Ugh... 92 Explorer Hell..

[natenkiki2004]

I found this out putting the ground strap on.

Is there not supposed to be a sound when you pull the lid off to see the fuses underneath? Ya know, where it says "push the tab to open" ya know??

Kind of a plasticy snap sound maybe but nothing like you described. No clicking or computer sounds. A faulty relay may explain why your engine was dieseling, the computer may still have had power.

 

[MistahYebba]

Kind of a plasticy snap sound maybe but nothing like you described. No clicking or computer sounds. A faulty relay may explain why your engine was dieseling, the computer may still have had power.

I took a video of it for you. I hope you can hear it.

There is a computer sound very similar to a disc drive closing, then a spring-like sound coming from under or near the throttle body.

It didn't happen every time as you can see, but as you see I was jiggling it and punching it and when I slammed it down one time it did it.

 

[natenkiki2004]

Ok, forget EVERYTHING else, that is your #1 priority right now. You have relay or relay harness issues, without a doubt.

Was the key in the "on" position when you did this? If not, that's even more dangerous. Do not drive the vehicle in this condition, it can suddenly die or keep running when you turn it off. Either condition results in you losing control of the vehicle.

Unplug the negative battery cable and remove the power distribution box. You should be able to see broken/bad wiring. If not then take a look at the relays themselves. You can't really tell on the outside if they're bad. But look for burn marks, breaks in the wires, cuts... anything.




Just an FYI, that click and whine sounds like the fuel pump coming on. That click is what all relays do, those sounds are GOOD as long as they happen when you turn the key or push a button. You're probably hearing the fuel pump sound coming through the fuel lines and into the fuel rail. Liquid conducts sound pretty well.

Also something I saw in one of your previous videos... don't twist the key on so fast. Turn it to the on position and listen for the fuel pump then crank the engine. Good habit to get into. Builds fuel pressure and you can make sure things are coming online before cranking.

 

[MistahYebba]

Ok, forget EVERYTHING else, that is your #1 priority right now. You have relay or relay harness issues, without a doubt.

Was the key in the "on" position when you did this? If not, that's even more dangerous. Do not drive the vehicle in this condition, it can suddenly die or keep running when you turn it off. Either condition results in you losing control of the vehicle.

Unplug the negative battery cable and remove the power distribution box. You should be able to see broken/bad wiring. If not then take a look at the relays themselves. You can't really tell on the outside if they're bad. But look for burn marks, breaks in the wires, cuts... anything.




Just an FYI, that click and whine sounds like the fuel pump coming on. That click is what all relays do, those sounds are GOOD as long as they happen when you turn the key or push a button.

Also something I saw in one of your previous videos... don't twist the key on so fast. Turn it to the on position and listen for the fuel pump then crank the engine. Good habit to get into. Builds fuel pressure and you can make sure things are coming online before cranking.

The key was only in the ignition. It wasn't turned at all. The accessories weren't even on.

So there is fuses in the power distribution box? And under that box, there is a separate housing for relays I'm guessing? How do I remove the box? You mean removing the entire thing that I'm simply taking the lid off of right?

What correlation does removing the lid have with making that sound?

 

[MistahYebba]

One more thing that I feel is important.. It goes "whuurrr" then "click"... then about 1 second later a very faint "tink".. That "Tink" is what's throwing me. The whurr and click are in 1 place, but the tink is under the throttle body. That's the spring sound I was referring to.

 

[natenkiki2004]

Yea, you really need to fix that then. That's your first priority and it could very well be the cause of all your issues.

Under the power distribution box lid is... the power distribution box It has the high-amp fuses. You can take some time to visually check them and maybe put some dielectric grease on their contacts. But, under THAT is a couple of relays, they're larger and they control power to high-amp devices like the EEC-IV computer, fuel pump and more.

*EDIT*
Relays click on and off. I suggest you look up a video on YouTube to see how they physically work, they're pretty neat. You only hear the second click because the first one is quickly followed by the whirring sound. If you listen close, you should be able to hear it click on. It's the same thing that will happen when you turn the key to the on position.

 

[MistahYebba]

All we know is that there's a fuel/air mixture issue. Where, that's the big question.

If it's the fuel pump relay, I could be using more fuel (however that works) in theory, right?

With the IAC plugged in, it could further mess with the air/fuel mixture, right?

This would also possibly explain my severe lack of MPG recently?

Also, it could somehow be associated with the code 57 being as it's electrical and in the area?

Could it also explain the dieseling earlier?

 

[natenkiki2004]

If it's the fuel pump relay, I could be using more fuel (however that works) in theory, right?

With the IAC plugged in, it could further mess with the air/fuel mixture, right?

This would also possibly explain my severe lack of MPG recently?

Also, it could somehow be associated with the code 57 being as it's electrical and in the area?

No to all of the above. Your fuel pump runs at a constant rate when the engine runs, the fuel pressure regulator is responsible for pressure to the injectors and the computer is responsible for flow from the injectors.

Could it also explain the dieseling earlier?

Yes, if the computer still had power, indicated by your relays turning on (the computer turns the fuel pump on) then when you turn the key off, the computer still runs the engine.

 

[natenkiki2004]

Watch this video, it'll open your mind up and has information that is identical to our Explorers:
https://www.youtube.com/watch?v=6UPe5f1s2ak

 

[Bobmbx]

This might help

http://www.explorerforum.com/forums/showthread.php?t=208097

 

[MistahYebba]

Well drop the "fuel pump" part of my question. Could any relay or any wiring short cause all of that stuff?

 

[natenkiki2004]

Be sure to read my above replies.

At this point, I feel that the IAC is a coincidence and a victim of the problem, not a cause. I'm 98% sure your problem lies in relays or wiring nearby. Focus on that, learn about that.

 

[MistahYebba]

Be sure to read my above replies.

At this point, I feel that the IAC is a coincidence and a victim of the problem, not a cause. I'm 98% sure your problem lies in relays or wiring nearby. Focus on that, learn about that.

Watching that video now. Thank you.

 

[MistahYebba]

So.

Before work today I decided to pop the hood and give the PDB a good whack. Turns out it's not only popping the lid off -- you were right about it being vibrations! Just punching it activates that sound. However, you were saying the relay clicks. I definitely hear the relay clicking, but the whine and the "spring sound" I hear is definitely not coming from the relay. I thought the fuel pump was in the back of the car? So what is that sound? Like I said, it's coming from right around the throttle body area.

Interestingly enough, I kept punching it to keep activating this sound.. Then, I started the car. By doing that, I was able to very smoothly drive the car with everything hook up how it is supposed to be! Crazy, huh?! I would guess this means I was sort of "priming" it with whatever is activating when I punch it.. like a lawn mower!

However, I thought the fuel pump was in the back of the car. So why can you hear it up front?

As ScannerDanner would say, CAUSE OR EFFECT GUYS, CAUSE OR EFFECT?!

So...

That tells me whatever is "barely" plugged in must be activating or disabling some sort of vital function that allows the car to run. Whether that be a sensor, a fuel function, or some sort of... I don't even know.. Clearly it is creating an issue!

What do you reckon I'm most likely to see when I pull this PDB off? 2 exposed wires very close together, or something not visible?

Time to troubleshoot further but unforunately I'm at work right now.

Glad that, with your help, I'm slowly getting to the bottom of this mystery.

 

[natenkiki2004]

Like I said, you're hearing the fuel pump through the fuel lines & rail. Liquid conducts sound very well. It's why sonar is such an effective means of seeing what's around you underwater, as well as communication. The fuel rail is right underneath the upper intake plenum and the fuel lines are under the throttle body.

I guarantee the "spring" sound you hear is a relay. Most are located under the power distribution box so I'm not sure why you'd hear it elsewhere but it's definitely a relay. Have a watch:
https://www.youtube.com/watch?v=DWmt6gorzUg

You've got some kind of short in the harness or faulty relay or something.

 

[MistahYebba]

Like I said, you're hearing the fuel pump through the fuel lines & rail. Liquid conducts sound very well. It's why sonar is such an effective means of seeing what's around you underwater, as well as communication. The fuel rail is right underneath the upper intake plenum and the fuel lines are under the throttle body.

I guarantee the "spring" sound you hear is a relay. Most are located under the power distribution box so I'm not sure why you'd hear it elsewhere but it's definitely a relay. Have a watch:
https://www.youtube.com/watch?v=DWmt6gorzUg

You've got some kind of short in the harness or faulty relay or something.

Have you heard the 3rd sound in the video yet? If you turn it up nice and loud?? You might be able to hear what I'm talking about.

When I punch it I hear the relay sound you speak of I believe.

But I hear a different sound that is higher pitched coming from the same place that the whine comes from.

I guess none of that really matters though. You're right; clearly something is wrong. The fact that punching it multiple times in the morning before turning on the car allowed it to run so well.. I'm gonna say whatever is wrong is what's wrong with EVERYTHING. (that's just me being hopeful).

So.... I wish it wasn't freakin pouring rain here.

I understand that I clearly have a short or faulty relay or whatever. Is there any way you could explain how?

In my imagination, if it was bad wires; I can see 2 exposed wires touching eachother whenever I punch it.

If it was a bad relay; what would it look like? Or exactly how would the punching coincide with the faulty relay?

This is relatively unimportant information, I just want to know how it works.

In the end, we just know that whatever this electrical problem is; it needs to be fixed.

Wouldn't have gotten anywhere without ya.

 

[natenkiki2004]

It may be 2 wires rubbing together, it may be another wire grounding out, it may be a loose/broken coil in the relay, it may be burned/melted contacts, it may even be as simple as a loose relay. The fact that you're activating it with the key off makes me think that the negative side of the control coil is being grounded out. That technically shouldn't affect drivability, it would just mean that your computer is on all the time, regardless of key position.

But yea, you're going to have to take a look and maybe swap relays around, look for damage in the connectors & wiring.

 

[MistahYebba]

It may be 2 wires rubbing together, it may be another wire grounding out, it may be a loose/broken coil in the relay, it may be burned/melted contacts, it may even be as simple as a loose relay. The fact that you're activating it with the key off makes me think that the negative side of the control coil is being grounded out. That technically shouldn't affect drivability, it would just mean that your computer is on all the time, regardless of key position.

But yea, you're going to have to take a look and maybe swap relays around, look for damage in the connectors & wiring.

Hiya Natenkiki!

So, I took the PDB fuse box off today. Underneath it was the relay housing. Tapping on that with my hand even lightly would make the FPR activate. I noticed this only happens with the key in the ignition (not turned at all)... not with the key out. What is the difference between key in and key out?

Interestingly enough, after taking the relay housing off and wiggling all the wires and relays around, etc, I couldn't replicate the problem.

Either it was a loose relay like you mentioned, or I got unlucky with the positioning of the wires.

It started to rain of course, so I put everything back. After it all being back together, I was still unable to replicate the issue. I wonder if it'll come back.

Next on the diagnostic list was the TPS.

Get this:

Having everything plugged in (MAF, TPS, IAC), the car stalls either right away, or soon after starting.

You already know this; unplugging the IAC stops it from stalling right after startup.

However, here's something I messing with today.

Keeping the IAC plugged in, I tried unplugging the TPS instead. Interestingly enough, it idles very nicely. In fact, it idles the best it has in a few weeks... unfortunately it idles a bit high (about 1200 RPMs).

HOWEVER; with the TPS unplugged, if I give it too much throttle, it stalls right away. Therefore, it's undriveable that way. I can slowly rev it up and up and up and up and up.. but if I give it a lot of throttle in one go, it stalls. Keep in mind this is all at idle.



So, symptoms in a nutshell:

- With everything plugged in properly on my truck, it stalls right away.

- With the IAC unplugged, I can get from place to place okay, but it'll stall occasionally at idle or when not applying acceleration rarely.

- With the IAC plugged in, but the TPS unplugged, it'll idle like a dream (albeit a bit high), but I can't give it gas or it'll stall.

 

[natenkiki2004]

Hiya Natenkiki!

So, I took the PDB fuse box off today. Underneath it was the relay housing. Tapping on that with my hand even lightly would make the FPR activate. I noticed this only happens with the key in the ignition (not turned at all)... not with the key out. What is the difference between key in and key out?

Interestingly enough, after taking the relay housing off and wiggling all the wires and relays around, etc, I couldn't replicate the problem.

Either it was a loose relay like you mentioned, or I got unlucky with the positioning of the wires.

You shouldn't even have the battery hooked up when you mess with the power distribution box. There's serious amperage there and plenty of damage can be done if you inadvertently short something out.

Key in vs key out... if the computer comes on with the key removed, the best case scenario is a dead battery. Worst case scenario, you've lost control of the vehicle. If the computer powers off with the key on, that's less dangerous but still a serious issue.

You need to pull the relays out and look at the wiring, look at the pins, make sure there's no corrosion or burn marks. Swap the relays, test them, test the wires. Also check the fuses out too, it could just be that they're faulty.



No need to mess with the TPS or any other sensors until that wiring issue is solved. Your engine will not run reliably or predictably without the computer working properly.

 

[MistahYebba]

You shouldn't even have the battery hooked up when you mess with the power distribution box. There's serious amperage there and plenty of damage can be done if you inadvertently short something out.

Key in vs key out... if the computer comes on with the key removed, the best case scenario is a dead battery. Worst case scenario, you've lost control of the vehicle. If the computer powers off with the key on, that's less dangerous but still a serious issue.

You need to pull the relays out and look at the wiring, look at the pins, make sure there's no corrosion or burn marks. Swap the relays, test them, test the wires. Also check the fuses out too, it could just be that they're faulty.



No need to mess with the TPS or any other sensors until that wiring issue is solved. Your engine will not run reliably or predictably without the computer working properly.

My battery was unhooked while removing everything because I was unsure what threats would lie in my path.

Once everything was out, I had everything nicely organized, then I hooked my battery back up to test again. Don't worry, I took exceeding caution.

I think you may have mistaken what I meant by the key in/out thing.

With the key out completely, nothing happens with the computer. The "punch test" does nothing.

It's when the key is simply in the ignition that I'm able to do the "punch test" on it and get the fuel pump to activate.

Even more interesting, if I turn on accessories (and I can hear the fuel pump activate is it's supposed to), the "punch test" doesn't work either.

In other words, the key has to be in the ignition, but not turned at all, in order for punching the PDB to make the fuel pump activate.


Everything looked fine. I pull every relay, all the relay harnesses.. Everything.

After doing so, I was unable to recreate the "punch test" when I hooked everything back up properly.

Either it was a loose fuel pump relay (fixed now), or I just wasn't punching it hard enough!! Haha.

-----

and since I assumed the fuel pump relay was now seated properly and my PDB passed the "punch test", I decided to start diagnosing other things, hence why I moved on to the TPS.

Any clues?