Exhaust smell on cold start

Hi,

Commonly, a sweet smell is related to engine coolant, so just make sure it isn't low. If it isn't, then I would suspect it could be related to the engine coolant temperature sensor (ECT). The ECT is what helps the computer determine the air/fuel mixture needed for the engine to run based on temperature.

If the check engine light isn't on when the engine is running, what I need you to do is get your hands on a live data scan tool. This type of scan tool will tell us what temperature signal is being sent when the engine is cold, before starting. It should be very close to the ambient temperature.

Additionally, short-term fuel trims are very informative and can be gotten via the same technique. That would tell me if the engine is running too rich or too lean. Too rich will cause a specific type of chemical odor, so that is another possibility. It could be the result of excessive fuel pressure, a bad fuel pressure regulator, or even a leaky fuel injector. If you want, here is a link that shows how to check fuel pressure. You will need a fuel pressure gauge, but most parts stores will lend one to you.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Let me know if this helps explain possible issues or if I confused you. LOL Also, let me k now if you have other questions or what I can do to help.

Take care,

Joe