Problem with headers i just purchased

[twiggy]

Good Afternoon all,

Just today i purchased some extractors and a magnflow cat converter for my civic 92 eg.

Early last year i had put on a muffler and some piping, so all i really needed to finish off my system would be the cat and the header +flex...

So i get the cat and header +flex on today and am driving out of the shop and i wanted to boot it to feel the difference and in 1st gear i hit about 4 thousand revs and it starts to shake and jerk as i am accelerating thus making me look like a dick head in a civic:wave:

So i change down a gear to 2nd and put my foot down to make sure it just was not a one off, it did it again jerking an uneven balance of sound and acceleration.


I take it back to the shop and the guy drives as i am sitting next to him and nothing happens, it drives perfect while he is driving it. He said it could possibly be my spark plugs or my ecu in my car..

So i thank him and then piss off again back home, about half way home as i am doing a even 60 km/h it starts to shake again and almost like farting out of my exhaust over and over again.

I really dont know what it could be? Do i have to wait for my headers or high flow cat to work in or what? Is it my ecu? Could it be my compression is much higher now and the engine is freaking out?

With the high flow cat he put on my car he gave me a 2.5 inch and then welded that into 2 and a 1/4 inch and then into 2 which is what my original piping is

Or maybe this B@$T##D has not connected my extractors to my engine properly leaving air to sink into the gases??

I dont really know what it could be but I would appreciate everyones input into this especially civic drivers who have full exhaust kits:D

Other then the jerking and the car not being able to stay a decent speed evenly the extractors are great real great mod..

Twiggy

[kid_dynamite]

I had a similar experience with an exhaust install once where the catback was slightly askew and but above a certain speed and turning it was foul against the driveshaft and cause all manners of horrendous vibrations throughout the car. Adjusted the hangers and it was all better.

[VT3C]

yeah your 'hi-flow' cat and header may have a different length to your OEM header and cat.. so the new header and cat is longer/shorter than your old one so now it may be rubbing.. this is very common with aftermarket header and cat changes.. you may need to shorten or lengthen your B-pipe to suit the new header and cat. I didthe exact same thing and it was rubbing up near the rear LCA.. took her to exhaust shop and had 1.5" cut out and then was perfect (not my spoon system LOL)..

[twiggy]

Im sure its not that, maybe i need to reset my ecu?? My car is considerably quicker now and i think the computer is really confused.

[maracer]

So did you find out what the problem was?

[SeverAMV]

any chance you could be more specific with the shake and jerk? is it kinda like a shake and jerk that most new drivers do when they first drive a manual? or a really annoying rattling with the whole car shaking?

if its the former, check theres nothing obstructing your intake (happened to my brother's car with a hole in the intake hose). if its not that, then ask another mechanic.

[weezer]

did they disconnect the battery while they were welding?