Chris620

Hi guys iv just brought an 03 plate st170 and wen driving its lovely but if I ty an put me foot down it won't go past 4000k iv have it plugged in to diagnostics and it sed cat is blocked/ nackerd I just wanted a second opinion before I spent a lot iv money buying 1 it's had a ful service with all filters and plugs and coil pack back in December the owner told me and I have receipts for this Just wounderd wat pple thort of this as its rrli annoying not being able to use all the power I no is there lol thanx in advance Chris

oldford

Which code number do you get? P0420? That usually is a dead catalyst.
How to check a cat: http://www.picoauto.com/tutorials/cat-efficiency.html

A failing coil pack could have destroyed the cat, happens quite often.

Chris620

I didn't get to see the code the machanic did it all and then sed it was the cat wat u say makes seance as the coil pack was replaced not long ago thanx for the help mate

Chris620

Just Tryed putting me food down when the engine as still cold ish I no I shouldn't !but wanted to see if it was any dif But it seemed to be abit better and allowed me to rev to just over 5k before it started juddering and hesertating as like before is this normal when the cat is nakered would this indercate something else ?
Thanx

Chris620

Also after putting £25 worth of fuel in it tonight it's better with more fuel its revs higher anyway but is still pritty flat power wise and wouldn't go past 6k sounded like it was chocking or being starved like straining

gingerturbo

iTrader: (2)

Yeh if its bin misfiring it could of melted the honeycomb inside the cat

oldford

It sounds like you have a fuel starvation problem. Possibly a seized fuel pump or even water in the fuel tank.
I think this has been going on for quite some time now and it may have set several fault codes like misfires in the past. That's probably why the previous owner replaced the coil pack, but that didn't cure it.
Because of these problems the cat has died and I think this is the reason why the car was sold.

Measure fuel pressure and/or fuel flow to start with.
Do NOT replace the cat before the engine is running perfectly, otherwise the new cat will be damaged as well.

Any chance of returning this vehicle and getting your money back? Because I also saw a post about problems with the Traction Control/Abs.
Or do you want to keep the car? Then get a trained mechanic to do a thorough diagnostic on it, not just the engine, but all other systems (Abs, Airbag, etc.) as well.

gingerturbo

iTrader: (2)

Yeh as said do a fuel pressure check as it sounds like its running lean, but also check ya air mass and lambda as that will control the air fuel mixture and cause it to run lean, on some cars you can check the flash codes manually unless ya can get a read out

Chris620

Thanx for the help iv only had an engine diagnostic so far and it only showed cat at fault. So if I get a fuel pressure test usbut shows low presume will this be the fuel pump that's nakerd I take it ? And nah I can't take it bk lol and I wouldn't want to rrli I like it a lot and I got a bargin on it with all it's extras lol and quick question can I clean the mass air flow with break cleaner or sum thing ? Thanx again lads

Chris620

Also tomorrow or Tuesday I'm going to remove the cat and test drive it so the ill no if it's that at fault or not and ill get me machanic to do a fuel pressure test while we're there any ideas what pressure it should be running ?

gingerturbo

iTrader: (2)

When ya do the test don't assume it's the pump if its low as the fuel filter could be blocked, you can clean it with a bit of brake cleaner but if its a hot wire type make sure its dry before plugging it in, also if its running lean it will through up the lambda fault/cat fault, was you there when they did the diagnostics

Chris620

Yh I was there at the time but didn't see the code the guy just sed it's cuming up with cat at fault and ill clean the maf when I take the cat off to See if it's that and if not ill get it pressure tested and go from there so Sony think its the cat or pump at fault or ? Also the fuel filter was replaced bk in December with the service although the guy told me it was quite dirty

gingerturbo

iTrader: (2)

Take it to an mot garage and get it read on the emissions machine as that will give you a cat read out, if they read your car with a snap on code reader there a waste of time, as said on the other post you put up check everything as you may have other restrictions causing it not to rev

Chris620

I don't no what he used I no it was wirless tho ? My Otho mate has a data tool / scan tool I think are they any better ? I'm a complete novice with cars I didn't realize it could be so many different things causing the problem lol

gingerturbo

iTrader: (2)

There not bad they just give out flash codes, most start with P stating its management related

Chris620

Ow right ok well I try and get it pluged in to me mates data tool tomoz and let U no what it comes up with

gingerturbo

iTrader: (2)

Also check to see whether your has a pre and post lambda or just the 1, it should start with P04-- if its cat related

Chris620

Will do thanks for that will it make much diferance if it has 1 lambda or 2 ?

oldford

Oxygen sensor behind the cat is required by law (EOBD) since 2001.
Without the 2nd Oxygen sensor you would not get a fault code on the cat.
So, you should have this 2nd sensor.

Chris620

Right I see just to check I'm ok to remove the cat and test drive it to see if it solves the problem it won't throw and light up and any problems will it other than being very loud lol

gingerturbo

iTrader: (2)

Yeh as if its a post O2 sensor it won't pick up the exhaust reading, if ya take it off then just look in side the cat at the honey comb meshing to see if its collapsed/melted or blocked

pani_k

iTrader: (1)

I know you said it had a full service and all filters changed but check to see if the fuel filter has been changed as it sounds like this could be blocked...

Chris620

Nice 1 for that saves me causing more problems when I don't need to lol

gingerturbo

iTrader: (2)

Yeh I'm thinking that too check the air filter too

oldford

If a filter is blocked, whether that's the air or fuel filter or the catalyst, adding 25 pounds of fuel would make no difference.
It could be down to coincidence but it looks like a fuel pump problem to me.

The Underdog

sounds like pump problem has others have said. i have also had nightmares wit my fuel pump. it was not as severe as yours sounds.

page 5 of my build thread will let you know my troubles

Chris620

Ill go over and check all the little things that's been sed where about is the fuel filter located ? Thanx for all the advise guys ur all way more knowledgable that me and help full thanx it's much appreciated

Chris620

Well iv just iv just plugged it in to my mates scantool and his autosnap and it's not showing any faults but on the way her the car seemed to be better allowing me to rev higher under load but didn't seem like it had full power iv noticed that the manifold was blowing slightly so iv tightend the bolts and il go test drive it later and see if it's any better it's rrli confusing y there's no codes now tho wen it had 1 before for the cat ?

pani_k

iTrader: (1)

If it feels better with more fuel in it, then it won't surprise me if the fuel filter has not been changed. It is something you should do apparently every 30000 or 50000 miles or something stupid like that but I done mine every two years or about 12000 miles in my case they are not expensive so why wouldn't you change it. Not sure if the ST170 is different due to its different fuel system but on a normal MK1 is it located at the rear of the car near the OSR wheel.

P0420 is the normal cat efficiency message, I got that quite a bit on my decatted MK1. Usually it is lambda sensors that go first before the cat and MK1 Focuses commonly eat lambda sensors. You can pick them up off ebay pretty cheaply they are Bosch items and are fitted to Fiestas and Pumas and KAs and also all other petrol Focuses. IIRC they are all the same including that of the ST170. Green plug and wire I think is number 2, number 1 is blue but again same sensor just different attachment I think at one point I had two green ones running. To check if your cat is knackered, get someone to rev the car whilst having your hand behind the exhaust and see how it feels, if it is blowing reasonably well then I'd say it isn't a knackered cat. If you have an IR temp gun, get the car in the air whilst it is up to temperature and move it along the body of the cat and have a look at the readings. They should be fairly consistent. If they suddenly drop somewhere along the cat then you have a blockage.

This does sound like to me a case of a clogged fuel filter. I wouldn't be surprised if it got left out as its underneath the car people can't check it.

Chris620

Ill have a look at the fuel filter tomoz but the guy told me it was replaced with the service in December but he could of lied lol it's just rrli wierd cus if jut been for a drive and it's seems fine now Althing dont rrli no how fast it's soposed to be as its had this problem from when I had it I hit 70 and 7000rpm do it seems gd

Chris620

Wahoo problem now solved it turned out to be the vvt sensor in the rocker cover took it out cleaned it and it runs great now so off down the parts show for a new 1 thanx for all the help guys hopefully it stays working now lol