AFM Disable Options

mikez71 said:

He pulled up and put my front wheels on the rollers! (no rolling, although the rollers were rolling when I left..) Plugged into OBD port..
Maybe checked that the check engine light works, visual inspection of engine compartment.
Revved up engine in park, about 2500 rpms for about 5-10 secs for the sniffer.

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So, at least the version of the bum sniffer you were put through was in Park / Neutral, at idle and at ~ 2500RpM.
I do not know if the EGR Valve is normally functional in Park / Neutral.
I ALSO don't know if the EGR Valve can be commanded to function in Park / Neutral with California's OBD2 dingle in your OBD2 dongle.

Do you remember if the state computer's dingle was connected to your dongle DURING the bum sniffer?

Rest assured, your checksums and CVNs were verified by California when they connected to your vehicle; your tuned checksums and CVNs are therefore identical to GM OE.

Those who did not understand the previous may continue living in fear of California at your inconvenience.

Marky Dissod said:

Do you remember if the state computer's dingle was connected to your dongle DURING the bum sniffer?

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Sorry I didn't pay close enough attention..

Marky Dissod said:

Do you remember if the state computer's dingle was connected to your dongle DURING the bum sniffer?

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mikez71 said:

Sorry I didn't pay close enough attention.

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This is one of the things I think might have been changed.
I THINK California wants the vehicle to stay plugged in during the bum sniffer?

Marky Dissod said:

So, at least the version of the bum sniffer you were put through was in Park / Neutral, at idle and at ~ 2500RpM.
I do not know if the EGR Valve is normally functional in Park / Neutral.
I ALSO don't know if the EGR Valve can be commanded to function in Park / Neutral with California's OBD2 dingle in your OBD2 dongle.

Do you remember if the state computer's dingle was connected to your dongle DURING the bum sniffer?

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I'm still pretty sure we don't have egr valves. all that ended on ls engines a while ago.

Marky Dissod said:

This is one of the things I think might have been changed.
I THINK California wants the vehicle to stay plugged in during the bum sniffer?

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it would be smart to leave it plugged in as you see the actual rpm and stuff.


back in the day before obd2 stuff was common. Florida has emissions testing. they stuck a probe in the tail pipe. if you failed idle, they would raise the rollers. it was mph based and you drove yourself with a target on the screen. if you could slip the clutch a bit with a manual taking off in 4th gear then shift to 5th it was super easy to pass compared to a auto shifting thru gears.


if that didn't work, we'd hooked up an electric smog pump to blow air into the exhaust. they would then pass with no problem. it only tested for 2 things and a mirror to check that it had a cat. which was just an empty housing on all our cars back them.


to be honest it was probably a good thing back then.. old carb junk on the roads would leave smoke trails before they started testing.

In NYC, for several years, they'd put 2WD vehicles (FWD or RWD) on a dyno, clamp onto one cylinder's spark wire to track RpM,
and drove with a target on the screen.
There was an uphill portion which pretty much required at least a one-gear downshift, and a long deceleration from about 58MpH-0MpH.
I am CERTAIN that this test cycle allowed the EGR Valve to briefly get involved, which helped to lower NOx a bit,
whereas the stationary-in-Park / Neutral tests almost certainly do NOT involve the EGR.
Fulltime AWD / 4WD vehicles got to avoid the rollers, and did the idle & 2000RpM bum sniffer tests.

j91z28d1 said:

I'm still pretty sure we don't have egr valves. all that ended on ls engines a while ago.

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Ya got me!? It did say EGR in the Tech2 readyness monitor.. I'll try and check later and take a pic..
The paperwork from the smog station read "EGR and/or VVT" So I'm wondereing if it's just a VVT timing for emissions that replaced the EGR?

mikez71 said:

Ya got me!? It did say EGR in the Tech2 readyness monitor.. I'll try and check later and take a pic..
The paperwork from the smog station read "EGR and/or VVT" So I'm wondereing if it's just a VVT timing for emissions that replaced the EGR?

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They might have the same result when it comes to emissions ?????
But egr system takes some of the exhaust gases and routes them back into the induction system, IMO nothing good comes of that.
VVT makes for a more efficient/powerful engine.

donjetman said:

They might have the same result when it comes to emissions?
But egr system takes some of the exhaust gases and routes them back into the induction system, IMO nothing good comes of that.
VVT makes for a more efficient/powerful engine.

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One of the side effects VVT can have (depending on the valve timing adjustment) is to trap some exhaust gas in the cylinder.
That actually seems more elegant than letting exhaust gas leave and rerouting some of it back into the intake only to wind up back where it started.