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scottcmb
January 11th, 2013, 08:17 PM
Gidday I have a Stock 2002 Blazer 4.3 with a LS1B ecm.........could you guys look at my log to let me know if my O2 sensors are behaving normally or does it look like they are a bit sad and need replacing?. The voltage on both fluctuate up and down consistantly is this normal?

Cheers Scotty14378
Mr. P.
January 12th, 2013, 06:03 AM
Yes the O2's are supposed to "switch" from high to low like that when the PCM is in closed-loop operation. And it takes a few seconds from startup before they begin to work (you can see that in the log). Separate question, why is your MAP sensor only reading 94 kPa at WOT? It should theoretically be 100 kPa at WOT - possibly a dirty air cleaner or other air restriction before the intake manifold?

- Steve.
scottcmb
January 12th, 2013, 09:49 AM
Yes the O2's are supposed to "switch" from high to low like that when the PCM is in closed-loop operation. And it takes a few seconds from startup before they begin to work (you can see that in the log). Separate question, why is your MAP sensor only reading 94 kPa at WOT? It should theoretically be 100 kPa at WOT - possibly a dirty air cleaner or other air restriction before the intake manifold?

- Steve.

Thanks steve.......where i live we are about 1200 feet above sea level.....always get low readings here.....my LS3 also shows low static readings.......the best i have ever seen it here was 98 on a good day.......when i go on a drive to the coast and do some logging at the same time.....when at sea level i get the 100kpa readings.....that way i gauged that my map sensors are ok and also the intake track is ok too :).

But granted i do agree with you on the intake of the blazer being restrictive with flow to the manifold when at revs. We have not long got this vehicle and i will be making up a cold air intake for this animal. I have already taken out the restrictor cup in the throttle body and de catted the exhaust. When im done im going to have to study up on how to tune this LS1B. Im use to only tuning E38's and see that this is similar to tuning but not the same :)

Scotty
joecar
January 12th, 2013, 05:25 PM
Looks normal; there's a little difference between the two banks.
ScarabEpic22
January 12th, 2013, 06:58 PM
Scott, look at the Calc.VET for getting the VE and MAF tables dialed in. With a WBO2, it works really slick, 1 good datalog and you have the VE and MAF tables 98-99%. :D
scottcmb
January 12th, 2013, 08:02 PM
Scott, look at the Calc.VET for getting the VE and MAF tables dialed in. With a WBO2, it works really slick, 1 good datalog and you have the VE and MAF tables 98-99%. :D

Cheers Scarab....that was my next thing to do on the list.......wire up the wideband and start logging............just wanted to get your guys opinion on the the state of my NB o2's before anything else :)....will be interesting to see what the economy will be like after tuning this animal.......my wife is complaining that its RATHER thirsty...lol

Cheers Scotty
ScarabEpic22
January 13th, 2013, 12:03 AM
Cheers Scarab....that was my next thing to do on the list.......wire up the wideband and start logging............just wanted to get your guys opinion on the the state of my NB o2's before anything else :)....will be interesting to see what the economy will be like after tuning this animal.......my wife is complaining that its RATHER thirsty...lol

Cheers Scotty

Sure thing, and dont get your hopes up. My parents had a 96 Jimmy with the 4.3 and it was pretty thirsty as well. Our 02 TrailBlazer with the 4.2L I6 was only ~1mpg better, but has 80hp and 25tq more.

Clean up the VE and MAF, probably good for 1mpg. But, the shift points and midrange power usually makes it worth it.
Boost
January 13th, 2013, 01:03 AM
Erik those are super impressive power results with the I6! Yeah, all the 'Blazers' are thirsty.
scottcmb
January 13th, 2013, 09:58 AM
Erik those are super impressive power results with the I6! Yeah, all the 'Blazers' are thirsty.

Hmmmmm..........i wonder if an LS1 will drop into it easily???
ScarabEpic22
January 13th, 2013, 10:25 AM
Erik those are super impressive power results with the I6! Yeah, all the 'Blazers' are thirsty.

Well not that impressive lol, the 4.3 in the Blazers are rated at 190hp/250tq and the 4.2L I6 started off at 270/270 for 02 and only went up from there (head redesign in 06 added ~15hp too). Only about 10-15hp is in the tune on premium (91+ octane), the stock spark map knocks on 87!


Hmmmmm..........i wonder if an LS1 will drop into it easily???

It will...:) You already have the LS1B PCM, swap engines and full flash a fullsize OS (I think there's a certain one floating around that has 4LO intact). Done. :D
scottcmb
January 13th, 2013, 07:41 PM
Well not that impressive lol, the 4.3 in the Blazers are rated at 190hp/250tq and the 4.2L I6 started off at 270/270 for 02 and only went up from there (head redesign in 06 added ~15hp too). Only about 10-15hp is in the tune on premium (91+ octane), the stock spark map knocks on 87!



It will...:) You already have the LS1B PCM, swap engines and full flash a fullsize OS (I think there's a certain one floating around that has 4LO intact). Done. :D

4LO???.....whats that?
Boost
January 14th, 2013, 02:09 AM
Transfer case setting, scottcmb. I usually race in 4HI. In 4LO you can almost do a mini wheelie in some trucks. Neither is good for driveline wear.... oh well
scottcmb
January 14th, 2013, 07:06 AM
Transfer case setting, scottcmb. I usually race in 4HI. In 4LO you can almost do a mini wheelie in some trucks. Neither is good for driveline wear.... oh well

Arrr now its clear....thought you might have been referring to some strange model number or something like that..lol

Thats cool....this is just for daily driving. I dont think my wife wants to race it..lol