hdi 90 - hesitation at low revs and coming off clutch pedal

[sirwiggum]

sounds like you hit the nail on the head then mate, air entering via the 3rd pipe.

Starting issue for sure hopefully. I will report back once the Bosch unit arrives.

Then back to the hesitation-at-low-revs hunt (unless by some miracle the Bosch unit fixes it and it turns out the old Bosch unit had a bad seal somewhere).

Thanks FlySpeck.

[FlySpeck]

no prbs mate, did we already consider the DBW TPS unit for the low revs hesitation? Also MAF failure can do this for sure, and the HDi 90 does have one...

My scoob did that and it was the maf, lost calibration at low airflow so it stuttered and cut out pulling away from a junction and would only rev with lots of throttle - same thing happened on the VR6 too...

[sirwiggum]

no prbs mate, did we already consider the DBW TPS unit for the low revs hesitation?

Yes that is on order from fleaBay, should be arriving at some point too! Cheers.

[FlySpeck]

ah ok, would maybe be an idea to plunder a maf off a scrapper to swap out as there are hundreds of HDi's in the breakers yards.

mine cost £15 from a local scrappie and did the trick no probs.

[sirwiggum]

no prbs mate, did we already consider the DBW TPS unit for the low revs hesitation? Also MAF failure can do this for sure, and the HDi 90 does have one...

My scoob did that and it was the maf, lost calibration at low airflow so it stuttered and cut out pulling away from a junction and would only rev with lots of throttle - same thing happened on the VR6 too...

Original MAF was cleaned and made no difference.

Have one of those on order too but obviously the volcano must have backlogged the post between the Peugeot components factory and sunny Belfast

Although it is the case that you will order something to be delivered by a parcel company, and after a couple of weeks waiting, about to phone up and complain that it hasn't arrived, you notice something behind the plantpot on the step....

Luckily the local opportunistic thieves aren't big into Peugeot components and old video games

[FlySpeck]

cleaning didnt help mine either as the elctronics that converts the airflow into a voltage was faulty.

[sirwiggum]

cleaning didnt help mine either as the elctronics that converts the airflow into a voltage was faulty.

Worth a try though. Carb Cleaner and air intake cleaner.
Occasionally works for things like idle control valves.

WD40 and duck tape are other 2 items in my inventory of amateur mechanics tools

[sirwiggum]

MAF arrived, fitted, the car feels a lot better below 2000rpm.

However, the fuel filter arrived and it turns out mine mustn't be a Bosch, as it is the wrong shape. Will have to send the Bosch one back.

The one I need is similar to the Siemens filter, but I need the 2 pipe instead of the 3 pipe.

Tried a bolt with PTFE to block it, but it just started eating through the side of the plastic.

Fun and games

[sirwiggum]

MAF arrived, fitted, the car feels a lot better below 2000rpm.

However, the fuel filter arrived and it turns out mine mustn't be a Bosch, as it is the wrong shape. Will have to send the Bosch one back.

The one I need is similar to the Siemens filter, but I need the 2 pipe instead of the 3 pipe.

Tried a bolt with PTFE to block it, but it just started eating through the side of the plastic.

Fun and games

OK the 190162 fuel filter housing is impossible to obtain easily. I ordered one from the pug dealer but as I needed the car to move flat I also got one from a scrapyard.

It is not running perfectly, the hesitation seems to be there. I will grant though, that the 2nd hand filter housing is an unknown quantity. The dealer "new" housing arrived and hopefully, when I get a chance, will swap it round.

Otherwise, the TPS never arrived though I was refunded. If the new filter doesn't help this will be the next swapover.

When I get a further spare moment, I intend to open the 3 pipe and the 2nd hand housing and swap the filter elements, therefore having a "new" fuel filter housing, seeing as these things are like hens teeth.

What is the best way of opening the Siemens-style filter housings? I'm thinking of trying an oil filter strap.

[sirwiggum]

One thing I've noticed is that in town driving, resting the foot above the bite point while driving (I know, I know, it's not the best way to drive), the acceleration is fine.

It is when I take my foot *fully* off the clutch pedal between 1500-1800rpm (ie. just after changing gear) that the misfire feeling / hesitation is most noticable.

Probably a new clutch then.

[Welly]

Resting your foot on the clutch may make it slip (the 406 hydraulic clutch lets go as soon as you press the pedal).

Having your foot off the clutch and feeling this hesitation makes me think about a tiny little switch fitted atop the pedal to turn off the cruise control (when fitted/activated).

Some cars come with pedal sensors even if they don't have cruise - it's a long shot but might be worth a looky?

[sirwiggum]

Resting your foot on the clutch may make it slip (the 406 hydraulic clutch lets go as soon as you press the pedal).

Having your foot off the clutch and feeling this hesitation makes me think about a tiny little switch fitted atop the pedal to turn off the cruise control (when fitted/activated).

Some cars come with pedal sensors even if they don't have cruise - it's a long shot but might be worth a looky?

She has no cruise but I am intrigued by this, will have a looksy this weekend.

[sirwiggum]

Apologies for not being on much recently, busy busy busy!

Anyhow, I was hoking about the car last night and I think I may have found the cause of the lumpiness between 1500 and 2000 rpm.

Above the clutch pedal is a little switch (as suggested by Welly). In true 406 diagnostic style (see EGR) I disconnected this.

Car now doesn't jerk when coming off the clutch, and doesn't stutter at low revs when coming off the clutch changing gear.

If this switch is for cruise control, then why is it on a non-cruise control car?
Why does this affect the ECU of a non-cruise control car?
Why does the ECU work better on a default disconnect value?
What affects will running with a diconnected clutch switch cause? Other than a stored code.

I can change gear OK so the clutch mustn't be too reliant on clutch-by-wire.

I will run it a while and report back but it definitely drives a lot smoother now.

Cheers!

[Welly]

Sweet Jesus - I think I may have helped someone properly

[sirwiggum]

So,

Running the car with the clutch switch disconnected, in stop start traffic when stopping the revs would occasionally dip down to about 600rpm, as if it was about to stall.

In a funeral procession on Saturday it was difficult to drive at walking pace. On the clutch it was juddering then with a bit of throttle it was wanting to lurch forward. Not very smooth and a bit embarrassing as I had the other half's family in the car.

Then on Sunday, I was driving to my dads for Fathers day, got into his street, as I dipped the clutch it stalled.

So reconnected the clutch switch and it stopped that carry on.

The drive in this morning it was back to it's usual tricks of being jerky when coming off the clutch pedal, and misfiring between 1500 and 1800rpm.

Web searching reveals that many people have this same issue with HDis, from Picassos to Berlingo vans, but with no results of what actually *cures* it. Injector cleaner, new fuel filter, new MAF etc. all tried.

Having a love-hate thing with this car. Severely tempted now to weigh it in and get something with a really basic engine and avoid fussy HDis forever.