MAF and Swirl Flaps

[Rjessy]

Hi all,

Fairly new to the club after picking up a 2.2 HDI Coupe last Thursday. I have learnt from consultation that it is most likely the MAF, swirl flaps or EV's.

Are there good guides on checking and diagnosing and replacing the swirl flaps or EV's? I believe the MAF is at least at fault as pulling it off made a marked improvement but on checking the car revving there is no movement to the actuator (diaphram) on the end of the swirl flap - it is upright at all times but is free to allow me to push it backward using my finger.

Also one final question is it essential to buy from Peugeot for items like these? They are quoting £116 ex VAT for the MAF which is much more expensive than eBay or some Motor Factors. For the £23 ex VAT I will just buy the swirl flap actuator from them but if I can save £100 on the MAF and still get a comparable item that would be best.

[GingerMagic]

Hi, if you want to double check the swirl diaphragm you can follow the pipe from the actuator to wherever it goes ( I can't remember where ) and pop the end off and give a quick suck and the little flap on top should move. If it moves then diaphragm is okay and there is a vacuum leak somewhere else, I believe. If it still doesn't move then its probably buggered.

I checked my EVs by taking a picture of them on my phone for reference, then basically moved the pipes and electrics to the EV next to it and go for a spin. There is enough slack on the pipes and leads to do this and hopefully by the process of elimination you will know which one, if any, is duff.

Lots of MAFs on ebay, I think they are all pretty poor quality and really you are better off getting a good one from a motor factors, mine was £117 inc VAT.....

[Doggy]

Not completely sure, but I think the swirl flap actuator needs vacuum to lift it and it should drop back by itself - this may indicate a failed electrovalve rather than the actuator. I'll try disconnecting a ppipe from mine tomorrow & confirm.

[Rjessy]

Thanks guys

Appreciate you looking at that Doggy.

[Doggy]

Right, now first off, I was wrong - it is spring loaded to extend the actuator rod upwards.

Correct behaviour:

Engine stopped - actuator extended [UP]
Engine idling - actuator retracted [DOWN], (electrovalve open).
Engine speed > 2200 RPM and injection quantity > 40mg - actuator extended, (electrovalve closed).

The actuator can suffer a split diaphagm, which will stop it retracting and quite possibly give you other vacuum system issues.

Replacement:

Reference Description Quantity Price - VAT Price + VAT
0000036387 DIAPHRAGME 1 18.72 GBP 22.46 GBP

There's a PSA 2.2 HDi technical guide on the coupe forum: http://www.406coupeclub.org/PHPBB3/view ... 82&t=27699

and an excellent vacuum system fault finding guide: http://www.406coupeclub.org/PHPBB3/view ... 82&t=35570

[Rjessy]

So I started some exploration last night and found something's that either make fault finding easier, or give me more headaches. On reading the threads/doc attached to the last post from Doggy I have the theory in place but maybe what I see below makes things more clear any more experienced guys out there.

See the details with the photos below:

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[dirtydirtydiesel]

You want to seriously think about ditching the tuning box (bad) & go for a remap (good) there are plenty about for the 2.2, ask Doggy or Gingermagic .
Are you sure the blanked off vac pipe is not for the E.G.R valve

[Rjessy]

Yes I was not too happy about the box. Will need to get it removed but I want to make sure that however it was out in will allow me to just pull it out without much fiddling about.

I assumed the blanked vac pipe was from the unit just to the left of the pipe (that it is actually resting on in the photo. The reason for it being blanked is the mystery I need to solve now.

[dirtydirtydiesel]

I'm fairly sure that the pipe in you last photo is for the vac unit on the E.G.R valve & the one on the bulck head is also to do with this ,
I am also fairly sure someone who know's for 100% will be along shortly

[Doggy]

Can't be certain from the last pic, but it looks like the air doser actuator.
On 2.2's this is used to route the air from the turbo through the intercooler most of the time, but during warmup or dpf regen, the air passes through the alternative, water-heated exchanger.

[Rjessy]

It is just under the front right of the engine cover. I was hoping to get a handle on the issue before needing to get my mechanic involved but as he will have the readers it may be the best route now.

Whoever was at this before me did a good job of messing it up!