Gauge or Sensor?

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digginfool
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Gauge or Sensor?

Post by digginfool »

I've got an issue with my temp gauge. Ever since I installed the LSA, the temp gauge has shown a temperature far higher than what the coolant temp could possibly be. In fact, with engine cold, the gauge shows 150 degrees. When running, shows ~220-230. I know it's not that hot since I can grab the return pipe without burning my hands. I've heard that sometimes there is a mis-match between sensor and gauge that requires a resistor to correct. I've also been told that my gauge is bad. Others have insisted my sensor is bad. The sensor is what came with the motor. The gauge is by Auto Meter. Any suggestions? It doesn't really bother me too much since the computer will protect against overheat (computer has its own separate sensor) but it would be nice to know what the temp really is. It does get bothersome when people riding with me start to panic when they look at the temp gauge. :lol:
“When plunder becomes a way of life for a group of men living together in society, they create for themselves in the course of time a legal system that authorizes it and a moral code that glorifies it” - Bastiat

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scottyroll
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Re: Gauge or Sensor?

Post by scottyroll »

I've noticed a similar pattern with my LQ9 6.0 Iron block.

The gauge plugged into the head reads a mere 160-170 (cold) but the OBD2 port scanner reads 200-210 (typical running temp for LS).

I've heard aftermarket gauges will often read differently than factory OEM sensors.

If you want to know what it is really running I guess you would have to shoot it with an temp gun yet still you would see a variance from true temp.

But at the end of the day it appears you have ran your boat and found out the right numbers for normal operation.

Perhaps you would benefit from downloading the torque app to your phone and pairing it to the Bluetooth OBD2 connector like I have done.

It's always nice to have a second opinion!
:Scotty-Roll:
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1999 14ft Alumitech deckover. ZZ502. 2.37 Stinger. 4 blade WW Falcon Prop

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digginfool
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Re: Gauge or Sensor?

Post by digginfool »

scottyroll wrote:I've noticed a similar pattern with my LQ9 6.0 Iron block.

The gauge plugged into the head reads a mere 160-170 (cold) but the OBD2 port scanner reads 200-210 (typical running temp for LS).

I've heard aftermarket gauges will often read differently than factory OEM sensors.

If you want to know what it is really running I guess you would have to shoot it with an temp gun yet still you would see a variance from true temp.

But at the end of the day it appears you have ran your boat and found out the right numbers for normal operation.

Perhaps you would benefit from downloading the torque app to your phone and pairing it to the Bluetooth OBD2 connector like I have done.

It's always nice to have a second opinion!

I've used a laser thermometer on it before and it never read higher than 185, if I remember right. Haven't done it in quite a while. The only problem is the MEFI5 doesn't use OBD2; it uses a different style connector. Worth looking at, though. It would be a handy device.
“When plunder becomes a way of life for a group of men living together in society, they create for themselves in the course of time a legal system that authorizes it and a moral code that glorifies it” - Bastiat

One Eyed Gator
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Re: Gauge or Sensor?

Post by One Eyed Gator »

I wanted to use the stock location for water temp but went with a carb. So no LS wiring harness. I believe the stock sender work off 5v.

I also believe there are 2 or 3 different resistances for sending units based on max water temp.
I found this 12mm sender and it works fine with my VDO gauge.

http://shop.classicinstruments.com/sn12mm

Info blew is a direct Cut and paste form VDO Website.
Water Temperature Scale

Voltage (V): 5 323-801-005-001D
Fixed Resistor (W) 910 90C = 51.2ohms

Tabe 1
Volts: Temp C R/Ohm:
4.651937 -40 12162.35
4.659163 -35 12439.50
4.547017 -30 9134.53
4.407126 -25 6764.48
4.238825 -20 5067.60
4.040872 -15 3833.89
3.815073 -10 2929.90
3.559871 -5 2249.44
3.285057 0 1743.15
2.999182 5 1364.07
2.708536 10 1075.63
2.132865 20 676.95
1.627856 30 439.29
1.212941 40 291.46
1.041964 45 239.56
0.890869 50 197.29
0.753458 55 161.46
0.641888 60 134.03
0.556467 65 113.96
0.481853 70 97.05
0.414970 75 82.36
0.357711 80 70.12
0.307972 85 59.73
0.266383 90 51.21
0.232207 95 44.32
0.202800 100 38.47
0.177019 105 33.40
0.155039 110 29.12
0.136447 115 25.53
0.120329 120 22.44
0.106211 125 19.75
0.094022 130 17.44

Note: All Temperature sensors are designed to work with VDO gauges only. Sensors are matched to gauges according to maximum reading on dial face. All sensors are standard ground (sensor case to common ground). Please note: VDO sensors have tapered threads and DO NOT require the use of Teflon tape or pipe sealant. This will interfere with grounding causing incorrect instrument readings.

Temperature Switch Technical Specifications:

Switching Capacity: 1.2W to 3W, non-inductive for monitoring various mediums
Normally Open, Single Circuit, Standard Ground Systems
Rated Voltage: 6V to 24V
Type of Contact: SS = contact closes as temperature rises
Break Point: 5o C max. below make point
Contacting Mode: Slow-acting

Dirtman
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Re: Gauge or Sensor?

Post by Dirtman »

Diggin if you call the Autometer tech line they will most likely be able to give you the info you need. More than likely it is a sensor mismatch that is causing the problem
IO520 on a 12"6" Lazer with a 72" Q #20814
Build in progress: 14x7'9" JB w/ GSO540 &80" Razor

Waterbugger
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Re: Gauge or Sensor?

Post by Waterbugger »

Use a mechanical gauge. Go to a Mack or Freightliner dealer and you can get a mechanical gauge with up to a 12 foot long lead/sending unit for about $74. Mechanical gauges are always more accurate and if installed correctly will give longer service.

EastBay
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Re: Gauge or Sensor?

Post by EastBay »

Hello,
New to site a bit back. So where is the dianostic(sp) port for a LSA supercharged motor?
Appreciate it!
Eastbay

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