What did you do to your OBS GMT400 Tahoe/Yukon Today?

[SunlitComet]

My cats are original at 244k and they are definitely not plugged. hand it was the msd cap specifically. You do spend a significant time in the cold so it does kind of make you thing you might have condensation issue deterioration. Just a thought.

---------- Post added at 09:37 PM ---------- Previous post was at 09:36 PM ----------

Get a back pressure test done on the cats and determine for sure if you have a clogging problem.

 

[noJeepshere]

My cats are original at 244k and they are definitely not plugged. hand it was the msd cap specifically. You do spend a significant time in the cold so it does kind of make you thing you might have condensation issue deterioration. Just a thought.

---------- Post added at 09:37 PM ---------- Previous post was at 09:36 PM ----------

Get a back pressure test done on the cats and determine for sure if you have a clogging problem.

What doesn't make sense in this scenario (for the cap) is that it started happening after 5 weeks of over 90 temps. I will investigate and report back.

 

[SunlitComet]

Don't know but when you get it off get some pics for diagnosis.

---------- Post added at 09:59 PM ---------- Previous post was at 09:56 PM ----------

Perhaps the water or air temp sensor could be iffy. or a dirty MAF sensor not responding to air density well. Time will tell.

 

[_Dylan_]

If the cats were stuffed you wouldn't be able to drive it, well you could but your not going to get anywhere fast...

O2 sensors unlikely, the engine will run fine in default mode.

Distributor cap is possible. Any codes pop up?

 

[SunlitComet]

well if he does not it does narrow it down to cat problems or high tranny line pressure. weak ignition output could do that too but a failure in the cap would likely be flashing misfires or an alignment code.
Riley you got any type of scanner or scangauge unit?

 

[noJeepshere]

Only codes that pop up are the ones for the EGR valve, which I blocked off years ago and those codes have been there ever since in warm weather. No misfire codes or anything like that. It's odd, it'll run bad for a while after starting, then 20-40 minutes in, it'll smooth out and run like a champ. Hmmm...

 

[retorq]

Dropped my trans ... like it was hot. Time for rebuild ... bigger and better this time. \m/

Also took a better look at my exhaust, mandrel bent 2 1/2 Y-pipe and stock cat that is ... gutted. Maybe exhaust upgrades won't be next on my list ...

 

[noJeepshere]

Big dust storm moving in, so no popping the hood this afternoon...

 

[SunlitComet]

Only codes that pop up are the ones for the EGR valve, which I blocked off years ago and those codes have been there ever since in warm weather. No misfire codes or anything like that. It's odd, it'll run bad for a while after starting, then 20-40 minutes in, it'll smooth out and run like a champ. Hmmm...

which has me thinking because no egr your combustion temps got to high and slightly overheated your cat to a partial blockage. My theory anyway. maybe even a screwy temp sensor some where in the drive-train.

 

[Fishintahoe]

installed blue leds in HVAC control and 4x4 shifter to match the cluster