exhaust
 

hey guys whats up? havent been able to be around for awhile. ive been working on my car a little bit and i have a questions for you

Header:
i put on the pacesetter header and the y-extension pipe is really starting to piss me off. when i'm speeding up from a stop normally and when i turn to the left it sounds like it's bouncing up and down. it doesn't do it all the time though. it's kind of hard to explain. i got under my car and i had to retighted the clamps on the extension pipe but it didn't seem like it helped. also after i put the header on my gas mileage decreased a lot, to 6 miles per gallon to be in fact. i called my local performance shop and they said i needed to get an apexi fuel controller. is this true?

test pipe:
just the other day i made my own test pipe instead of buying one. isn't it going to increase the sound? it did a little bit but not a lot. it did however help out a lot. one problem with this test pipe though, when i put it on it made my "bouncing noise" occur more frequently. also when i come to a stop, my steering wheel, dash, and god knows what else shakes. what is up with this? i'm half tempted to take that darn thing out. another thing about the test pipe is that it took the nice sound of my muffler away.

any help would be appreciated

When you come to a stop, and it shakes, are you saying it is shaking at idle?? or the brakes???

I've never liked clamp together exhaust. To much 'losening' problems.
Your motor shifts sideways when you excelerate. if you have an automatic, you can have someone sit in it and give the throttle a quick punch to see if its moving to much. Maybe that's why the exhaust pipe bangs.

it shakes when i've come to a stop and holding on the brake. when i have it in park nothing shakes

first is your car auto. or 5speed. this is what happen to my bro. in law mk2. he got an intake leak so when he stop and his iddle is low and when he put in park his iddle got increase so the car didnt shake at all.... so we get the air leak fix and nothing happy now more....
this is another problem might as well.... sometime the alternater is poor didnt charge good.... when you came to stop sign or stop at red light... your taillights on... and the alternater didnt give alot of juice so your iddle is low to so thats why you can have a shake on the car for a low iddle tho... cause this is happen to my probe gt now this day.... correct me if i wrong....

So it is likely an engine misfire problem. could be an intake leak, which dilutes the fuel mixture. Not so noticeable except at idle.

Could be a spark problem. Cap, rotor, wires, plugs. Usually more noticeable under a load (accelerating or mtn uphill.

I'd check/replace these items. They are cheap enough, and new/good ones will help keep you running better.

yeah.... u got it... check those point too... hope you come out with something..

everything is fine on my car, plugs, wires, alternator, everything. this just started to happen after i put my header on and got worse after i put in the test pipe

and yes it is an automatic

what about the bad gas mileage. before i put the header of i was getting 21mpg but right after i put on the header it dropped down to 11 and eventually got down to where it is now-5mpg. do i need to get a fuel controller or is there something else wrong

That's weird !! gas mileage problem. It sure appears to be something other than just doing the header. Is the 02 sensor connected properly??
It is the main sensor for mpg.

the pacesetter header didn't have an O2 sensor mounting spot on the exhaust manifold, it was on the extension pipe. so i had to extend the wire. theirs nothing wrong with that is there?

i also noticed when i bolted the sensor into place it wasn't sticking into the pipe. do you get what i'm saying?

i also replaced the sensor last summer

The 02 should be dounted down into the exhaust gas flow. The wire extension is ok. You might check the intake vacuum system, and you may save time and $$ by having it diagnosed by a pro.

could the O2 sensor not actually sitting inside the piping cause it to not function properly?

more than likely the gas mileage prob and the shaking are related. it doesnt make any sense that the exhaust would have done anything to the intake or fuel would it? i mean the motor would still burn the same amount and air and fuel right?

Yes. It needs to be in the stream. It needs to heat up, and it needs to read the 02 content to create the voltage the computer reads, so the computer can adjust the fuel mixture needed for the engine conditions (load, rpm, throttle position, etc).

ok, i'll have to get it up on the lift and fix it this weekend or the next.

is there any other clamps besides the c-clamps that i can use to connect the header to the extension pipe? i dont like the c-clamps and i can't weld it because if i do i wont be able to get the header back into the car because of clearance problems

i dont remember if i said this yet but before the header i was getting 21mpg and almost right after it dropped down to 11mpg(put on the header last summer). just a month ago it dropped down again to 5mpg. My question is will it take this long to bring my gas mileage back up?

Well, it sounds like you may have some other issues. After the 02 is re-installed deeper into the pipe, it should help.

You just would not believe all the times a car can have something repaired, and soon after some other thing goes wrong.

Ignorant people (closed minded ones), (not meaning you) immediately think the repair and the new problem are related. I've heard many times over the years, "it never had this problem till you worked on it".

Like changing the spark plugs is why the muffler fell off, or the transmission won't shift out of reverse.

i'm not trying to be closed minded, it is just a coincidence that it happened right after the header was on. i just ran a diagnostic and it showed me the codes 25 and 26 which deals witht he O2 sensor, intake, etc... i'll just have to start checking each one

thanks for all of your help

does anyone know where i can get an O2 simulator for my 1991 supra? do they even make them for that old of a car? since i put in the test pipe my check engine light has come on and this kid that i was talking to said that i needed to get an O2 simulator.