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New owner with questions


Kevin94XLT

Member
Joined
Jul 27, 2017
Messages
6
City
Kennesaw, GA
Vehicle Year
1994
Transmission
Manual
I just purchased a 94 with the 2.3L, 285k miles. It would not pass emissions, too much NOx and running way lean. I found the original cat was still installed so i replaced that along with a new O2 sensor, you could hear the honeycomb material rattling around. I also fixed a bunch of air leaks from vacuum lines not being connected/corroded. It passes emissions now, but there are still a bunch of little things i think need to be done to get this thing running right.

First off it threw a code 116 for the coolant temp sensor. The temp gauge never really enters the "normal" zone on the dial. It will only reach just before the letter N, but when i run the A/C for a while it increases slightly. The sensor itself looks like its never been changed, but when i read the voltage as its warming up it appears to be working. I just have no reference as to what voltage i should be seeing at normal engine temperature and was wondering if there was a chart that i can reference? Its either the sensor or the thermostat is stuck open, but want to know for sure.

The EVAP system on this truck is kind of weird, i have a small plastic line running from the fuel tank to the carbon canister up front, it was cracked so i fixed it with some vacuum line. However when i did a smoke test of the intake, smoke was coming from the top caps of the carbon canister itself, im assuming this is not normal or is that how it vents? I was also surprised there is no purge solenoid, its just a line that runs from the canister straight to the throttle body. I capped off the opening on the throttle to prevent an air leak for now until i can get a new canister. Plus the fuel filler neck has a crack on it, so the EVAP system isnt going to be tight anyway.

The intake air temp sensor I suspect needs replaced, but again is there a reference chart that shows what its supposed to be reading at certain temperatures? I took it off and measured resistance while hitting the sensor with a hot air gun and the resistance changed immediately so it might be working fine, I just dont know.

Also what is the deal with the intake pipe that runs off the side of the exhaust manifold and over to the intake inlet before it hits the air box? It also has a vacuum valve on it with a line that runs from the valve to the air box itself, i just cant imagine it would be good for the intake to suck in hot air like that?

Overall im surprised how well this truck is working for so many miles and considering its 23 years old. Its also very easy to work on, especially compared to the BMW's i work on at my job. Thanks for the responses in advance...
 
2.3l should be running a 190 or 195degF Thermostat, someone may have put in a 160 or 180degF

There are TWO temp units on the engine
Temp Sender is for the gauge, it is located drivers side toward the back near the oil pressure Sender, Senders have just 1 wire connected

ECT Temp Sensor, uses two wires, it connects to computer only
If engine is running too cool(wrong thermostat) then you can get ECT code 116
ECT sensor got moved around on the 2.3l Lima engine
1994 should be on separate heater hose pipe next to the upper rad hose pipe, but have seen it on the heater hose itself.

ECT gets 5volts from the computer, that 5 volts is shared by IAT(air temp), TPS(throttle position sensor)and MAF(mass air flow) sensor.
ECT sends back about 2.5-3volts when coolant is cold, then under 1 volt when coolant is at 195degF, about .7volt
Graph here: http://www.allfordmustangs.com/foru...p-sensors-gauge-fan-not-working-ect-graph.gif


IAT(intake air temp) sensor is about the same volt range, although it doesn't get that hot, lol.
Graph here: http://repairguide.autozone.com/zne...6b43f/80/99/84/03/medium/0996b43f80998403.gif


The tube from the exhaust manifold is to pull warm air from around exhaust manifold into the air filter housing and then the engine on Cold Start.

Liquid gasoline won't ignite with a spark
Only gasoline vapor will ignite with a spark
This is why ALL cold engines need to be Choked, run a Richer mix

I.E. if an engine needs a minimum 30% gasoline vapor to start and run, and cold gasoline in cold engine is 15% vapor, then you need twice as much fuel to get engine started.
After startup the gasoline will start to heat up and the hot cylinders help, but warmer air really helps, because colder air is denser so needs even more fuel to get a good mix and that can drown a spark.
Cold Air Intakes are great, and every Ranger came from the factory with one, but they can only be "great" AFTER engine is warmed up.

Many do eliminate the air pre-heater tube, and valve, up to you really, gets engine to warm up faster, which is also great in Northern climates, faster heater warm up :)


I think positive pressure, smoke test, would see smoke out of those caps on canister.
After Filler hose is repaired or just pinch off the line going back to tank and then suck on the vacuum line to see if canister holds pressure.
It is a very basic system in 1994, after engine is off vacuum in EVAP will dissipate and caps then vent, "filtered air" :)
 
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To make a short comment, in line with the above, I'd replace the thermostat with a Stant, Robertshaw, Motorcraft or other brand that you recognize. I would not waste a dime on the 'house brands' that the stores peddle. "Hecho in Wherever" does not instill confidence that they will work or last much past the due date on the credit card bill.
If you pull both house and OEM/non-OEM out of the box at the store, and inspect them, you'll see the difference. Go with the factory recommended temperature. Don't try to be an engineer until you get out of GATECH.(if you were going...) I hear they may still throw diplomas at cars that drive by... (chuckle, not really, a good/excellent school).
When you start a cold engine in the AM, let it idle, and check the upper radiator hose. It should essentially stay cold and then go HOT in a short time as the stat opens. The idea is that it stops coolant flow until the coolant around the cylinders & in the head get to the 195F number, and then allow coolant to flow. In a lot of cases, it will not flow much as all as the 2.3 runs cool. Unless the timing is off.
tom
 
Thanks guys! I think i will start with a thermostat since you can get them for like 15 bux on rockauto, im pretty sure the sensor is reading correctly it just might be the wrong/broken thermostat. I did not know the temp gauge was reading off of a different sensor, the wiring diagram in the Haynes manual does not show one, but the section about cooling says it is there. Thanks for the specs on the voltages, now i can back probe and test to be sure they are reading correctly.

Right now im getting 18mpg, but i dont think its from the cooling system alone. I replaced the cat, but i can hear cat material rattling around in the muffler which im sure is creating too much back pressure. I can hear the exhaust making a "put put" sound randomly when idling, as if the exhaust is building pressure and shooting out of the tail pipe at certain times. I do plan on replacing the cat back exhaust, but one step at a time.
 
I think you can do better on a stat at a local store. Fifteen seems a bit high. I think it is normal to have a putt every once in a while. The engine & systems are not perfect, but the misfire should be around 1 in a 1000. Very intermittent misfire is to be expected, at least as far as I figure for my old truck.
I would expect better than 18mpg unless it is totally in town, stop and go driving. An engine that does not reach proper temperature can and most likely will use more fuel than normal.
Failure of the IAT is pretty rare. The sensor can get coated with oil from the PCV system, and of course all the other crud that gets fed into the engine. But they mostly have no problems.
tom
 
I just put in a new thermostat today, it was a Beck/Arnley one from rockauto thats listed for 192 degrees. When i removed the old thermostat I noticed the seal for the old thermostat was still in the housing. So i removed it, then noticed another seal below that one that looked the same but quite older. I guess whoever replaced the thermostat last time didnt remove the gasket from the old thermostat before putting in another one.

Well i got the new one in and start bleeding the coolant system, but notice the temp gauge still isnt climbing even after letting it idle for a good 10 minutes and revving the engine to get the coolant circulating. Also its not blowing hot air, just warm. So i drove the truck home thinking maybe I just need to drive it for a bit, but now the temp gauge doesnt even reach the N in the normal range, it barely moves off the dash for the cold side. But after driving about 10 miles or so i can feel the heat getting better, although i wouldnt consider it hot. This is puzzling to me, its a brand new thermostat but the engine temp now shows even colder than it was before.
 
Thermostat should keep upper rad hose cold until engine coolant temp reaches 195degF or so, usually +/-3degF, at thermostat, and thermostat is not full open until it is 15degF above its rating so 195 would be fully open at about 210degF

Heater core is part of the engine system, so should warm up to same temp as engine coolant while radiator remains cold.

So during warm up feel upper rad hose AND both heater hoses, water boils at 212degF, so 195-210degF is very HOT to the touch.
Upper rad hose should not warm up with the engine, heater hoses should.
The warmer heater hose is the IN from engine, cooler the OUT to engine.
If the OUT hose is alot cooler than IN then heater core is plugged up.

Heater core itself has no IN or OUT, when you change coolant(every two years) you should reverse these hoses, this Back Flushes out any larger bits that might block passages in the core.

Long shot but could your fan clutch be stuck on
2.3l doesn't generate alot of extra heat, many have to put cardboard in front of rad in winter months to keep temp up/heater working
The fan clutch operates by radiator heat not engine heat, so if radiator is cold the fan spins freely, not engaged for cooling.
Before starting cold engine, try to spin the fan manually, it should be hard to turn, tight.
Start engine and run if for 20-30 seconds, you should hear a whooshing sound of the fan "grabbing lots of air" then sound will diminish as fan clutch disengages, in about 10seconds.
Turn off engine and spin fan again, should spin easily, not tight at all
If fan is still tight then replace fan clutch.

Because the 2.3l doesn't generate that much extra heat the air flow by fan being on all the time doesn't let it warm up, same as colder winter air needs to be blocked from flowing thru radiator to engine bay.
 
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I tried to spin the fan before I ran the engine, it will spin but immediately stop once you let it go, will not free wheel. I cut the engine on and ran it for about a minute, the fan was engaged the entire time. After i cut it off the fan had the same amount of resistance on it, it would not free wheel but would stop in place.

I guess this means my fan clutch needs replaced, which is causing my engine not to warm up then? Seems like a simple fix, ill get one coming and let you guys know what happens. Ive always driven cars with electric fans, so i was not aware of this issue, thanks!
 
Think a minute. If the fan is blowing, who cares? If the thermostat works, there will be no coolant for the fan to cool, so it cannot cool 'more than needed' by blowing air past a radiator filled with coolant that is not flowing...
Your thermostat is either flaky, or was not installed so that it seals. I think there are legs on the stat that need to be bent and placed to keep the 'front' of the stat pushed tight against the seal area machined into the thermostat housing. The stat sort of gets jammed in place, the seal pushed tight, and then the legs are positioned so their 'feet', flat metal, can sit in the machined low area on the gasket surface. If it is not tight and sealed, coolant will seep by, and the engine not get up to proper temperature.
As noted, the upper radiator hose should stay cool, and then, boing, the stat opens, and all that hot HOT HOT water/coolant is allowed to flow towards the radiator. If it is warming up from cold slowly, the stat is leaking or defective.
You should replace with the temp OEM suggested for best performance. They do actually try to put in the most effective parts as a 190 costs the same as a 180 as a 195, etc, so their number should be the best to use. If your cooling system is in good shape, it should not matter which you choose, and you'll get optimum fuel efficiency. IMO.
tom
 
An update to this, I did install a new fan clutch recently and it made a slight difference. But it appears either i need a new thermostat housing or the thermostat is not installed to where it seals properly. I decided to put a piece of cardboard in front of the radiator and the coolant temp has now climbed to normal levels so I think im just going to leave it alone for now lol. However, i think i need to flush the heater core or replace it, hot air only blows for a few seconds before it gets luke warm. I still like this truck though, its been dependable since i bought it and is approaching 300k miles.
 
Many use cardboard in front of radiator on the Lima engines, they just don't generate alot of heat and the block bleeds heat pretty fast with air flow in engine bay

Yes, your description of HOT at first then luke warm is "textbook" symptom of plugged heater core.

Heater core is very easy to change on a 1994 Ranger
4 screws and 2 hose clamps, takes about 20min the first time you do it
The 2 hose clamps are obvious, lol
The 4 screws are on bottom cover of air box behind glove box, screws all face up
3 are at 3 lower corners of box
One is up higher, fold down glove box all the way to see it

I think they are 8mm heads

Put a towel down, you have to tip heater core a bit to wiggle it out
 

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