Hi -

I have a '96 Ranger with a 3.0 and about 350,000 miles. It was 'hiccupping' at highway speed, then one day it cranked but wouldn't start. I checked the codes and the computer said it was only getting spark to 2 cylinders, so I checked for spark at the plug end of the wires and confirmed. Got myself a new coil pack, and it started right up ... but it was still hiccupping a bit. Today, it cranks but won't start, and I'm getting misfire codes for 3 cylinders. Also getting a code for low fuel pressure bank 2.

So, if you were in my shoes, what would be your next item to test or replace? I've owned the truck since new, but it's now a 'spare' truck and I'm not interested in pouring a lot of money into it. It's got high mileage and body damage and a questionable head gasket, and I bought an '11 Ranger 4x4 to replace it a couple of years ago. So if the answer is that I probably need to spend a couple-three hundred on a new PCM or something, it's probably time for me to junk the old girl.

 

Looks like it needs a new fuel pump.
If it's been over heated at one time, that would explain a questionable head gasket.
Head gaskets don't fail on their own, something has to cause them to fail, and over heating the engine is the most common cause.

Removing the bed to get at the pump is much easier then dropping the tank.

At any rate, I just wouldn't junk it, I would sell it as a whole for spare parts or try to get something from it, rather then just junking it.

There are other things that will need replacing like the 3 oxygen sensors, if they have been in there since new, they've done their job.
Even though you may not get a code for them, they have a limited life span.

I'm sure the DPFE sensor is still of the metal type, so that should be replaced by the plastic one _ assuming the 96 has one _ it's part of the EGR system and it's mounted right by the throttle body with two small hoses coming out of it.

 

The head gasket is my fault. I did overheat it once. It's like my dad's old tractor at this point, where every time I take it out I have to check the radiator and the oil first. Heater doesn't really work, AC system leaks. The truck doesn't owe me anything. But I'm also paying insurance & annual registration to drive it to the dump once a week, which maybe I should reconsider.

Removing the bed? At this stage in the truck's life, I'm more open to just cutting an access hole in the floor of the bed than removing it. I tried removing the bed once to replace the filler neck and I ended up just jacking up one side to give myself enough room, which was a lot easier than taking the whole thing off by myself.

 

Removing the bed will take some friends.
Me personally, I hate working on the underside of vehicles where it involves removing the gas tank.
Dealing with the dirt, dust and debris falling in my face and eyes isn't fun.
Even with goggles, I still manage to get crap in my eyes and they always get steamed up to the point where I can't see.

The truck sounds like it has passed it's usefulness anyway.

 

It really has - I've just hung onto it because I wanted to keep it running as long as I could. I just squirted WD40 on those two nuts that hold the PCM in place. If I can find a decent deal on one, I might just slip it in and see what happens. Otherwise, it does have a few parts that I wouldn't mind transferring to my '11 (sliding rear window and third brake light with bed illumination jump to mind).

I found a PCM online for $132, which is what I'd expect to pay a shop to spend a couple of hours diagnosing things.

Before I worry about other stuff like O2 sensors or a fuel pump, I'd just like to get it to start and run fairly reliably. That's goal one before I contemplate putting any other money into it. (Goal two is to keep it limping along as cheaply as possible.)

 

Don't start throwing electronic parts at it like the PCM and the sensors.
The PCM doesn't usually give problems, the same for the sensors, they rarely fail, if ever, especially the PCM.
If you want to do something clean up the engine bay grounds.

If the CEL (check engine light) comes on when the key is turned on, then that indicates the PCM is healthy.
If it doesn't come on, then check for a burnt out bulb.
If you remove the PCM, open the cover and look for burned circuits and swollen capacitors, but it's highly unlikely that you're going to find anything wrong visually.
As I said. the PCM is the last thing that usually fails.

I would do a fuel pressure test, but I can't tell you how to do that.

Also clean the MAF sensor, use the special cleaner for this, it's fragile _ don't be tempted to touch the filament.
It's found just after the air filter in the cold air intake tube.

 

"If the CEL (check engine light) comes on when the key is turned on, then that indicates the PCM is healthy.
If it doesn't come on, then check for a burnt out bulb."

It does come on when I turn the key to the 'on' position, then goes out when I turn the key further to crank the engine.

I'm just trying to figure out why 3 cylinders aren't getting spark.

I was thinking that a misfire code meant that my spark plug wasn't firing, but upon further reading I see that misfires can also be caused by low fuel pressure, low compression, bad sensors (including O2), and even a bad catalytic converter - any of those things could apply here. I have the original cat still on the truck, original O2 sensors, and ewith 350k my compression can't be what it was at, say, 100k.

I've read how to do the fuel pressure test, and that looks pretty straightforward. I hear the pump run for a couple of seconds when I turn the key on.

I should probably do a compression test, too - but when I start thinking about doing a bunch of tests, and what I could be doing with that time instead, I gotta admit that the thought of downsizing my Ranger collection by 50% is starting to look like the logical choice. I should have traded it in when I bought its replacement 2 years ago, but I just had to hold onto it a little longer (and it has helped me keep the mileage on the '11 lower). If the '96 truck had a decent body, I might be inclined to think about a remanufactured engine. But it got sideswiped pretty good years ago, and I left the dent.

I did pop open the PCM this afternoon and didn't see anything obvious inside. Looked pretty clean and solid, actually.

Well, luckily, I don't have to be in a hurry to do anything (and that's how trucks end up behind the barn with weeds growing through them).

 

I would add that it's been a long time since I changed the fuel filter, so if I just wanted to experiment without tossing a lot of dough at it, I should probably put a new fuel filter in and see what that does. Could be the cause of the low pressure reading, and that can pop a misfire code.

 

Update: I put in a new fuel filter, which it really did need, and that didn't magically solve things. It sputters and seems so close to starting, but it just doesn't quite catch. But now it also backfired a couple of times as I tried to start it.

My next step is going to be to test the fuel pressure with Key On Engine Off. I can do that test for free and it'll tell me something about the fuel pump. I can also clean the MAF sensor this weekend without investing anything but time.

I still think the problem is that 3 cylinders aren't getting spark, and it's not going to run without spark. The plug wires aren't that old, and I recently put in a new coil pack, so I doubt it is failing after a week or so. But a fuel pressure test will give me more info, before I give up on the old girl.

 

If you found a bad coil and replaced it and now it will not start.

My guess is high resistance in the plugs and wires could have caused high voltage from the coil to fry itself again.

Since you are dealing with a old truck with high mileage, I am guessing you are dealing with more than one problem.

If this was my truck, before I spent another dime on it, I would pull a compression test.

This will tell you if your old friend is worth saving or if it needs a few hundred rounds of ammo to finish it off humanly.

 

Thank you EA Outlaw and Jeff R1 -

Updated update - I put a fuel pressure gauge on the fuel rail schrader today and got 40 PSI that holds well after the key is turned off. So it looks like the fuel pump is OK.

I agree on the compression test - I've got a gauge and some free time next weekend. My only other two guesses at this point are that the timing chain has jumped a tooth, so the timing is just too far off for it to run, or that the injectors are clogged. From the way it's been running rough for a while, clogged injectors might be a good guess, but as you say it could be multiple problems.

I put a spark tester in each of the plug wire sockets on the coil and got a spark at each one, so I'm still getting spark from the coil pack. The plugs and plug wires aren't all that old - I've been good about changing the plugs and I did the wires at a year or two ago.

I don't know how to test the injectors, but I imagine I can find a tutorial on youtube.

 

The compression should be up at around 160 to 165 psi if that's healthy.
Very unlikely the timing chain has jumped, there's no tensioner involved on these engines, just two simple sprocket gears and a big chunky chain
I've never read anywhere that in all the years that the Vulcan engine was in production that a timing chain has ever jumped, or broke for that matter.

If you think the injectors are clogged then run a few cans of Sea Foam through the tank.
And yes, there are several videos on how to test and clean fuel injectors, but that requires the removal of the upper intake manifold.
Not difficult to do, but requires a fair amount of undoing to get at the fuel rails.

Check your spark plug wires anyway.
If you don't have one, get your self an ohm meter, they come in handy for many other things too, not just working on cars.
My longest wire is at 1.46k ohms _ not very high.

Manufactures use Kevlar in their wires, that stuff breaks down after a while and when the wires are handled, especially incorrectly, they stretch and the resistance goes through the roof.
Heat also breaks down Kevlar causing expansion and contraction of the wires increasing the over-all resistance.

Fuel pressure is low, but it may be OK for your 96, my 99 spec is much higher at 60 to 65 psi.

When was the last time the oxygen sensors were replaced ?
If they have been I there for the whole 350,000 miles, then they need replacing.

EDIT:
Also check your fuel dampener, it's right next to the Schrader valve with a vacuum line coming out of it.
With the engine off, pull the vacuum line of, there will be no smell of fuel or any fuel in the vacuum line of it's healthy.
The dampener will also hold vacuum if you have a vacuum pump to test it, if it's working properly.

 

Thx - good advice. I was thinking of a couple different ways to test my wires this morning; ohm meter was not on the list. I have a multimeter with ohm function, so that'll be the easiest way.

I think fuel is probably not the problem. I gave the intake upstream of the MAF a good shot of starting fluid & cranked the engine as in this video - - and it didn't start. That suggests to me that my main problem is spark related (as does the way it was 'missing' for a while leading up to this) rather than fuel related. The pressure reading I got was within spec for my year, according to my Chilton's.

If these engines aren't known to jump timing, then plugs and wires are about the only thing left. It would be kind of funny if it was just bad wires - my neighbor and I checked them at the plug end and he wasn't getting spark, which is why I changed the coil pack. Then I tested the new coil pack at the coil itself ... so the wires haven't been tested. I think I'll do that before I do a compression check. If a $20 set of wires gets it to limp along for another year or two, I won't worry too much about the compression at this point.

 

I tested the spark plug wires this evening. With the ohmmeter set to 20,000, the lowest reading I got was 4.82 (shortest wire) and the highest (longest wire) was 7.10. There was a 5.3, and the remaining 3 were in the high sixes. So, if I understand my ohmmeter correctly, my wires are in the range of 4.82k and 7.10k ohms, which seems within spec from the reading I've done. They looked to be in decent shape (no cracks, etc.)

So I guess it's not going to be as easy to fix as just sticking on a new set of plug wires. This weekend I guess I'll do a compression check and test my spark plugs while I have them out.

 

Sorry, I have been reading my meter wrong.
My longest wire is reading at 1.46k, so it looks like some high performance wires were installed.
Not 14,000 ohms...
I'll correct my other post.

My wires are new.

My truck sat for 8 years and the owner sold it through a local garage and he put the new wires in. (amongst other things)

Check the gap and resistance of your spark plugs too. When I've measured resistor plugs in the past, they are around 5000 ohms.
Out of the box gaps are not always right either.

 

Hi Jeff,

Thanks! That certainly makes a difference. I just did some extra reading this morning and from what I'm reading it looks like it should be not less than 1000 ohms/foot and not more than 10,000 ohms per foot. So if a wire is 18 inches 1500 ohms is the lowest it can be and 15,000 ohms is the highest it can be. I'm hitting right about in the middle of that range, so I don't think the wires are my problem. At least, I'm not convinced enough that they're the problem to invest $20 on new ones.

Time to do a compression check this weekend. At this point, I'm almost hoping it has too low compression on multiple cylinders so I can call the mystery solved and call it quits on the truck.

 

So, I got some compression readings today. I only did a dry test - knowing whether it's the rings or the head is kind of beside the point for this truck, as I'm not going to fix low compression. I got 5 spark plugs out and #6 cylinder is stuck in there (and I've managed to crack the porcelain).

Anyway, the readings I got are 1. 100 2. 92 3. 90 4. 110 5. 109 6. ?

The manual says none should be under 100, and all should be within 75 psi of highest reading, so I've got two below spec and one that's barely within spec, plus two more that are well below that 'healthy' number of 160 or so.

I think my poor old truck just doesn't have the compression it needs.

 

The low readings may be from fuel washing the rings, I would do a wet test after I disabled the fuel pump.

Do not give up on the truck till you know what is wrong for sure.

add one ounce of clean engine oil into each cylinder then crank it over with rags over the holes to collect as much of the oil coming out as possible.

Then do the compression test again.

If you keep cranking a engine while it is delivering fuel but no spark you will wash the oil from the cylinder walls lowering the compression.

I think the compression will come back.

If this is the case let us know and we can try and help you further.

But you will need to get that other spark plug out. so do not give up on that yet.

 

Remember to hold the throttle body valve open all the way when doing a compression test.
And by holding the throttle valve open, you tell the computer that it's in a "flood" mode.
This will shut the injectors off.

 

Sadly, the #6 spark plug broke in half, so the threads are still in the hole but the half from the hex nut on up is in my trashcan. To fix that would require the head to come off, and if I were doing that it would make sense to do a complete rebuild ... and on a truck this old with a bunch of body damage it just isn't worth it. Time for me to give up. :-(

 

That sucks, but there are extraction tools.
This happened to someone else here.
If the whole insulator came out then there should be hole to get the tool into.

It depends how patient you are.

At any rate with compression numbers like that, it needs a valve job for sure.

If it wasn't pushing blue out the exhaust, the rings are probably still OK _ or as good as they can be at 350K.

 

The insulator cracked and part of it came out with the ring of metal around it - so part of the insulator is still in there and I don't think I can get an extraction tool in. Doing a valve job is more than I would want to put into keeping this truck going. It's time for me to let it go, and enjoy my 2011 4x4 Ranger. I only have 35k on that one, and mostly I ride a motorcycle anyway.

 

OK...
Yeah, with the insulator still in there...

I think you've done all you can to make sure the truck isn't salvageable.

 

I am sure there may be some well armed people in your area that can and will help remove that stubborn spark plug.