1993 sts won't fire below 32 degees

[vantage1112]

does this 4.6 have any type of control sensor on the intake which could prevent the engine from firing in cold tempertures.
It starts and runs above 36 degrees

[JimLucky]

Air charge temperature sensor.Price $27-45.($43.99 Autozone)

Location : Under hood, driver side, upper engine, mounted on end of intake manifold

There is another air temp sensor but that one just tell your climate control computer the temp outside the car for your climate control display.Its a Ambient Air Temperature Sensor.


http://www.autozone.com/R,APP223173/...ductDetail.htm

[Ranger]

Start by pulling the DTC's.

[Gearheaad43]

One thing to check would be water/ice in the fuel line. Water freezes and fuel can not get to the injectors... If you suspect this, take a hair dryer and heat up the fuel rails a bit to melt any ice that might be blocking the FUEL RAIL PASSAGE. Prevent this by adding gas line dryer to your gas tank on your next fill up.

[vantage1112]

the sensor you are referring to, will it prevent the car from firing if it is bad?

[vantage1112]

Ranger,
I have had the car in for service to three shops each time they claimed to have the problem fixed, however my car sets outside and will start if the temp is above 35-36 degrees.
the shops changed the crankshaft sensor, cleaned the throttlrbody,replaced the idle speed control valve, put 2 cans of heat in the gas tank,changed the ignition switch.
I can park it in the garage and it will start every time. one day i parked inside then drove down the road about three miles and it stopped and would not start. the next day i i went to tow the car home but it was 38 degrees out and it started and ran fine.

[Gearheaad43]

Sounds like ice forming in the fuel line.... Where, is anybody's guess..

[Ranger]

I think Gearhead is on to something. Do you have 10% ethanol where you are?

[vantage1112]

I live in northern indiana and usually burn shell only

[Ranger]

If it is 10% ethanol, that should absorb any moisture in the system.

[vantage1112]

Ranger,
It was 55 degrees on Monday here so i took a chance and drove the car. it ran fine all day i made several stops and starts with no problems. By 5:00 pm
the temp dropped to 35 degrees and the car would not start.
Once again i am asking is the sensor on the intake capable of preventing the car from firing if it is bad or out of adjustment?
vantage

[Ranger]

I don't think so.

[vantage1112]

do you have any thoughts besides the water in the lines idea.
I have put a total of 3 cans of heat in the tank plus lucas gas treatment.

[Ranger]

It ain't water in the lines. Not at 35 degrees with 3 cans of heat. I'm not sure what to say anymore.

[kdcing]

Originally Posted by vantage1112

Ranger,
Once again i am asking is the sensor on the intake capable of preventing the car from firing if it is bad or out of adjustment?

I do not believe that a bad Intake Air Temp Sensor would prevent the engine from firing, but the wiring diagram shows that its ground wire is tied in w/ the ground from the Throttle Position Sensor. If the ground is bad at low temps then both the Intake Air Temp Sensor and the TPS would be taken out.

To prove things out try the following:

• At ambient temps when the engine will run, start the engine. Stop the engine. Unplug the Intake Air Temp Sensor. Attempt to start the engine. If it starts w/ the IATS unplugged, then the IATS is likely not the issue.
  
• Something is causing the engine not to start at low ambient temperatures. Let's go back to the basics. Check for codes. (Press OFF and WARMER on the HVAC readout for 2-4 seconds.)
  
• For what its worth, my '93 Eldorado 4.9L had a no fire/no start condition a few weeks ago at 0 degree temps. 2 days later when it finally got above 25F, the engine started right up. I suspect the fuel lines were frozen. My 4.9L is almost always fed from the Mobile pumps in Hammond. Perhaps there is something about the gas in northern Indiana.