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Instrument voltage regulator

400exr1

New Member
Joined
Feb 20, 2011
Messages
28
Hey all,

I've done some reading and think my Ivr is bad. Temp reads about 40 degrees high and oil stays almost pegged. I tried grounding the Ivr to the dash with no luck.

First question, does anyone know of a company who sells an adjustable Ivr? Id like to be able to dial in the gauges.

Also, anyone had any luck adjusting the factory Ivr? I couldn't get needle nose on that little fitting. Any suggestions? Also how much adjustability is there in that factory Ivr?

Thanks so much for all your help. This has been quite a pain.

Blake
 

Viperwolf1

Contributor
electron whisperer
Joined
Aug 23, 2007
Messages
24,316
Before you go adjusting stuff you need to use some standards. The standard resistance for 1/2 scale reading for temp, oil and fuel gauges is 23 ohms. So, if you put a 23 ohm resistor (1/2 watt) in place of any of those senders you should see 1/2 scale reading on the gauge. I recommend trying all 3 before adjusting anything.

I've seen adjustable electronic IVRs on Ebay. I don't know the range of the stock IVR adjustment.
 

Bronconaut

Contributor
Jr. Member
Joined
Apr 23, 2006
Messages
79
Thanks Oleguy for posting that. I need it to fine tune what I've done.

My problem:my temp gauge would read "correct" when you first turned the key on but would then slowly move down to zero over the next few seconds.

Everything checked out. I could ground the wire at the sender and it would peg. I replaced the wire from gauge to the sender, then from IVR (instrument voltage regulator) to gauge, new sender - all the same. All the other gauges worked fine. I happened to have replaced the IVR before I started troubleshooting this. I had also replaced the ammeter with a voltmeter so I connected the IVR output to the voltmeter so I could see the pulse. I was only getting one pulse every 2-3 seconds. I've read on here and elsewhere that it should have been 2 per second.

Rather than spending another $50 or so on a new IVR, I found several schematics and built a digital one using Radio Shack parts. I was then able to adjust the voltage output so the temp gauge "works" - I need to verify temp, oil pressure, etc. now for accuracy but for right now I know what the "ranges" are for normal on each gauge. I was able to adjust the output using the potentiometer from 2-7 volts. Right now I'm having to run it almost at 7 for the temp gauge to work.

Here is the result of my $15 Radio Shack IVR build:
 

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