Electrical Advice

[flyingriki]

I have an electrical mystery (to me) and no skill at all in things electrical. I have a Westach dual instrument for oil pressure and temp. Yes I know they are not the best..... For some time the temp would drop to zero for a bit then jump back to temp. Did this for a several months. Then one day I found if I turned off and on the strobes it would read again instantly. Now it seems to stay reading. So.....
The other day I had the strobes off and when turned on I see the temp dips a tiny bit in time with the strobes. Strobes off and nav lights on - the temp drops about 20 degrees and stays there until nav lights off then full temp again.
Any ideas on what I can check or do to troubleshoot further? It's not that big a deal but isn't right and I'd sure like to correct it.
Thank you!

[CarlOrton]

Not saying I know the answer, but a bit more information could help.

Homebuilt or spamcan? Engine? Separate alternator or one integral with the accessory case like an AeroVee? Internal or external voltage regulator? Are you sure that your alternator (regardless of homebuilt or not) has enough capacity with everything else running? As in, if you're running a 10A alternator, lights in general pull a big drop in voltage. Your Westach may be sensing severe voltage drop.

Does this happen at all engine speeds or only at idle?

[flyingriki]

Not saying I know the answer, but a bit more information could help.

Gladly Carl!

Homebuilt or spamcan? Homebuilt

Engine? O-320-E2A

Separate alternator
external voltage regulator

Are you sure that your alternator (regardless of homebuilt or not) has enough capacity with everything else running? Yes

Does this happen at all engine speeds or only at idle? I'll check but what I have been observing is at cruise.

Thank you!

[malexander]

Sounds like a bad/corroded ground to me. A bad ground can make lots of things do goofy stuff.

Marshall Alexander

[Richard Warner]

I agree about the ground. That's the first thing that came to my mind.

[gyrojohn]

If all these items are using the same ground terminal this sort of feedback can happen. Try running a seperate ground wire to the engine block for your gauge.