791XV remote start hot weather problems

I have a Viper 791XV alarm with remote start professionally installed in a 2005 Infinity G35 automatic transmission coupe. The remote start feature fails to fully start the car in extremely hot weather. I live in Florida and have to park in a parking lot that is exposed to the heat of the sun. Needless to say, the interior of the car gets quite hot.  After several hours in the sun, when I initiate the remote start feature (after disarming the alarm), the starter solenoid and starter motor engage, but the engine fails to "catch" (for lack of a better term). The starter motor goes through the same cycle three times, then the alarm/remote starter disables any futher automatic attempts in that series. If I cancel the attempt during this failed series with the responder remote, I can start the car manually with the "computer chip" transponder key. If I don't cancel the attempt, I will often have to go through an alarm arm/disarm sequence before the car will manually start with the key. All other features of the alarm operate perfectly in direct sunlight. If the car is parked away from the heat of direct sunlight, the remote start feature works every time.

The alarm main module is mounted under the dashboard away from direct sunlight. There is a dedicated "computer chip" transponder key that has been sacrificed in the transponder bypass module.The main alarm unit has been replaced with no correction of the problem. Questions placed to the manufacturer's tech support line have have yield no answers. It seems that the main Viper 791XV module is not the problem, since replacing the unit with a brand new one has not solved the problem. The only thing I can think of is that the heat has somehow interrupted the pickup of the signal from the dedicated transponder key to the main alarm unit.

Has anyone else experienced such a heat related problem with the remote start feature of the Viper 791XV alarm?

I know these cars have 2 starter wires.....in the cold, without both, the car will NOTstart. I don't know how this might apply to HOT weather?

I'm guessing....if you can't tell?

Any of you DEI guys out there think any problems could come from that tiny little relay pack?  HOT and small?

You might also try this. In a controlled area (safe to avoid theft) put the key in ...(I don't know how the smart key works) and let the car sit in the sun and get as hot as possable. Then try to remote start. ??? again, just stabbing in the dark, about what to maybe look for.

Chris,

I greatly appreciate your input. It is obvious you are familiar with this vehicle. I have tried the first half of your suggestion. Now I have to wait for another hot day to test the rest of the sequence.

My only question is how does the repositioning of the key cylinder sensing coil help with the keyless remote starting sequence prior to insertion of the key? It is my understanding that the sensing coil around the key cylinder sends a signal back  to the 556u transponder bypass unit after insertion of a properly encoded key into the key cylinder. (A signal is also sent to the factory transceiver depending upon the factory setup.) This should in turn initiate a signal back to the 791XV main unit and informs it not to trigger an ignition "kill" signal and interrupt the maintenance of engine RPM so a properly coded key can allow the vehicle to be driven. So how would adjusting the cylinder coil affect the sensing of a key that is not there? (Of course, there is the possibility that I am completely wrong, also.)

Once again, many thanks from a very hot place. At least there aren't any more ice storms.

Chris,

I now have the full sequence of events:

-- On a cool day, the red LED remains off during the remote starting sequence, and the engine starts up successfully.

-- On a hot day, the red LED is continuously glowing during the cranking cycle, and off in between cranking attempts. The engine does not start when the red LED is glowing.

I guess you are right. As you stated, the car must not be  "seeing" a valid transponder key. I 'll work on correcting this problem.

---- Again, many thanks for your knowledge and help.

wow, i just finished reading this post and am very interested in what is going on with this vehicle. my question is to Chris, what is making the difference between the vehicle starting at different temperatures? are you thinking that the heat is changing the ring position somehow or is it possible for extreme heat to change the resistance in the transponder key? or is it something completely different? very interesting situation but i will keep an eye on this one to see what turns out to be the problem. btw, do you think that maybe jroymd is changing his HVAC controls differently depending on where the vehicle is parked and somehow the installer maybe got onto the wrong wire and that is what is causing all the problem. very interesting.