Tach blinking

[Boxer12]

I don't know what else to say to describe this but my Tach has started blinking. Anyone else experience this? What should I look for as far as a cause? Sensor? Wiring? PCM? GEN IV w Mopar PCM. I don't notice a skip in the motor, it seems to be purely an electrical issue.

 

[ViperGeorge]

What is blinking? The arrow shift light? The back light on the tach? or is the needle moving around at random? Check the connections into the PCM, front left in engine compartment. There are three. I had one get loose and my tach needle would jump all over the place at times.

Mind you that was on my old Gen 3, not sure if Gen 4 connections are the same.

 

[Thom]

I assume you mean the skip-shift light is blinking? This light also functions as a high-rpm light.

Check to see if your skip-shift solenoid is working. If not, it may have become disconnected. Or, if you have a skip-shift eliminator connected in place of the solenoid, the eliminator may have become disconnected.

 

[Steve-Indy]

Jim, IF your car was a stock street Viper...I'd say check the battery first. This heat wave has been killing 1.5-2.0 year old batteries(prematurely) around here in ALL types of vehicles.

 

[Boxer12]

By blinking i mean the needle drops to 0 rpm for a quick second then back. I will double check the connections. I don't think it's the battery Steve since its not the entire elec system that blinks just the tach.

 

[Steve-Indy]

Thanks, Jim...my point was centered around ae misinterpretation of "blinking" on my part. I assumed it to mean tach needle jumping all around...often followed by spedo doing same thing...then, car goes dead...or at least won't restart.

 

[Hirkophoto]

Do you have or have you installed any new electronics **** as stereo equipment? I know the Mopar ipod adapter causes similar problems in some Vipers when installed.

 

[M_viper]

when I installed my ipod connector the tachometer wasn't blinking but rather too slow to catch up with the revs

 

[Steve-Indy]

Guys, I am confident that there is NO WAY Boxer 12 would have an i-pod installed in his track-only ACR....I hope !!

 

[Hirkophoto]

Guys, I am confident that there is NO WAY Boxer 12 would have an i-pod installed in his track-only ACR....I hope !!

I don't know him so you never know.

 

[Boxer12]

Nothing new, and no ipod adaptor (its a ******** model). (Steve knows me well!) I guess its just a gremlin.

 

[Boxer12]

Ok, upon closer inspection, not only does the tack skip or jump or flutter, but so does the Speedo (simultaneously). I have checked all the connectors that seem obvious, like the ECU and anything in engine bay. I have no codes. You guys think an intermittent short somewhere like the O2 sensors could cause this? Need new ideas. Anyone?

 

[Allan]

I have seen and repaired instrument clusters with similar symptoms. Didn't respond before cuz problem described seemed to be isolated to the tach only. Anyway, on other Chrysler vehicles, there has been an issue with the solder joint cracking for the ground circuit on the back of the printed circuit boards on some vehicles. This causes an intermittent or non-functioning gauges condition. This may or may not be your problem, but would be worth investigating if there are no other leads. To inspect/repair, you will have to remove the instrument cluster from the vehicle, and dis-assemble it to access the printed circuit board. The cracked solder joint will not be apparent to the naked eye. I have found that a strong magnifying glass will expose the cracks. -So the gauges will work when the circuit is making contact, and then it bugs-out when there is a little resistance or no contact on the ground circuit. -usually from vibration, like the road, or the motor running and shaking the car (in a Viper). .....hope this info helps. -Allan

 

[Boxer12]

Thanks, I will inspect/test the cluster further.