have any sort of doser/throttle body?

[Welly]

Mmm, I was kinda thinking the same as Ollie and Wiggy.

There's a few components within the inlet tract that I look at and just pray they stay there and don't crap themselves. To be honest I've not studied how the DV6 functions and don't want to know either, it's more a case of changing the oil every 6 months and praying

Average fuel consumption according to trip computer is a mediocre 43mpg.

[OllieNZ]

Assuming that yours is the same/pretty similar to the one I had in the 307? DV6 4TED iirc. The inlet system is pretty complex, it has an air doser with 2 electrically actuated butterflies. One butterfly is fed directly from the turbo and the other via the intercooler.
Operationally, the direct feed is used until the engine gets up to temp and then for initial acceleration even once warm. The intercooler feed is used the rest of the time. The butterflies are also used to force the engine to pull air through the EGR by closing/partially closing as required. The difference in air flow is measured by the MAF and if the EGR is blocked any any way the car will throw an aunty pollution fault along the lines of "EGR flow insufficient, mass air flow higher than expected"

[steve_earwig]

Oh dear, two more possibilities, if one of these is clogged/sticky/rubbish. Or are they just open or closed? No idea, bluddy modern cars

[OllieNZ]

Oh dear, two more possibilities, if one of these is clogged/sticky/rubbish. Or are they just open or closed? No idea, bluddy modern cars

They certainly oil up, and probably see a bit of backflow from the EGR. They're variable rather than open/shut AFAIK.

[trufflehunt]

Mmm, I was kinda thinking the same as Ollie and Wiggy.

There's a few components within the inlet tract that I look at and just pray they stay there and don't crap themselves. To be honest I've not studied how the DV6 functions and don't want to know either, it's more a case of changing the oil every 6 months and praying

Average fuel consumption according to trip computer is a mediocre 43mpg.

Phew....., 43mpg from a 1.6 HDI ?

Why are you keeping it ?

[Welly]

Phew....., 43mpg from a 1.6 HDI ?

Why are you keeping it ?

We were given it, have done 40K miles in it now, 43mpg was better than our previous 1.8 pez Vauxhall and the C4 has working a/c, an auto* box and bluetooth, which her indoors likes.

Around the corner though is the dreaded Eoloys fluid top up / dpf clean / reset. Soon enough it'll have to go as it has as many negatives as positives in terms of being a car apart from snapping a spring recently it hasn't let us down or failed any MOT's.

I did spend quite a bit bringing the maintenance up to date, when it arrived it had 30K miles but was 6 years old so I got the cambelt, warty pump and aux belts done, new fuel filter, brakes etc and it's had 6-monthly oil changes which no-one will thank us for. Strangely is appears to be a factory *improved* DV6 with some kind of turbo after run oil pumpage and injectors that don't leak.

[steve_earwig]

some kind of turbo after run oil pumpage

That's the first time I ever heard of that, I wonder if it's on the parts Manuel.

Phew....., 43mpg from a 1.6 HDI ?

Why are you keeping it ?

Is that bad? The only way the Toyota would do that would be in free fall

[Welly]

Steve after turning off the engine there's a distinct humming/buzzing noise from the turbo area that seems to run on a timer, I'd love to know what it is. There was talk of some 'upgrades' following the spate of turbo failures with this engine.

[OllieNZ]

Steve after turning off the engine there's a distinct humming/buzzing noise from the turbo area that seems to run on a timer, I'd love to know what it is. There was talk of some 'upgrades' following the spate of turbo failures with this engine.

I believe said upgrades involved deleting the filter on the turbo oil feed pipe and the upgraded injector seals, I'm not sure much else changed tbh, but I've not really followed the updates since I ditched the 307. It would be good if they've put an electric oil pump on there to feed the turbo after shutdown but I'd think that's an unlikely expense? It'd be far easier to let the ECU shut the vnt vanes to stop the turbo impeller and idle the engine for a couple of minutes.....

[steve_earwig]

I've no idea which C4 I'm looking for but I took a stab at a DV6C, on the turbo lubrication diagram there's something called an electro valve (1618 PE), no idea what that is but I can't imagine why the ecu would need to turn the lubrication on and off. Unless it shuts it off when the car is turned off so the oil doesn't drain

Trouble is with idling the engine most people want to rock up in their wheels, key off and jump out, few owners care enough to want to sit there taking in the scenery. A pump run by the ECU would be a much more practical idea if one could be made cheaply enough.

[Bailes1992]

All my DV*'s buzzed after you turned them off. I was advised by Ford that it was the EGR self-cleaning cycle.


Reading this makes me happy I have a conventional automatic in my Volvo. It'll be getting 20k oil changes and I don't expect to have any issues with it. Interestingly the Aisin Warner TF-71SC is only rates for 280nm of torque and the engine makes 355nm out of the factory. Heico tuning are happy to push that will into the 450's too, even on an auto.

I actually have a very similar gearbox to what I imagine is fitted in Steves Toyota and experience the occasional drop back to idle when you lift off going up hill. Because you're accelerating the torque converter is open to allow the engine to spin slightly faster, when you lift off it sometimes lets the revs fall to neutral as opposed to locking the converter and engine braking, mine usually does it when it's cold. In fact until the transmission oil hits 25°c it doesn't lock up the torque converter, quite noticeable on a cold morning and operates very much like a CVT.

We just recently chopped the Wife's Duster in for an Sandero to reduce our monthly outgoings a bit. It's got a little 3 cylinder turbocharged engine with a displacement of just 900cc! It's a hoot to drive, it makes 90bhp and loves to rev, it even sounds like an old V6 or V12. What makes me even more happy is that it takes ANY ACEA A3/B4 oil (cheap, easy to get hold of and best for engine protection over say an ACEA A5/B5 which is for fuel economy), it has a timing chain, port injection and a standard, basic no thills or frills turbo.

[OllieNZ]

All my DV*'s buzzed after you turned them off. I was advised by Ford that it was the EGR self-cleaning cycle.

Having had the EGR valve on mine apart that makes sense, it's certainly electrically actuated and is some sort of funky rotating plunger thing.