bought an obd 2 - usb cable for the laptop...

[4xcrazy]

Yup, bought an obd 2 to usb cable for the laptop to hook it up and see if anything looks out of place, odd or just not working right when the engine in the Avy does its weird, random stumbling thing. ...

Now I just need to figure out how to read all the stuff / information it's collecting.

Engine will idle, then just out of the blue start sounding like it has a hot cam or something. Really weird. Yeah, this along with morning piston slapping, getting tired with it.

So far all sensors seem to be all over the place, which seems odd to me. Advance stays pretty stable, fuel flow is all over the place as is mass air flow sensor. Two O2 sensors bounce up and down, the others remain stable. No instances of a misfire..


Still playing with it a bit though.

Any ideas what I should be looking for?

 

[Babaganoosh]

Thing I like to do is clean the mass air flow sensor. In some cases it's almost like putting in a fresh set of plugs. What software are you using?

 

[Russell]

The MAF should be relatively stable while the engine is running smoothly. It'll bounce around if the engine is surging though. A typical reading would be 1-9 g/s at idle and upwards of 230 g/s at full throttle. This depends heavily on your elevation.

The Bank 1 & 2 Sensor 1s should both be crosshatching (going rich / lean repeatedly) if they are working correctly. Bank 1 & 2 Sensor 2s should be steady after the catalytic converter as the converter uses up a bunch of the O2 in the exhaust.

Your MAP should be steady and indicating around 18 - 20" mercury column (inHG) gauge pressure at a steady idle. You'll likely need to do some unit conversions to figure out what it is in inHG. Keep in mind the MAP sensor reads absolute pressure, not gauge pressure. Take the atmospheric pressure (what the sensors reads key on but the engine not running) and subtract the value you see while the engine is running. The difference is the gauge pressure. The atmospheric pressure should make sense for your elevation. Typical atmospheric pressure at sea level is around 14.7PSI or 101 kPa

Make sure the air intake and coolant temp sensor readings make sense too.

Engine timing should be fairly steady around 20 degrees BTDC at idle.

 

[4xcrazy]

Thing I like to do is clean the mass air flow sensor. In some cases it's almost like putting in a fresh set of plugs. What software are you using?

MAF gets cleaned, as far as the program, I probably should have researched more and got a different cable hookup, possibly will later, I think this setup is more like a hookup to access all live data sensor readings like the high dollar handheld units. I don't have any control as far as changing any programming in the truck with this one.

It says it will log live data. I'm still trying to go through everything and figure out how it all works.

Just a cheapo ScanTool Elmscan5 or something like that.