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760 Cold Start issue

wyattswasey

New member
Joined
Dec 2, 2021
Location
Utah
Hey! I own a Volvo 760 and I replaced the engine coolant temperature sensor. I bought it aftermarket from IPD and after putting it in I got a CEL on plus it is having a really hard time starting cold and it is driving me insane! I got the code 1-2-3 meaning its not getting a right reading from the sensor I just replaced.

I determined that either I messed up some wiring or the new sensor was bad. I bought another sensor from IPD (same aftermarket one) and it reads differently on the dashboard but it still has the CEL on and the same cold start issue. Do you think I need to buy an OEM sensor or is it the wiring, it ran perfectly fine before replacing just ran lean because the previous sensor was making the gauge bounce around occasionally and read it was running cold all the time. Sadly I cannot put the old sensor back in because I threw it away and lost it in the garbage. Any help would be very helpful, thank you!

Here is the link to the sensor I bought:
https://www.ipdusa.com/products/165...T-Sensor-for-Volvo-Aftermarket-1346030-126002
 
You need to use an ohm meter to test the resistance of the sensor wiring at the computer connector. Disconnect the battery and remove the connector for the fuel computer and measure the resistance of the whole circuit from back probing the contacts. I forget the pin numbers to use but they are listed in a Haynes or Bentley manual.
 
What year 760? The sensor you linked "fits my 1991 740 Turbo". If you have a 1989 or older 760, I think you have the wrong sensor.

You should always confirm the circuit is good before replacing the sensor. You could be dealing with:

-spread/pushed back female electrical terminals
-oxidized crimps
-open/high resistance/shorted circuit
-failed computer
-incorrect component
-failed component


Temp gauge bouncing means bad wiring or gauge. The forward sensor in the head is for the gauge. The rearward sensor is for the computers.
 
....I bought another sensor from IPD (same aftermarket one) and it reads differently on the dashboard....

....because the previous sensor was making the gauge bounce around occasionally and read it was running cold all the time....

As ZVOLV said, the sensor you replaced does not have any influence how the gauge reads because it's a different sensor.
 
What year 760? The sensor you linked "fits my 1991 740 Turbo". If you have a 1989 or older 760, I think you have the wrong sensor.

You should always confirm the circuit is good before replacing the sensor. You could be dealing with:

-spread/pushed back female electrical terminals
-oxidized crimps
-open/high resistance/shorted circuit
-failed computer
-incorrect component
-failed component


Temp gauge bouncing means bad wiring or gauge. The forward sensor in the head is for the gauge. The rearward sensor is for the computers.

I have a 1990, so I know it fits it. I?m not good with wiring. Do you think this would be an expensive fix at a mechanic shop?
 
I would probably charge an hour to figure it out and a couple hours to fix it. Plus parts.

You need to unplug the temp sensor connector inspect the female terminals. I would then peel back the boot and inspect for any corrosion on the crimps.

I would measure the resistance on the two wires tip-to-tip. One wire goes to the fuel computer and the other to the ignition computer. I would expect about 0.4 ohms on each leg of the circuit. If that tested OK, I would probably try a $40 junkyard computer.

I would also inspect the grounds at the intake manifold. At the fuel rail bolts. And inspect the harness going thru/under the intake. I have seen crumbling wiring here.
 
What year 760? The sensor you linked "fits my 1991 740 Turbo". If you have a 1989 or older 760, I think you have the wrong sensor.

You should always confirm the circuit is good before replacing the sensor. You could be dealing with:

-spread/pushed back female electrical terminals
-oxidized crimps
-open/high resistance/shorted circuit
-failed computer
-incorrect component
-failed component


Temp gauge bouncing means bad wiring or gauge. The forward sensor in the head is for the gauge. The rearward sensor is for the computers.

This is what I was going to ask.
 
Hey! I own a Volvo 760 and I replaced the engine coolant temperature sensor. I bought it aftermarket from IPD and after putting it in I got a CEL on plus it is having a really hard time starting cold and it is driving me insane! I got the code 1-2-3 meaning its not getting a right reading from the sensor I just replaced.

I determined that either I messed up some wiring or the new sensor was bad. I bought another sensor from IPD (same aftermarket one) and it reads differently on the dashboard but it still has the CEL on and the same cold start issue. Do you think I need to buy an OEM sensor or is it the wiring, it ran perfectly fine before replacing just ran lean because the previous sensor was making the gauge bounce around occasionally and read it was running cold all the time. Sadly I cannot put the old sensor back in because I threw it away and lost it in the garbage. Any help would be very helpful, thank you!

Here is the link to the sensor I bought:
https://www.ipdusa.com/products/165...T-Sensor-for-Volvo-Aftermarket-1346030-126002

The coolant sensor would make no difference on the dashboard temperature gauge. The temperature sender would have that job.

Also the part number you linked to is for earlier than 1990 cars. Double check the terminals with an ohm meter. There should be resistance at both pins to the threads. If not then you have an ECT for LH2.2.
 
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The coolant sensor would make no difference on the dashboard temperature gauge. The temperature sender would have that job.

Also the part number you linked to is for earlier than 1990 cars. Double check the terminals with an ohm meter. There should be resistance at both pins to the threads. If not then you have an ECT for LH2.2.

I'm pretty sure that it is the correct sensor for a 1990 760 with lh2.4. if not please prove me wrong cause I recently bought the same sensor with full confidence that it was the right match!
 
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