viper 4204 05 silverado crank/no start

Hello all, I've done a lot of searching but can't quite figure out my problem. I apologize if this has been covered before. I installed a Viper 4204v in my 2005 Chevy Silverado. I'm using an Xpresskit GMDLBP bypass module. The R/S is being fed via an 8 GA wire to a distribution block straight from the battery. Connections: - The 3 ignition wires and accessory wire of the truck are all connected to the R/S. - The bypass is programmed (#4), and operates the lock/unlock as it should. - The bypass is connected to the data wire (pin 2). - The bypass ground output is connected to the activation input of the R/S - Tach wire is fed directly from rear of cluster to R/S tach input. - All grounds go to same point under dash - Neutral safety toggle ON - Bypass door lock/unlock connected to R/S (works properly) - Brake and hood switch are NOT connected as of now. The issue is that the truck cranks but won't start. It sounds like it fires for a millisecond, but that's it. I've attempted to program the unit into auto trans, tach wire mode. I've also tried messing with different crank times. It seems like no matter how many times I try to program it, it doesn't appear to save the changes. For instance, when I go into menu 3, feature 1 (trans type) and change it to #2 for auto, it doesn't save it. If I go back into that menu, it will start flashing once. Also, even though I've tried to alter the crank time, it doesn't seem to change. I read that I may have to have my door triggers connected to program it. Is that right? Also, do I have to press unlock before attempting any programming? Any other ideas on why it might not start? Thanks so much for any help Jim

Not sure if I understand your terminology right but....

" The bypass ground output is connected to the activation input of the R/S "

The GMDLBP Brown NEGATIVE GROUND OUTPUT WHEN RUNNING wire should go to the Vipers' Blue wire called (-) Status Output.

 

Soldering is fun!

Yes, that's the wire I was talking about. I guess I had it running to the wrong wire. I'll switch that and let you know. Thanks so much for the info ! Jim

Also, do you know if I need to connect the door input to program the RS? Is there some step that I'm missing that I need to do to "save" the changes that I made?

Are you remembering to hold the valet button when changing the settings?

Kreg, good to know I don't need the door input. I always key on/key off before programming. Lurch, yes, I hold the valet/program button in while using the remote to select the options. If I select option 3 for instance, it will flash 3 times. However, if I were to start the program process over again, and go back to that same function, it would blink for the default setting. That's what was throwing me off. I'll try again tomorrow with the dark blue wire and see how it does. Thanks again for the help guys

Has this unit been bit locked. If it was installed by a shop in another vehicle they may have bit locked it.

Went out today, and switched the brown wire from the bypass from the activation input, to the status output. The truck fired right up! Thanks so much for the help. That's one down, one to go. Now I'm going to tackle the wife's 09 CRV. I'm installing a Viper 4203 and PKALL bypass. Hopefully, it will be smooth sailing. Thanks again! Jim

Glad to here you got it going, good luck on the next one.