93' Ranger 4.0L misses throughout driveing range.
has new plugs and wires, spark look orange so I replaced the coil pack. no change. I also changed fuel filter and had the EDIS6 Ignition Module tested (good)
could the crank pos sensor cause this?
thanks Rip

oh yea what is the fuel psi susposed to be? I'm getting about 35psi.

 

Wlcome to FTE.

Orange/weak spark, have you had the electrical system load tested????

If the battery or alternator, or battery cables & their connctions on BOTH ends, are laying down on the job, it can cause a weak spark.

Under what condition was the fuel pressure measured????

As posted it's on the low side, but any of the above could affect it too.

When last was the fuel filter changed????

Just some thoughts to ponder.

 

Addition questions.

What brand wires did you use. What brand spark plugs did you use. Does the engine have a good ground? Have you run a good injector cleaner through? A bad MAF sensor can cause a bad misfire, try disconnecting it. If the operation actually improves, then you have a bad MAF, try cleaning it. Or you could just replace it.

 

The fuel psi was checked: engine off key on.
the fuel filter is new.
no haven't had it load tested.
the plug wires are Car Quest (they are new) the guy I bought the truck replaced them as well as the plugs and fuel filter chaseing the same problem (he gave up and sold the problem (truck) to me .....cheap .....maybe
I just picked up the truck and It was in this condition when I got it (good price, good body)

I'll check the stuff suggested.......Thanks for the help
Rip

 

OK, on the fuel PSI check, what reading did you get with the engine running?????

I can't remember for sure, but I think your 93 has the fuel pessure regulator on the fuel rail, if so, pull & plug the vacuum line with the engine running & look for about a 10 psi pressure drop, if the regulator is working.

If you don't see a psi drop with the vacuum line disconnected, also inspect the vacuum line inside, for the presents of fuel.
If it's wet inside, the regulators diaphragm is likely going bad.

Once you know the electical system is providing the needed voltage & current to the ignition system, you can move on, in your trouble shoot.

On the plugs & wires, Bear River has a good points on the dirty MAF sensor & plugs & wires.

The weak, orange colored spark has me concerned.

With the waste spark coilpack ignition system, you'll need double platinum plugs, of the proper design & heat range, to prevent excessive plug electrode wear.

This system works the plugs & wires TWICE as hard, as the single coil/distrbutor type ignition system, because the plugs are fired on the power & exhaust stroke, so the wires & plugs have to be designed right for the system to operate as specified & to tolerate this extra work load.

Because our ignition system is a big R/C (Resistance/Capacitance) network, we must be mindful, that the R/C of the plugs & wires need to be within Fords specifications, lest the spark timing, duration, heat, ect, be adversley affected.

Most folks stay with the OEM Motorcraft plugs & wires, as they have to meet Fords specifications & their quality is good.
Some have successfully used Autolite, which makes Motorcraft. This doesn't mean we can't use someting else, just that we should be sure they meet Fords specifications.

Just because the plugs & wires are new, no matter the vendor, doesn't automatically make em good, so if your other checks come to naught, take the time to check each spark plug & plug wires resistance from end to end & wiggle them a little & look for any big change in resistance. The plug wires should be about 1000 ohms per inch of length, 30K ohms max, regardless the length.

Check the plugs for inside & outside ceramic chips or cracks & make sure they are torqued to spec.

If you haven't had the vehicles computer scanned for set, or pending trouble codes, I'd consider doing that also, as they could offer up good clues on where best to look next, in your trouble shoot.

Let us know how it goes.

 

Thanks to everyone for the help.
I haven't worked on it in a couple of weeks (been too busy)
trying to get back to it today, will let you know how it went.
rip

 

Clean the maf with maf sensor cleaner or electrical contact cleaner, Gas line dryer sounds like it sits around a lot with less than a full tank, Overnight the tank inhales all this humid summertime air and it sticks to the empty space in there, Eventually it builds up enough to cause problems. A couple bottles of dedicated gas line dryer will burn out the water!

 

----Blue Beast the maf sensor looks real clean (new condition)
Will put in dry gas tomorrow (done for the day)

----Paw Paw I checked the fuel psi regulator like you said and there was gas in the vaccume line, so I replaced it. No change.
Then I tested the fuel psi with the engine running and it was 30 psi, then I unpluged the vaccume line, plugged it and retested. the psi went up to 40 psi not down.
?????????

I checked the plugs and they were inproperly gapped so I fixed that. still no change.
(after I fixed the plug gaps it smoked when I started it?)

 

oh yea Paw Paw, I checked the resistance in the plug wires and they were within range......
the #5 plug was wet with gas....but the wire checked good.

maybe the plugs just aren't hot enough. do you know the Autolite plug that is the right range for my 4.0 (don't really want to buy new plugs and wires if that isn't the problem)

I'm kind of getting tired of chaseing problems with money.....
I don't feel bad about the $100.00 I spent on the psi regulator because there was gas in the vaccume line so it was going bad.........anymore Ideas?

 

It wouldn't hurt to clean the maf especially if you have a K&N or don't change the air filter as recommended. Just a couple micron deep of dirt on it and it will throw off the reading it gets! It is a heated wire that with the air rushing by it cools it down and the amount of energy it takes to keep it at the set temp. is what tells the comp. how much air is getting pushed into the motor. So a bit of dirt coating will insulate the wire and throw it out of whack!! What color was the smoke? What color is the plugs insulator? That can tell us how it is burning and if they are too hot or cold!

 

My you've been busy today ripetro.

You may have more than one problem.

Your fuel pressure looks ok now.

On rereading my above post I see I miss posted about the fuel pressure dopping, when the regulators vacuum line is removed, it should rise as you found.
I think I got confused with the test below.

When you do a KOEO pressure test, the pump should run for about 2 seconds, to build fuel pressure, then shut off & the fuel pressure should hold steady at 35-45 psi & not leak off, for the specified time.

THEN, when you start the engine, with the regulators vacuum line attached, the pressure should drop 3-10 psi & it should regulate between 25-35 psi at idle.

With the engine at idle, when the fuel pressure regulators vacuum line is removed, the fuel pressure should be between 35-45 psi, like it was at KOEO (you should see it rise, just as you did).

Since you've noticed the #5 spark plug was wet with fuel, I'd kinda suspect the #5 fuel injector is leaking down, so the above KOEO fuel pressure leak down test, may tattle on it.

Good idea imo, to replace the fuel pressure regulator, since you found fuel in it's vacuum line. That was a unmetered fuel leak.
Sooner or later the regulators diaphragm would likely have completely layed down on you.

On the spark plugs, look in your owners manual. My repair manual shows AWSF-42p, for the 93-96 4.0L, but if you have the EDIS coil pack ignition system, you'll need double platinum (PP) plugs, to avoid excessive electrode erosion wear.

Good idea to regap the plugs & test the plug wires resistance & good to hear the wires all tested ok, so now you can remove them from your suspect list.

How does the spark color check out now???? That orange color you posted about, is still bugging me. It should be blue & really snap smartly.

Did you ever have the electrical system load tested????? A weak, battery, alternator, high resistance battery cables, or connections, can cause a weak spark & fuel delivery problems.

Most atoparts stores will do a no cost electrical system load test .
While there have them scan the computer for pending or set trouble codes & post ALL that are found.

Just some more things to ponder.
Keep us posted on your trouble shoot.

 

---blue blast the smoke was blueish (maybe a little oil seeped in when the plugs were out?) and the insulator color looked normal (kind or rust colored) except #1 that looked a little black (rings or valve seal leaking?) I'll go ahead and clean the Maf (it sure looks clean though)

---paw paw do you think I need to replace the #5 injector?
I haven't had the electrical load tested (truck isn't street legal yet, kind of wanted to get it running good first, but it looks like that is what I'll have to do)
as far as the spark color looks I haven't rechecked it yet.
I did notice that the pos battery cable had been replaced. (the new one is kind of long) not sure why, it was like that when I got it.
Can I do a load test with a multi-meter or is that something I need special equipment to do?

 

OH yea can someone tell me what the two vacumme lines under the center of the I.P are for I found them just hanging and one was sucking so I plugged them both.
one is black the other is white.

 

The loose IP vacuum lines likely go to the Heater/AC control panel.

Yes you can do a sort of home made load test of the electrical system, while monitoring the battery & alternator's output with your DVM.

First, if you don't have a hydrometer to measure each battery cells state of charge, or if you are using a sealed battery that you can't get to the electrolyte, to meaure it's specific gravity (sg), then you can check the batteries no load, state of charge, with your DVM, by turning off all electrical loads & measuring the battery voltage accross the posts.

99% = 12.60 vdc-- sg = 1.265
90% = 12.50 vdc-- sg = 1.250
80% = 12.42 vdc-- sg = 1.235
70% = 12.32 vdc-- sg = 1.220
50% = 12.06 vdc-- sg = 1.190
40% = 11.90 vdc-- sg = 1.180
30% = 11.75 vdc-- sg = 1.160
20% = 11.58 vdc-- sg = 1.150

So if the battery state of charge checks out ok, then measure the battery voltage at it's posts, while craking the engine, it shouldn't fall below 10 vdc.

Then with the engine running, turn on all the lights & switch the blower speed to MAX & check the voltage accross the battery terminals & at the power distribution box. It should read at least 13.2 volts, or higher, if the alternator is outputting ok & the battery cables & their connections are clean, bright & tight.

This will sorta check how the alternator, battery & battery cables & connctions will handel the electrical load. It's not as good as the load tester, but should give you a rough idea, for instance, if the ignition system may be seeing low voltage & giving a weak/orange colored spark, or maybe the fuel pump, or fuel injectors are recieving lower than needed voltage, to operate as specfied.

On the #5 fuel injector replacement question, I think you first need to make sure some basic things are checked.

Like perform the fuel pressure leak down test, to maybe get a clue as to whether the injector may be leaking & to do the electrical system load test, so you know all things electrical, are recieving their specified voltage to properly operate.

No need to throw parts at a percieved problem. Just because we suspect the #5 injector may be leaking, doesn't make it bad, it may just be drty, or not getting enough voltage to operate properly, so test, verify, THEN if you have to, replace.

The fuel injectors impedance should be between 12-16 0hms, so if you can get to it to remove it's electrical connector & check the injector with your DVM's ohmmeter.

If you decide to clean the MAF sensor, remove it & use a on residual cleaner that says it's formulated to clean MAF sensors.

Let us know how your troubleshoot goes.

 

Just thinking about it I remember my old f250 with a 351 had rust colored spark plugs once. Had a tendency to run warm. Had it run on a scanner/computer they found dirty injectors. I replaced them all, but they can be cleaned if you have an injector shop nearby. I think I paid around $30 each to replace them then, about 7 years ago. So they should maybe be cheaper by now.

change the fuel filter and clean the lines before you put injectors in if you go this route.