People that work on LSX motors????

[stealthrunner1]

Got a question for LSX owners/people that work on them....What would be the first thing you would look for if while running your fresh buggy motor...seems to run ok untill it gets warm...then acts like its loading up on fuel?????Any help appriciated!!!!!! Hey Crash any ideas?????:corn::corn:

 

[zukkev]

Runs ok cold, then loads up warm? I have seen more than my fair share of shorted O2 sensors cause this symptom on LS motors...when the signal shorts to ground, the comp thinks it's running lean, and in turn richens the mixture in an attempt to compensate for the perceived lean condition. Problem is, the O2 signal never changes as the mix is thickened, so it loads up...rev it a few times to smooth it out, and the process starts all over again... If it is a shorted sensor signal, a scanner that has datastream for the O2 circuits should let you look at the signal voltages, they should swing between close to 0 volts and close to 1 volt---a lab scope would be best, as it can catch glitches better if it's an intermittant thing...Oh, and the first ones to look at are the pre-cat sensors... Hope this all helps Bill! :awesomework:

 

[zukkev]

Oh, and if you've eliminated the post-cat O2's, be sure the precat O2 are plugged into the pre-cat circuits, not the post-cat...just a thought...

 

[stealthrunner1]

:awesomework: Thanks Kev for the Ideas!!!Just waiting on my OBD2 adapter to show up so we can read all the voltages on all the sensors and see what the heck is going on!!!!:awesomework::beer:

 

[Avanteone]

Thermostat, coolant temp. sensor?

 

[thursday]

Thermostat, coolant temp. sensor?

i've seen the older gen 2 motors (non lsx) do this when the coolant temp sensor was bad. Basically the motor would warm up normal, but once the computer tried to read temp thru the sensor it would think it was -100 degrees and run it super super rich. I think we diagnosed this sensor by checking impedance and discovering it was shorted open.

 

[stealthrunner1]

I'll grab a new one on the way over to the shop later with some crc maf cleaner!!!!i'll let you guys know what me and Phil come up with when my OBD2 adapter get here also!!!:awesomework: Thanks Stealthrunner:beer:

 

[zukkev]

Whhen you say 'acts like', does it blow any black smoke out tailpipe when you rev it to 'clear' it out? If not, it may well be doing the exact opposite of loading up...ie: leaning out to the point of misfiring due to a shorted rich O2...... I'll say this, typically a bad stat won't necessarily cause an LS to load up at idle, and a bad temp sensor will typically act up as quickly as if flipping a light switch when it reaches the point that it fails or goes open ckt.....for giggles, unplug the coolant sensor, and you'll see what I mean...

 

[stealthrunner1]

Whhen you say 'acts like', does it blow any black smoke out tailpipe when you rev it to 'clear' it out? If not, it may well be doing the exact opposite of loading up...ie: leaning out to the point of misfiring due to a shorted rich O2...... I'll say this, typically a bad stat won't necessarily cause an LS to load up at idle, and a bad temp sensor will typically act up as quickly as if flipping a light switch when it reaches the point that it fails or goes open ckt.....for giggles, unplug the coolant sensor, and you'll see what I mean...

I'll try that in about an hour and pick up a new coolant sensor....Lets put it this way Kev the tail pipe is black in side!!!!!!

 

[zukkev]

All pipes are gonna be black inside, it's just whether or not your fingers come out blacker 'n binder's ass! :redneck: Really though, if you can see the smoke out the pipe, chances are yer runnin' rich...and as for the coolant sensor thing, it'll run like complete doodoo, or not idle at all if it goes open circuit...

 

[stealthrunner1]

All pipes are gonna be black inside, it's just whether or not your fingers come out blacker 'n binder's ass! :redneck: Really though, if you can see the smoke out the pipe, chances are yer runnin' rich...and as for the coolant sensor thing, it'll run like complete doodoo, or not idle at all if it goes open circuit...

Now it will idle but the idle is not smooth....and when it starts to get warm it starts stumbleing and wants to die..it will clear out when ya rev it but just loads up again after ya clear it out!!!

 

[stealthrunner1]

cleaning the maf one of the wires had a little dirt on it.....got my adapter!!!! more info soon...:awesomework:

 

[stealthrunner1]

Well it runs good now but only because the driver side O2 sensor is not hooked up! ????? any thoughts??????:eeek::eeek::wtf: and what is the routing on the PVC hoses on the motor????:corn:

Oh one more question ..on the GM parts web site it says that there is specific left and right side o2 sensors What are the differances between the 2 o2 sensors????

 

[stealthrunner1]

http://youtu.be/yXHY0xeaP5U


http://youtu.be/JmKsVX1RJ30

:redneck:

 

[zukkev]

The precat O2's are no different left to right except maybe the length of the wire off the body of the sensor...If you unplugged the sensor and it runs better, chances are that O2 is shorted...What code did it set?

 

[stealthrunner1]

The only code that comes up is an evap code so far....:eeek:

 

[Chevyjoe]

call Gary Lattin here in Yakima. 509 965 3385. tell him his neighbor Joe sent ya :beer:

 

[stealthrunner1]

call Gary Lattin here in Yakima. 509 965 3385. tell him his neighbor Joe sent ya :beer:

Thanks for the numberChevyJoe!!! But the guy that built the motors shop is in kennewick so if i need to take it some where it would be his place he has a wheel dyno that he does tuning on !!!!! And between me and Phil we have a few buddys that are local that have and run LS motors...But thanks again for the info might have to look him up some time so i can have alot of opinions to pull off of!!!:awesomework:

 

[stealthrunner1]

And an update from tonight.....the motor runs pefect when both O2 sensors are unhooked..... if you hook the driver side up it runs on the verge of rich and if ya hook both up it goes back to stumbleing and loading up!!!!!Oh ya the oil that was in it smelled like gas....so that got changed and when it is run with no O2 sensors hooked up the exhaust smells like warm non rich exhaust.... so we are thinking that the O2 sensors i had are crap.....Duh they where made in Japan....so next pay day time for some ac/ delco or Delphi sensors....:awesomework:

 

[zukkev]

Bosch are good sensors...
Delphi or A/C delco I believe are hecho en mexico!:redneck: