Engine dies when cold

[urmull]

Hi there.

I have a slight problem on my 91.

Whenever I start it in the morning and the teamperature is hotter than it has been in the night the engine dies when I put some strain on it, i.e. when I put it in gear, when I back out of the parking space. This then stops after half a mile or so when the temp gauge rises.

Is there something I should worry about or is this something I live with? I could let the engine run for 10 mins or so every morning and heat up.

Explorer greatings from Iceland.

 

[nitro71]

I've noticed the dying issue on startup and reverse on my 5 spd manual in the AM also. I attribute it more to a tuning issue that needs to be pursued. I have a post in the 91-94 forum about power and there were some suggestions for what to trouble shoot. Very first thing is to resolve any check engine lights. Pull a spark plug and check it. Check your plug wires. If they are OEM replace them. Replace the air filter if it's dirty. General tune up first.

 

[MrQ]

Hmm, you say when the temp gauge rises? Can you give me a letter position on the temp? I.E. N-O-R-M-A-L. Also what do you mean hotter. Can you give us some temp degrees?

 

[dogfriend]

I would check the ECT (engine coolant temperature) sensor which provides information to the PCM (computer). This is not the same sensor that provides the gauge info, it is a separate sensor.

 

[tomjt714]

Try cleaning the MAF sensor probes. Worked wonders for my '94 4.0L. There is a link to an excellent document pg. #8, 'List of useful Explorer & Ranger "How To" threads detailing the procedure. I have it saved on my computer in .doc format, so it would probably be much easier to find the link and save it yourself. Hope it helps.

 

[fixxxer]

The IAC valve, MAF, ECT and IAT could all cause this issue, they are all sensors that in some way provide a signal or information about intake manifold air flow, air temp. and coolant temp. to the PCM which uses this information to adjust the amount of fuel, duration of fuel injector pulses, fuel injector timing and spark advance.

The following information is borrowed from www.freeautomechanic.com without permission. This article was published in reference to 1994-1998 Mustangs but should be very similar to the Explorer/Ranger 4.0 V6.

"All Sequential Fuel Injection (SFI) systems use the EEC system. The heart of the EEC system is a microprocessor called the Powertrain Control Module (PCM). The PCM receives data from a number of sensors and other electronic components (switches, relays, etc.). Based on information received and information programmed in the PCM's memory, it generates output signals to control various relays, solenoids and other actuators. The PCM in the EEC system has calibration modules located inside the assembly that contain calibration specifications for optimizing emissions, fuel economy and driveability. The calibration module is called a PROM.

The following are the electronic engine controls used by 1994–98 Mustangs:

* Powertrain Control Module (PCM)
* Throttle Position (TP) sensor
* Mass Air Flow (MAF) sensor Intake Air Temperature (IAT) sensor
* Idle Air Control (IAC) valve
* Engine Coolant Temperature (ECT) sensor
* Heated Oxygen Sensor (HO2S)
* Camshaft Position (CMP) sensor
* Knock Sensor (KS)
* Vehicle Speed Sensor (VSS)
* Crankshaft Position (CKP) sensor

The MAF sensor (a potentiometer) senses the quantity of airflow in the engine's air induction system and generates a voltage signal that varies with the amount of air drawn into the engine. The IAT sensor (a sensor in the area of the MAF sensor) measures the temperature of the incoming air and transmits a corresponding electrical signal. Another temperature sensor (the ECT sensor) inserted in the engine coolant tells if the engine is cold or warmed up. The TP sensor, a switch that senses throttle plate position, produces electrical signals that tell the PCM when the throttle is closed or wide open. A special probe (the HO2S) in the exhaust manifold measures the amount of oxygen in the exhaust gas, which is in indication of combustion efficiency, and sends a signal to the PCM. The sixth signal, camshaft position information, is transmitted by the CMP sensor, installed in place of the distributor (except 5.0L engines), or integral with the distributor (5.0L engines).

The EEC microcomputer circuit processes the input signals and produces output control signals to the fuel injectors to regulate fuel discharged to the injectors. It also adjusts ignition spark timing to provide the best balance between driveability and economy, and controls the IAC valve to maintain the proper idle speed."

 

[jklee3]

Explorer ECT sensor problem

Hi. I'm new here and my 95 Explorer Check Engine light came on few times, so scanned with OBD-ll. It says ECT sensor. Following Haynes manual I checked the registance It read 290 ohms which is way too low. It supposed to be about 40k. I then checked the supply voltage. Its zero. How do I trace the line? Irs so crammped in there. Also My sensor has only one leg, not two lines going to the ECT sensor terminal. What next? Since the car runs OK, do I need to fix it? Thanks for your advice. James Lee in Tallahassee, Florida

 

[dogfriend]

. Also My sensor has only one leg, not two lines going to the ECT sensor terminal.

There are two sensors: the sensor with only one wire is for the gauge in the instrument panel; the one with two wires is the ECT that supplies a signal to the PCM (computer).