Cold Issues

[JEWC_Motorsports]

Car is a 2012 with 40k miles and has a built engine and on E85. When the temps outside or in the 50's or colder the car will not come up to temp. I thought it was the thermostat because i had a slightly cooler t-stat in it and thought either it stayed open too long or was stuck. Replaced with a new ford t-stat and still have the issue. When its warmer it operates fine. The issue is that after driving it a distance the check engine light comes on and the car is down on power, my guess is its running too rich. Its happened a couple times so i just quit driving it for now until i can figure out why it just started doing this. The codes are for the engine not reaching operating temp, didn't even know that was a thing. I have not found anything online nor have a couple friends that are master ford techs so here i am, asking for advice.

 

[Dino Dino Bambino]

Did you test each thermostat in a pan of hot water to see if they open at the appropriate temperature? If you have an infrared thermometer, it would be easy to find out. It wouldn't be unusual for a new thermostat to be duff right out of the box.

 

[JEWC_Motorsports]

Yes both were tested and both opened at the correct temps.

 

[RED09GT]

What coolant temperature is it getting to on a scan tool?
Are the codes O2 sensor codes? Do you have longtubes?

 

[JEWC_Motorsports]

What coolant temperature is it getting to on a scan tool?
Are the codes O2 sensor codes? Do you have longtubes?

It gets to 135 degrees (didnt use a scantool, used a infared thermometer), longtubes yes, not o2 codes.

 

[RED09GT]

I would data log it to see if the CHT sensor has an issue.

The O2 sensor data will let you know if it is running in open loop mode as well.

Is it misfiring?

 

[JEWC_Motorsports]

I would data log it to see if the CHT sensor has an issue.

The O2 sensor data will let you know if it is running in open loop mode as well.

Is it misfiring?

No codes for any misfires. Im thinking its the cht sensor. Why couldn't Ford just use a sending unit...

 

[Dino Dino Bambino]

Yes both were tested and both opened at the correct temps.

OK. Then it's possible that the CHT sensor is feeding false information to the ECU that the cylinder head temperature is lower than it actually is. A datalog would either confirm this or rule it out. The datalog would also show if the upstream O2 sensor voltages remain close to 1.0v, indicating that the engine's running rich and the ECU is still in open loop.

 

[Sky Render]

What radiator are you running? Are you using antifreeze or straight water? Can you watch the AFR while you drive around?

 

[JEWC_Motorsports]

What radiator are you running? Are you using antifreeze or straight water? Can you watch the AFR while you drive around?

Stock radiator, ford antifreeze, and afr's were around 11.3 while cruising. When i drove it on a warmer day they were 14.1ish. IIRC my afr at wot is in the 11 range lol.

 

[Sky Render]

Oh I forgot you're on ethanol, which has a different AFR than gas.

 

[JEWC_Motorsports]

Pulled and tested the cht sensor this weekend, its dead. No change in resistance at any temp. I have a new ordered and hopefully this fixes my issues.

 

[Sky Render]

Where is that sensor located?

 

[JEWC_Motorsports]

Back side of the passenger head.