I'm seriously ticked off (exhaust)!!??

[viperkd77]

Ok, i had slight mods to my dsm before i had an exhaust put on this september. I ahve a 97 gsx auto. I had an intake and mbc, thats about it. I was set at about 14psi. I was running well, gettin like 19mpg in town and 23-25mpg highway. I have a 3inch no cat exhaust put on. Megan dp with custom piping with megan muffler. Straight back, no cat. To get the old exhaust off it was a pain. The rear 02 was a pain to get out,etc. Either way, put the new exhaust on, real tight fit, sturdy though and it seems there are no leaks. It sounded decent pullin away from the garage, It seemed the car was tryin to get used to it, sluggish shifts, etc. Now my mpg is like 10-12mpg. NOt really much black smoke at first, but not it is awfully black. During this problem, i purchased dsmlink and a 1g tb. Test for boost leaks, none. Dsmlink showed good voltage on the 02. Also, i have no cel's from cat removal. The car seems to run and sound worse everytime i drive it. Granted it is an auto, my shifting is awful, the car runs and idles at higher rpms. Honestly, its slower. I dont know what is going on. I acutally bought a new front 02 and am trying to install it now. Could be $100 waste??! Somebody with some real knowledge, please help me. I cant afford to have the dsm sittin around and im serisouly jsut fed up with this car right now. thanks.

 

[viperkd77]

Any way of determining it to be the a/t tranny?...

 

[BISHILVR]

Thats a tough one, if you are'nt used to how a good auto tranny should behave/feel. Do you have a buddy with a auto that fast or runs real good?, maybe take a drive with him. Also, count how many shifts the car makes when you pull out and drive up the road (make sure it makes 3 shifts)

 

[viperkd77]

I can do that, but what do u mean by limp mode. Sometimes it seems the car is slipping between two gears maybe and its almost as if the car doenst know when to shift. Could my overdrive be shot now since i put the exhaust on an essentially added more power to the car and the tranny couldnt handle it???

 

[BISHILVR]

Limp mode, is when the tranny control unit (tcu) finds that the transmission has slipped and then will lock the transmission in a certain gear (usually second) and you will end up starting out in second gear all of the time, (and the car will feel just like that if you think about it). The tcu can set a slip code before you even notice that there is a problem, because it can act in milliseconds. So, if you notice a slipping problem then I would say that the tranny has already caught it long ago and is keeping it in limp mode. You will have to have a scanner put on the tcu to find out for sure what codes are in it, and have them erased to see if they come back.

 

[viperkd77]

Ok, can i use dsmlink for determining these codes in anyway or what kind of scanner would i need to look at these codes? A regular scan tool? Something at a mitsu dealer? thanks

 

[jarero]

It's been a while since I owned my automatic dsm but I had a problem with the tranny going into limp mode and found that I had a loose electrical connection on the tranny (I don't remember what plug it was). Since the exhaust shop was working around your tranny when they did the install did you take a look to see if everything was plugged in and none of the wires were burned?

 

[BISHILVR]

I would say a mitsu dealer.

 

[viperkd77]

jarero, i see ## thought as a possibility. Ill ahve to check it out. hopefully it may be soemthing like that. Otherwise i mighht have to have someone i know at a mitsu look at it maybe. thanks

 

[yekrahs]

Have you checked for any pre-turbo exhuast leaks? or any exhuast leaks, it can cause exaclty what is happinning. Check your bolts from your exhuast manifold to your head, exhuast manifold to your turbo, turbo to o2 housing, and o2 housing to downpipe let us know

 

[viperkd77]

ok, i know i ahvent looked at this thread in a while, but im home from school and workin o the whip. One thing i did was replace a ground strap that i hear can be very important. The ground strap connecets the frame of the car to an exhaust clamp/flange right near the rear 02 sensor t give it proper voltage. I have done that, but i cant tell really if it runs better bc i have only driven it around the block (no cat, expired inspection). Can this be important. I can get a log with me driving around the block if needed. please help i need to get this beauty on the road, .