dville_gt

iTrader: (5)

So I tried taking the ls-stang out and ran into a little problem. It runs like ****. I think when I pulled the heads I must have effed something up. The side I pulled header is getting much hotter then the other side, it is baking the paint and there is some slight smoke that seems to be coming from that sides exhaust dump. The motor is real rough, slow to respond to throttle off idle, and very poor accelerating. The side I didn't touch doesn't appear to be getting nearly as hot (I don't have a laser thermo, but my spit test indicates it is running much cooler). Any ideas?

Oh, and what are the odds I didn't screw up the valves if this is the case? I only took it down the road and back, not even a 1/4 mile, but it probably has 20 min of run time.

Pulled the plugs, all were brand new with about 20 min run time. Drivers side are completely black (carbon not oil) passenger side look okay I guess. Any ideas now?

Driver side

Passenger side

Driver side

Passenger side

All of them

dville_gt

iTrader: (5)

Almost forgot, this is a 2005 esclade motor lq9 in a mustang w/th350, stock cam with Dynatech longtubes and off road h-pipe. Doesn't throw a check engine light but I have no scanner.

65panel5.3

my first thought was 02 sensor, seen this happen before and replaced the 02 and it was fine. 20 mins run time might not be enough time for it to throw a code, may have to be run multiple times to get a code to pop up. drivers side 02 would be where i would start. Anyone else think otherwise? when you pulled the head you may have gotten antifreeze or other crap on the o2 and messed it up.

lsvega-s

The O2 was my first thought as well. Good luck.

dville_gt

iTrader: (5)

Can you unplug them to see if it runs better or does that not work?

zipster

iTrader: (5)

no that wont work, but you could fwitch sides and see if the spark plug problem goes to the other side.

bozzhawg

You prob won't see it because the O2's do not process unitl at least 20 mins or more, when you crank and first start the car, you are in a sense running open loop....... The O2's do not process until later...... The best thing to do is take it to your tuner or data log it with whatever tunning software your using so you can see what is going on with your fuel tables and trim....

In simple terms the O2's do not process at start up or even a short time of 20mins..... Prob not throwing a code either do to this fact, its running open loop at first or start up.....

Bozz

Jimbo1367

Good to know !!!

dville_gt

iTrader: (5)

Well, I am embarrassed to say, but I figured out what the issue is. Somehow I got the u2 sensors mixed up, I had the drivers plugged into the passengers and vice versa. To make it even worse the way I had to modify the o2 harness to work with the vette style o2 made it where it will go on backwards and lock in. So I actually had the o2s swapped and the one that was controlling the driver side was plugged in backwards. I took it on a little spin but quickly found out there was air in the brakes and they started applying themselves, so I quickly got home and bled them all.

I think there might be something wrong with the trans though, I am going to make another post about that though.

How do the plugs look now? I am almost thinking it looks lean now?


Driver

Passenger

65panel5.3

are those new plugs or the old ones cleaned up a bit? lean will leave a white residue on the plug, you can still see some brownish black on those so id say your ok, drive it for a while and see again in a few miles.

Old Geezer

iTrader: (3)

No accurate way to read plugs that were as FUBAR as those were. Suggest a new set B4 you draw any conclusions as to what the problem[s] are, if any.

mrvedit

Hey, I'm relatively new to GM PCMs, but I have spent time with aftermarket PCMs and your "at least 20 mins or more" doesn't sound right to me.
* Some aftermarket PCMs let you set a "closed loop delay time", which is typically 60-90 seconds.
* My GM PCM (as seen in HP Tuners) has a "Closed loop enable Coolant temperature" table which is typically set to 94 degrees. I suspect there is a built in delay too, but would also estimate it at 60 seconds.

I'm also new to this forum and don't want to be nit-picky and just trying to learn as much as possible. If it really is 20 minutes, that would hugely affect my tuning procedures. Thanks.

mrvedit

Thank you for the detailed explanation. BTW this tread was very informative to me as I have been trying to figure out if I need two o2 sensors; I posted my questions as another thread.

SoCal01z28

iTrader: (11)

You are correct. The most it should ever take a pcm to run in closed loop is 3 minutes, most people's average drive isn't even 20 minutes.