My AutoMeter Pyrometer “3344” had intermitted malfunction issues. The needle would just bounce around for no apparent reason. Anything would set it off… Lights, brakes, single lights, hazards… even if it was raining!
This seems to be a common theme for Autometer Pryo gauges. You can read it all over the net. It can happen to any vehicle.
My HJ60 (with a 12HT swap) is 24V, the gauges are 12V.
I ran the gauge through a DC512 Cellstar 24V-12V DC to DC convertor.
I wired the Converter directly to the batteries. Pos and Neg side of the batteries.
I ran the Pyro Gauge power wires directly to the converters Pos and Neg binding post.
Ran a 4/0 cable from the engine block to the neg side of the battery.
Still have interment issues with the gauge.
How I solved the issue.
Some say the gauge or the probe is faultily and to just get a new one… but before I do I need to be assured it wasn’t the power source.
I plugged the gauge into a 9V battery and drove it around a bit and it worked perfectly!
I determined it had to be a voltage or ground issue. The HJ60 with 12V headlights are notorious for having ground loops.
This lead me to believe that there is a connection issue. I installed larger gauge power and ground for the convertor.
I took the pos right to the B+ (24v) battery terminal.
I relocated the ground wire from the convertor to the bolt/bracket that supports the intake runner to the exhaust manifold… which is basically 2” away from the Pyro Probe. (This is closest I could make the connection without the wore getting too hot from the exhaust.)
That did the trick!
I guess the Pyro Probe and Gauge ground need to be at the exact ground potential. I’m going to believe that the exhaust manifold has a poor ground connection to the rest of the engine.
Mike
This seems to be a common theme for Autometer Pryo gauges. You can read it all over the net. It can happen to any vehicle.
My HJ60 (with a 12HT swap) is 24V, the gauges are 12V.
I ran the gauge through a DC512 Cellstar 24V-12V DC to DC convertor.
I wired the Converter directly to the batteries. Pos and Neg side of the batteries.
I ran the Pyro Gauge power wires directly to the converters Pos and Neg binding post.
Ran a 4/0 cable from the engine block to the neg side of the battery.
Still have interment issues with the gauge.
How I solved the issue.
Some say the gauge or the probe is faultily and to just get a new one… but before I do I need to be assured it wasn’t the power source.
I plugged the gauge into a 9V battery and drove it around a bit and it worked perfectly!
I determined it had to be a voltage or ground issue. The HJ60 with 12V headlights are notorious for having ground loops.
This lead me to believe that there is a connection issue. I installed larger gauge power and ground for the convertor.
I took the pos right to the B+ (24v) battery terminal.
I relocated the ground wire from the convertor to the bolt/bracket that supports the intake runner to the exhaust manifold… which is basically 2” away from the Pyro Probe. (This is closest I could make the connection without the wore getting too hot from the exhaust.)
That did the trick!
I guess the Pyro Probe and Gauge ground need to be at the exact ground potential. I’m going to believe that the exhaust manifold has a poor ground connection to the rest of the engine.
Mike
