I have a problem with my 1993 Volvo 240 wagon that will not start when it is cold, but will start with a little trouble when the outside temp is 60 or above.

It can be started when cold by spraying ether into the intake in one of the vacuum ports, it will start this way but is still hard to start.

When I do a diag test it shows the fault code of 1-2-3 which is the FI coolant sensor. I replaced te sensor and cleared

the code and the sane code in the ignition system.

I erased the codes and they just code back after the engine has been running for a while.



I have replaced the following items:

FI Coolant Sensor

Throtle Control Sensor

Spark Plugs, Rotor & Wires

Water Pump & Thermostat



Items Checked and are in working order:

Idle Control Motor

Engine Ground



I have completed a complete Diag test and everything checks okay except the IF Coolant Sensor.

The vehicle runs fine when it is warm, no starting problems at all.

Does anyone out there have any ideas of what is causing the cold start problem short of replacing the coolant sensor again?

Thanks for any help!!

 

Maybe a dumb question here but are you replacing the correct coolant sensor. There are 2 as you know and the one in the rear is the cold start one. Just asking.

 

Yes I replaced the two terminal coolant sensor…

 

Its best to test the coolant temperature ohming it out from the connector at the ECU. That way your not just checking the sensor but the sensor circuit as a whole.

 

according my notes the resistance readings of the sensor should be

4 deg F 15-16000 ohms
32 deg F 5800-6000
68 deg F 2200-2400
104 deg F 1000-1200

 

Thanks for the comments!
I will be checking the connectivity between the coolant sensor.
I ordered a new Bosch OEM coolant sensor to install, I’m thinking that I may have a defective one installed…
Made a couple of test leads today to complete the task!

 

The air mass meter has an air temp sensor in it. I have replaced a few air mass meters because of hard/no starts in cold weather due to the air temp sensor in the air mass meter not doing the right thing. Does not happen much, for I live in the south.


But a 123 code on a 240 indicates the engine temp sensor is having a problem. With the sensor itself or interference with the sensor signal. Years ago I had a car that kept producing a 123 temp code. Tried everything. Eventually replaced the spark plug wires (factory bourgicord (sp)) and the code never came back. (the car always ran perfectly, before and after the new wires) That car did not have a cold start problem (I'm in the south) just a recurring code.

 

Thanks! I did replace the spark plug wires and plugs, plug wires are the Belden from Napa, the best they had and I have a spare AMM and I’ll give that a try…
Thanks Again!

 

The 123 code is for the water temp sensor in the engine. So a replacement AMM won't change that. The car may start/run better though.

 

I'm having a similar problem with my '93 240. I'm wonderin if I got a defective temp sensor. It's showing the correct resistance across the two terminals. I'm trying to figure out if it's supposed to show resistnace across each terminal and ground. If I test from either terminal and ground it's completely open. I'm looking all ove the internet and can't find an answer. I hope someone here can help.