Sometimes diagnosing engine trouble is the hardest part

I'm leaning toward the problem being the fuel pump, and I'm working on testing it and probably some other fuel system stuff. I got the bed off (thankfully it's a pickup, whereas with the other daily driver I'd have to drop the gas tank). My oldest brother had the same year/model/engine and had to do a fuel pump, years ago. I asked him what the fuel pump failure was like, and he said he was driving and the engine quit.

I'm considering that the one wet spark plug might be a sign that the fuel system is the problem. The scenario is that there's just enough fuel (volume) and pressure at the fuel rail that it ALL (or nearly all) went to the first fuel injector that opened. Again, I'm not confident that I did a good job with trying to start it with starting fluid, so that's still an unknown.

I'm leaving the spark plug in, for now, so I don't risk having to pull the head, for now.

 

I got an inexpensive ELM327 OBD2 Bluetooth adapter, downloaded a "Car Scanner" app, had it in the port with the ignition "ON," and while I was trying to get the app set up and working there was unusual electrical switching noise that seemed to be coming from the passenger footwell area, which is where the ECU resides. "Glump." Some online stuff says it's impossible for the gizmo to fry the ECU, some others say it can and will.

I'm thinking that I'll see if it still has spark, and if it does, I'll try again to get it running on starting fluid.

 

Sometimes when a scan is accessing a module it will send power to test. For a Hvac module it typically actuates the blend doors. Might be what you were hearing.

 

Does the electric fuel pump make a noise when you turn the key on ???
No sound means bad pump or blown fuse...
6sally6

 

I tried that real quicklike with the runner, and I couldn't hear anything. The manual makes it seem that the fuel pump doesn't run till the engine's moving or something because it says you have to connect the battery to the fuel pump electrical connector to test it.

I was getting close to testing the fuel pressure, but the banjo fitting adapter in the loaner test kit broke when I was torquing it.

 

Most of the EFI stuff I've run across powers the fuel pump for 5 seconds when you first turn on the key. Then if the ECU doesn't see what it wants from the multiple sensors, it shuts the furl pump down.

You probably can't turn on the key and then get down by the pump in the tank to hear it run by yourself. You need to be where you can hear the pump when someone turns on the key. BTW, turning on the key does not have to crank the motor to power the fuel pump for that 5 seconds, it merely needs to have power to turn on the pump (ignition on).

 

I'd get another test kit. Tie into the line before the fuel filter and test pressure. Also test pressure after up by the fuel rail. Rent a noid kit and test injector firing.

 

This is commonly called 'prime' as in priming the system. It has the 5 second time, then looks for RPM more than cranking speed, or shuts off. Older EFI stuff this is often able to be heard, but some of the newer stuff especially DI it's not as easily confirmed.

 

Maybe one or a few people can chime in and help with this. The only way I see a dongle and app could "fry" the ECU is if it somehow provided excessive electrical energy to the ECU. 0 to 5 volts was mentioned in this thread. Does the ECU in normal operation only see up to 5 volts, or does it see (and/or is powered by) up to full battery voltage?

Also, I'm guessing that the 2001 model doesn't have HVAC components that are actuated electronically, other than some of the underhood A/C components (what, just the compressor?). That seems like more modern car stuff.

 

Should be electric powered off the hvac control module in the center dash. As for the scanner, I've never seen them do damage. I have seen "fuel savers" that when stay plugged in divert power to certain circuits that don't usually maintain constant power. For ecm it depends on which circuit. Some will maintain a full supply others can be 9-12v and others less.

 

Thanks for that, John.

The weekend's over, so I'm back at it. I checked for spark on one plug and it sparked, so I believe that means that at least that part of the ECU is working. Maybe I'll need to do ECU testing, if the problem isn't found and resolved. It very well could simply be the fuel pump or the fuel filter. When I turned it over, two of the coils (that go in the valve cover and on the plug) went on a trajectory because I didn't have them bolted down. "Oops. Slow down."

 

If the pdf will load for you, might help you out.

 

Wow. Thank you very much, John.

 

* The main question is: Is there any problem with using vice grips to connect each wire to its post?

Also, I'm thinking I'll put a piece of cardboard between the two wires at the connector to keep them separated since they're not secured. *

I'm set up to do a fuel pump pressure test, but I'd like some assurance that my setup is safe. The instructions are to have the key ON and put battery voltage (~12 V) across the fuel pump electrical connector. As I interpret that, it activates the fuel pump, until the key is turned OFF. I don't think that the pump will run with just battery voltage to it (without the key ON), but I'm not positive about that. So, I've got another battery with two substantially thick wires which I plan to clamp to each battery post with vice grips, and the thick wire looks like it'll work pretty well in the connector. I hooked the positive wire to the positive battery post and I don't know if it was the battery but then I started smelling a little burning plastic odor. It could be that I'm smelling smoke from a neighbor that does a lot of open fires in their yard (cooking and campfire type fires).

[pictures deleted]

 

Alright, I got over my fears of powering the fuel pump with jumper wires from a battery and I think I've got it diagnosed. The fuel pressure was low at the fuel rail, so I connected the test fitting to the inlet fuel line and the inlet side of the fuel filter and the fuel pressure was about what it should be. Hopefully replacing the fuel filter will get it running again, and then I'll go from there.

 

Fuel filter sounds a lot better than rebuilding a motor. Hopefully that fixes it for you.

 

Please check where this 5/16" vacuum hose goes. There's a gizmo under the upper plenum (intake manifold), and above the lower plenum, pretty much in the center in that space between the two plenums. There are two hoses coming off this gizmo. One hose is horizontal and goes to that vacuum chamber-looking gizmo. The other hose goes down vertically. I don't know where the other end of that hose goes. On my '99 it goes to the metal intake pipe that attaches to the TB. The 2001 has a plastic intake pipe and no nipple for this hose.

 

25860E? That's a Vacuum Switching Valve or VSV. I've had mice chew through the vacuum lines under the hood, would throw PO402 code, but couldn't tell a difference in how it ran. I did replace the VSV while chasing those issues a few years ago.

 

I saw that diagram and I don't think it shows the component I'm trying to plumb. If you're able to look at your 2001 3RZ, I think that'd work best.

I'm looking at the throttle body that came off my '99 3RZ (it's plumbing is different, as mentioned in #77). The component is the idle air control valve (22270-75030; searching part numbers is very helpful in properly identifying gizmos). The last hose I have to plumb before I can try starting it is the larger diameter one that comes off the bottom of the IAC.

 

I'll double check & snap some photos of mine when I get home this evening. I drove my Ford to work today.

 

I'm pretty sure I just got it figured out. Thanks for offering, and I apologize if you spent time trying to find it, especially because it's impossible to see what's going on with the hood on and the intakes on.

 

It just started and ran. The fuel filter (it might've been the original one) was the main problem. I'm surprised at how quickly it went from driving normally to not running. Since I had fuel components off, I pushed it out into the street, had a fire extinguisher and garden hose as precautions.

Thanks to everyone who helped and the HAMB for letting this thread stay. I figured it wasn't going to last long.