Here's my problem. Installed a set of speco gauges on my ca18det. I am using the stock ca18 water temp sender for the dash to run my gauge. It's mot even close to to accurate. I couldn't use the one speco supplied as it was the wrong thread. Please help... Also ca18 oil sender same problem couldn't fit the speco supplied sender cause its to big... Reads max scale when engine off... I assume the stock one is a switch not a transmitter...

Stock ca temp sender is 300ohm and speco is 1500

Get an adaptor to suit both threads, you need to run the correct senders as some are earth based some arnt

You actually thought they would work off the stock senders?

Get a t piece for the oil pressure senders and put the water temp in the bottom radiator hose joining piece that circulates water down to the back of the engine.
will require some brazing skills

For oil pressure/temp guages you generally need to install a sandwich plate under the oil filter. The water temp also shouldnt be touched as it might impact the ECU's input for temp. For water there are sections you install into radiator hose to mount the temp sender.

Ca manifold has 2 water temp senders...
One has injector style plug which goes to ecu. Other is smaller spade style connection which only feeds dash. I guess I will have to look into t piece for oil pressure