Cold Starting Issues.

TiredRetired · Jan 12, 2018

Yesterday, for the first time I noticed my 05 FX/4 4.0 starting a little harder then normal after being off for at least a half an hour or more. Temp around 30F.

A search here had a few recommendations, specifically to clean the ICV on the top of the engine to no avail.

Truck runs great. Idles great. Good power with no hesitation. Plugs, wires and coil replaced at 75K so I am due at 155K. I will be doing that as soon as the weather breaks a bit and the temps go up to half human levels.

Are there any other things a shade tree mechanic like myself should be looking at? One of my fears is I may be loosing fuel pressure while it sits and or the fuel pump is faulty. However, like I said truck runs like a top so not sure about the fuel pump thingy. Seems to be getting plenty of fuel with great acceleration.

Any advice or directions I can be pointed in would be appreciated.

TIA

RonD · Jan 13, 2018

You can try turing key on and off 3 times and then try to start engine
Computer Primes the fuel system for 2 seconds each time key is turned on, but only for 2 seconds, that increases fuel pressure by 10-15psi.

1998 and up Rangers used 55-65psi fuel pressure, normally, with engine/key off the pressure should hold above 40psi, so the 2 seconds is enough.

So try the cycling of the key to see if that helps, if so then most likely problem is the check valve/back flow preventer inside fuel pump, not a big deal, it doesn't mean pump will fail, just loose pressure when it sits.

Cold temps means cold gasoline, and thats why Chokes were needed and still needed.
For a spark to ignite gasoline that gasoline needs to have 30% fumes/vapor, Choke caused more gasoline to be pulled into engine to get enough to reach that 30% level, i.e. if gasoline at 40deg was 10% vapor then you needed 3 times the "normal" amount of gas to get to that 30% level for startup.
Computer does the same thing, instead of a choke plate computer just injects more gasoline based on temp to get to the 30% vapor level.
Once cold engine starts the gasoline gets heated(more vapor) as it enters hot cylinders so less gasoline is needed.
But getting that COLD engine and COLD gasoline to startup still needs that 30% vapor level.
Compression is HEAT so each time you crank the COLD engine each cylinder gets a little warmer on compression stroke, which warms up the gasoline coming in as well.
So as temps get lower it may take a little longer cranking time to get enough vapor to start.

In VERY COLD temps people need to use Ether(Quick Start), which has a much lower vapor point than gasoline, for starting

chewy012 · Jan 13, 2018

Not sure on your year, but some have a valve (canister purge or something?) That basically allows for the recovery of gasoline vapors from the tank to aid in cold starting.... I think. Anyway, that valve may be sticking and need cleaning. Mine is on the driver side kind of between the power steering pump and over flow reservoir.

Gas cap?

Sent from my XT1254 using Tapatalk

TiredRetired · Jan 13, 2018

RonD said:
You can try turing key on and off 3 times and then try to start engine
Computer Primes the fuel system for 2 seconds each time key is turned on, but only for 2 seconds, that increases fuel pressure by 10-15psi.

1998 and up Rangers used 55-65psi fuel pressure, normally, with engine/key off the pressure should hold above 40psi, so the 2 seconds is enough.

So try the cycling of the key to see if that helps, if so then most likely problem is the check valve/back flow preventer inside fuel pump, not a big deal, it doesn't mean pump will fail, just loose pressure when it sits.

Cold temps means cold gasoline, and thats why Chokes were needed and still needed.
For a spark to ignite gasoline that gasoline needs to have 30% fumes/vapor, Choke caused more gasoline to be pulled into engine to get enough to reach that 30% level, i.e. if gasoline at 40deg was 10% vapor then you needed 3 times the "normal" amount of gas to get to that 30% level for startup.
Computer does the same thing, instead of a choke plate computer just injects more gasoline based on temp to get to the 30% vapor level.
Once cold engine starts the gasoline gets heated(more vapor) as it enters hot cylinders so less gasoline is needed.
But getting that COLD engine and COLD gasoline to startup still needs that 30% vapor level.
Compression is HEAT so each time you crank the COLD engine each cylinder gets a little warmer on compression stroke, which warms up the gasoline coming in as well.
So as temps get lower it may take a little longer cranking time to get enough vapor to start.

In VERY COLD temps people need to use Ether(Quick Start), which has a much lower vapor point than gasoline, for starting

Currently the situation is resolved. Possibly for the time being, time will tell. After cleaning the ICV the situation did not resolve. Next day and the day after there are no issues. I have no answer for that other then the possibility it took a day or so for the carb cleaner to do its thing. Hope for the best, prepare for the worst. I have read on one of the Ranger Forums this helped some and not others. It was certainly a quick and easy thing and too easy not to try. 5 minutes tops really. Thank you for that informative explanation on gas combustion. Learn something every day or stay in bed.

chewy012 said:
Not sure on your year, but some have a valve (canister purge or something?) That basically allows for the recovery of gasoline vapors from the tank to aid in cold starting.... I think. Anyway, that valve may be sticking and need cleaning. Mine is on the driver side kind of between the power steering pump and over flow reservoir.

Gas cap?

Sent from my XT1254 using Tapatalk

2005 Ford Ranger FX/4 with the 4.0 of course. Gas cap OK, first thing I checked. LOL. It has turned really cold right now so checking things out will be misery right now. I started the truck just fine today about 3 times and it started great. This morning the first start was at 13F and no issues.

I will keep all informed here as to future developments in the hope that I find something someone here has an answer to and also to supply more info into the database as I cannot be the only one over the years to have a similar issue.
Thanx All

Bruce2 · Jan 13, 2018

I have a 2002 ranger with the 4.0 and every now and then it wants to not start right away, it has done that since i bought it with 43,000 miles on it and it now has 266,000 miles on it and still running strong.

TiredRetired · Jan 13, 2018

Bruce2 said:
I have a 2002 ranger with the 4.0 and every now and then it wants to not start right away, it has done that since i bought it with 43,000 miles on it and it now has 266,000 miles on it and still running strong.

LOL, remarkable story. One of my former work aquaintance's still has his 92 Ranger he bought new and it has something like 330,000 miles on it and still going strong.

Check that ICV valve. 5 minute job and easy peasy to do. May or may not help but only 5 minutes out of your life. Good luck.

Cold Starting Issues.

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