A while back I posted about this issue and it did go away for a bit after the previous fix and now has reared its ugly head again with a vengeance. This truck is not my daily, so it does sit for sometimes up to a week or so before I drive it. The current status of the truck is (1992 Ranger 3.0 2WD):

On A Cold Start:

• Key on - Fuel Pump continuously runs.
• Key start - engine turns, but no attempt to turn over. (Will continue to crank until I drain the battery.)
• Short shot of Starter Fluid on air filter - Engine Immediately Starts But Runs poorly. The engine knocks like a misfire and has a check engine light on. After the initial start it seems to run fine on its own fuel supply. However there is a little bit of bluish white smoke out of the tailpipe. Any increase in throttle bogs the engine down and it cant get over 2500 RPM. Sometimes this lasts for 30 seconds sometimes it can be 10 minutes. Then there is a brief "belch" or "woosh" accompanied with a quick fluctuation in RPMs and a small cloud of black smoke out the tail pipe. Check engine light goes off and it works perfectly fine for the rest of the day.

After that initial start sequence there are no traces of the problem until I let it sit for more than a few hours. The fuel pump turns off like normal, no hesitation in starting, no lack of power or bogging down, no smoke, and no check engine lights. Any ideas to help me narrow this down would be much appreciated.

 

I would pull out the computer and have a look at the circuit board, and plan on replacing the 2 or 3 Blue or Black Capacitors, look like little cylinders
These leak and corrode after 20+ years, thats almost for sure why fuel pump was running full time with key on

These have +/- side so take pictures, they also have specific values like 47uF 16v written on the side, you have to match the uF value exactly but the 16v(volt) can be higher just not lower, so 47uF 16v can be replaced with 47uF 50v
No, I won't know what values yours are they varied over the years

Example computer seen here, it has 3 Blue capacitors: http://www.auto-diagnostics.info/ford_eec_iv

Its under a $5 fix

Thats where I would start, because if computer is the issue you will be chasing your tail for awhile looking at other things

Clean contacts on main connector, and visually look for any corrosion

 

Okay so a special thanks to RonD. I followed your advice. I only had 2 caps on my board. One was a 47uF 10v and the other 3.3uF 63v. The latter was hard to come by so i used a 3.3uF 100v. Both of the old caps were leaking on the bottom by the pins so it was hard to tell they were bad without careful inspection. I put it all back together and tried to fire her up. She started right up and ran fine. It has been an intermittent issue so it will require further testing. That being said leading up to this post 90% of the time the issue manifested on a cold start. Thanks again, and ill keep you posted.

 

Good work

And thanks for the update, it will help someone else down the road

 

Update: Further testing proved the issue has not been resolved. The fuel pump is behaving better. (Turning on and off like it should.) I may have had several gremlins that I mistook for one larger problem. I noticed that the behavior primarily when it is wet or humid out. For the initial test we had dry conditions and then a front pushed through and every day that it has been rainy or humid it hasn't want to start on its own. Since I know that the truck starts immediately if I give it a shot of starting fluid, I would normally assume that it is a fuel or injector issue. The truck stays running after it starts on its own though, so it seems it seems its getting air, spark, and fuel. After doing some research and reading similar posts I think it may be possible I have an issue with my distributor, coil, plug wires, or MAF. I will be checking out the components after work today to see what kind of condition they are in. I will keep this thread updated with any relevant information/findings.

 

It can be battery voltage as well
Battery voltage while starter motor is active shouldn't fall any lower than 9.5volts, 10volts is expected
You can test this by pulling the coil wire off the coil or distributor, so no spark
Put volt meter on battery, key ON, should see 12.3v(5 year old battery) to 12.8v(new battery)
Then crank engine over and watch voltage drop, 2.5volt drop is acceptable, as long as it stays above 9.5volt, below that and spark voltage drops off quite a bit, Starting fluid has a much lower ignition point than cold gasoline so easier to fire in low spark condition

An older battery can still crank engine but its voltage drops too low while releasing enough amps to turn engine
Failing starter motor can draw too many amps, so battery voltage drops too low
Battery cables can also cause too many amps to be needed, which also drops battery voltage during cranking

But yes you could be losing spark voltage in coil, cap, or rotor, check coil + voltage key on, should be exactly the same as battery voltage key on
Distributor itself or TFI module doesn't have anything to do with spark voltage, just spark timing

Spark plug gap matters as well, slightly wider gap means a "hotter" spark for cold starts

 

The Cap And Rotor have definitely seen better days. I will start there and continue testing with the multimeter. I replaced the coil a few years back, but it definitely warrents testing.

 

Update: The new Rotor and Cap were installed. She fired right up. Once again will be monitoring over the next week or so to see if the problem shows again. Since I was replacing the cap and rotor, I didnt check their voltage. I did check the battery voltage (12.46V key on) and (11.12V cranking coil disconnected). Given the state of the distributor, it actually makes a lot of sense why the starting fluid worked over the gas. Thanks again RonD.

 

With that old cap & rotor I'm surprised it even ran at all.

Good job.

 

Me too lol. I think it was the original from 92.

Thanks!

 

Good work

 

Update: I had the same behavior present the next morning after the cap & rotor. The truck ran significantly better once it was running. I decided to look closer at the coil and found it to be bad or at least on its last leg. Corrosion had been eating away the coil pretty good all over, and center/core of the coil was loose and could wiggle all around. It looks like the adhesive/coating they used broke away. I went ahead and just replaced it to save myself some further headache down the line. As usual the truck started right up and ran great. Last night we had another front push through and the weather was wet. Once again no start this morning. Will keep digging on this and post any new relevant information. Pics of old coil below.

 

After seeing Cap, Rotor and Coil, I think it's time for Plugs and Wires also.

 

I agree. I am curious to see what condition the plugs are in. They were replaced a while back and don't have many miles at all on them. Maybe a couple thousand.

 

Cold engine and high humidity No Start is almost always a spark issue, external or internal
External are what you have already addressed, loss of spark voltage via coil, rotor and cap
But there are also spark plug wires and spark plugs, in higher humidity older wires can arc more, losing voltage

Spark plug gap on the 2.9l should be 0.045, I think spec was 0.042 to 0.044
Slightly wider gap makes for better spark on cold start

Water vapor(humidity) suppresses ignition by spark, "bad gas"(high water content) cause misfires because of that, water injection prevents pre-ignition(knocking) because of that
Once a cylinder gets hot, fires a few times, outside air humidity doesn't matter as much, the gasoline vapor level gets higher when heated by the cylinder, which is why starting fluid works when its humid outside, it has a lower vapor point than gasoline when cold, so a spark can ignite it easier

Spark plug gaps are determined by voltage of the coil and its recovery time needed between sparks
Wider gaps are better for cold starts and low RPMs, idle, but takes long for coil to recover(charge up) for the next spark
Narrow gaps are better for high RPMs(racing) as the coil has longer recovery time

2.9l OHV and 4.0l OHV are basically the same engine, yet the 4.0l uses 0.054 gap
That's because the 4.0l has 3 coils, not just one, so each coil has a longer recovery time between firing even with a very wide gap
Spark plug gap is like tire air pressure in that its USERS CHOICE
So you may want to try 0.047 gap to see if you have better cold start with humidity, but can also do highway speeds after warm up, i.e. no issues with recovery time

And after doing rotor and cap its always good to test/redo base spark timing as these two units can change that a few degrees

 

Update: Changed the spark plugs and checked the lightning hoses. The parts store didnt have any replacement wires, so I figured id just give them a good inspection. That being said the plugs were all gapped to .050 - .055 ... not optimal. They also had seen better days. The plugs are arranged in accordance to the firing order.



The new plugs made no difference in behavior. It would not fire it would just sit there and crank. Then I remembered i had an extra fuel filter lying behind my seat. I swapped that out just because. Still no success. Tried holding the pedal down and cranking. No luck. Then just did some good old key cycles. After 10 I cranked, and it turned over. After repeating this process 3 times it started under its own will. (Fuel Pump or EEC?) The downside is now i have a mystery check engine light. I will try my OBD1 scanner and see if it sheds any light on the code. The madness continues.

I also went back about 30 minutes later and tried to fire it back up to move it. It started right up, but barely stayed running. It was loping so hard it sounded like I had put a very agressive cam in it and it was running sub 500 RPMs. But it wasnt stalling. Turned it off key cycled it a couple more times and it started and idled normally. Still a weird check engine light and bogging above 2500 RPMs.

 

Update: OBD1 Scanner would not self test. The fuel pump is back to running continuosly. While under the hood I noticed I could hear what sounded like a leak near the schrader valve on the fuel rail. I am unable to determine where it is coming from. After some fenagling with relays I was able to determin the fuel pump and EEC relay were clicking on and off with the key. More messing around with the test port actually got the OBD1 Scanner to enter test mode, but the test would not complete. There has been alot of testing and very little running. Throwing the battery on the charger to make sure that isnt throwing me further off track.

I charged the battery and same results. I went ahead and checked the pressure on the fuel rail. It was 40 PSI on the nose, but the fuel pump continues to run. Upon turning off the key the pressure began dropping. It dropped 10 psi in around 30 seconds. Will continue to troubleshoot and update with relevant information.

While reading about the FPR I saw it was controlled by vacuum. Considering I heard a leak I did a further inspection on the lines and found a couple broken. I cleaned the PCM connector, the grounds by the PCM, replaced the broken/cracked vacuum lines under hood, and one white vacuum line under the passenger dash. I turned the key to the on position and it was still running the fuel pump continuously. I tried cranking same result. Went back under the hood with the key on and noticed one of my lines broke again. I began to work on fixing it again and out of no where the fuel pump shut off. Now the problem has seemed to go away for now sans vacuum line. Everything works like it should. Will wait and test again. Included are the repaired locations. One was on a T with a diaphragm. The connector to the diaphragm was cracked and the other line was broken (which broke again on testing) leading to a connector bundle on the fire wall. The second was under the passenger dash.

This is a pic after the test. One broken line and the other one still good.


The line ran down to that bundle with the ROYG wires. The black line coming out across screen to the left is the broken one.

I have no idea what this line does. It has been broken for years. But figured while I'm here do it. I could only get black lines.

I'm wondering if it is a bad electrical connection or a short and messing with the lines temporarily corrected it. Will keep testing.

This morning it was back to not starting and fuel pump was not shutting off. Will continue to pinpoint problem.

 

Update: Finally broke down and got a remanufactured PCM. Truck was in a failure state, swapped it out with the new one and immediately fired up. Will continue to test more and give an update in a few days.

 

Update: Tried to start the truck this morning and she fired right up. This is the first time I have been able to do this in weeks. This seems promising. Will continue to test.

Side note: Between the Cap, Rotor, Plugs, Coil, Oil Change, Fuel Filter, Fixing of Vacuum Leaks, Throttle Body Cleaning, Injector Cleaner, Seafoam, and a new PCM - not shockingly - she is running better than ever. If the trucks stays tried and true, I am thinking she will become my daily again. I did notice that the Oil Pressure gauge now has developed a dance. At idle it bounces in between the "NO" in normal, and then when accelerating it is all over the place. Maybe it is just the sending unit, but that would be unfortunate because I just replaced the sending unit the last time I replaced the clutch. Will dive a bit deeper to see if it is worth cause for concern.

 

Pull the connector off the oil pressure switch and then put a jumper wire between the 2 wires so they are connected, this is what the oil switch does internally when oil pressure is above 5psi, connects the 2 wires together, that's all it does, no ohms no volts, just connects the 2 wires together, its a switch nothing more

Then drive around that way and see if oil pressure gauge stays steady, if so gauge and wiring are OK, the oil switch is the issue......but, could be oil switch has a clog at its passage
Remove oil switch, look if passage is clear, no obvious blockage
Unplug Coil pack(s), you want a NO START
Put towel/rag around open oil switch passage
Crank engine over, this will push out any debris/clogs in that passage

Inspect oil switch, make sure it looks clean inside
Re-install and reconnect
Test if jumping needle is gone, if not then replace oil switch

 

Update: It appears the no start condition has been resolved. Thank you all for all of your help. As for the oil gauge, I was looking all over for the pressure switch and from what I have found, it is on the PS of the block by the head. It was a single pin connecter like similar to this:


Funny enough the connector was not connected. So I plugged it back in and the oil pressure gauge is now pegged at 0.

 

On the 3.0l Vulcan engine the oil switch is on the block behind passenger side head

Picture here: https://www.ranger-forums.com/attach...h-dscn0413.jpg

That's the rear of the 3.0l you can see the cam synchronizer and to the right the oil pressure switch behind the passenger side head

Use a jumper wire and Ground the connector wire for that switch, then turn on the key, oil gauge should show about 1/3 to 1/2
If gauge doesn't show that then gauge is the issue, maybe the wire, but longshot on the wire

The oil switch is the Ground for the gauge, when oil pressure is 5psi, or higher, the switch closes and the wire is connected to the Threads of the switch, so wire is grounded to the engine block
So leave lower threads bare when installing this type of switch
The Gauge has a resistor inside so it will show a partial ground, 1/3 on gauge, but will go up and down a bit with voltage changes from alternator

 

Update: I have been driving the truck to work every day. The no start condition still has not come back. More troubleshooting looking into the oil pressure and looking into your troubleshooting steps, RonD. Plugged everything back together for the night and it started working again. I assume either a wire is going or it was a loose connection. At this point I am going to call all of the issues resolved. As of right now the only thing left on my list to find the squeak coming from under the hood and full brake job. I think it is an idler pully or tensioner pully. Thank you again for all your help. I really appreciate it.