1997 Vortec Specific

[EagleMark]

Figured I'd start a 1997 Vortec Specific thread for TunerCat OBDII info.

Couple questions as to how TC handles Fuel and Air Diagnostics? There's options to report, not report, no error reporting (Type X) etc, but also a Check Box? Would this box just turn it off?
Specifically for Post Cat O2 Sensors.

Found the PE delay!

Tips and tricks?

Working on 388 cubic inch = stroker with .060 over bore and small cam.

[1project2many]

A B and C error reporting are for how the error is reported. Type A turns on the light at the first error. Type B waits until a second failure is seen. Type C only reports the problem if you check with a scan tool. A code can still be stored but the check engine light won't turn on. If you uncheck the box then it won't run the test. This means the OBDII monitor won't set and dependent tests won't run either. For example, if you don't run the secondary O2 tests then the cat converter test won't run. If you select "no error reporting" the test runs and passes instantly... readiness monitors show "ready" and dependent tests run. In places where you have to do the OBDII plugin emissions test you're better off with "no error reporting." If you know the system isn't on your vehicle and there's no side effect to unchecking the box, go ahead and remove the check.

[EagleMark]

:happy:

I'm also back to post cat O2 sensor readings. Had this issue on my 98 with one bank varied, one bank steady.
Would go steady at higher RPM, not idle.
Repalced the post cat O2 sensor and idle reading was steady.

Now on to the 1997 and both post cat O2 sensors are all over the place? Diagnostics I've read seem to indicate a bad cat? But above I had a bad/lazy O2 sensor.

Question is, Should post cat O2 sensors be a steady reading or switch like pre cat? Or could this change in vehicle or year?

[1project2many]

The post cat readings should be fairly stable around .450 - .500 when the cat is warm and working. Snapping throttle should show readings lag behind primary O2 and no extreme rich / lean readings. An infra-red gun can help determine if the cat's working. Low heat = not functioning properly.

[Playtoy_18]

Front should be bouncing and rear should be flat for the most part.
if you have an aftermarket cat don't bother with it,just turn off the codes and the COT stuff.
GM is pretty tight on their tolerances,not many aftermarket cats are up to snuff. Most of those that i've heard of working are california compliant.

[Hog]

Type A-MIL on 1st error
Type B-MIL on 2nd error
Type C-SVS on error (service vehicle soon)
Type D-No MIL (malfunction indicator lamp)
Type X-No error reporting

You can lean off the PE multiplier til you get the right lambda you want.

As for pre cat and post cat O2 sensors, I pretty much agree.

Up here in Ontario Canada, we went from the Cali style chassis dyno cycle test to the basic Scan tool emissions test. I'm thinking this has really helped me out as I can just set all the emission stuff I need via TC2.

Usually the more expensive the cat the better they are. I used a couple $100 Catco OBD2 cats and passed the chassis dyno test without egr on my 1997 L31. Any cats that are California approved are pretty much double the money than OBD2 cats. There is a nice Magbnaflow bolt on cat setup with mandrel bent pipe instead of teh horrible crimp net stockers.


1/2 ton Magnaflow mandrel bent
http://i1202.photobucket.com/albums/bb373/Paul_Schermerhorn/halftonmagpipes.jpg (http://s1202.photobucket.com/user/Paul_Schermerhorn/media/halftonmagpipes.jpg.html)

Magnaflow 3/4 ton front half
http://i1202.photobucket.com/albums/bb373/Paul_Schermerhorn/maggieheadpipes.jpg (http://s1202.photobucket.com/user/Paul_Schermerhorn/media/maggieheadpipes.jpg.html)

Magnaflow 3/4 ton rear half
http://i1202.photobucket.com/albums/bb373/Paul_Schermerhorn/backmaggieheadpipe.jpg (http://s1202.photobucket.com/user/Paul_Schermerhorn/media/backmaggieheadpipe.jpg.html)

bends)3/4 ton front half(look at those nice 90º bends and big piping)
http://i1202.photobucket.com/albums/bb373/Paul_Schermerhorn/walkerfrontpipe.jpg (http://s1202.photobucket.com/user/Paul_Schermerhorn/media/walkerfrontpipe.jpg.html)

half
http://i1202.photobucket.com/albums/bb373/Paul_Schermerhorn/walkerbackpipe.jpg (http://s1202.photobucket.com/user/Paul_Schermerhorn/media/walkerbackpipe.jpg.html)

Catco 3/4 ton front(see how the bend quality in those 90º turns isnt as good as the Magnaflow and Walker)
http://i1202.photobucket.com/albums/bb373/Paul_Schermerhorn/catcofront.jpg (http://s1202.photobucket.com/user/Paul_Schermerhorn/media/catcofront.jpg.html)


http://i1202.photobucket.com/albums/bb373/Paul_Schermerhorn/catcoback.jpg (http://s1202.photobucket.com/user/Paul_Schermerhorn/media/catcoback.jpg.html)

c 350 pipes that measure 1 7/8" but crimp WAYY down almost to 1/2 of that in the major bends, the stock 3/4 ton pipes are MUCH better.
http://i1202.photobucket.com/albums/bb373/Paul_Schermerhorn/l31exhaustside.jpg (http://s1202.photobucket.com/user/Paul_Schermerhorn/media/l31exhaustside.jpg.html)
http://i1202.photobucket.com/albums/bb373/Paul_Schermerhorn/L31exhaustfront.jpg (http://s1202.photobucket.com/user/Paul_Schermerhorn/media/L31exhaustfront.jpg.html)
http://i1202.photobucket.com/albums/bb373/Paul_Schermerhorn/l31exhaustback.jpg (http://s1202.photobucket.com/user/Paul_Schermerhorn/media/l31exhaustback.jpg.html)


Also notice a BIG difference between the /2 ton and 3/4 ton setups. The cat which is BANK 1 is not BANK 1 of the 3/4 ton setup.
The 1/2 ton setup has the right cat being fed by the passenger side Bank of cylinders, while the left side cat is being fed by the drivers side cylinder Bank. This reverses in the 3/4 ton setup with the drivers side cat being fed by the drivers side Bank of cylinders and the passenger side cat being fed by the passenger side Bank of cylinders.
So which is Bank 1 and which is Bank 2? I was taught that the Drivers side cat is Bank#1, and the Passenger side is Bank#2? or is it the exhaust gasses from 1,3,5,7 are Bank 1 and the exhaust gasses from 2,4,6,8 are Bank 2? And which is right, and which is correct for both the 1/2 ton and the 3/4 ton? Or is the 3/4 ton and 1`/2 ton harnesses reversed? Its kind of important that if you are having a code for a Bank 1 Sensor 1 that you know which sensor to change, it appears that it is different between the 1/2 and 3/4 tons.

weird ehh??

[Playtoy_18]

Post up your cal and i'll look thru it and see if I can point anything interesting out.
I'm assuming you've found the TM tables.
I learned tunercat on my 98 yukon,I by no means figured everything out but i'm familiar with them.
I will also generally up the shift pressures about %10 and raise max line pressure to 110.
I was still nervous though and while it ran great I never thought it was perfect.