Cant seem to figure out 4.0 issue -- finally have to ask!!!!

withoutfear33 · Jul 11, 2014

i have a 1994 ford ranger 4.0 5 speed 4x4. i have been searching and searching the forum to try and find my answer but i cant find exactly what mines doing so i finally have to ask..

im having an issue with the truck missing on initial start up but its only certain times.. here is what it is doing.

typically i only have a 5 minute drive to work and the truck runs great almost every single day going to and from work, maybe 1 time out of 10 you have to crank it a little longer to get it started but other than that it runs great. but like i said i only have a 5 mile drive to work.

so here is where the missing starts:!!!!!

when the truck misses is when you have been driving it like 20 plus miles, the truck is at operating temperature and you turn the truck off to go into the store ect. when you come back out and start it up you immediately have a miss and it misses at idle and while driving for about 5 minutes. it will finally clear out and it will run perfect again.

i have replaced the plugs and wires so far on the truck as well as running transmission fluid through the tank..

im about to go on a fishing trip and really need to get this worked out, im afraid it wont make it.

withoutfear33 · Jul 11, 2014

also to add to this i do get a slight smell of antifreeze everynow and then but the truck never comes close to running hot or anything. i figure i have a line under the filler tank kinda loose or something. i have no visable leaks on the ground.. not sure if this has to do with the issue im having but throwing it out there.

Tbarnes93 · Jul 11, 2014

The filler neck tends to dry out I just replaced mine a few months ago. Sounds to me like it could be a ect (engine coolant temp sensor) it's not the one wire that's just for the gauge but it screws in on the intake I believe. My connector went bad it had a plastic piece separating the terminals and it fell out. The sensor might be reading cold instead of operating temp. That makes it run rich and can also cause the smell

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Tbarnes93 · Jul 11, 2014

The ect is a 2 wire also btw

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withoutfear33 · Jul 11, 2014

I will check that out man. I'll go buy a new on and see if it fixes it. Wouldn't that make it run bad while running. My truck feels more like when you turn it off maybe somthing gets on the plugs and it misses until it burns off if that makes sense.

withoutfear33 · Jul 11, 2014

I replaced the ect next to the thermostat housing. Mine only had 1 wire plug on top. Is this the right one? I won't know if it's fixed until tomorrow and drive around for a bit in the sun

SenorNoob · Jul 12, 2014

Why does this sound so similar to a bad TFI module on an earlier truck? Could it be the same type of problem just with the ICM it uses? I didn't think they got very hot though. Mine's been just hanging loose under the hood for the last year and half.

/End crazy rambling.

RonD · Jul 12, 2014

withoutfear33 said:
I replaced the ect next to the thermostat housing. Mine only had 1 wire plug on top. Is this the right one? I won't know if it's fixed until tomorrow and drive around for a bit in the sun

No, that is the temp SENDER for the dash board gauge.

The ECT sensor looks the same except it will have 2 wires, also in that same area, lower intake near thermostat housing.
Computer uses this sensor to set air/fuel mix based on engine coolant temp(ECT), cold engine needs rich mix, like setting the Choke on a carb engine, warm engine would struggle with rich mix.

All fuel injected engines have a 2 wire ECT sensor(for computer) and separate 1 wire ECT sender(for temp gauge), this is not a Ford thing.
Since fuel injection doesn't have "jets" a Choke plate won't work to "suck in" extra fuel when engine is cold, so the fuel injection controller(computer) needed a way to to tell if engine was cold or warm, to run richer or leaner, that is what the ECT sensor is for.

4.0l also had issues with bogging and missing because of dirty MAF sensor, good read here on cleaning MAF:
http://www.therangerstation.com/tech_library/CleanMAF.shtml

withoutfear33 · Jul 12, 2014

I replaced the correct two prong ect sensor and cleaned the maf but it still didn't correct my problem. It truly feels like somthing gets on the plugs when it's hot and once it clears out it runs great again.

RonD · Jul 12, 2014

Valve guide seals may be worn out, you could be getting enough oil leaking down to foul up the fuel/air mixture.

Next time engine is cold, and you have the time.
Disconnect the coil connector and crank the engine a few times, pull a couple of spark plugs and see if there is oil mixed with the gas on the tips

Buckmaster14 · Nov 17, 2014

Was this problem ever solved? my truck is doing the same thing and can't figure out how to fix it!

AllanD · Nov 17, 2014

This actually sounds like an "issue" I have with my 1993 4.0 engine.

an issue I call "Winter mix gas syndrome"

Understand that gasoline compositions change due to government regulation
and that refiners by the way refining processes work create a surplus of the 4-carbon hydrocarbon, known as butane.

Butane is produced as a byproduct of catalytic cracking of heavier long chain hydrocarbons
to reduce them to the more desireable shorter chain hydrocarbons.

The issue with butane is that it boils at 1degC. so even o a fuel injection vehicle you can get a "Vapor lock" effect as the fuel rail becomes filled with butane as it flash vaporizes when hitting the aluminum fuel rail (which is heated by bring tightly bolted to the aluminum intake manifold.

This "syndrome" as I have experienced it is far more common on the first warm days of spring before the switch back to summer mix, and typically exhibited not while running, but as difficulty doing a hot re-start after the engine is warmed up (I usually experience this when making a run to the post office.

I clear the problem either by cycling the key to run the fuel pump until it times out 3-4 times (tedious) or by pulling the fuel pump relay and inserting a wire jumper and letting the pump run for 60-90 seconds to circulate cold fuel through the rail to chill it.

I have on occasion simply stuffed a couple of snowballs on the intake manifold to cool it
this is also effective...

I don't know this is your problem but you can play around...and learn, I'm just trying to give you a hint

pbgutterguy · Jan 8, 2015

Sounds like the beginning of the end of a cylinder head.

Cant seem to figure out 4.0 issue -- finally have to ask!!!!

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