Hey everyone, so I had my friend install my badmab shorty today. Used Gm gaskets and install went very smoothly. Everything fits perfect. Header looks great and I can really feel a top end difference. Everything is good other than my idle is messed up a little now. Its a little rough and my a/f is bouncing between 14.8-16.0. I unplugged the battery for ten minutes to see if my o2 sensor could readjust. started the car up and it was dead on at 14.8 but as soon as i blipped the throttle it kept on fluctuating between 14.8-16.0 again. Anyone know why this is? o2 sensor placement? Edit: Not only is a/f off but my idle is bouncing now when i drop it into neutral.

 

exhaust leak prob

 

x2

 

no. had a leak before and it didn't do that. No leaks now. Just replaced old gaskets with brand new gm ones. Any other guesses?

 

when you did the install, did you tighten everything down in a specific pattern? or did you jus go around the clock?

 

I didn't do the install. Paid my mechanic friend 50 bucks because I have no time for the next couple weeks. Hes been a mechanic/fabricator for 7 years. He knows everything about cars. One of the first people to do a v8 conversion in a ford ranger. I know he used the right pattern. You would hear a ticking anyways if it wasn't sealed.

 

16.0 would be lean not rich

 

lol. exhaust leak can cause fluctuating idle from a foot or 2 downstream but hey if you know the answers why did you ask.

 

True that's what I meant. mixing up my ratios. damnit.

 

I dunno. I guess when I re tighten all the bolts up again after a few more drives it will help. Just don't think its an exhaust leak because the only spot that may be leaking didn't cause this problem before and I used brand new gm gaskets for the manifold and manifold to dp. My friends one theory was that maybe because of the o2 sensor placement instead of getting the air stream from all the cylinders like on the stock manifold it's only getting the air stream from one cylinder/primary. Ill check for leaks when I tighten it back up.

 

AFR is always going to bounce at idle. IMHO

 

not 14.8-16 if tuned correctly

 

So I found a leak today.. blown gasket that my friend didn't replace that goes from end of dp to rest of exhaust because the studs will snap if we touch them because they are pretty much rusted and fused into the flange so I'm gonna have to go to an exhaust shop since his welding stuff is in his hometown. BUT he doesn't think the leak would affect my wideband that much since the sensor is a couple feet up but it's definitely a possibility. He thinks that the 02 sensor on the header is only getting a sample of one primary since the location is different than the stock manifold due to the bigger size of the collector. Because the sensor may only be getting a sample of one primary he thinks that its taking fuel out and my wide band is reading that. We will see once I get my gasket fixed. If that doesn't work he thinks my tuner should just run a loop between 1-2k rpms or so.

 

no exhaust leaks eh

can have an effect a few feet back so i wouldn't completely rule it out. is it the root of the issue, guess we'll find out.

only getting from one primary is false also, look at the header, the o2 sensor is in the collector, where all 4 primaries merge.

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