Guages powering up but not reading
 

Hello guys,

I have been chasing this problem for a couple days now with no success.

i have a 38zr with 700s. I rebuilt the engines and installed them back in the boat.

When turning ignition gauges are getting power as the needle is moving to the max and back to zero as normal and lighting up but when engines are started they are no moving or providing data. This is for both engines there for I don’t think it’s an issue with the agi as it would be specific to one engine.

i have noticed one wire in the harness is not connected and cannot seem to trace it. I have attached a picture. I do not know if this would be of any meaning to the equation.

appreciate any help that I can get

thanks
https://cimg2.ibsrv.net/gimg/www.off...fe5d40101.jpeg

Maybe a bad engine ground issue? Assuming these are all analog gauges? If so, 1 wire sensors are resistance based and grounded through the engine.. multiple wire sensors will have a ground wire but still typically through the engine.. Check the engine harness ground wire on the back of the block and make sure its tight..

And a ground strap from engine to engine
my spare red wire to engine area was for NON battery switch power requirements i.e. auto bilge pump

Red wires are "typically" power wires for something but if someone has done repairs all bets are off. Do you possibly have any pictured from before you pulled the engines that might show the wire ?

now after going through I don’t think it’s related to my guage issue.

i cannot figure out why I’m not getting engine signal to my guages.

i have gone through everything.. would appreciate any help out there!

thank you

Here is back of engine if I’m missing something?

dash wiring is good


https://cimg5.ibsrv.net/gimg/www.off...c54e9a913.jpeg

The engine ground straps are located on the flywheel cover top bolts. 3 ea. straps for twins 1 each engine to battery ground amd one from engine to engine for a common ground reference.

I'd start at the gauges now and see where the sender wires head to,what they look like and how they are bundled.wondering if these are data /digital driven gauges and that your missing an ecu connection.

I don't know specifically how the AGI boxes work, but it sounds like they are possibly not powering up or possibly not receiving the signal to send through to the gauges.
The gauges have there own power source from the dash. The AGI box only converts sends the signal to them.

someone has told me to check location on sci if they are set correctly..

has anyone heard of such affecting guages?

thanks