g35 2005 viper 5301 no cold start

Yep, grab tach at the ECU under the passenger dash. Kevin Pierson

from my experience... DEI units do not work with Idata's tach O/P......Kevin Gerry

Certified Electronics Technician

MECP First Class Installer

Owner/Installer

Classic Car Audio

since 1979

Good News Bad News The Good: I changed the engine checking mode to "tach" and there were no problems reading the tach signal from the Idatalink. The car has been consistently starting all day even after sitting for long periods of time AS LONG AS I UNLOCK THE CAR FIRST! The BAD: Now that I have discovered the car only remote starts after unlocking.....Why is that???? For example: If the car is locked and the blue Viper light is blinking the car will crank (for about 7 seconds) and never turn over. I finally figured out that if I hit the unlock button then remote start the car fires up every time. IS this a normal procedure?? Any suggestions?G-35 & FJ Cruiser Remote Start Viper 5301 & Pyton 4203--Alpine touchscreen A/V system w/Camera, Sat radio, SWI

The answer is quite simple actually... You need to hook up your keysense wire. Here is a quick test sit in your car arm the vehicle, stick the key in the ignition cylinder, and proceed to remote start the car. If it works then by using a relay, Convert a - to a + and use the 2nd status output on the viper brain. Keysense / BLACK/ pink / + / ignition harness or BCM, pin 37 Hope this helps and solves your issue. Also check your orange wire Ground when armed if it is connected to anything. (-500 ma)

DCMAN41, I can't thank you enough....you are absolutely right! AFter running into dead ends with BestBuy Viper installers and the smaller shops as well you were the only one to diagnose this issue. You really helped me out, anything I can to return the favor? Any online business I could buy something from........... I wasn't thrilled that I needed a diode to reverse the polarity for the "keysense" but found a great place to mount it cleanly and got it done. Works like a champ!! Yes my "ground when running" is connected. Again, let me know if there is something I can do to return the favorG-35 & FJ Cruiser Remote Start Viper 5301 & Pyton 4203--Alpine touchscreen A/V system w/Camera, Sat radio, SWI

Quick question: Does Viper forget the learned "tach" signal when battery is disconnected? My current theory is that the Viper does forget. Any advice is appreciated. I had problems cold starting today but did not yesterday. The only change is that I unhooked the power to the viper yesterday. So I just relearned the "tach signal". I"m still getting the tach signal from the interface, but Viper has no issues learning it. G-35 & FJ Cruiser Remote Start Viper 5301 & Pyton 4203--Alpine touchscreen A/V system w/Camera, Sat radio, SWI

No, the Viper shouldn't ever forget the tach signal. Rewire your tach signal to the fuel injector at the ECU and you won't have any more issues. Getting tach from a data module is not near as reliable as getting the tach from an actual tach signal.Kevin Pierson

Ive never encountered any issues running virtual tach on any of the cars ive done. As far as your cold start issue goes, did you make sure to hook up the RED / black, RED / white, red Heavy Gauge wires? As those are used to power the ignition, starter, and flex output wire. Does the cold start issue occur when you start the car with the key too? Or is it only when you attempt to remote start the vehicle ? Does the car crank and not catch or does it not do anything at all ?

All of the heavy gauge wires are hooked up as outlined on page one. I even tested that the flex relay is outputing the "second starter signal". Yes the Red, RED / black, RED / white are all powered and even have seperate wires going to the battery. The cold start issue, does not happen with the key. If the car is set to the "tach" input it will crank but not catch. When set to voltage it will crank only for a sec or less and not catch. Now that I have solved the "keysense" issue. I may give the "virtual tach another shot. Since when I previously tested that function I still had the "keysense" wire not hooked up. By the way I have been looking at the ECM harnes and there are lots of wires and no way to identify by # (you mentioned pin 23). I did look at he coil wires and see there are some common wires and uncommon. I have read any of the uncommon wires will provide the tach signal.G-35 & FJ Cruiser Remote Start Viper 5301 & Pyton 4203--Alpine touchscreen A/V system w/Camera, Sat radio, SWI

I should mentione the remote starting has been inconsistent. Sometimes it starts but most of the time not if it has sat for very long. Yesterday it seemed to start all day long as long as it was unlocked. Then of course I found out the keysense issue was why I had to unlock it first. Anyway just a quick FYI I"m going to try the virtual tach as promised. G-35 & FJ Cruiser Remote Start Viper 5301 & Pyton 4203--Alpine touchscreen A/V system w/Camera, Sat radio, SWI