2G 2g coolant temp sensor issue?

[ncarson91]

So I replaced both sensors for engine coolant temp. I know they are picky and specific to which sensor has to be installed, make or model or trim ect can throw it all out of wack. Need specific sensor for mine which is a 98 GST. ANYWHO! I 300% made sure I have the correct sensor but my engine coolant temp is reading -74 degrees.
Now how is that even remotley possible? I'm at a hard confusion now, old sensor says same.

Yes I have two, thought 1 was faulty when clearly wasn't. It's reading fine through multimeter. Car starts, runs, I hit gas it commits suicide. Stalls out. Mind you I wired all my excess gauges to a switch to its own mounted terminal. Thus allowing me to switch them on and off besides logged wideband. Has its own seperate ground location so its not interfering with any sensors.

ECU is in mint shape had ECMlink check it out with the addressed 55$ inspection cost. Plz halp.

 

[99dsmer4g63]

Seems like -74 is probably the max reading for that direction. Seems like your sensor is fine and is most likely the ground or signal wiring shorting out or being open causing your -74 consistent reading.

I would do some continuity tests from the ect plug to the ecu plug.


-Daniel

 

[steve]

-74F is what the ECU reads when it's not connected.

 

[ncarson91]

-74F is what the ECU reads when it's not connected.

Ty very informative! I think I might just clip at the ecu and run the wires up myself. If it’s possible? I don’t want to f*** up a circuit. Any recommendations on how I could easily do this without beating my head against a wall

And sorry pardon my language I swear like a sailor without even realizing it sometimes my apologies

 

[steve]

The FSM and a multimeter are your friends. You can measure the resistance between the ECU pins and the sensor to make sure the wires are good and measure the resistance across the sensor to verify it's good.

In both cases the items under test should be disconnected to make sure nothing is providing a voltage that would throw your measurements off.

 

[ncarson91]

The FSM and a multimeter are your friends. You can measure the resistance between the ECU pins and the sensor to make sure the wires are good and measure the resistance across the sensor to verify it's good.

In both cases the items under test should be disconnected to make sure nothing is providing a voltage that would throw your measurements off.

Okay I’m a newbie what’s a fms and so I tried to tinker. With it and it isn’t working out so well anywho give me 2 mins I can upload datalog see if you see anything unusual or any readings that might raise another concern ect ect. My fans absolutely will not kick on for what reason I’m unsure of I bought the mishimoto slim fans that i believe are just plug and play. I mean had the same fan connectors.

Omfg… think my stupidity got the best of me….. so I have a 95 ecu eprom… so thus I’d need a 95 sensor and pigtail right? Correct me if I’m wrong

 

[Mello]

All the 2G (1995-1999) 4G63 turbo use the same Coolant Temp Sensor (p/n MD182467) for the ECU input. Tranny does not make a difference for the CTS.

 

[jed344]

Should be same coolant temp sensor I think. Sounds like you have a wiring issue.

 

[ncarson91]

Oki doki I’ll look into it more old owner had it butchered. But also my fans do not turn on at all even if I turn the fans on for like the AC and such

I know in link my internal temp also reads -74

And both 02 have strange reading where it’s 0 - so I have my wideband in front 02 and spliced it in with the front 02 pin. Power is on a inline fuse to fuse box so that turns on when ignition is turned on and ground is by radio

 

[ncarson91]

Should be same coolant temp sensor I think. Sounds like you have a wiring issue.

Welp grounded coolant temp to thermostat jousting and bam reads temp now. Now other issue is all the other codes went off

 

[99dsmer4g63]

I suggested to check your wiring about a week ago.

-Daniel

 

[steve]

Okay I’m a newbie what’s a fms and so I tried to tinker.

Factory Service Manual. Portions can be found in the site Resources

 

[ncarson91]

I suggested to check your wiring about a week ago.

-Daniel

Which I have been.