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Discussion Starter #1
The throttle on my girlfriends 307 stuck absolutely flat out the other day, it wasn't my favorite experience.
I know the accelerator is fly by wire so my first thought was dirt or rubbish in the pick up at the top of the pedal or something to do with the mat. It looked clean, I give it a spray and checked the connector then removed the mat.

I started it again and it was fine UNTIL it revs reached 3000rpm and it took off again! Ohh my god. I haven't moved it since. I'm afraid to keep trying things or give it to someone who doesn't know what they are doing in case it happens again. I can't imagine what would happen if the girlfriend is driving.

Cutting the ignition wouldn't stop it, i had to stall the engine in 6th gear. Even then it didn't want to stop and would rather burn the clutch out!

Any help would be much appreciated. Ive had it plugged in by a friend and the only fault code that came up was related to the 'anti pollution fault' and pointed to diesel additive. The accelerator seems to be quite a common fault (though not flat out) but I haven't been able to find any fixes online.

I did contact the main 'Stealer' who said they would plug it in. I inquired as to what they would do then if that didn't show anything? He said they would run more tests (£100 to plug it in). I was expecting a Peugeot expert to say something like... yes we know of this problem, it will either be this or this etc. He didn't want to explain anything at all really, basically said "do you want to book it in or not". ...He didn't fill me full of confidence. I was imagining being stolen from by a massive stealer while they 'tried' things.

I hope you guys can save me some money and possibly my life!
 
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Will Looks like I will be the Bringer Of Doom I'm afraid. Sounds Like you have 'Diesel Runaway' this happens when oil gets past the seals on a turbo and is forced into the combustion chamber in the engine :mad: This Is usually Terminal as the engine runs and runs until it basically implodes :( Usually a result of poor servicing & Maintainance Google it as there is plenty of info out there and even a few videos of other peoples experience. I would get a second opinion as I am only going off your described symptoms but hey just my thoughts.
 

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Discussion Starter #3
Thanks for your reply.

I did worry about this to be honest. 1 thing that made me think that it maybe electrical rather than the turbo was the way it would rev. It would rev flat out for about 5 seconds then drop down to tick over very briefly, then flat out again. Then repeat. like you I was thinking if it was the turbo it woukd just keep going, injesting oil. It very well could be the turbo, but I hope not!
 

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Discussion Starter #6
It wouldn't switch off on the key (when it was flat out). I havent tried it since to know if it does while just idling though. Yes when I restarted it' it was in neutral and happened again. It revved normally up and down but as soon as it reached about 3000rpm it went beserk.
 

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Discussion Starter #8
It Arghh, definitely? Can I ask what the difference is between it happening n gear to in neutral?
I haven't topped up with oil, but when I checked the oil after this happened and it is a bit over filled. I thought this was odd as nobody has put oil in, I checked it a few weeks ago before a long trip and it was on the button. You think maybe this could of caused it? Where would the extra oil come from?
 

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Just to check if it wasn't just something that happened when the car was in motion, drain some oil out first then see if it happens against if it does its a seal gone somewhere letting oil in the pistons

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It Arghh, definitely? Can I ask what the difference is between it happening n gear to in neutral?
I haven't topped up with oil, but when I checked the oil after this happened and it is a bit over filled. I thought this was odd as nobody has put oil in, I checked it a few weeks ago before a long trip and it was on the button. You think maybe this could of caused it? Where would the extra oil come from?
Hi

Look the other guys are more knowledgable than me on this issue but re sump level has fuel economy dropped thinking fuel passing into sump reducing viscosity

No idea if I am sprouting rubbish though

Good luck


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I fdunt disagree. Cud b true. I have no explanation. Maby checked when fluid cold. Then fluid hot. On a hill
Car been stood the oil drops to sump. Bigger level on stick. Run the car the pump takes it n goes round engine. Leaving lower lvl in sump?

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It could be that excess fuel is getting into the cylinders and not fully burning off. The unburned fuel would then seep past the rings into the sump. Perhaps too much pressure in the fuel rail, leaking injector seals are a couple of possibilities.
 

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As above IF the oil is higher than normal and its not deliberate ie mistakenly put too much in the diesel is getting in somehow.

If the oil level is higher than normal this will stop the return oil from the turbo flowing fast enough back to sump this in turn means the oil tries to get out another way IE past the seals and burns it causing the runaway you are experiencing.

Sounds like you have 2 problems !!
 

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Hi, a very simple test- remove BOTH air hoses of of the Doser valve ( on the inlet manifold). This will stop any oil from the turbo getting into the engine and using it as fuel. Start the engine, rev it, if it just go's straight back to normal, then it is the turbo, not the electrics. If it is the turbo, you may also get a oil mist coming out of the hoses to. The engine will keep dropping the revs back if the turbo is leaking, because the ecu is using the Doser valves to shut down the engine. As soon as the revs drop, they will open again, hence the cycle happens all over again.:nono:
 

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Just in case you can't get the engine to stop, shove a damp cloth in the air intake to kill it. No air, no burn.
 

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Discussion Starter #19
Fixed.

Thank you for all the replies. Sorry for the slow reply but I haven't had much time to work on the car until now.

I think bertye mentioned how to check if the problem was electrical or mechanical:thumb: When I pulled of the two hoses and got it up to temperature, there was no throttle issues but like bertye mentioned there was some spray/droplets of oil coming out of the bottom hose (going to the dozer).

So oil was clearly getting passed the turbo seals, but why? I wasn't ready to condemn the turbo, low milage car, has'nt had a thrashing, full history, it shouldn't go. It's had the standard Peugeot 'depollution system' fault come up a few times (I'm pretty sure every 307 has had this at some point) but didn't think it was related.

Bottom line, depollution system is the DPF (Diesel particle filter) system, This is to contain the soot diesels churn out under euro emissions. Most of you will know but basically it's a big 'go away' filter in the exhaust. It's metal but with very fine holes going through it. The theory is; The soot collects in here over a period of time until it's quite full, when it needs cleaning... The next time you drive your car at over 50mph for over 10 minutes, the management system switches a load of components on in the car, such as heater plugs climate control etc, to put more load on the engine, getting the exhaust gasses hotter. The car also has a small tank of fuel additive which it injects into the fuel periodically after you fill up (There is a sensor on the filler cap).
So the exhaust gasses are hotter, the management system injects more additive in and it gives a big blast through the dpf, blasting all the crap out of there. This as known as regenerating.

This is what is MEANT to happen. but in reality it's flawed. It doesn't always work, allowing the dpf to build up crap and become blocked. Also anyone who doesn't get their car serviced by a main stealer or a specialist, might not get the additive tank topped up. In which case it definitely wont work. Also I think rubbish supermarket fuel plays a part and obviously lack of servicing.

What happens when the system FAILS;
The the DPF sensor sends a signal to the management system saying that it's full and it can't handle all the exhaust gasses. When you accelerate the car tries to limit the amount of exhaust gasses by not injecting all the fuel your asking for into the cylinders. The excess gets injected into THE SUMP:mad: Unbelievable. Oil gets thinner, level increases bit by bit until the only place it can go is past the turbo. In the end you get overrun. The oil that's pushing past the turbo seals gets into the cylinders, the engine starts running off this even when you take your foot off and off it goes until in blows up. You'll never stop it unless you partially destroy the clutch trying to stall it in 6th (like i did). To be fair some other manufacturers suffer with this dpf problem, even the Fiat 500.

The FIX
Either; Get the dpf changed, You can do it yourself its actually not too difficult, just fiddly. Also get the additive tank topped up as this is probably the reason it's blocked up in the first place.

OR; Get the dpf off and blast it out with a pressure washer, also getting the additive tank topped up. You might have to do this every 6 months or so unless you can get to the root of the problem.

OR; Get the dpf off, smash it to bits out of the exhaust with a hammer and chisel (I also used a drill and masonry bit to speed things up). You end up with a nice clear section of exhaust like the car ideally needs to breath properly. You don't need to worry about the additive tank.
Downside is you need to go to somebody who does ecu remapping and get the dpf file deleted. This will stop the management system from trying to regenerate the dpf which isn't there anymore (causing blue smoke).

Results for me are; The car goes a lot lot better without the dpf in place (even when it was working). Its a 2.0 hdi xsi so it wasn't sluggish before but now it's noticeably quicker, better response and you can hear in breathing better. MPG increase as well, its 5mpg better so far and I haven't been on a tidy run yet. There's loads of videos and pages about how to do this. One thing I would say is make sure you wear gloves and a mask as the dpf is full of all kinds of crap.

Don't bin the turbo like a few mechanics told me. Turbos now are so good they should really last the life of the engine if your servicing properly. If you get 'Dpf filter' warning or 'Deppolution' warning do not keep driving you car. fuel is being injected into the sump!

Hope this helps a few people.
 

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I am pleased that you have solve the problem. Just so others know how it works 9 or doesn't). The additive in the small tank, is only pumped into the fuel tank when the fuel cap is removed to refill with fuel ( the cap has 2 magnets it that can full out, which is another problem). The ecu then works out how much additive to add. When the dpf is blocked, the ecu switches of the egr valve so more oxygen is available, plus injects more diesel on the exhaust stroke to burn in the exhaust, rising the temperature burning the soot out of the dpf. This will not work on short journeys, or if the DPF has past it's service life. A car used all the time on motorways, will rarely get problems. Note- the DPF can't just be gutted, as there will be no pressure difference between before and after the filter. Once it reaches 10% difference or about, it go's into regen. If there is no difference it will go into limp mode, so needs to be mapped out, along with the additive system. I have bee told by car dealers, that routing out 5mm deep into the surface of the metrics removes the ends of the blanked ends of the filter, which will allow the exhaust gas straight throw, but will give just enough pressure difference to keep the ecu happy. The other edge of the metrics must be left in tact so the the filter doesn't slide up and down the box, or it will brake up in quick time. I have made my own de-fap de-cat pipe, and my own pressure system to fool the ecu, with no back pressure at all, and go's like stink. It has been on for 10 months now, and no warnings.
A picture of the basic workings of the DPF
http://www.castrol.com/liveassets/bp_internet/castrol/STAGING/brand_assets/Castrol/Europe/images/other/slide3_515x223.gif
 
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