So I have a 1994 2.3L that has intermittent starting issues. If I let the truck sit over night and go outside she値l fire right up. If I drive the truck about 10-15 mins and shut it off, come back 20-30 mins later, I値l have to crank on her for about 10 seconds to get her to start. I can hear the fuel pump humming if I turn the key for a couple of seconds. It has a brand new fuel filter on the truck as well. The battery is good as well. Any thoughts?

 

Welcome to the forum

If you want you can confirm its not a fuel issue buy doing the 50/50 test
Get a can of Quick Start(ether) or put some gasoline in a spray bottle
Run engine until its warmed up then shut it off
Try to restart to confirm its not starting
50/50 test
Spray fuel into the intake manually
Try to start
If it starts up and then dies it IS a fuel delivery issue, not spark issue
If it doesn't start then it IS a Spark issue, can also be a compression issue but wouldn't restart cold so.............not that
50/50 instant results


Common issue on the 1989 to 1994 2.3l Ranger was the ICU(ignition control module), it is located on the front side of the lower intake manifold, it faces the fan for cooling
The ICU controls spark and spark timing, the "computer" controls fuel injectors
Many auto parts stores can test these, but they may test good cold and fail after they are warmed up from use, they do get hot

BUT...........I would first test the coil packs
On the 1989 to 1994 2.3l only the exhaust side coil pack and spark plugs work when starting the engine, the intake side is disabled, until engine starts(RPMs above 400)
So a failing exhaust side coil pack can also cause your symptom

You can swap coil packs around, to see if symptom goes away, if so replace the original exhaust side coil pack

Just FYI, this engine can start and run just fine on only the exhaust side coil pack and 4 spark plugs, this 2.3l engine only used 4 spark plugs from 1974 to 1988 in many Ford vehicles.
The 4 extra spark plugs were added for better power, just like on the Dodge Hemi engines that ran dual spark plugs for extra power, BOTH spark plugs fire at the same time, there is no "alternating" or there would be no advantage to Dual spark plugs
Times changed and now engines use 4 valves instead of dual spark plugs for the extra power

Now what you can do periodically is to run the engine on only 4 spark plug to see if all 4 are working, no misfires, because you won't know if all 4 on one side are working since only 1 is needed to fire a cylinder
So use exhaust side coil pack to start and run engine with intake side coil pack unplugged
Then if all is well move intake side spark plug wires to exhaust side coil pack and repeat test

 

Thanks for the reply. I should have stated in my initial post that, the truck runs fine once it starts and idles smoothly. The only time I have this issue is upon startup when the truck is still warm after having recently ran. I have spark on all 8 spark plugs and I have voltage at the fuel pump. I did replace the fuel pump relay because It would chatter while running.

I can do 50/50, but is there anything else I could possibly look at as well?

 

Do the 50/50 test, first

Then we can look at the problem

Be sure to confirm there is a No Start before testing

There is no way to test spark and spark timing except 50/50 test
There is no way to test if fuel is getting into engine except 50/50 test


It really is the first and only test you need to do when there is a No Start
THEN you can look at spark or fuel depending on results

 

So, I did the 50/50 test. She fired right up and ran just fine. I turned it off,waited 5 mins, went to restart her and same thing. It took about 10 seconds and me pushing the throttle in for it to start and run.

I did the 50/50 test again and it fired right up and ran just fine.

I did the 50/50 test one more time and it was struggling to start, like sputtering to a start and then it leveled out and ran fine.

I know the fuel pump is running And priming when I turn the key and I have tested voltage at the fuel pump.

So I知 assuming maybe the coil pack and/or spark plugs?

 

OK, but how would it "start right up" if there was no spark?

Fuel pump running is good, but doesn't mean fuel injectors are opening

Now in the 1989 to 1994 2.3l the computer has no connection to starting engine, its just on, but doesn't know when someone is try to start the engine

That signal comes from the ICU, so problem could still be spark system related, but not no spark

When the starter motor turns the crank shaft, the Crank shaft(CKP) sensor sends a pulse to the ICU, and that starts spark at the exhaust side coil pack
The ICU then sends out that CKP pulse to the Computer, THEN computer starts injectors

So 50/50 test showed that Fuel was the issue, spark was working, now assuming fuel pump is working, and injectors have fuel, then it comes down to injectors are not opening
And than comes down to computer not opening them
Which can be a problem with ICU not sending out the timing pulse to computer or the wire that timing pulse is on

Heat seems to be the reason for the No Start, and heat can effect wires, but long shot
Heat does effect ICUs, TFI modules had same problem.

I would pull off the ICU and inspect its wiring harness, also have it tested, but since it works cold not sure a test will show an issue, maybe
You may have to replace it on speculation


And just an FYI about fuel injection
There is no "gas pedal", its not like a carb engine that squirted gasoline into engine when you press down on the Gas Pedal
With fuel injection its an Air Pedal, when you press down on the pedal it lets in more AIR, not more gasoline
So if you needed to push down on the pedal to get it to start then engine was FLOODED, had too much fuel so needed more AIR not more fuel

The computer calculates air flow using MAF sensor and throttle sensor, but ONLY after engine is above 400RPMs, so during startup the "gas" pedal is only an Air Pedal
This can help with diagnosing problems

i.e. "Pumping the gas pedal" on a fuel injected engine has a totally different meaning than it does on a carb engine, as far as diagnostics

 

I知 not arguing, rather curious, but if it is a fuel issue why do I not experience anything while driving or just idling? If the ICU is the culprit, would it only give me trouble upon startup and not while driving? I ohmed out my injectors and got roughly 14-16 ohms on all four of them, which from what I looked up means they池e good. I looked at the wiring harness on the ICM and they both seem okay. Where would I take the ICM to be tested at?

 

From your description the problem only occurs once engine is fully warmed up, i.e. "has to sit 10min before restart"

From the 50/50 test "the engine started right up" when it was WARM by adding fuel manually, so that makes it for sure a fuel issue not spark

Now computers and fuel injector are not known for being temp sensitive

Coil packs and ICUs are known to be heat sensitive, but its for sure a fuel issue..................so whats the connection???

Well the only thing I can think of is that the computer(fuel supplier) doesn't "know" you are try to start the engine when engine is warmed up
The Computer waits for the Timing Pulse from the ICU and only then will it start the fuel injectors

It could be the ICU is getting "heat soaked" when engine is off, when you shut off an engine the fan goes off so everything under the hood starts to heat up
The ICU runs hot, so when you do want to restart engine ICU its too hot so no Pulse to computer
Once it starts fan is on and cooling down the ICU so it sends the timing pulse to computer and everything works fine until next shutdown and restart

I read somewhere some one had similar issue with TFI module and held a bag of ice against it as a test, and it restarted every time after it cooled down, lol

This is just a guess with info available

Call local autoparts store and see if that can test your 1994 ICU, but as said it may test OK cold

 

I had a similar issue with my 1994 2.3L a year ago. It turned out to be a faulty crankshaft position sensor.

 

Update**

So I decided to do a fuel pressure test on the truck. I read that the fuel pressure for my model truck should be 35-45 PSI when you turn the key to start. When I turned the key to start I only got 3 PSI. I turned the key again and only got 9 PSI. The third turn I got 12 PSI and it was slowly falling down when I turned the key off.

So I went to autozone and bought a fuel pump. I swapped the fuel pump out and the truck fired up on the first turnover. I did a pressure test again and I got 39 PSI on the first turn of the key. The problem is fixed now and it only cost me 69 bucks.
Also, if anyone else runs into this problem who doesn稚 know, fuel pressure test kits are 20 some odd bucks at Harbor Freight.

Thanks for the troubleshooting advice guys.

 

Just curious, what brand of fuel pump you bought?

 

Good work

Thanks for the update and fix

 

So I bought the cheapest fuel pump Autozone had. The brand was Premium Fuel System.

 

Update 2


So I started having the condition again yesterday and today. My temperature gauge hasn稚 worked on this truck Since I bought it a month ago and from what troubleshooting I have the coolant temp sensor is bad. There is roughly 5VDC going to the sensor.

So my question now is does the Coolant temp sensor Play a role in starting? I know some vehicles the temp sensor sends a signal to the computer letting it know if it is hot or cold and the computer thus determines if more fuel is needed for start up. I was having issues where it seemed like the engine was being flooded upon startup and I had to push the throttle in for a bit to get it to start. I unplugged the harness from the coolant sensor and she fired up immediately, multiple times. I知 going to buy a new one today, but just curious if this is for sure something that effects starting.

 

Yes, the coolant temp "sensor" plays a roll in starting, and it should have 5volts from the computer, and 2 wires, because its a "sensor"n called the ECT sensor
ECT sensor "sets the choke" for cold engine to start

Most sensors share that 5volts, just FYI, usually a grey/red stripe wire

On ECT sensor, it gets 5v and then sends back 3v when Cold, and under 1v when warmed up, on the "other wire", you can use a sewing needle to pierce a wire to read voltage from that wire, doesn't damage the wire

Temp gauge
The temp gauge on the dash uses a temp "sender" 1 wire, and its a 12volt sender like oil pressure sender for dash gauge
On the 1994 2.3l the temp sender and oil sender are on drivers side towards the back.

Diagram here: https://cimg4.ibsrv.net/gimg/www.ran...96a27c731c.gif

If you pull off the 1 wire from temp sender and ground it, then turn on the key, the temp gauge should go up to HOT, that means wire and gauge are OK, replace sender
DO NOT use tape on the sender threads, it NEEDS to be grounded to the engine to work
If you feel the need to seal it then leave 2 or 3 threads at the bottom bare metal

 

So I assume I need to replace the sender and the sensor, both?

 

I would test the wire and gauge for sender, but yes its usually the sender that goes bad, or wire fell off or corroded

ECT Sensors are not too expensive so most replace them on speculation...............IF engine starts or runs poorly when Cold but fine when warmed up, or starts and runs fine cold but starts or runs poorly when warmed up, but NOT both cold and warm issues, that's not the ECT sensor

 

Do you know if there is a torque value for the ECT sensor? I bought just because it was 17 bucks. Installed it and it starts great now, but idles rough like it is going to die. I tested the gauge and it seems okay

 

Not much torque on ECT sensor, 12-15ft/lb


If gauge goes to HOT with wire grounded then replace sender

The 2.3l, as you can see, has the temp sender in the back of the engine instead of the TOP front of the engine, where engine coolant is hottest, like most "normal" temp senders, lol
So gauge reads low when is working, should be at least 1/3 on gauge when fully warmed up, other Ranger engines read just below 1/2 after warm up
In later years Ford moved it to a heater hose, top front of engine, so it would be closer to other Rangers and Fords, just below 1/2

 

When you did a pressure test with the new pump and got 39 PSI on the first turn of the key. Would it hold onto that pressure for an hour or so?

 

To be honest I didn稚 test it that long.

 

so I bought a code reader Yesterday... I did a KOEO test this morning and got a 111 which means no faults according to the book. It did the pause 10 code then spit out a code 118 from stored memory, which is the engine coolant temperature sensor above max voltage. How do I fix this now? Yesterday before I bought a new sensor it was giving me fault code 116 when I did the KOEO test.

edit: the truck seems like it struggles to idle now. Drives great, turnover and starts great, barely maintains an idle.

 

Either you have a bad ECT sensor or the wire is loose. In my case, it was a bad pin inside the wiring harness. You can monitor the sensor using a voltmeter while you are driving. You should see the voltage drop from 5v (cold) to 0.7v (warm-up).

You can retest the fuel preesure with your kit and see if it will hold up the pressure for 5 mins or so.

 

I would encourage you to go ahead and replace the ICM.
When they fail, it is not a hard failure. It will put the engine in 'Limp Home' mode. And OEM are prone to failure.

It is a PITA to swap out if you have an AC compressor (and don't want to pull it), but it can be done.
DO NOT forget the thermal paste. (I got the cheapest option at Best Buy).

 

So I forgot to update. I got the truck running perfectly fine. The guy that owned it before me had adjusted the idle set screw all the way out because the engine kept flooding and he could not figure out why. I believe that coolant sensor was bad and reading cold, thus the ECM was constantly flooding the engine. When I put a new coolant sensor in the truck the engine was getting the proper amount of fuel, but was not getting the right amount of air. I adjusted the idle set screw until it sounded good to me. It has been over a month now and I haven稚 had any problems. Also, I replaced the coolant sending unit too, so I could actually see what the temp is on my truck. Replacing the sending unit was a bit of a pain, but I think it was necessary.