41 replies to this topic

[rickyzero]

Over the past two nights I managed to get my old exhaust off and fit a full Milltek system that I purchased from a member. I also installed two new lambda sensors because one of my old one's was faulty anyway. I had also taken out fuse 8 whilst fitting the new exhaust. After starting it up for the first time it was immediately obvious that something wasn't right. I could feel the whole car vibrate and shudder when pressing the accelerator and it wasn't running smoothly. Took it for a short test drive and it seemed to be in limp mode, no power and felt like it wasn't firing on all cylinders. The fan even came on for the first time in my ownership! Any ideas? It's a 2.2 NA with no engine mods. It was running absolutely fine before I fitted the new exhaust, just had the EML on for a faulty o2 sensor. Now there is no EML on but I can't use the car! I really hope it is something simple as I have just gone through two nights of pain to get the Milltek fitted! Any help greatly appreciated.

[siztenboots]

aren't there two lambda plugs for the first manifold , but only one is the right one on an NA.

[old codger]

Sounds strange, you could try putting the old Lambda sensors on and see if it makes any difference. I think that the 2 sensors are different parts so do you have the right sensors? Someone with more knowledge of the sensors will hopefully be along.

[rickyzero]

Yes I'm pretty sure they are the correct sensors, I got them from vauxhallpartswarehouse on eBay. They looked the same and had the right connectors. I would need to solder the old sensors on as I cut them to make removal of the exhaust easier.

[zimmer]

There's only one place to put the pre cat lambda on, so that shouldn't be an issue. The pre and post cat lambdas are different though, make sure you haven't mixed the two up. If the EML light was on but the car was running fine I'd assume it was the post cat lambda that was faulty previously, so I'd try putting the old pre cat lambda in and see if that solves the problem - it is the one that controls the fuelling after all.

[zimmer]

Sorry just read the soldering comment - must be someone nearby with an OBD reader +/- spare lambdas to test?

[slindborg]

aren't there two lambda plugs for the first manifold , but only one is the right one on an NA.

I think its post cat has two plugs... I got it wrong on a certain blue N/A back in the day

[vocky]

yes there are two plugs for the post cat sensor on some vx220's, one works fine, the other ...

[rickyzero]

Thanks for the suggestions chaps, I'll go and have another look but I'm pretty sure there was only one available plug for the post cat sensor. I definitely didn't get them mixed up either. Won't be able to try my old sensors, them and the old exhaust are scrap! I've just ordered an OBD2 interface so I'll see if that comes up with anything.

[rickyzero]

Another issue I should mention is how the exhaust is sitting... It's really low and resting on the clam. I've read about a hanger/bracket for the silencer U-bend but mine doesn't have one. Anyone got a pic of the U-bend bracket?

[Marco Polo]

The U bracket should be retrieved from the original fitting...

Here is a borrowed pic (from the French Forum) of the bracket (which is too short in that pic, the owner had to built a longer one to fit with his 3rd partry exhaust):

[rickyzero]

*UPDATE* Managed to get the tailpipes to sit nice. I was able to adjust the brackets at either end of the silencer in situ, it feels solid and has raised it a good bit. The car is still running like a dog though...I've tried uplugging the pre-cat sensor and I also put the old sensor in after re-soldering it. Didn't want to screw it in fully as the thread seemed a bit knackered but nothing has made a difference to how the car is running. Would a cracked manifold cause a loss of power and rough running? I'm wondering if I've disturbed it by fitting the new exhaust. I've had a ticking sound which disappears after start up for a while now. The sensors I bought from vauxhallpartswarehouse on eBay were Denso branded, but are apparantly OEM spec and used the same part number. Could they just be incompatible? Hopefully the OBD2 I've ordered turns up tomorrow so I can see if any codes come up.

[rickyzero]

I've just taken a quick vid of the car running, let me know if anyone has any ideas. http://www.flickr.co...N03/4832194394/

[Marco Polo]

Sounds bad indeed ! First I would check the exhaust line from manifold to silencer for exhaust leak, mainly at the gaskets... (remove the heat shield from the manifold, no harm to do it for a while sitting idle in a garage) BTW did you put new gaskets all the way ?

[rickyzero]

Merci Marco! I fitted a new gasket between the downpipe and manifold but didn't use one between cat pipe and silencer. I used plenty of exhaust paste on both connections though so I'm quite confident there are no leaks there but the manifold may be cracked. I was unable to remove the lower manifold heatshield as one of the bolts I just couldn't get a grip on, I presume the lower heatshield has to be removed before the upper one can? I'm starting to think it could be the new lambda sensors I bought. The sensors that were in the old exhaust were NGK and the replacement parts are Denso. The sensor tips themselves look different although they were the correct part numbers. My Op-com interface arrived today so I'll plug that in tonight when I get home from work and see if it tells me anything.

[Marco Polo]

The lower heatshield is bolted on the upper one... You might be able to remove them together (at leat I can do it, rear clam removed though ! )

[sworks]

Merci Marco!

I fitted a new gasket between the downpipe and manifold but didn't use one between cat pipe and silencer. I used plenty of exhaust paste on both connections though so I'm quite confident there are no leaks there but the manifold may be cracked. I was unable to remove the lower manifold heatshield as one of the bolts I just couldn't get a grip on, I presume the lower heatshield has to be removed before the upper one can?

I'm starting to think it could be the new lambda sensors I bought. The sensors that were in the old exhaust were NGK and the replacement parts are Denso. The sensor tips themselves look different although they were the correct part numbers.

My Op-com interface arrived today so I'll plug that in tonight when I get home from work and see if it tells me anything.

There isn't a gasket used between cat and silencer. Also, you SHOULD NOT use paste on the connection before the cat (can damage the cat).

[rickyzero]

I've plugged a code reader in to the car and there are no fault codes showing. As I looked through the output data the Air/Fuel ratio for Bank 1 Sensor 2 was reading Rich permanently. Bank 1 Sensor 1 was flicking between rich and lean as it should do. Does this mean the post-cat sensor is duff, or could the problem be elsewhere? I'm going to take the cat off as I had used some exhaust paste before the cat. I'll clean up the faces and put a new gasket on minus the paste!

[Marco Polo]

There is one gasket post-cat (Milltek down-pipe) :

Edited by Marco Polo, 27 July 2010 - 07:14 PM.

[rickyzero]

Right, I've taken off the cat, removed any exhaust paste residue and refitted everything with a new gasket. The exhaust appears to be on perfectly with no leaks. Car is running worse than ever and I've had the following code come up; P0300 - Random/Multiple Cylinder Misfire Detected (00) - Present Can anyone tell me what my next step should be? I don't understand how fitting a new exhaust could cause it to run so badly all of a sudden. Could faulty o2 sensors be the problem? Help please!

Edited by rickyzero, 27 July 2010 - 10:26 PM.