I finally had the opportunity to check the fuel pressure on my truck today and here are the results:

(All tests done with EEC #6 pin grounded)

-Key on, Engine off, regulator vacuum connected/disconnected--38 PSI

-Engine idle, regulator vacuum connected--29 PSI
-Engine idle, regulator vacuum disconnected--38 PSI

-Engine on, wide open throttle, regulator vacuum connected--32 PSI
-Engine on, wide open throttle, regulator vacuum disconnected--38 PSI

I'm still looking for my manual to check the manufacturer's specifications. In case I don't find it before I log on here again, are my readings within the limits?

 

Here are the specs:

Key On Engine Off 35 - 45 psi
Key On Engine Running 30 - 40 psi


Did you happen to run a High Speed test (same setup as above w/vac off, under hood, accelerate engine manually) and watch for pressure to remain within 5 psi..........? This is a load type test and picks up on any restrictions at the filter, restrictions at pump (or bad voltage) or improper adjustment of the regulator.....

Good luck !

 

What's the build date of your truck? Not to be picky but your truck is titled according to the 'manufacturers statement of origin' (MSO). '96 models went into production 7/95. No such thing as a '95 sold as a '96… not since the Feds got involved in the late 60's.

If the 10th digit of your VIN is "S" it's a '95… if it's a "T" it's a "96"….

 

Still running the original ignition coil?

What do the plugs look like? lean? rich? normal?

Fuel pressure tad low no load and while might not be a problem (say nothing more than small error in your gauge for example) need to hook up the gauge so you can see it from the drivers seat for road test. Monitor fuel pressure under road conditions engine under load and at speed.

You stated back there someplace you had replaced the fpr? no? if so pinch off rubber section of the return line up by the fuel rail see if the pressure value increases, pressure should continue to rise more you restrict flow back to tank (same thing fpr does you'd be forcing the issue verify pump is up to the task if conditions are otherwise "normal").

If not suggests pressure, or rather the fuel, is being pumped to other tank and or the pump you installed is faulty, fuel pickup screen is restricted/clogged etc (but you'd suspect that, you've seen inside the tank failed to clean it as necessary, doubt that is the case).

 

"No such thing as a '95 sold as a '96" is what you are gathering out of this but that's not exactly what I'm saying. What I'm saying is that it's a '96 according to registration, title, etc. but was built in '95 to be sold as the '96 model year. You obviously know what I'm talking about how vehicles sometimes are built in one year but get sold as the next years model since you listed exactly what I'm refering to. I feel like I'm talking in circles with some of you. What about this is not clear? I know what year my truck was built, what year it is, whether or not it has a MAF sensor, and just about every other detail about it. Did you read all the information I listed about my truck and what I've had to work on? For someone to do all that but still not know their truck was a MAF equipped vehicle would be quite surprising.
In order to help people over the internet you need them to be sure of all the details, I'm aware of this, but how many times do I need to say it's an OBD1, non-MAF 460 made in 1995?
All this nonsense aside, what does it being MAF or not have to do with my issue anyway? I've fixed many vehicles this year alone that had MAF issues and the way it's acting does not feel anything similar to the way they were acting aside from the lack of power.
My truck has no hesitation, no sputtering, no backfiring, none of the usual symptoms of a dirty or faulty MAF sensor. None of this really matters anyway because my truck does not have a Mass Airflow Sensor.
Please, no more talk about MAF sensors, you're giving me a headache.

 

The model year is important… clouding the issue with "built in '95" isn't helping. The first '97 F150's were built in '95 for the January, '96 intro… the build date is only important when there was an engineering change of some component and you need to know that date to get the correct part.

We ARE trying to help here… I hope you get it sorted out. My work here is done.

 

The answer to your question is in the post of mine which you quoted.
According to the specs I'm within the limits. I was hoping this would be the problem.

 

Did you ever check the compression? You stated in your original post that you would, and I just read through the whole thread again without seeing any numbers you may have found. Your fuel pressure numbers sound good enough to me according to the ranges given by others here, your spark is obviously good with the easy start and revving. Lost compression is the only other thing that could cause a power loss in my opinion.

I know this thread got a little off track with "what about this, that, and the other?", but compression is one of the basic things an engine needs to make power.

 

The only other thing I can think of, and what I would check if it were mine, is to see if the timing is advancing beyond the base timing. Maybe the distributor is locked up somehow preventing ignition advance or the wiring for the ignition circuit is somehow compromised.

The symptoms you describe sound just like an old *****'s jeep my dad had that the mechanical advance had seized up on.

 

When did I ever say anything that would lead anyone to believe I thought the model year was not important? However, when it was built is not, nor was ever in question seeing as how I made it painfully clear very early on that my truck was built in 1995 and does not have OBD2 nor does it have a MAF sensor. You are the one "Clouding" up clear as day statistics.
Again, why are you bothering to cloud things up with an example of an F150 being made two years before it's model year when I was the one who first stated that vehicles are sometimes made in one year and then sold in another? You're not telling me something new. That was the whole point of all this about my truck being made in '95 but sold in '96.
I know some of you are trying to help and they have helped but you, for some reason or another, do not believe there is a possibility that someone might actually know when their truck was built and all you're adding to the mix is an off topic discussion on build date semantics.

 

No, I didn't do the actual compression test yet because for some reason or another, I thought it was more important to check the compression on my '78 Bronco which I don't have on the road instead of the truck I actually drive. I actually have not even touched my F350 until today when I did the fuel pressure test. I did however take the easy road quite a few weeks ago when I was suppose to do a compression test. I used an infrared thermometer to check the temp of each header primary tube and every tube was within a few degrees of the other indicating all cylinders are functioning as they should.
To answer the question of the other guy who asked about the coil and spark plugs, yes, the plugs and coil were both changed back when power first started to drop. No difference was made then but that doesn't mean changing my plugs now wouldn't hurt any.
Thanks for the suggestions guys. See how nice we can all get along when everyone stays on topic!

 

That's a good suggestion but I checked timing when this whole power problem started and it was at 10°BTDC. I've considered bumping it up to 12 or 14° but that is not going to cure the problem. Usually a timing bump will add a little pep but I don't think it'll help an engine that feels like it has 70hp suddenly jump to 245hp.
When I checked the timing at different RPM's it advanced as it should so I don't know if there could be an issue with the distributor or not?
I've been chasing down this issue for so long now that I've started to consider just swapping in a complete donor engine(one without an exhaust leak at cylinder head).
The sad thing is, my engine only has 90,000 miles. It ran like a champ when I first bought it but after it sat for a 6 month period, it was never the same truck again.
I've taken this truck to the same garage for it's annual state inspection for the past 17 years and he never noticed anything wrong while doing his inspections. When he tests it he says it's a nice truck but he's never hauled a trailer with it nor has he ever stomped on it to feel it fall flat on it's face. Being that I've always done my own repairs whether it's an oil change, a valve job, or an engine swap, I have not asked him to diagnose the problem. I figured I'd find the problem long before having to take it to a garage and have to pay out the you know what to chase down some mystery problem.
Being that I installed a new gas tank, fuel pump, fuel filter, new spark plugs, new plug wires, new ignition coil, new air filter, swapped in a 5-speed (which ruled out a faulty torque converter on the C6), checked fuel pressure, checked timing, checked brakes(to feel for dragging), gutted catalytic converter, replaced O2 sensor, installed headers(hoping to improve power), and checked the temperature of all header primary tubes to check for loss of spark or compression at each cylinder, at this point with no such improvement in power, I'm at a loss.
I'm ready to just buy a complete, running EFI 460 and just use my engine for parts. I really don't want to pay a garage to "fix" it and end up paying just as much for their repair as I would for just buying another complete engine.
I have to put a new roof on my house(by myself) in two weeks, find out why my tractor's backhoe lost power and when that is done I have to dig diversion ditches on the back 40 of my property, lay french drains around my property, and then dig up around my foundation and install a water barrier. My friend also wants me to install a new PTO shaft in his tractor, my wife needs me to put new brakes all the way around her Escape and install new front wheel bearings. My wife and kids are on my back to clear land in our back yard to expand it.
Lets see, what else? Oh, some dorky kids two farms down the road are bugging me to restore their Massey Ferguson MF10, my mom needs new brakes on her car and new exhaust before inspection runs out this month and I refuse to let her take it to a garage so they can stick it to some old lady on a fixed income, and when those few tiny little tasks are taken care of before summer's end, I hope to have time to get my F350 fixed and my 7 year long '78 Bronco restoration finished with time to spare to get my treestand repaired before opening day of bow season. Perhaps I could even find the time to finish putting together an old tractor that I planned on bringing to the tractor show in the fall......TWO YEARS AGO!
It seems as though everything I own is either junk or is falling apart. I swear, everything I own needs at least some degree of repair and there just never seems to be enough time. There is not enough time to fix that which I NEED to fix let alone time to fix up the things I want to fix for fun. All work and no play makes Johnny a dull boy!
Sorry for the lengthy post and I know everyone has their own problems but I wrote this to let you guys know why I haven't solved this issue with my truck yet. I'm not lazy, but when I'm not battling health issues I'm trying to fix 10 other things besides the problem with my truck.
I thank you guys for sticking with me thus far.

 

Man --- that "to do" list sounds like mine and I can tell you honestly that no matter what you own ALL of us feel sometimes that "it's either junk or falling apart" --just part of life (I guess)..........I got so frustrated with a Ford engine in my 2004 (and had some of the best diesel mechanics going scratch and shake their heads (in frustration) too) I decided to yank it out and do a full conversion...............

 

That is not possible. The engine vacuum should drop and the fuel pressure should go up at WOT and the vacuum connected to the FPR.
The only way to get that is with a bad fuel pump or a bad fuel filter or a plugged strainer under the fuel pump.

The fuel pressures for your truck should be 30-32psi at idle with the vacuum connected engine running and near 40psi at WOT or the vacuum disconnected from the FPR with engine running or with pin #6 of your self-test connector grounded and the engine not running on your 1996 OBD-I EEC-IV system.

Do not go by the shop manual fuel pressure specifications as they are misleading.

My vote is that you have a dirty fuel tank with junk in it plugging up the sock on the bottom of the fuel pump.
Here is a video of one doing the same that had a junk in the tank. It also had a new fuel pump and FPR.:

/

 

The only other thing to verify is the compression then. If it checks good, then I would go over the fuel system again. Maybe it is going lean under constant load in a manner that the wot test doesn't show and the knock retard is pulling timing.

If the engine's basics are sound, I can't help but think that the timing is getting pulled back and the reason it is getting pulled is what you need to find.

Subford posted before I finished this. I agree with his post.