Stalling On Cold Start After Winter Storage

[Jon_Purdy]

Hello everyone. Need help diagnosing a problem. I did indeed do a brief search but didn't find anything that resembled what I am seeing.

Took the car out of winter storage and on a cold start, the engine revs to about 1000 then drops to 500. It will eventually stall if I don't apply some throttle. Whats also concerning is that the radiator fan does not come on when the engine temp get to the low speed fan number. Once warmed up, I can shut the car off, wait a little bit, then restart it without any rough idle or stalling.

To me, it sounds like its temperature related. What should I be looking at?

Thanks in advance for your help,
Jonathan

 

[Dino Dino Bambino]

It sounds like the engine is running lean upon a cold start and not getting the enrichment that it needs. The fact that your cooling fan also isn't coming on when the engine gets up to temperature tells me that the likely culprit is a bad ECT sensor. If the fan comes on when you unplug the ECT sensor and when you use the AC, this will confirm my diagnosis.

 

[GriffX]

I guess it is not your first winter storage, did you disconnect the battery?
Are you able to write a datalog? If yes, I would disconnect the battery to reset the idle set-up, connect the Xcalibrator to write a datalog (https://www.bamaperformance.com/article?id=201797909&cat_id=200199175), do the idle learn procedure from the Mustang manual and watch the temperatures. Oil and water temps are calculated from the cylinder head sensor and not measured.

 

[Jon_Purdy]

Thank you for the quick reply Dino. The act sensor is located under the intake manifold, correct?

 

[Jon_Purdy]

I guess it is not your first winter storage, did you disconnect the battery?
Are you able to write a datalog? If yes, I would disconnect the battery to reset the idle set-up, connect the Xcalibrator to write a datalog (https://www.bamaperformance.com/article?id=201797909&cat_id=200199175), do the idle learn procedure from the Mustang manual and watch the temperatures. Oil and water temps are calculated from the cylinder head sensor and not measured.

The battery was actually out of the car on a little stand I made to keep it off the cold floor, was doing headers and other things. I have an old X3 handheld, can I use that to adjust the idle? Its concerning that the radiator fan is not coming on which Dino thinks indicates a bad ect sensor. Is there a way to test the ect sensor without taking the blower and intake manifold off?

 

[Jon_Purdy]

It sounds like the engine is running lean upon a cold start and not getting the enrichment that it needs. The fact that your cooling fan also isn't coming on when the engine gets up to temperature tells me that the likely culprit is a bad ECT sensor. If the fan comes on when you unplug the ECT sensor and when you use the AC, this will confirm my diagnosis.

I have an Aeroforce Interceptor gauge and just realized that it can read cylinder head temps. Correct me if I'm wrong but if I am getting a reading that means the ect is working properly right?

 

[GriffX]

The idle is self learning, the procedure is in the Mustang manual. I would just watch the temps, if they are plausible the sensor should work, but it still can be off. (I had once a coolant sensor on a Mercedes that was 10 °C off, was way too rich running in the morning)