mot fail on emissions and fault codes

[alanh6687]

Hi all. I took my car for the mot and it failed on emissions. Aparently a co reading max limit should be 0.5% and mine was 10.0% lol

I knew the exhaust was leaking gases before the 1st lambda sensor, due to a faulty bend on the cat, so was expecting it to fail.

I got my car back and replaced the cat. Reset codes and added some fuel treatments, but its still idling awful.

Now the engine light has come back on with:

16514 Oxygen sensor B1 S1 malfunction in circuit Po130-35-00

17705 Pressure drop between turbo and throttle body P1297-35-00

16684 Random misfire P0300-35-10 intermittent

16699 Cylinder 4 misfire P0304-35-10

I'm thinking the faults are all relating to a faulty lambda sensor? The pre-cat one?

Just wandering if anyone else has had anything similar, before I buy the new sensor

 

[8bit]

Poor idle and the Random misfire code might suggest fuel issue, possibly dying fuel pressure regulator or old, dirty fuel filter. The FPR has a vacuum line going into it which may also be split.

Cylinder 4 misfire and poor idle suggests dead or nearly dead coilpack on that cylinder. Start the engine then disconnect the electronic cable going into the injector on cylinder 4 (think that's the passenger side one). If the idle gets worse or the engine cuts out then try the opposite end one.

Code 17705 is usually a boost leak so check all the hoses and pipes from the turbo right round to the intake manifold. Also, what dump valve have you got on the car? If it's a Forge 007p then check it's not sticking. If it's the standard one then it may be the diaphragm has torn allowing turbo pressure back round into the TIP.

You can look up fault codes for more info here - http://wiki.ross-tech.com/wiki/index.php?title=Category:Fault_Codes&from=02070

 

[alanh6687]

I've got the Forge split R valve on it at the minute.

I replaced the precat lambda sensor today, added a fuel treatment, reset codes and took it for a 20 mile run, when I got back it seemed alot better, without any codes or poor idle etc..

A couple of hours later I started the car up and the revs were all over the place again

So it only seems to do it mainly when cold.. :s

 

[8bit]

I've got the Forge split R valve on it at the minute.

How have you got that set? The Leon's aren't configured for dump valves discharging air out of the system. They'll see that as a boost leak, hence the code 17705 about pressure drop between turbo and throttle. If you can, set it up so it's fully recirculating, i.e. dumping all the charge air back into the turbo intake, then clear it and try again.

I replaced the precat lambda sensor today, added a fuel treatment, reset codes and took it for a 20 mile run, when I got back it seemed alot better, without any codes or poor idle etc..

A couple of hours later I started the car up and the revs were all over the place again

So it only seems to do it mainly when cold.. :s

At a guess I'd say you'd want to get your throttle body cleaned out then do a throttle body alignment with vagcom. Possibly change the coilpack on cylinder 4 also.

What codes have you got now, if any?

 

[alanh6687]

I've still got the 17705 and thats it at the minute.. I'll try and get it fully recirculating..

I've just been reading some other post saying that a faulty rocker gasket could course rough idle :s

Only reason I'm thinking this could strangely be true is that I replaced mine just before this problem occured :s Think I need to check its all fitting flush etc

 

[young79]

on my cupra the 17705 Pressure drop between turbo and throttle body P1297-35-00 was the crankcase breather,replaced it and sorted it.

 

[alanh6687]

Did you have any sort of rough idle with the breather fault?

 

[8bit]

Did you have any sort of rough idle with the breather fault?

More likely to be dirty/misaligned throttle body and/or duff coilpacks or spark plugs.

 

[young79]

no idled fine but chucked up that code

 

[alanh6687]

I disconnected each coilpack, one at a time whilst it was running and each time the engine struggled to run, so think there ok?

Think Imight clean/re align the throttle..

 

[8bit]

I disconnected each coilpack, one at a time whilst it was running and each time the engine struggled to run, so think there ok?

Think Imight clean/re align the throttle..

Probably rules out the coilpacks in terms of your poor idling but if that code about misfire on a specific cylinder comes back then I'd be suspicious of the coilpack in there. Also when were your sparkplugs last changed, or at least checked?

Clean and reset the throttle body as you say, should help the idle or at least rule that out.

 

[alanh6687]

I changed the spark plugs and maf approx 2-3 months ago.

Today I had a few spare minutes on my lunch break, so I started the car up and it idled perfect for about 10 minutes, then the revs were all over the place again, then back to normal, so seems to have got slightly better, but seems intermittent :s

Whilst I had the car running I was checking for some split pipes etc, but couldn't spot anything :s

Going to try and clean the throttle body out, on saturday, when I've got a bit more time.

 

[8bit]

Ok so unlikely to be spark plugs, could still be a coilpack tho - when you tried disconnecting them was the engine idling OK at the time or idling rough?

Still worth doing the throttle body clean and reset too.

 

[alanh6687]

Yea it was idling rough at the time I disconnected the coils one at a time..

Im hoping to get some time tommorrow to clean the throttle body out and do the re-alignment etc, sounds like that could be a possible fault and a cheap test

If its still the same afterwards I might try some new coilpacks on it..

 

[alanh6687]

Today I completly removed the throttle. It was fairly dirty, but not as bad as I expected..

I got it really clean on both sides and the flap etc, then I refitted it, went to do the alignment on the vag com, but it said something about me not having permission and that I need to register etc. I've only ever used it to clear engine codes, so not needed to register before..

Anyway I decided to start the enghine and see what it was like. Seemed to idle ok, compared to yesterday, so I gave it a bit of a rev etc, then 2 lights came on the dash. The EPC light and for some reason the Traction control light??? Then it wouldn't rev over 2.5k.

I checked for codes and the only 1 present was 17953 Throttle Valve Controller Malfunction

I thought it might just be due to the throttle position adjustment not been carried out, but don't get why the TCS light came on?

 

[8bit]

EPC light will come on as the electronic (fly by wire) pedal controls the throttle valve, just does it electronically instead of a traditional cable. Makes sense that the TCS light would come on as if the throttle body is far enough out of alignment compared to pedal inputs then the ESP won't be able to trust it in order to close it if it needs to cut power in a skid.

You'll need to either register your Vagcom or get someone with registered version to do the throttle body reset - sorry, I assumed you had it registered, should have mentioned that!

Not revving over 2.5k, could be that it's going into limp mode because the throttle body is far out of alignment.

 

[alanh6687]

Cheers mate, that makes alot of sense now I'll try and register it tonight..

 

[alanh6687]

The vag com that I bought was from ebay. I think it was something like £9 for the disc and lead..

Do you know if I can activate it, with it just being a cheap ebay one?

 

[8bit]

Sounds like the same one I got. If you install the VCDS-Lite program rather than whatever unregistered VAGCOM came on the disc then you can register that and use it with your cable, yes. Last time I looked on the Rosstech website it was US$99 which works out about UK£63 or something.

 

[alanh6687]

Bit skint atm, didn't realise you have to pay to activate lol

Tried the alignment without vag com today. I know alot of people say it doesnt work, but thought nothing to lose in trying...

Afterwards I took it for a run, but revs don't seem completley right and sometimes it would idle around 2k, so I think it still needs the vag com..

I noticed the exhaust sounds alot louder than it should (standard one) and a bit of 'popping' noise from the exhaust.. Don't know if its from the over fuelling?

I know a garage down the road have vag com, so might see how much they'll do the alignment for, as it should only be a 5 minute job..