LB7: temp gauge sensor install?

[THEFERMANATOR]

Lol ferm, you told us in another thread that fan won't fully lock or kick in till above the temp your having issues at..... And your only having issues between those temps..... You really think they don't coincide? I didn't say the fan won't work at slow speed, all I said is it was a fan issue. To be specific, it's not kicking on earlier enough.

My fan doesn't start to kick in until around 220 or so, and I have yet to get it hot enough to fully lock it in. Regardless this is not a fan issue. This is a heat soak issue, and adding in a heater control valve can reduce heat soak through the HVAC box(espescially when it is a known poor HVAC design from the factory, and GM added in a heater control valve to single air BURBS because of it).

 

[Chevy1925]

Alrighty!

 

[THEFERMANATOR]

For those who may be in a simliar situation, I found a MUCH simpler sloution to this problem. GM used a dual purpose sender/sensor for the mid 90's in several of there engines(primarily the LT1/4's). It's a CTS that uses a 3 wire plug, 2 wires are standard GM CTS, and then the center one is a standard GM 1365-55 ohm coolant temp sender output. So if you have a GM with a late model gauge in it, and need to add a dedicated gauge sender, swap over to an 10096181 CTS, and put on a 12102748 pigtail, then hook to the 2 wires back in for your CTS, and use the center one for your stock temp gauge, and you're good to go. Going to be ordering mine here today to get this done, and then install a heater control valve. This having the A/C cycle to keep from freezing, and only 50 degree dash vent air sucks.

 

[duratothemax]

Great idea Ferm!! This will be great for standalone setups where guys want to run aftermarket gauges.

Ben

 

[duratothemax]

For those who may be in a simliar situation, I found a MUCH simpler sloution to this problem. GM used a dual purpose sender/sensor for the mid 90's in several of there engines(primarily the LT1/4's). It's a CTS that uses a 3 wire plug, 2 wires are standard GM CTS, and then the center one is a standard GM 1365-55 ohm coolant temp sender output. So if you have a GM with a late model gauge in it, and need to add a dedicated gauge sender, swap over to an 10096181 CTS, and put on a 12102748 pigtail, then hook to the 2 wires back in for your CTS, and use the center one for your stock temp gauge, and you're good to go. Going to be ordering mine here today to get this done, and then install a heater control valve. This having the A/C cycle to keep from freezing, and only 50 degree dash vent air sucks.

One thing I just thought of...have you actually tried this yet?

Since the Duramax ECM uses a "dual range" setup for the coolant temp sensor where it switches bias resistor values in the ECM around ~140*...would that cause issues for your dash gauge?

 

[THEFERMANATOR]

One thing I just thought of...have you actually tried this yet?

Since the Duramax ECM uses a "dual range" setup for the coolant temp sensor where it switches bias resistor values in the ECM around ~140*...would that cause issues for your dash gauge?

I haven't actually tried it yet. It is basically a sensor and sender in one from what I can find. Others who have swapped in late model LT1/4's that used the same CTS as the DURAMAX have swapped these in to allow the use of there factory gauge. Aftermarket LT1/4 cylinder heads from what I have found don't have the pipe tap port in the drivers head for the gauge sender, so this sender/sensor is the answer to make there gauge work again without drilling and tapping there heads. It was also used on many V-6 cars. Will find out soon how it works, hoping for the best here.

 

[THEFERMANATOR]

The LS swap guys are using the same sender/sensor for there swaps, but it uses a M12X1.5 instead of 3/8" pipe. The videos a bit drawn out, but the 1st one he shows is the one I referneced to use in the DURAMAX, and as he shows at the end it does make the GMT-400 gauge work. The one the LS guys are using is 12551708, and was only used in 98 for the CAMARO/FIREBIRD with the 1st gen LS engine. The same 98 CAMARO/FIREBIRD with a V6 uses the 10096181 as it is 3/8" pipe instead of the M12X1.5. It will be nice to do away with the brass block in the heater line, and get a heater control valve in like GM did from the factory on gassers and diesels with rear heat and no rear air.

https://www.youtube.com/watch?v=1Ew1YSm8jd0

 

[THEFERMANATOR]

Ok, the 3 wire CTS I referenced does work. The temp gauge reads about a needles width lower than the stock sender, but it does work. I hooked up the V2 and also made sure the ECM was seeing the correct temps from the CTS which it was. So this sender does work, and gives you a sender without drilling any holes to add one.

 

[duratothemax]

Ok, the 3 wire CTS I referenced does work. The temp gauge reads about a needles width lower than the stock sender, but it does work. I hooked up the V2 and also made sure the ECM was seeing the correct temps from the CTS which it was. So this sender does work, and gives you a sender without drilling any holes to add one.

Great info! Thanks again for the tip on this. :thumb:

If people are interested, I can make plug-and-play adapter harnesses that have the 3-wire plug on one end, and the mating connector for the stock Duramax coolant temp sensor on the other end...that way you dont have to cut/splice wires.

Ben

 

[Wingnutt]

Great info! Thanks again for the tip on this. :thumb:

If people are interested, I can make plug-and-play adapter harnesses that have the 3-wire plug on one end, and the mating connector for the stock Duramax coolant temp sensor on the other end...that way you dont have to cut/splice wires.

Ben

I know I'm resurrecting a very old thread, however I'm getting ready to install an aftermarket ECT gauge on my '07 Classic with the LBZ and would be very interested in either the harness or at a minimum a schematic of what wires go back into the factory harness for the ECU and which one I can use for my aftermarket electric gauge.

TIA!

 

[Wingnutt]

In case anybody was following this. I ordered a Max Tow temperature gauge from a vendor and attempted an install. Like some others, I wanted a stand alone gauge for personal reasons. Let me tell ya something; installing an aftermarket anything on a newer vehicle is a major pain!

After some thought I abounded the idea of an upper radiator sensor location, because that would only be accurate once the thermostats were open. Next I thought about putting in a tee where the stock sensor is located. So I ordered one and ooops, not enough room for both sensors. Lastly after studying the coolant flow, I ordered a heater hose adapter and installed it in-line of the heater hose coming out of the EGR cooler. Originally, I wanted to install it closer to the thermostat housing for a more accurate reading, but instead of a hose there, there's a tube coming out of the thermostat housing there. Additionally, the hose from the cooling tube to the EGR cooler isn't long enough for the sensor, so the adapter went into the hose coming out of the EGR cooler and into the heater core. This is the bypass coolant path which is upstream of the thermostats, so it will give accurate readings.

Also it took several hours to run the wiring and install the pod for the gauge. After forcing my hands into areas under the dash that the engineers from GM never designed human hands to go, they now look like I tried to give a cat a bath!

However after about 8 hours of work everything was hooked up and ready to test. I compared the gauge readings against my hand held scanner and it was consistently within 5 degrees (cooler) of what the scanner was showing. I will attribute this to the fact that my EGR is blocked off and the EGR cooler isn't trying to remove heat from the exhaust routed into the cooler.

So if anybody is thinking about going with a stand alone gauge instead of a Scan Gauge or a gauge the plugs into the OBD port, it is doable, but a little bit of a pain.