Viper Power valves without battery

stevek61

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Dec 1, 2023
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Recently picked up an 02 Viper ER thats pretty beat up. I took the electric start off it and out it on an SXR that's in good shape. Planning to sell the Viper pretty cleaply but the power valves don't appear to work and I get a tach needle bouncing back and forth. A friend that used to be a dealer told me the ER provided power to the valves thru the battery which I dont have any longer. Looking for a simple way to make the valves work, need to get them power I believe... Thanks for any help
 

I don't know if your dealer freind is correct or not. My 02 Viper without ER has power valves that work and I have no battery.
 
Yes, I know the non ES Vipers had the valves but mine is not working properly. I think I need to get it power, possible even add somehitng inline to condition the power as I have read there can be an issue if not. Does anyone know if the white/red strips wire to the valve controller is the power line? Learning more but not sure yet how to proceed. I do see some Viper condensers on line for about $15, application is Viper non ES.
 
look on the hood/wiring schematic on a standard 02 sx viper as they had a smoothing condensor mounted to eliminate the need for battery. there was a hack on here back in the day to power up the servo with a 9v battery if memory serves.

are the valves stuck?
 
Actually I had not considered that the valves might be stuck. Will check that out. Thinking i may need to run a power wire and possibly the condenser. I could not wind a wiring diagram. Where should I look? Thanks for the help, think I getting a plan.
 
If it’s a factory ES you will need to add smoothing condensers. They will be prewired, just have to add. Located at right footwell, The battery acted as smoothing condensers. Without the battery is reason tach is bouncing. The battery has nothing to do with the PV. They will work with or without battery, You must have something wrong. If you’re not flashing any codes they are most likely stuck or are working and you just don’t know it. They don’t do anything until higher RPMs.
 
Thanks. I think there are some on line for sale. Will look for the plug.
 
Also keep in mind if you decide its expensive and not worth the effort, you can run without working valves. Many drag racers used to remove the power valves and block off the opening with a homemade plate and gasket. The difference between working and not working probly not worth the expense and trouble.
 
I had thought about that also. The issue is that the tach swings back and forth whenever you hit the throttle even slightly. I ordered a condenser for $15. Will try that 1st. There has to be a simple solution, I hope. Its only a $1000 sled as its pretty beat up.
Thanks
 
Most everyone on this site has had tach trouble wild swings and headlight trouble due to wire rub though in the belly pan under the engine. All Vipers suffered this trouble. Typically sleds with higher mileage. To find this wire shorting unplug the wires at the belly pan hood intersection. Pull the wire harness under the engine and up near the carbs so you can inspect. You most likley will find a rubbed wire or two and a simple wire loom fix. Please Note: To make the reinstall a little easier tie a string onto the connector prior to pulling under the engine so the reverse install goes more smoothly.
---mac---
 
I did order a pair of condensers but dont find any plug. Just the ecm and a wire which I believe is for the tailight. Condenser wont be here til end of the week so I will check for worn wires. Seems less likely though as I believe tach was working ok before I removed the battery..
 
If it’s a factory ES you will need to add smoothing condensers. They will be prewired, just have to add. Located at right footwell, The battery acted as smoothing condensers. Without the battery is reason tach is bouncing. The battery has nothing to do with the PV. They will work with or without battery, You must have something wrong. If you’re not flashing any codes they are most likely stuck or are working and you just don’t know it. They don’t do anything until higher RPMs.
While looking for chaffed wires I found an empty small white connector wedged betwee the coolant tank and air box. It has green and black wires to it. Would that be where the condenser plugs in? Expect them on Friday.
Thanks
 
On my vipers they are tucked under plastic above right (mag side footwell) you have to remove the cowel to get at them. Non es had two of them.
 
On my vipers they are tucked under plastic above right (mag side footwell) you have to remove the cowel to get at them. Non es had two of them.
Thanks, will pull the cowling tomorrow. Thought the wire colors I found were not correct.
 
No plugs for condenser on my es viper. So i tapped into the red wire coming from the volayage regulator. Tach issue seems ok now but getting a red warning light. Seems steady flashes which means servo issue. I have read a few places that the servo is pwered from the battery. Is the red and white wire input power? Can I just run an accessory power wire to the servo? It obviously would notbwork until the engine starts.
 


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