Instrument panel voltage regulator questions

Hi, I recently had my ignition switch go out, so while the car ('67 200 conv. AT) was parked I decided to replace the IVR as mine was acting weird. Well I had a brand new one laying around that I had ordered from CJ Pony Parts. The installation was easy and straightforward, I don't see how you could mess it up because the wires and prongs are designed to mate only one way. Upon installation, the gauges were a little sluggish at first but then everything worked properly for a couple of days. Then today the gauges all read nothing, then later as the car and the weather got warmer the gauges looked ok, then later the gauges all pegged at max! Fuel, Temp, and Oil pressure are affected, the speedometer is fine, and the ameter never worked since I got the car 17 years ago. Also, the instrument lights dim in rhythm to the engine turning at times. Anybody have a suggestion? Could the problem be anything other than a defective Inst. panel voltage regulator? As always, any insight most greatly appreciated.  

mytbison:
Hi, I recently had my ignition switch go out, so while the car ('67 200 conv. AT) was parked I decided to replace the IVR as mine was acting weird. Well I had a brand new one laying around that I had ordered from CJ Pony Parts. The installation was easy and straightforward, I don't see how you could mess it up because the wires and prongs are designed to mate only one way. Upon installation, the gauges were a little sluggish at first but then everything worked properly for a couple of days. Then today the gauges all read nothing, then later as the car and the weather got warmer the gauges looked ok, then later the gauges all pegged at max! Fuel, Temp, and Oil pressure are affected, the speedometer is fine, and the ameter never worked since I got the car 17 years ago. Also, the instrument lights dim in rhythm to the engine turning at times. Anybody have a suggestion? Could the problem be anything other than a defective Inst. panel voltage regulator? As always, any insight most greatly appreciated.

The job on the IVR is to provide a constant voltage to the gauges that is stepped down to 5 volts from the cars random 12-14 volts. Gauges need a constant/precise level of voltage to operate correctly since they must operate in very precise manner compared to the rest of the car's electrical system.  The symptoms you've quoted all follow a defective IVR (even though its new).

However, one cause of your dimming lights is you may still have an issue with the mechanical charging system voltage regulator. The mech VR is susceptable to engine speeds and temperatures ranges that the electronic versions are not.

There are electronic IVR's available with PEIVR technology that eliminates the issues with standard IVRs. One I'm familar with is made by Coast, has pretty good specs and they're around 30 bucks.jlg  

jlg, thanks very much for the information. So, if you were I, you'd replace the charging system voltage regulator with a new one, and replace the defective IVR with an electronic one, correct? Thanks again for your help, I really appreciate it. I have installed a defective fuel pump, ignition switch, thermostat, spark plug wire, and IVR all in the last year. Parts aren't what they used to be!!  

When I rewired my 65 coupe my gagues all did that too for a bit. I had to double check the wires going to the gagues themselves. I ended up switching them around untill it worked. but the pulsating lights might be a battery thing, the battery might be getting low and it could be that and in combination with a failing alternator, but I wouldnt read too much into that part of it. And did u get it from the CJ Pony parts in York PA?  

CJ's is in Harrisburg, PA, about 25 miles from York. I have been a customer of their's for many years. Although the availability and variety of parts has exponentially increased since the early 90's, I can't say the quality of the parts has. Win some/lose some. It's got to be a lot to manage. The gauges used to work fine, then started getting a bit wacky about a year ago. But nothing like this. Didn't change any wires going to the gauges. I feel the pulsating thing is unrelated, but I mentioned it because I want to give the people on this board all the information I can. It's such a great source of knowledge, people are generous with their expertise, I feel lucky to be able to tap that when I don't know for sure. Thanks!  

Another thing that can cause flickering lights is the light switch (thanks MM for the blog on the site that discusses this issue deeper).
Personally, I would have the electrical system checked for voltage fluctation and if it's OK, go after a new head light switch first.jlg  

Thanks, the blog was an informative read. Can't help but learn useful stuff around here.