"Engine Antipollution System Defective"During Rain

jameslxdt · Post by **jameslxdt** » Mon Jan 29, 2007 7:33 pm

it looks like an oxygen sensor on a petrol and there's two, one fitted just before the particulate filter and one just after it

neildavies · Post by **neildavies** » Mon Jan 29, 2007 8:10 pm

I've found a pressure sensor on a Peugeot diagram (doesn't show where on the car it is though). It looks like the oxygen sensor pipes go into this and there's an electrical connector on it. Here's another generic diagram that I found:

it's B in this diagram

What I'm wondering is if it takes 2 hours to change this, or can I just buy the part and do it myself. I don't mind having to pay, but 2 hours seems a bit over the top. At the moment, since the car's been on the diag machine, the light has gone off. I'm also wondering if i can just cover this thing in WD40 to see if that may delay the fault for a bit.

jameslxdt · Post by **jameslxdt** » Mon Jan 29, 2007 8:13 pm

that diagram is a right mess but it think the pressure sensors are A

neildavies · Post by **neildavies** » Mon Jan 29, 2007 8:40 pm

Smack on again James, A's are pressure sensors. B is the"Differential" pressure sensor, which is what's gone on my car.

neildavies · Post by **neildavies** » Mon Jan 29, 2007 9:08 pm

Here you go, it's park number 6. This is a photo of a peugeot engine.

Any idea where this might be? And if it's difficult to get to (as in 2 hours difficult)

jameslxdt · Post by **jameslxdt** » Tue Jan 30, 2007 6:56 pm

sorry, i didnt read the previous post fully, it may not be the differential pressure sensor that is at fault, it maybe the filter is actually getting clogged, and the sensors arent lying to the differential sensor, have they taken the filter off to see if its clogged? and yes its a pig to change

Post by **Welly** » Tue Jan 30, 2007 8:06 pm

A differential pressure sensor does just that, it is looking at pressure variations across a known resistance, like your filter. Any increase in resistance above a known value and a fault will be triggered.

Have you tried a good thrash in your car, you know, a good high speed run, maybe try a bottle of forte injector cleaner too?

Why did they put all that gubbins on anyway? I know it can inject some fluid to raise the combustion temp to 'clean' the filter, but is it because the 2.2 emits more fumes? or is it just a 'green' move?

jameslxdt · Post by **jameslxdt** » Tue Jan 30, 2007 8:10 pm

it was an idea to reduce exhuast emissions and is great, untill it goes wrong, like now, the additive does raise combustion temperature to overheat the exhaust and burn of the soot, thrashing it will do nothing, its either the pressure sensors, differential sensor or the filter is genuinely getting clogged, or it may be BSi fault (unlikely)

neildavies · Post by **neildavies** » Tue Jan 30, 2007 8:22 pm

I don't know how he knew, but the mechanic said the filter isn't blocked, which lead him to believe the differential pressure sensor is at fault. As I say, I don't know how he knew it wasn't blocked.

I have taken the filter off before and cleaned it myself, so I know personally it's not blocked, but I didn't mention this to the mechanic. Whether he could tell by the exhaust pressure out of the tail pipe, I don't know.

Also, I've read about these being prone to water damage, and mine started as a problem in the wet. I take it by your comment James that it's not a DIY job, and worth leaving it to the dealer?

jameslxdt · Post by **jameslxdt** » Tue Jan 30, 2007 8:25 pm

you can do it yourself, but you need to remove the exhaust and even then, its still a pig to get at, especially on axel stands

neildavies · Post by **neildavies** » Thu Feb 01, 2007 8:00 pm

Sorry, missed the last post. But it wouldn't have changed my mind now. When you mention removing exhausts, I give up. The coupe's not got the best ground clearance, on stands or ramps. And the weather at the moment doesn't make it a pleasant experience.

Anyway, the garage phoned and it's booked in next wednesday. I'll update you when it's done.

jameslxdt · Post by **jameslxdt** » Thu Feb 01, 2007 8:03 pm

also i forgot to mention that you have to slacken off the brake servo aswell to get to it

neildavies · Post by **neildavies** » Thu Feb 01, 2007 9:08 pm

Confirmed then, definitely wouldn't have done it myself! One for the expers I say.

jameslxdt · Post by **jameslxdt** » Fri Feb 02, 2007 8:44 pm

i have never done one myself but watched someone do one and oh my was there a alot of swearing

neildavies · Post by **neildavies** » Sat Feb 03, 2007 9:59 am

I'm sooooo glad it's booked in!! I've worked under the coupe a coupe of times taking off the particulate filter, and it's not very roomy there. I don't fancy messing with the brake servo either, scares me a bit on these modern cars.