New exhaust - now idling rough and backfiring

[pieman18]

hey all

I’ve spent the last couple of nights after work chucking on a full engine back exhaust system on my vy clubby. New headers, cat deletes and 3 inch system

As I’ve given it a test drive, it started out fine on the drive, the it started idling very rough, backfiring on acceleration and also when cruising and idling
Seems to be more of an issue once it’s warmed/warming up

I replaced spark plug leads, and it’s actually slightly worse.
I made sure I was careful of the spark plugs when I was installing the headers, should I throw in a new set of them as well?

Any other ideas of what it could be?

Thanks guys

 

[dgp]

Check your plug leads, test them if you have a mega or multimeter.
Did you damage your O2 sensors when you removed them from the old system and put them in the new system.
I think your a bit crazy removing your cats, it will stink, and if caught by the EPA, you will need to sell your car to pay the fine.

 

[pieman18]

Yeah the cat deletes won’t be there for long, it’s just how the system came

Just a quick update, with new plug leads and new o2 sensors, literally no difference

The thing is, the day I removed the existing exhaust it was running perfectly, I don’t understand why it would be so much worse???

 

[dgp]

Check that your leads are seated properly on the plugs.
Are you using the same plugs? You may have damaged one, especially if you left them in while installing the headers.

 

[vr304]

Try new spark plugs mate, maybe an exhaust leak somewhere? Failing that you probably need a tune

 

[VP1993]

Does yours have the pre cat and post cat O2 sensors?
By deleting the cat, will stuff up the post cat sensors giving you the exact problem that your having

 

[Lachy_jeffery01]

hey all

I’ve spent the last couple of nights after work chucking on a full engine back exhaust system on my vy clubby. New headers, cat deletes and 3 inch system

As I’ve given it a test drive, it started out fine on the drive, the it started idling very rough, backfiring on acceleration and also when cruising and idling
Seems to be more of an issue once it’s warmed/warming up

I replaced spark plug leads, and it’s actually slightly worse.
I made sure I was careful of the spark plugs when I was installing the headers, should I throw in a new set of them as well?

Any other ideas of what it could be?

Thanks guys

Hey mate, I’m having a similar issue did you ever resolve this? I have replaced spark plugs and 2 drives I’ve done have seemed fine but it’s ever so slightly there. How’d it come up after a tune?