rpm drops below learned tach signal

I'm in the process of installing a Viper 5902 alarm system in a 2005 G35 Sedan and having issues with correctly learning the tach signal due dropping engine rpm.

When I start the engine the rpm is at approximately 1200 rpm.  After about 8 seconds it drops to around 600 - 700 rpm.  The problem is that you only have 5 seconds to start the tach learning process and the engine rpm doesn't drop until after the tach signal has been learned.  As a result the engine remote starts correctly and then shuts off after 10 seconds due to a low tach signal.  To verify that this is the problem, I tried placing my foot on the accelerator pedal after remote starting and holding the engine rpm at approximately 1500 rpm.  This works and the engine continues to run until I remove my foot from the accelerator pedal after which the engine shuts off about 3 seconds later.

I'm using the XK09 module flashed with the niss2 firmware.  It's wired D2D but I had to add the tach wire connection between the XK09 and 5902 to pick up the tach signal.  The tach setting on the 5902 is set to tachometer (option 4).

FYI - Virtual tach did not work either as the starter wouldn't disengage.

Any help is great appreciated!

Does quickly placing the car in gear ( assuming an automatic - reverse is best )  slow the engine enough before the Tach Learn period is over?

I had the very same idea but when I put the car in gear the ECM seems to compensate increasing the engine RPM to ~1100.

I also tried tricking the RS to delay the tach learning process by removing the ignition input/output wire (12 ga pink)  from the 5902, starting the engine and waiting for the rpm to drop to ~700 (where it normally is) and then re-inserting the ignition wire back into the connector and then immediately starting the tach learning procedure.  Didn't work.  All I achieved was putting the car into valet mode...  Does anyone have any idea which other input the RS is watching to detect when the engine is started?

Is seems like it isn't an issue to pick up the tach signal with the module and I'm guessing if I use a hardwired  tach input I'm still going to have the same issue with engine RPM.  If all else fails I'll likely still try this though.

Is there any way to delay, extend, or re-initiate  the tach learning time?

FYI – I remote started  the car today with the engine totally cold and it ran for several minutes until the engine warmed up enough that the RPM dropped below the learned tach signal shutting down the engine.

Ya I guess that's what I'm going to have to do.  Hopefully it works...

Can't say I think much of the XK09 module.  So far the only thing it seems to do right is the bypass.  Everything else either doesn't work or is flakey.  Is there another brand that works better?