Cold start issues

[Salt01]

I have an 2001 Ford Ranger. I bought it used from another person a few years ago. For the last couple years I have had an issue with it starting or rather not starting when the weather starts getting cold. Many things have already been replaced on this truck since I bought it about five years ago. The spark plugs, plug wires, ignition coil, air filter, oil filter, temp gauge and housing all have been replaced. The fuel pressure is excellent. I have read that the cold start valve could possibly be the issue. Heet treatment and ether shots have not worked. Although when the driver side of the engine is warmed up with a heat gun, the truck will start right up. However that's only a temporary fix since I do not have access to an electrical outlet on the outside of my place of work.

 

[RonD]

4.0l SOHC

When it does start cold what RPM does it idle at?
Should be above 1,000, the colder it is the higher the idle should be.
This high idle is set by computer using the IAC Valve, but based on engine temp read from ECT sensor.

On the thermostat housing there are TWO temp reading devices.
A temp SENDER, it is used for the dash board gauge only
And ECT sensor, it is used for the computer only

The ECT sensor is one of the first things the computer reads when you turn on the key.
This tells computer if engine is stone cold or already warmed up.
If cold computer runs in "Choke mode", so rich fuel mix, high idle and advanced spark timing.
And like in the old carb days, it is VERY HARD to start a cold engine without choking it.
ECT will have Light green wire and a Grey wire.
The ECT and sender are not interchangeable, and parts store guys often think they are.

Did you change that sensor?

Can you get an OBDII reader?
You can read the ECT temp with one of these to see what cold temp is.
Bluetooth OBD II reader works with a smartphone as the display and runs about $40, and works on ALL cars and trucks, 1996 and up.
Not a bad investment because you can watch real time data from computer while parked or driving.

 

[Salt01]

4.0l SOHC

When it does start cold what RPM does it idle at?
Should be above 1,000, the colder it is the higher the idle should be.
This high idle is set by computer using the IAC Valve, but based on engine temp read from ECT sensor.

On the thermostat housing there are TWO temp reading devices.
A temp SENDER, it is used for the dash board gauge only
And ECT sensor, it is used for the computer only

The ECT sensor is one of the first things the computer reads when you turn on the key.
This tells computer if engine is stone cold or already warmed up.
If cold computer runs in "Choke mode", so rich fuel mix, high idle and advanced spark timing.
And like in the old carb days, it is VERY HARD to start a cold engine without choking it.
ECT will have Light green wire and a Grey wire.
The ECT and sender are not interchangeable, and parts store guys often think they are.

Did you change that sensor?

Can you get an OBDII reader?
You can read the ECT temp with one of these to see what cold temp is.
Bluetooth OBD II reader works with a smartphone as the display and runs about $40, and works on ALL cars and trucks, 1996 and up.
Not a bad investment because you can watch real time data from computer while parked or driving.

My father was the one who checked my truck, thus how I found out it wouldn't start. I do not know what RPM ran up to. To my knowledge when the thermostat and housing was replaced, both sensors were replaced as well. I will double check, if not that very well may be the problem.

At the current moment I will be purchasing an engine block heater for my truck and see if that helps for the time being, since blowing a heat gun on the engine block helped my truck to start.

 

[RonD]

??
When you start the truck, after using heat gun, what RPM is it idling at?

Also turn key on and count to 3, then turn key off
Repeat this 3 times then try to start the truck.

What is the coldest outside temp in your area now?

 

[Salt01]

??
When you start the truck, after using heat gun, what RPM is it idling at?

Also turn key on and count to 3, then turn key off
Repeat this 3 times then try to start the truck.

What is the coldest outside temp in your area now?

It idles at about 1200 RPM's which is about where it idles all he time after start, it rarely if at goes under 1000 RPM's.

I did just that this morning as well as give the gas pedal a few good pumps and the truck started right up. The coldest temp we've had so far was around twenty degrees with a ten to twelve windchill. I picked up my new heater today I just need to get access to a garage to put it in.

 

[RonD]

Your problem is that you are losing fuel pressure when fuel pump is off, not cold weather.
You notice it more when it is cold because it takes more fuel to start cold engine.

Ford has a safety feature that prevents fuel pump from running when engine is below 400rpms, so fuel doesn't pump out of broken fuel line or ??? after engine stalls.

When you first turn on the key the computer runs the fuel pump for 2 seconds, it "primes" the system, fuel pump won't come on again until engine starts, this 2 second run time adds about 10-15psi of pressure.
Your system needs 60 to 70psi of pressure to work well.

There is a check valve in the fuel pump, basically a flap that lets fuel flow out but not back in, and when you shut off the engine/pump the fuel pressure should hold above 50psi for many months because check valve is closed.
And when you start it again the fuel pump runs for 2 seconds and back up to 60-65psi for starting.

If this check valve fails or leaks, you will lose fuel pressure over a shorter time, say overnight.

Turning the key on and off 3 times makes for 30-45psi pressure which is enough to start engine and get RPMs up so pump is on full time and pressure is back up above 60psi.

Just to confirm this may be happening, there is a Schrader valve on the fuel rail, looks like a tire's air valve, same kind of cap on it, and same kind of pin in the center to release the pressure.
After starting engine shut it off, still cold, then test if there is pressure in the rail, be careful 60psi will give a good squirt of fuel.
Go ahead and drive it.
Now the next morning or after it sits for a few hours, before trying to start it, test for pressure again.

You can also get/rent a fuel pressure gauge

Unfortunately check valve is part of the fuel pump, so.....................


Just FYI, pumping the gas pedal on a fuel injected engine doesn't do anything, there is no accelerator pump to squirt extra gas in like a Carb had.
Computer knows the best way to start engine, don't bother with gas pedal.

Now if you hold the gas pedal down all the way and then try to start engine, it won't start.
Gas pedal down all the way at 0 RPMs tells computer to turn off fuel injectors, it is a method/computer program to clear a flooded engine.


If you have a manual transmission engine should be idling at 600-650rpm after engine is warmed up, 750-800rpm for automatic trans.

If idle really never gets below 1,000rpms then there is another issue not related to the fuel pressure problem

 

[kimcrwbr1]

Get a gasket for the throttle body and pull it apart and clean everything good with carb cleaner as well as the plunger on the IAC motor. Clean the MAF senser with electrical cleaner or rubbing alcohol do not use harsh chemicals. You didnt mention the PCV valve probably the most neglected part of preventive maint. Change the PCV with spark plugs or oil changes. You cannot properly clean it just replace it regularly.

 

[Salt01]

Your problem is that you are losing fuel pressure when fuel pump is off, not cold weather.
You notice it more when it is cold because it takes more fuel to start cold engine.

Ford has a safety feature that prevents fuel pump from running when engine is below 400rpms, so fuel doesn't pump out of broken fuel line or ??? after engine stalls.

When you first turn on the key the computer runs the fuel pump for 2 seconds, it "primes" the system, fuel pump won't come on again until engine starts, this 2 second run time adds about 10-15psi of pressure.
Your system needs 60 to 70psi of pressure to work well.

There is a check valve in the fuel pump, basically a flap that lets fuel flow out but not back in, and when you shut off the engine/pump the fuel pressure should hold above 50psi for many months because check valve is closed.
And when you start it again the fuel pump runs for 2 seconds and back up to 60-65psi for starting.

If this check valve fails or leaks, you will lose fuel pressure over a shorter time, say overnight.

Turning the key on and off 3 times makes for 30-45psi pressure which is enough to start engine and get RPMs up so pump is on full time and pressure is back up above 60psi.

Just to confirm this may be happening, there is a Schrader valve on the fuel rail, looks like a tire's air valve, same kind of cap on it, and same kind of pin in the center to release the pressure.
After starting engine shut it off, still cold, then test if there is pressure in the rail, be careful 60psi will give a good squirt of fuel.
Go ahead and drive it.
Now the next morning or after it sits for a few hours, before trying to start it, test for pressure again.

You can also get/rent a fuel pressure gauge

Unfortunately check valve is part of the fuel pump, so.....................


Just FYI, pumping the gas pedal on a fuel injected engine doesn't do anything, there is no accelerator pump to squirt extra gas in like a Carb had.
Computer knows the best way to start engine, don't bother with gas pedal.

Now if you hold the gas pedal down all the way and then try to start engine, it won't start.
Gas pedal down all the way at 0 RPMs tells computer to turn off fuel injectors, it is a method/computer program to clear a flooded engine.


If you have a manual transmission engine should be idling at 600-650rpm after engine is warmed up, 750-800rpm for automatic trans.

If idle really never gets below 1,000rpms then there is another issue not related to the fuel pressure problem

That's great information! Thank you RonD. Guess I still need to learn a thing or two, heh my father could learn some more too as well. Quick thing, I have a check engine light on and it always reads that there is a small evap leak. Could that cause the problem I am having now?

 

[RonD]

Need exact code, but no, EVAP system is for the gas tank, it keeps negative pressure in the gas tank so gas vapors are not vented as "air pollution".
Basically there is a Charcoal Filter canister hooked to engine vacuum.
Then a hose from this canister to the gas tank.
Gas cap seals the gas tank.
When engine is running Computer adds vacuum pressure to canister and then monitors pressure in the gas tank, or on the hose going to gas tank.

EVAP system is why you hear a "whoossshing" noise when you open the gas cap to fill up, or you may not hear it any more in your case, lol.


But EVAP issue could be a vacuum leak in that system and that can cause high idle