SR20DET exhaust leak, made it worse.

[Dborne]

93 240sx S13 SR20DET

I changed my oil today and as I was finishing, I decided to see if I could figure out where my exhaust leak was. I found that one of my studs on my exhaust manifold was loose, after I took off all the bolts to the exhaust manifold and downpipe off. Thinking that was the leak, I put both the mani and downpipe back on. Tightened them all up and started it and it sounded a little rough. I noticed smoke coming off the godspeed exhaust mani as it got warm and thought it was just oil that got on there. As it warmed up, I noticed little smoke coming from down by the downpipe and was running rough. It would not hold steady at an rpm and barley idled. It didnt do this before, it didnt run perfect, but deff not like this.

Did I make a bigger exhaust leak? Is that why it was running worse?

Could the smoke be from me just changing the oil? It was still on jacks, would that matter?

I had problems before when I got it a couple months ago, They had the idle set way to high, and i think the injectors were dirty, also had a sticky one. Ran alot of injector cleaner through it and it kinda cleared up. But never has it been like this.

Ill have a video up soon.

[Dborne]

https://www.youtube.com/watch?v=RyaI55Rgiko

[cbcm2435]

just go back through and double check everything you touched

[TheRealSy90]

So did you replace the gaskets?

[jamg]

o2 sensor?

[Dan3312]

If it leaked before and you haven't done anything other then take it apart and put it back together it will still leak. Did you clean up the mounting surfaces (should have been able to clearly see where it was leaking both on the manifold and the engine) before putting it back together? As someone has already said, did you replace the gaskets?

[Dborne]

I didnt replace the gaskets, found the stud not tightened at all and thats what I thought to be some of the problem. I didnt take it all the way off to really see. It still sounds like crap from the engine bay, do Godspeed exhaust manifolds usually sound like that? Could it be the spark plugs to make it run that rough? Ill check the wiring on the O2 today because it looks pretty sketchy.

[Dborne]

It was too much oil that was making it run horribly. Took out probably more than 2 cups.

[Dborne]

Ok, new diagnosis.
I can start up the car fine, idles, maybe fluctuates a little. Let it idle, maybe rev it once or twice and then it dips real bad, stutters, then revs high, dips back down. While standing outside the car when it dips and idles bad there is black smoke coming out. Then after a while it will rev Ok, then it will start to do it again... Now messing with the exhaust should have nothing to do with idle and running rough, correct? It should be either the o2, spark plugs (ignition system in general) or injectors or fuel pump, or a vac line somewhere? This just started to happen after I changed the oil and messed with the gaskets on the manifold and downpipe.

[Dborne]

I used Lucas oil injector cleaner as kinda a "well i might as well"....and it worked. Not 2 mins after driving with a fuel bottle in a half a tank, idles like a dream, drives like its suppose to...Can anyone tell me how that happens...Thats the second time Lucas oil has came in clutch. getting some new injectors soon so hopefully it wont happen again.