[dataway]

I have a strange problem with my Autometer digital gauges.

They work fine in the ACC position, and the RUN position, but when I start the engine, one or both will go out and not come back on. If while the engine is running I disconnect their power and reconnect it they both come on and work great. I can even quickly shut the ignition off and back on and the gauges will come on and work great.

I'm thinking maybe the voltage drop during cranking may be causing an issue, or the circuit I am using to power them is cut off during cranking .. have tried using the heater circuit and clock circuit so far.

Last ditch solution I'd install an on/off switch for the gauges because they work fine if they are turned on after the car is running.

[Goatracer1]

I am very much interested in your problem and the answer to it. I have a new radio with a digital display that does the same thing.

[george kujanski]

Electronic stuff relies on a Power-On_Reset (POR) to come up in a proper state. During the starting process, the voltage AT THE GAUGES may drop but not sufficiently to trigger the POR. As a test see if you can run a jumper for the battery directly to the gauges with the gauges disconnected from the normal connection and see if the results are different.

Make sure the dash grounds and firwall grounds to the engine and battery negative are good also, otherwise you will get a voltage drop there also.

George

[dataway]

I checked the new battery last night, before charging it was 12.5v and the charger went to float within 15 minutes or so ... so guessing a low battery wasn't the issue.

A strange detail was that they worked fine after starting the first few times ... that's why I assumed it was a battery issue ... still could be I guess if the gauges are very sensitive to voltage drop ... maybe an auto shutdown of some sort. Maybe hooking up to a circuit that totally shuts off during engine turn over would cure it.

I checked the engine to firewall strap (new), added a frame to inner fender strap (new) and ran a jumper from neg batt terminal to body before testing, also checked and cleaned the gauge ground to the instrument panel metal frame work.

I guess I should also check voltage drop at the battery during testing, and if that drops lower than expected then put an Amp meter on the starter cable and see what it's drawing. Has a nice mini starter on it (new), new heavier than stock cables ... but the engine is fairly fresh and might turn over harder than it sounds like (turns over quite nicely).

I'll try running that jumper straight to battery.

George ... on this gauge pod I combined the power supply to the two gauges inside the pod and ran a single supply to the fuse box ... I used a left over section of the wire I cut off when combining the supplies to run to the fuse box ... in other words the wire Autometer included to supply one gauge, is now supplying two gauges ..... too small?

[george kujanski]

The gauges don't draw a lot of current. Usually on these cars after years, the feed from the battery thru the firewall to the fuse block to the ignition switch and then back to the fuse block gets compromised. Since the starter solenoid current goes thru this path and the ignition switch this path may have enuf of a voltage drop when cranking. The xtra battery jumper may tell the tale.

george

[dataway]

I'll give it a try. New engine harness too by the way.

I was surprised when I was swapping around the power source to the gauges that it made a visible spark when attaching to a different fuse .. not a popping spark, but enough to see, surprised me that they drew even that much.

[george kujanski]

Harness set up for HEI?

George

[dataway]

Plain old points.

One thing that confuses me is the first half dozen times I started and ran the car the gauges did not behave this way. Only variable I can imagine is the state of charge of the battery. Yet to make any further tests with a freshly charged battery, still have to run the jumper you recommend ... that will certainly narrow down the search.