2000 Ranger won't start warm

[Bill WV]

I have a 2000 Ranger XLT 4wd, 4L v6, auto. 240k miles, but the problem has existed a long time- just worse now. Starts fine cold but if it runs a short time and is turned off, won't restart. Cranks fine. I replaced the IAC solenoid since I had problems with that in the past. Swapped the fuel pump relay. When it does start, it runs fine. If it is fully warmed up, starts fine. I am going to check the fuel pump pressure, and I am going to clear codes to reset the check engine light then see what new ones come up. I was in Cleveland yesterday, at 25 degrees, it would not restart even after 3 hours. When it finally did start, it really ran rough for a few seconds then it was ok. I drove home to WV w/o turning it off for 6 hours, ran fine. Any other suggestions? Thanks- Bill

 

[RonD]

Fuel pressure test would tell you if you have a leaking fuel injector, after turning engine off fuel pressure shouldn't continue to drop.
2000 should have 60-65psi running
Shouldn't drop below 50psi after shut off.

There is a test you can do and might help on the restart.
All fuel injected engines have this, it is called "Clear Flooded engine" routine
Turn key on
Press gas pedal to the floor and hold it down all the way(this shuts off fuel injectors, but spark is still on)
Crank engine
It should NOT start, fuel injectors are shut off
If you release the gas pedal computer will start the injectors again, even while cranking.

If engine fires even a little with gas pedal to the floor then you have a leaking injector.
You can usually ID which one by repeating the test but unplug spark plug wires one at a time.


On a cold engine leaked fuel has had time to evaporate.
On a warm engine fuel evaporates fairly fast.

Not quite warmed up and then a quick restart could make for a flooded condition.

 

[Bill WV]

Thanks, I will try that. I think that is how it started in the past when I did that- not knowing it could help.

 

[Bill WV]

BTW, I just came back from Florida last week. I didn't have any problems there- and of course it's a LOT warmer in FL than Ohio and WV! If the injectors are leaking, would cleaning them help, or do they have to be replaced?

 

[RonD]

Depends on why it is leaking.
Injector uses a spring to hold needle closed, fuel pressure also holds it closed.
If spring gets loose or breaks it won't close tight because of fuel flowing after it opened.


You have a fuel filter on the fuel line and each injector has a built-in filter but particals can still build up and hold needle open.

Good read here: http://injectorrepair.com/knowledge-base/

Oh, and there is one other thing to check, at the rear of the fuel rail you will find the Pulse Damper, it has a vacuum line attached, remove this vacuum line and check it for fuel or fuel smell.
It has a rubber diaphragm inside and it can leak, vacuum line is there to keep fuel from leaking on to exhaust, a BAD thing, lol, but if it is leaking you may get same symptoms as leaking injector because fuel is sucked in to intake.

 

[Bill WV]

P0118 code

I got a P0118 code, and I confirmed a bad reading on the ECT sensor. So I am going to replace that. I haven't checked the fuel pressure yet, or the other things that were mentioned.

 

[RonD]

Just as a heads up, ECT(engine coolant temp) sensor will have 2 wires, it is only used by the computer(PCM).
There is a 1 wire Temp Sender that is used by the dashboard temp gauge, they look similar and are often located next to each other on the intake manifold by thermostat housing.

ECT sensor is a resistance sensor, computer sends it 5volts on one wire and gets back 3.5v to .5v on the other wire.

3.5v would be cold engine, approx. 50degF
.5v would be fully warmed up engine, 200degF

You can test it with OHM meter for open circuit
should read approx. 60k cold, 3k warmed up

 

[Bill WV]

It turns out that I had the SENSOR and SENDER confused.. so at least now I know what each does, and where they are. I replaced the sender and got a normal reading on the gauge. The sensor had a bad connection at the socket-- all codes cleared, the engine runs fine now, cold warm and hot. So the issue is resolved after 3+ years!!

 

[RonD]

Good work

Thanks for the update, will probably help someone else with similar problem.