Exhaust leak...found one...gonna get it fixed soon, but...

[BIGdaddy]

I'm wondering how much an exhaust leak is able to effect performance/ percieved symptoms. It's very apparent to me, at least, that there's a leak, because on the flange itself you can see carbon sprayed off in one direction. This leak is on the downpipe side of the exhaust flange that connects to the passenger side header...

No pics, sorry. Didn't have my camera with me last night when I was poking around underneath my Trooper, but I did whip up a quick drawing of what I saw:




My symptoms are:

-Bit of a stumble/miss but only under load. When it sits and idles you can't feel/hear a thing.

-Very, very slight exhaust smell in the cab when idling (notice it maybe once a week, for the last month or so. I thought it might be another vehicle near me whose exhaust was blowing my way...lol)

-poor economy compared to when I bought it. Most recent tank, filled up today, calculates out to 13mpgs. when I bought it and even when I put the bumper on, it was up around 17-18.5 or so.

-Lots of black carbon in EGR valve, throttle body, tailpipe, etc. I was thinking this was from oil consumption, but I'm wondering if the O2 sensors could be detecting the leak and interpreting it as a lean condition and then consequently dumping more fuel into the combustion chambers, richening the mixture. Does that make sense to anyone?

I'm gonna stop by my favorite exhaust shop this weekend and see if they can simply weld it up for me. I'm wondering what kind of improvement I'll see, though...


-

 

[JIMBO]

:sombrero: CARBON MONOXIDE POISONING-

If you letit go, ByeBye-

It's a serious (possible) problem-

Good luck

:costumed-smiley-007:wings: JIMBO

 

[BIGdaddy]

:sombrero: CARBON MONOXIDE POISONING-

If you letit go, ByeBye-

It's a serious (possible) problem-

Good luck

:costumed-smiley-007:wings: JIMBO

haha! I'm aware of the health issues related to exhaust leaks.

I just found the leak last night. Be assured I'm going to get it fixed in the next day or so.

 

[98OzarksRunner]

My symptoms are:

-Bit of a stumble/miss but only under load. When it sits and idles you can't feel/hear a thing.

-Very, very slight exhaust smell in the cab when idling (notice it maybe once a week, for the last month or so. I thought it might be another vehicle near me whose exhaust was blowing my way...lol)

-poor economy compared to when I bought it. Most recent tank, filled up today, calculates out to 13mpgs. when I bought it and even when I put the bumper on, it was up around 17-18.5 or so.

-Lots of black carbon in EGR valve, throttle body, tailpipe, etc. I was thinking this was from oil consumption, but I'm wondering if the O2 sensors could be detecting the leak and interpreting it as a lean condition and then consequently dumping more fuel into the combustion chambers, richening the mixture. Does that make sense to anyone?

I'm gonna stop by my favorite exhaust shop this weekend and see if they can simply weld it up for me. I'm wondering what kind of improvement I'll see, though...


-

Yep. It's getting oxygen into the exhaust before the O2 sensor so it's reading lean, and the ECM is richening the mixture. Common symptom on exhaust leaks ahead of the O2 sensor. Often it will cause rough idle and a miss at part throttle.

 

[BIGdaddy]

Yep. It's getting oxygen into the exhaust before the O2 sensor so it's reading lean, and the ECM is richening the mixture. Common symptom on exhaust leaks ahead of the O2 sensor. Often it will cause rough idle and a miss at part throttle.

10-4...Thanks for confirming. Hopefully this is the only one, as it should be fairly easy to get to...

 

[JIMBO]

:sombrero: KEWL Bd-

Carry on-

:costumed-smiley-007:wings: JIMBO

 

[BIGdaddy]

:sombrero: KEWL Bd-

Carry on-

:costumed-smiley-007:wings: JIMBO

:victory:

 

[TooTall'sTruck]

I chased my hesitation/ shudder when under load (when TQ locked up) and thought it was my trans going. Trans was going but it was still there after the rebuild, sort of like loose u bolts on the axle or wrinkle wall tires...just a barely notice but I am a mechanic, my wife had no idea. It ended up going away with a new plug wire set...one of the wires was weak and I had random misfires and could stall it and make it miss. Now I didn't check continuity of each plug wire because after 2 wires I had 150 ohms difference....changed the set!! My intake on my Vortec 350 is also very black, but oh well it has 160k on it.

You might buddy up with someone with a scanner that you can watch misfires and sensors output and even blindly search for the odd duck out.

 

[BIGdaddy]

Well, the trooper is at the muffler shop gettin' some lovin'.

-welding the downpipe
-New OEM flange gaskets
- New muffler

I climbed into the pit with my mechanic and we checked out all the problem area's together. Lots more leaks than just the one i had found, though my find was probably the main culprit.

 

[east_tn_81]

That sucks hopefully not to expensive.

 

[BIGdaddy]

Okay, well the drive home was eye-opening.

-No exhaust smell, at all
-I realized that the engine had developed somewhat of a drivetrain noise that sounded a bit like diesel clatter...that is completely gone.
-No miss or sputter upon accelerating
-Power during acceleration that i forgot this car had.


He even welded a tab on my hitch to stabilize my trailer wire connection - no charge.

I'm going to crawl under there this morning and take a closer look because it was sun-down/dusk when he was finishing up. Tenetively, simply from the test drive, I'd say it was a successful repair. LoL.

 

[JIMBO]

:sombrero: Kewl, repair to a danger and-

A star is born-

Congrads

:costumed-smiley-007:wings: JIMBO

 

[98OzarksRunner]

Okay, well the drive home was eye-opening.

-No exhaust smell, at all
-I realized that the engine had developed somewhat of a drivetrain noise that sounded a bit like diesel clatter...that is completely gone.
-No miss or sputter upon accelerating
-Power during acceleration that i forgot this car had.


He even welded a tab on my hitch to stabilize my trailer wire connection - no charge.

I'm going to crawl under there this morning and take a closer look because it was sun-down/dusk when he was finishing up. Tenetively, simply from the test drive, I'd say it was a successful repair. LoL.

You'll probably get better mileage too. The ECM was probably confused and trying all sorts of things to get the mixture right. It all works better when it all works as designed.

 

[BIGdaddy]

You'll probably get better mileage too. The ECM was probably confused and trying all sorts of things to get the mixture right. It all works better when it all works as designed.

Yeah, hopefully this new setup will lead my ECU out of the woods.