2.2 hdi136 economy

[mjb]

Pulled the plug off, no noticeable change at all at any revs/load . Doubt trying to clean it will do anything if it's this shot (and my back's killing and it's cold out) so ordered a new genuine psa 1920AG for an impressive £45 which should be here in a couple of days

Interestingly the C5 has that part on all hdis of that era but the 406 has a smaller diameter intake on the 90 and 110 (70mm as opposed to 80mm)

[jonsowman]

Wow, very cheap! Where was that from if you don't mind me asking?

Certainly sounds like it was the problem, let's hope the new MAF fixes it

[Doggy]

ordered a new genuine psa 1920AG for an impressive £45 which should be here in a couple of days

+1 That's a result.

Interestingly the C5 has that part on all hdis of that era but the 406 has a smaller diameter intake on the 90 and 110 (70mm as opposed to 80mm)

Interesting - dead C5 2.0 HDi's are easier to find than any 2.2. Wonder if the C5 110 plumbing would be better for a 'tweaked' 110 406 ?

[mjb]

Interestingly the C5 has that part on all hdis of that era but the 406 has a smaller diameter intake on the 90 and 110 (70mm as opposed to 80mm)

Interesting - dead C5 2.0 HDi's are easier to find than any 2.2. Wonder if the C5 110 plumbing would be better for a 'tweaked' 110 406 ?

From just looking at google images, it'd seem that all the C5s and the pug 2.2s have the same (small(?)) air filter box on diesels, whereas the 90/110 pugs have the same sized box as petrols

Reckon the turbo fitting's going to be the same, and I'm pretty sure the filter box mounting is the same (not seen it yet though) so swapping would be straightforward. When the 406 is sold and I get to do a service on the c5, i'll have a look for you all

lots of beauty panels to remove... gah. probably why the c5 is so ridiculously quiet though

[mjb]

Well the new MAF arrived yesterday - brand new still in the PSA bag What a faff to fit!!! Couldn't get my screwdriver (trusty Stanley 68-010) anywhere near the strange torx/flathead screws, and when I did manage it, the torx bit kept popping out. Stupid screws. Ended up lifting the air box up while trying desperately hard not to rip the rad hose, and used a torx key (like an allen key, but torx) to do the screws 1/6 of a turn each time

Anyhow, new MAF in, fired it up and things seemed much improved but I drove it to work this morning, and it's still unpleasant. 50/50 lacking power at the bottom end and it's now lacking power at the top end too Managed 24mpg

Will I need to reset the adaptations (yank the battery terminal) you think?

[Welly]

Could be worth forcing it to like it's new MAF, won't hurt. Have you ran some Forte injector cleaner yet? have you looked at the Intercooler for oil leaks? it might be leaking? any fault codes at all?

[mjb]

ECU's reset, no improvement. Not checked the filters yet - giving it a service next week though

Don't remember any faults stored, but I'll have to look again. It reckon's the FAP's in good nick, and last regenerated <500km ago. No obvious leaks, although I can hear a faint turbo whistle (is this normal for the 136/110? couldn't hear it on the 90)

Gave it some injector cleaner to about 15 litres of diesel the other day, but the MIL wanted taxi'ing around so got the wife to put a load more fuel in - urgh

As my bimmer was out of action for a few days I did get to give it a daily thrashing on the way to work (24mpg ) and it must be said I think it definitely lacks power/torque when you've got the accelerator on the floor. In fact I can't really tell much difference between about 20% throttle and 100%. Also, first thing of a morning, pulling away from my drive, it's really lacking power.

Any ideas anyone?

[Doggy]

Turbo whistle is normal particularly when cold - it bypasses the intercooler in favour of a water-heated exchanger when below 70c or during regens. When I first got a 2.2, I sometimes thought it was a distant emergency vehicle siren.....
(This also may in part explain less go when cold).

In fact I can't really tell much difference between about 20% throttle and 100%. Also, first thing of a morning, pulling away from my drive, it's really lacking power.

Have you checked the TPS values? If the clip's come of the throttle cable you may not be getting anything like 100%

[GingerMagic]

+1, the TPS may be a simple over sight. Keep it tight..
You can also set the throttle travel from inside the car ( ignition on - no throttle - then full throttle - then no throttle, ignition off. Start engine with no throttle.. )

My car is better/ quicker when cold but I have to hold back as it'll damage stuff, and my turbo whistle is especially loud when going past buses etc as the sound bounces off them.

I would have though the new MAF would have instant results....

[mjb]

New MAF and a service (oil, oil filter, air filter, diesel filter), with a full litre or redex injector cleaner ("pour 1/8 of the bottle into 50l of fuel") dumped into about 10 litres of diesel and now running on V-power. It's driving a fair bit better now.

I think it's boosting in 1st pulling away from stone cold now - which is good - and overall it's a lot less lethargic than before, but economy's still down. At 70mph on cruise control with a warm engine, it does 40-60mpg on the flat, but with any sort of slight incline it can drop to around 20mpg to give an average of around 40mpg (still 30mpg urban, tops)

Throttle pedal is purely electronic (no bowden cable)

Need to get Lexia on it again though, as I managed to set off an antipollution fault while doing the service (started the engine with the electrical connector on the fuel filter housing off ). Talking of which, that filter housing's a pain in the arse ain't it? Took ages to get it on such that it wouldn't piss diesel everywhere Cleaned up some oil spillage on my garage floor beautifully though

While I'm at it, is there anything I should be looking at in Lexia (like PP2000, but pig ugly, slow, and a royal pain to use) to help diagnose the consumption issue?

[Doggy]

See if your injector correction values have improved, they want to be within +/- 1.0 ideally at tickover, warm. I had a wonky injector or two on my previuos 2.2 - showed up as bigger correction values, lumpy idle, inconsistent MAF reading, (which actually reduced when you slightly increased the speed above idle).

Check your swirl flap actuator's working as you blip the throttle past 2100 RPM.

Look for close match between fuel pressure set and actual numbers, check the HP pump 3rd piston solenoid is working properly.

The other thing that could waste fuel would be a boost leak, (MAF value too high = running too rich).

[mjb]

Check your swirl flap actuator's working as you blip the throttle past 2100 RPM.

The what? how? Would it be "DIAPHRAGM" on the the diagrams (part 036387 if the same as pugs) which is attached to the gearbox-side of the engine and appears to rotate what seems to be a linked set of 4 butterfly valves on the "intake manifold" (which appears to be the cylinder head) via a rod and ball joint?

check the HP pump 3rd piston solenoid is working properly.

The electrical connector on the HP pump? Presumably there'll be a lexia test to activate it with the engine off?

The other thing that could waste fuel would be a boost leak, (MAF value too high = running too rich).

Just looking at the servicebox (i'll just call it 'servicebox' - the citroën variant is called 'service'. stupid ambiguous name) and there's what would appear to be two intercoolers - an 'air-air distribution chamber' and a smaller 'air/water exchanger' which i think i remember seeing diagonally engine-side of the radiator and looks more like an exhaust section. At the bottom end they go into the same pipe, but at the top they're switched(?) by this 'air dozer' thing I've heard about but know nothing of. What is all this voodoo? Additionally, there would appear to be an "intake air pressure sensor" (map sensor?) which I'd assume would be more important than the maf for fuelling?

Can you tell what an expert in diesel engines I am? Should have gotten her a V6... much simpler

Interestingly, the intercooler's got a "glove-box lid stop" on it

[jonsowman]

The what? how? Would it be "DIAPHRAGM" on the the diagrams (part 036387 if the same as pugs) which is attached to the gearbox-side of the engine and appears to rotate what seems to be a linked set of 4 butterfly valves on the "intake manifold" (which appears to be the cylinder head) via a rod and ball joint?

Yep that's the one. Should move towards you on acceleration at 2100rpm and away from you on deceleration at 1900rpm (as you're looking into the engine bay).

Just looking at the servicebox (i'll just call it 'servicebox' - the citroën variant is called 'service'. stupid ambiguous name) and there's what would appear to be two intercoolers - an 'air-air distribution chamber' and a smaller 'air/water exchanger' which i think i remember seeing diagonally engine-side of the radiator and looks more like an exhaust section. At the bottom end they go into the same pipe, but at the top they're switched(?) by this 'air dozer' thing I've heard about but know nothing of. What is all this voodoo? Additionally, there would appear to be an "intake air pressure sensor" (map sensor?) which I'd assume would be more important than the maf for fuelling?

The MAP sensor (manifold air pressure, even though it's not monitoring the manifold) is for monitoring turbo function and is just as important as the MAF for fuelling. Check the pipe that runs between the MAP and the intercooler, it often swells or breaks at the intercooler end (though I'm certain this would give you an EML).

[mjb]

Yeah, the ball joint on the swirl flap's snapped off a plastic rod which has what feels like pneumatic pressure pushing forward. Bit of a giveaway that there's a couple of small zip ties attached to the engine-side of the ball joint

There's some clicking when I run the actuator test, but no movement and there's always forwards pressure on the snapped plastic. Perhaps the valve's been blanked off?

[mjb]

See if your injector correction values have improved, they want to be within +/- 1.0 ideally at tickover, warm. I had a wonky injector or two on my previuos 2.2 - showed up as bigger correction values, lumpy idle, inconsistent MAF reading, (which actually reduced when you slightly increased the speed above idle).

idle: 2.5, 2.1, -3.2, -1.5
1700rpm -0.2, 2.6, -1.5, -0.8
2500rpm -0.7, 2.8, -1.4, -0.8
idle: 1.7, 1.7, -2.5, -0.9

hmm