Hey guys new member here and proud owner of a Volvo s70 2.0 Turbo 226HP

Need some help though
On cold starts i am having issues
The engine will fire right up no issue but i have to accelerate straight away and hold it at 2000 rpm and even then sometimes it stals only by the third time i start it in a row it will run a bit rough and then after few seconds runs smooth no problem.
what could the problem be? Thanks guys

 

It could be the coolant temperature sensor. Next time you first start it after it has sat overnight, look at the temperature gauge. If it reads warm right away, that is a good sign that it is a bad sensor. The coolant temperature sensor sends a signal to the computer to adjust the fuel ratio based on actual engine temperature, as well as sending the temperature signal to the dash gauge. If the sensor is bad and thinks the engine is warm, it will send that signal to the gauge and the computer. The computer will then think the cold engine is actually warm and reduce the amount of fuel. Less fuel to a cold engine, and it will run rough or stall. Once the engine warms up it will be given the correct fuel ratio and will run fine. Hope this helps!

 

Thanks for the responses unfortunally my temperature gauge is in the cold position when this happens and goes up accordingly. :/

 

Still could be a bad temperature sensor. Not all of them show warm on the gauge right away, some do, but not all. Since it runs fine, when warm, I would still look at changing the sensor. Last time I replaced one it was about $20 and a half hour of work. The sensor is usually located right under the thermostat in the same housing. Disconnect one plug and unscrew. You can google it for your specific model and engine. Also is the check engine light on> If so, read the codes as that will also be a big help.

 

+1 on the temp sensor as the best starting point. You can measure the resistance of the coolant temp sensor to see if its ok - just unplug at the connector and test cold with a VOM. You can google for a resistance at temperature chart but as a general rule of thumb, resistance goes down as the temp goes up. For a Volvo, I'd expect 3500 ohms at 70F , 7500 ohms at 40F - even higher as it gets older... Other possible cold start causes are fuel pressure (pressure sensor/pressure regulator/fuel pump or intake air leaks - including a gummed up idle air valve, vacuum lines etc. As noted cold engines want a richer mix so anything that can mess with that is a suspect.

 

Perfect thanks guys for the help ill go ahead and just replace it, im flushing cooling system at moment so ill change thermostat and sensor
Thanks for the help ill give an update once its done

 

For future reference, you can see what temperature the engine thinks it is using a scan tool. It's one of the easier things to verify. The engine doesn't know it's wrong but of course you would.

 

Definitely let us know. If it is still acting up we will help you pin it down.

 

No updates?