Anyone have electrical engineering expertise? I am having trouble getting a new water temp sender to register correctly on my VDO marine gauge. The original was acting up, gage traveled to correct temp, then gradually creeps to full hot, then flys back down to cold. Then repeats. Engine is not overheating, thermostat is opening at 142 ( its marine rating), like it should. ( Digital temp gun.) New sender moves to full hot and stays there. Engine: 350 chev, 260 hp.,mercruiser, 1987, with original VDO gages. Got to be a way to add a resister in-line, to bring gage down to middle ground on gage scale. Thought about just buying new gage, but dash access is more than a bugger to get behind. I even tried an old sender from my 71 Buick iron 4bbl intake, but it was DOA. Hey, thought I was on to something! The old original sender reads abt 1,060 Ohms at ambient temp., new sender reads abt 560 ohms at ambient. Voltage is 8.6, current at 60 milliamps. Any ideas? The Walleye are coming and I troll @ 1.3 mph so temp gage is necessary.
I'm a mechanical engineer, not electrical, but... Does the gauge have a single wire connection? If so it may use the threaded connection as a ground and you don't want to use Teflon tape. I found this in the FAQ section where I bought my gauges: May be something to look into. If you have a 2 wire connection from the gauge to the sending unit, I'm not sure why it's not working right. BTW, the walleyes are pretty much done in the Detroit river. 4th of July weekend is usually a good time for the St. Clair River hot spots! We troll too, handline with raps.
Can you add a 500 ohm resister in series ( in line) to get back to the old ambient reading and go from there?
Called VDO tech support and got a compatable sender sent to Napa! All is good! Back to my fishing! I did try various ohm resisters, they did not bring gage into usable range. Tried a 50, 330, and 390, seperately and in series.
