Precat

yorkie200

Hi All

I have a Vectra sri150, when dropping down the gear ranges it is popping (like a small backfire) at first i thought it was the rear rose bushes knocking as they are bloody noisy at the mo. but i revved it hard on the drive and it pops.

Could it be the pre cat blocked? is it worth me dropping the front pipe and drilling it?

It has standard system, with letterbox rear box. brand new middle section.

If the pre cat is blocked could this cause enough pressure to cause the car to be burning a bit of oil?

I have to drop the back box to clean it up anyway, so I thought i may as well drill the precat and drop the whole system, check for damage and put new gaskets on

Cheers in advance

astra22bertoneauto

everyone will always say "remove the precat" its a pain in the arse and causes the manifold to crack. Get rid of it anyway and you will get an increase in power too!

As for the oil it could be the valve stem oil seals need replacing

yorkie200

Thanks for that. Job for the weekend.

I'm trying to eliminate other problems with the oil leak before i spend stupid amounts of money on getting the valve stem seals replaced.

re-doing compression test tonight with wet and dry runs.

is the popping normal? it's the first "vaux" iv'e had. the 2.0 mondeo and focus 1.8 had standard exhausts on and it ran like any other car, this one sounds like a monster because of the exhaust note 😃

monkeyboy

ya my vec sri does it to and the exhaust is standard
why does it do that? dunno..

astra22bertoneauto

ive had a few vauxhalls in my time and valve stem oils seals always seem to go at some point, usually when the car gets too hot or the breather hoses are blocked.

What mileage has the car got?

yorkie200

Cars done 95000.

Iv'e only had it a few months :thumbdown:

breather hoses were blocked and it looked like it hadn't been serviced for a while, Iv'e fully serviced it. opened the air box up a bit (cuttin the pipes inside the box back to widen them) moved the vacuum pipe off the air intake pipe onto the manifold, taken EGR valve off and blocked the holes (including the VW mod under the throttle body) cleaned out breather hose (was all cra**ed up).

Done compression test dry all 12 bar. but No.2 park plug is oily. replaced spark plugs with new bosch redline and going to do wet and dry compression tests tonight.

oh yes and got a rocker cover gasket to put on (doesn't look like its's leaking but may be worth a try) but am getting hold of a hex socket

I have cleaned the throttle body, but not ported it yet as i didn't want to start doing it until iv'e stopped the oil.