Surging/ WOT Power Loss Issue!!

[94Sport5]

Hello..I'm just another longtime forum lurker that needs some help!! I have a 94 Explorer Sport 4x4 with the m5od. When I first got it, this problem had NEVER occurred..I remember because I have clocked acceleration times before when I first got it before ever doing anything to it or even having it worked on... (9.3 sec 0-60 w/ 3.27 gears btw! ) I could give it WOT in any gear and it would seem very happy and healthy, and would actually pull through the entire gear's power band..so I know I have something odd going on. Well anyways, after having weird coolant problems and later on blowing what happened to be an intake gasket, then having some work done to fix it (intake and valve cover gaskets replaced, and later had the transmission replaced due to internal lockup, and more work later on), only this one problem has come up and never went away. OK, If for instance I need to get on the throttle to pass somebody or in an event where heavy acceleration would need to be used, once the rpms climb to about 3700-4000, I literally lose all my power..the poor thing just falls flat and the engine will even begin to surge like it's trying to push harder but it's being held back. When this is happening there are some times where the rpms will get up to a certain point (3700-4000) then they just wont go higher at all, like I stopped accelerating and power is severely diminished, then other times when it gets up there it will begin to surge as its trying to push through like I said before. I think the clutch is good, it shifts great actually..2nd and 4th gears will grind if i try to shift quick but i can prevent it by timing the shifts right. (Junkyard transmission- bad synchros?)Things I have done to try and help it are: I replace spark plugs and wires (had high hopes this would work because of the symptoms and knew they both needed to be replaced badly anyway), replaced intake tube and box with ifab kit(definitely helped power and added some growl, but did not help the problem I'm having, nor made it worse), replaced the fuel filter, changed oil with full synthetic, and I also went through the koeo and koer diagnostics and it passed both tests...I understand I have some obvious stuff to check yet that I havent listed like checking condition of the coil, or monitoring the fuel pressure while the truck is having the problem..and that's what I'm leaning toward next, that it's possibly the fuel pump (I have run her out of gas a couple times). I have noticed last winter and in the beginning of the year that I was having to cycle the key as much as 3 times to fully prime the lines, but lately it has been doing it in just one cycle. On humid days though or like I said when winter comes around, it gets that way to where I will surely have to cycle the key multiple times to get it to start quickly and as it shoulf. Would that make the problem lead more toward the fuel pump? Or could it possibly be an injector issue? One other thing I'm unsure would have an effect..but I know for sure that when I replaced the thermostat I by accident put the weep hole portion pointing towards about 5 o'clock..I did it in -20 degree weather and definitely rushed it..it wasn't until a week after it was done I had read the weep hole should be up at 12 o'clock specifically. I plan to turn it back before the snow hits anyway so i possibly have a lil better heat, but yeah just so thats out there. I have thought maybe the computer isn't letting me have full throttle because the temp wont hardly ever even reach the n in normal, but it does get into the brackets..and I do get heat so the thermostat must work, but that idea just isn't fitting with the severity and consistency of the problem.. But hey sorry for the big post (I know there's plenty on here) and the rambling..and I apologize if this is in a wrong section as this is my first time posting. Any help will be greatly appreciated and I will be detailed about anything someone needs to know! I absolutely love this truck and I feel it can/will last me a helluva long time! Thanks!!

 

[974X4BLACKSPORT]

Definitely need to check the fuel pressure when under load. Also, check for kinked or pinched fuel lines, the metal and rubber ones, this can restrict fuel and cause a loss in fuel flow.

 

[94Sport5]

Thanks for the reply! Will be testing the fuel pressure today while recreating the issue, I will post what I figure out.

 

[Michelle Dandurand]

How are your catalytic converters ??? Are they plugged, mine were and caused the same thing. I just removed it and replaced it with a piece of pipe and all good. I do live in a non emissions test area.

 

[Turdle]

^^ good suggestion.

You might also read through this thread, and compare your ecm to this

4.0 ohv running issues

 

[94Sport5]

Well today I attempted to check the fuel pressure and the test kit at o'reillys didnt have an adapter to fit the shrader valve. Of course this is the case..I have read a few posts regarding this exact issue but nobody specified where they found an adapter to work?? I think i found one online but really want to find one in store..And on another note, I believe my truck has a camshaft position sensor/camshaft synchronizer. I have the infamous bird chirp that will inevitably start happening the longer I drive. It's definitely coming from the rear of the engine about in the middle, and i know the synchronizer is hard to get to. Would this be causing an issue that im having? Would it throw a CEL? Also, I plan to get a full cat back installed in the coming weeks for $275, they plan to remove the rear cat and replace all piping with 2 1/4" and replace muffler with a flowmaster 40 'clone'. I myself have wondered about the cats. How would a guy go about testing them for flow?

 

[94Sport5]

Some more info.....I used to have a constant CEL. Never remembered when it came on cuz this was around when I first got it but upon inspection of the fuse box I realized the o2 sensor fuse was blown, so I replaced it and the light never came back. I have also found while doing an oil change that the vehicle has ran for an unknown amount of time with the pcv valve unplugged and just dangling from the intake manifold! Haha I plugged it back in of course but again am unable to remember if this surging under WOT problem started in the time of those problems..I wish I remembered a little more but yeah, any useful info I remember I will post it! Thank you everyone for your replies! This forum is and always has been amazing!

 

[massacre]

That PCV valve will cause a big vacuum leak
Surprised it ran like that

 

[94Sport5]

Exactly what I thought when I seen it, in all honesty I remember it not making much of a difference plugging it back in, except a very slight noticeable mpg gain. Same with that o2 sensor fuse! Any thoughts on the camshaft synchronizer "bird chirp"?

 

[massacre]

Exactly what I thought when I seen it, in all honesty I remember it not making much of a difference plugging it back in, except a very slight noticeable mpg gain. Same with that o2 sensor fuse! Any thoughts on the camshaft synchronizer "bird chirp"?

Well if you remove the belt and it is still chirping, I would suspect cam synchro.
On my motor I had to remove lower intake to replace cam synchro as there was not enough room with lower intake installed.

 

[Turdle]

Well if you remove the belt and it is still chirping, I would suspect cam synchro.
On my motor I had to remove lower intake to replace cam synchro as there was not enough room with lower intake installed.

I think you meant to say "upper plennum had to be removed" .

 

[massacre]

I think you meant to say "upper plennum had to be removed" .

Nope, I removed the upper plenum and that was enough to get at the hold down bolt and I could turn the housing and lift it up, but not enough height to remove it from the block.
Maybe I was doing it wrong but I could not get it out. The lower intake sticks out over the top of the synchro on my truck.

 

[massacre]

You know the more I think about it, maybe I was doing it wrong. But I tried to remove it with lower intake in place, and could not no matter what angle I tried.
Could have just been me though, def try it with the upper off and the lower on, maybe you will find a way to get it out. It’s definitely worth a try for sure

 

[Centaurious]

You can try introducing about 1/2 of a shot glass worth of motor oil into the Cam Synchronizer, it is the top bushing that is dry. Pour it in and wiggle the shaft to get the oil down the bushing. It is not an optical sensor so any oil will not matter. Distributors used to have a felt washer that you saturated to keep that bushing oiled.

Did the problem occur after you tried to remove the Cam Synchronizer? That controls the timing of the injectors. If you didn't get it and the shaft back in the same position it may be your problem.

There is a procedure to set the timing without a plastic holder that is located in the forum that you could use to test your current cam syncro timing and to set it if it is wrong.

Best of luck.

 

[94Sport5]

Great reply! No i haven't attempted to remove or oil it yet. It's kind of weird because while I'm driving it will start bird chirping out of nowhere and usually get progressively worse, then when pullin into the driveway and the vehicle stops, the chirp goes away. Again this is not the belt or pullies but as I suspect, the cam sync..I have a feeling its either this cam synchro or the fuel pump giving me this loss of power! Where can I get an adapter fitting locally to hook up fuel gauges? Oreilly auto's kit doesn't have the correct size or the fuel pressure would have been checked by now. Also to note...the other day I was running out of gas, not on purpose, and before i realized it was going empty, when i would accelerate it would cut out power the exact same as when it has say quarter or half tank in it, except the power loss was way more noticeable and at a lower rpm. Is this pointing me to a weak fuel pump?? I'm starting to lean that way. You said the cam synch times the injectors, if its squeaking the way it is would that mean its failing in any way? Could it be contributing to this problem? If i can oil it ill definitely try. Would I just take out the 2 screws, barely lift it straight up and squirt oil down into there? I always have lon g posts sorry! Plenty of questions. Thanks again! Every bit helps.