Im trying to find out if my cat is clogged.

I have a 97 ex d16y8.

did a vacuum test and it was steady at about 20 and reved up to 2500 and let go and the needle went to 35 and slowly back to 20.

can anyone tell me what this reading means? it's not described in my manual.

 

bump

 

drive the car if it cant go over 40 mph iirc then its clogged

 

whats are the problems yur having

 

I keep blowing the gasket between the header and down pipe and I smelt the sulfur or the egg smell twice last week. my car also had a cracked header when I got it. now I got an after market one.

it does go past 40 but it seems like in low rpm it is slugish and at high rpm it blows stuff out of the exhaust sometimes. I did a comp. test and got 190-200psi on all cylinders.
and I already did tune up wires. etc.

 

bump

 

anyone?

 

are u installing the gasket properly

 

check rear of exhaust and see if you have a lot of exhaust coming out while you rev the car.
or
drive the car hard, high rpm for a mile or so at night. look under the car and see if the cats glowing red.

or

you dont have the lower part of your header connected to the block for support.

 

20 in/hg (inches of mercury) is perfect vacuum so that is not your problem

 

vacuum is fine the only way to check for back pressure is to unhook an 02 sensor and stick a gauge on it, you could have a plugged cat or just look at your exhaust pipes visually if there are any dents or ding or kinks

 

you throwing a code for it? Its possible that your cat is clogged.

 

I dont have a check light on.
I haven't gotten a chance to do much lately but my exhaust was welded on wierd at the place I took it to so the cat is hanging about 1 1/2 to 2 inches lower than normal so with it scraping everything that might be the cause of the gasket, but I will try looking at it this weekend. just in case I picked up a used high flow cat back exuast that is straight, and hopefully won't scrap, for $20.

thanks to everyone.

does anyone know why my vacuum never went to zero though? what does that mean?

 

usually means your throttle is stuck.

 

what do you mean the throttle is stuck?

 

means that the butterfly is getting stuck, or your intake/filter is clogged.