How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Matt Your Own Question
Matt, Engineer
Category: Car
Satisfied Customers: 21607
Experience:  Honors degree in Mechanical Engineering, worked 8 years as a Formula 1 engine engineer.
Type Your Car Question Here...
Matt is online now
A new question is answered every 9 seconds

Scion Tc: Scion fuel injectors

Customer Question

Scion fuel injectors stay open too long (over 100ms) flooding cold engine will not start. Getting spark. Heavy fuel odor.  Once it starts, it runs fine when reaches running temp, and will start up after two rotations of the starter, like nothing is wrong.

Submitted: 3 years ago.
Category: Car
Expert:  Matt replied 3 years ago.

this sounds like it could be incorrect fuelling due to a faulty water temp sensor. If this is the problem then the ECU will never control the 'cold start' extra fuel as it should

if the car starts OK when warm then I 'd look into changing the sensor.
Customer: replied 3 years ago.

Tested voltage at the coolant temp sensor and all is fine... Could that still be the issue?

Expert:  Matt replied 3 years ago.
Hello Rob

the temperature sensor is a resistance type that changes with temperature so its this resistance the ECU 'sees' unless you can access the temperature signal into the
ECU just measuring the feed voltage isn't going to tell you much

the symptoms you describe do match a faulty coolant sensor pretty much exactly and they're cheap so I'd say its worth trying a replacement
Customer: replied 3 years ago.

Is that the sensor on the water inlet neck on the block? That's pretty much what I have it narrowed down to.


Expert:  Matt replied 3 years ago.
Hello Rob

The coolant temp sensor is on the side of the cylinder head