djk19

I was getting a consistant a/f ratio problem and my 02 sensors would throw a lean fuel condition on both sides at the same time. Everyone said to check the intake for leaks and I checked, double checked, triple checked and there were no leaks at all so I figured it had to be an exhaust leak on BOTH sides. OR i had a whole bunch of messed up fuel injectors or somthing...

I WAS RIGHT!!!

I found that the second spark plug back on the passenger side was actually WIGGLING!!! It was so loose I loosened it with my fingers!!! I did not do my plugs the last time they were done which was when I had the headers installed, I tightend it up and cleared my pcm and after I let it warm up and idle guess what happened. The DRIVER side threw a lean fuel condition!!

WHAT THIS TELLS ME? There has to be an exhaust leak somwhere between where the headers connect to the heads and the collector. That is not a large area and although I have listened and watched and looked I can not seem to find this problem! I am so happy that I know it has to be limited to that small space but now it is a matter of figuring out what the hell it is. I am going to start by tightening the 02 sensor although it is very tight and hopefully tighten the flange at the collector and my header gasket is nice and tight so I know it is not that.

I can't wait until I fix this final gremlin and have a perfect running f-body... It will be a first since I owned the damn thing.

mrmint69

From reading all the posts it appears like some never completely fix all the problems. I hope you find them all but those little buggers are hard to see and find. It seems the harder you look the more weird things you find only on these cars. The heater cores that clog up, opti issues, leaking intake and exhaust, battery voltage reading, mysterious shutoffs and on and on. Still would never get rid of it.

Dave1980

it could be worse. My freaking 3 series has more unexplained ****.

djk19

yea these cars are actually about as simple as a car can be these days without having a carbeurator. Especailyl the LT1. it is like an updated old sbc engine. Can not get more simple then that. I have fixed every little issue engine wise and this is the last one. I am hoping it is not a pinsized rust hole in my headers. i have ceramic bbk headers but down around the collectors there are little rust spots and I hpe it is not the headers. I am hoping it is just the flange that I can tighten up and see the end of this issue that draves me crazy

djk19

Ok. I got under there and had the engine nice and cool. I had someone start it up and put my hand around the bottom of the headers and the flange and the flange seemed nice and tight. I felt two spots where exhaust is leaking through a weld where a shop shortened the Y-pipe to fit right. The weld is pretty much touching the 02 bung on the drivers side and it has a spot right near the 02 sensor and a spot directly on the other side that have tiny pinhole leaks. It has to be the problem!

There are no other leaks of any kind anywhere and it is amazing how sensitive those sensors are. I am going to brush down the rust and pack some jb weld in there all around the whole weld seam and see if it holds. They are pinholes so they should hold ok and after that I might smother it in rtv. I dont care what I have to do because this is such an annoying problem. it is crazy that two little pinholes right at the 02 can cause a stumble and a trouble code. ANNOYING

I will post results tomorrow

btw what are my y-pipe options for this car. should I have a shop create a y-pipe for me or do nice stainless pieces exsist for our cars. I was looking at the design and the passenger side has less distance to travel to get to the exhaust. this must hurt performance. Now I see why everyone wants long tubes. Is there a away for the y-pipe on shorty headers to be run the same way longtubes are so the pipe comes down and back and connects back in the middle under the car instead of crossing over almost touching my k-member and come together on the passenger side. I hate the design of the current setup....

mrmint69

If they are truely pin holes you probably have more problems then them. You might have a very small issue with that small of a hole but it sounds like yours is somewhere else also. I had a leak where the egr hooks up to the headers and it was so bad i could feel an air stream coming from it. I fixed the leak but it only made a tiny difference in the way the car ran.

djk19

If it was an intake leak both sides would be affected. I just fixed the passenger side and it only throws the code on the drivers side. It has to be between the header flange and the falnge for the y-pipe/header because the 02 is right there. I have felt with my hand and the only leaks are two tiny pinholes in the crappy weld some dumb shop did to my crumby y-piupe which is the only non prety part of my exhaust. It is the only possibility. There are only inches of pipe before the 02 sensor on the drivers side which doesn't leave much room for a leak and I have checked everything. the only leaks are the tiny pinholes and they are directly before the 02 probably within a centimeter. Has to be it.

Injuneer

Did you check the driver's bank for loose spark plugs?

TobyZ28

Heres another thing to check, assuming u still have the AIR system hooked up, check the 1 way valves on those to make sure theyre still only letting air 1 way... There should be 1 on each side.

djk19

no air system or emissions on my car. the holes on my headers for the air system have some nice brass threaded caps that are on nice and tight. No leaks anywhere. that was a good idea though. because it has to be at the header or after... but only back to where the header connects to the y-pipe. Like I was saying that doesn't leave much room for a leak.

I am going to see if j.b. weld works if I smother it with the stuff. They are tiny pinholes so jb weld should work if I clean up the area a bit. I know I want a different y-pipe setup for my exhaust so a quick fix is all I need.

mrmint69

Use aluminum foil and a clamp. I works great for a short term fix. I fold it about 5-10 times to make it thick enough for what im sealing. You could use it with the others or all by itself.

djk19

just mixed up some jb weld. That is some sticky stuff! Turns gray and then it is ready to go. I mixed up a couple of batches and squished it in all around the weld seam where the two tiny pinholes were. It seems to be covering them up well and the stuff actually smooths out when you let it sit. I know it is covering the places where there were little streams of air coming out. I am letting it sit over night and testing it tomorrow. I will clear my pcm again and start it up and let it idle. that will be the test. The car has been running awesome for the most part and the loose spark plug was definately a worse problem then the tiny pinholes near the 02 on the opposite side but they still affect the idle and it will be nice to see the end to this problem. I am crossing my fingers and if this does not work then it has to be leaking around the flange. If that is the case I( need a shop to do up a new y-pipe. Hoping that is not the case.