Peugeot 205 STDT rough idle

[Madeinwigan]

Hi, long time lurker, first time poster.

My 205 drives well but can suffer from a strange idle most of the time. If left say idling it will go in a cycle of stuttering and then building up to a heavy rev which then calms down. I think this video shows it well



What would you suggest is the cause?

Thanks

[spider]

I still miss mine.

Are you doing that ?

Its almost like it going to go into 'runaway' but not quite. I thought about air before I saw the video but I do not think its that. The 'ticking' to me indicates its trying to run on its own oil.

1. Clean out *all* the breather hoses you can get at, pay careful attention to the ones around the back of the oil filler if its got one there.
2. I'm assuming its not overfull with oil ?

[white exec]

Maybe air-in-fuel, or a dirty/misbehaving injector (run some good diesel cleaner through it)...

[Goc3k]

The haze of blue probably noses toward oil consumption.

I'd also look in the intercooler / intercooler piping to see how oily it is in there (while rummaging around following spiders suggestion). If it's seriously coated with oil it might point to a tired leaky turbo, coughing out oil spray while on idle. Whats the oil consumption like?

[Peter.N.]

I would agree, is sounds as though its trying to take off but the fact that it slows down again seems to indicate that its only burning a small amount of oil at a time. Sounds like a small leakage of oil into the air intake, or possibly fuel?? Is it a turbo, if so could be the oil seals leaking.

Peter

[spider]

If it was air I'd expect whiter smoke or surging and rough idling too. The back of block fuel heater is the prime suspect on these 1.8TD units. Its easily bypassed but you need to take a bit of care in the routing of the fuel feed pipe to keep it away from the exhaust / turbo if you bypass it.

Plus you may want a new fuel heater, I made one , and it worked well for a few years. details available if required although a google for '205TD fuel heater' may return the specifics of this. You need a small length of 15/16mm of copper pipe and a length of microbore c/heating pipe, some solder and a bit of patience.

The other favourite air intake part apart from the Lucas pump top itself and spindle (90% of 205TD's are Lucas equipped, N/A's are 50/50 on either pump type) is the fuel filter assembly. Again easily replaced, I used a 'spin on' replacement for mine, much easier to change the filter too (no mess either down the wing if the filter lives there) or having to undo a long through bolt and pour derv onto the gearbox if its behind the battery. Changing the spinon is very easy then its just like the 106TUD filter, a strap wrench and a rag is all that's required. You can get filter heads with a primer button too so there's no messing about with the pipework either.

[Madeinwigan]

Thanks everyone.

It's a strange one. I've not had the car long and have spent a lot of time getting it ready for MOT. It had surged the odd time when I'd been moving it around but it became more frequent. It sat idling for 20mins for the MOT without a problem which was a relief.

I don't know if it's relevant but my drive is on a steep downward slope, I wondered if that might contribute to it. I'll have an experiment today when I have a few minutes. It's a little embarrassing when you're sat in traffic and it has an episode!!

[Madeinwigan]

I then took it for a 20 mile run and it behaved well, as soon as I reversed onto my drive it started misbehaving. Definitely incline related.

[white exec]

What happens if you point the car the other way on that slope?

[Madeinwigan]

Pointing downhill is what causes the partial runaway, I can leave it running pointing uphill and it runs brilliantly.

[white exec]

Right. Understood.

[chinkostu]

oil not draining properly from the turbo?

[spider]

oil not draining properly from the turbo?

That's quite a good thought.

Given the drain pipe is a rubber hose and easy to get at (kind of) I would suggest removing it (at least the end going into the crankcase) to check its not either collapsed internally or otherwise restricted.

[CitroJim]

Another possibility is oil sitting in the cambox and tricking down the valve stems. This may indicate worn valve stem seals.

The cambox holds quite a puddle of oil and the position of it will change depending on how the car is parked...

Ordinarily, the oil will be at the back and away from the valves but if parked on a really seep slope then it will stand much more in the valve wells...