P0505 + throttle body cleaner = dead engine

[Mall'er]

If the fuel tank isn't full, it probably isn't the fuel pump.

In my experience with failed fuel pumps, they always fail when the tank is full. Unless you can access the pump without dropping the tank, then they fail in rush hour traffic on a narrow bridge.

Seriously, you won't see constant voltage if the engine isn't running. It should run the pump just for a few seconds after the ignition is in the run position, and then it shuts off if the engine isn't running. If you aren't fast enough to switch the ignition to on and get to the meter in two seconds, (I know I can't, too fat and old) you can use the functions on your meter to capture the high reading. Long leads work also.

Easier to test at the relay panel and then test continuity to the pump connection. This way you can be sure power is being sent to the pump.

And if you really want to test the pump without removing it, use a power probe or another 12v supply to the pump to test it without removing it. You already have the plug exposed.

 

[jeff6times7]

If the fuel tank isn't full, it probably isn't the fuel pump.

In my experience with failed fuel pumps, they always fail when the tank is full. Unless you can access the pump without dropping the tank, then they fail in rush hour traffic on a narrow bridge.

Seriously, you won't see constant voltage if the engine isn't running. It should run the pump just for a few seconds after the ignition is in the run position, and then it shuts off if the engine isn't running. If you aren't fast enough to switch the ignition to on and get to the meter in two seconds, (I know I can't, too fat and old) you can use the functions on your meter to capture the high reading. Long leads work also.

Easier to test at the relay panel and then test continuity to the pump connection. This way you can be sure power is being sent to the pump.

And if you really want to test the pump without removing it, use a power probe or another 12v supply to the pump to test it without removing it. You already have the plug exposed.

The tank has ~9 gallons.

Referring to my previous reply with the attached picture of the fuel pump connector, only pins 1, 3, 4, and 6 have wires.

I do see constant voltage after the ignition switch has been in the ON position. For many, many seconds. With a partner turning the ignition on and off at my command, I see voltage appearing and disappearing. With the ignition switch in the ON position, I see constant 12 V between pins 1 and 3 and between pins 6 and 3. At no time do I see any voltage at pin 4. Don't even know what pin 4 is for.

The blades on the fuel pump relay's pictogram are labeled 1 to 5. What corresponding sockets do I check for resistance to the fuel pump? What range of resistance is ok? Can I check it with the battery connected?

More evidence that there's no fuel pressure is that I disconnected the fuel delivery line and my partner cranked the engine. Not one drop came out. I unplugged the connector and repeated the voltage test. Constant 12V between pins 1 and 3 and between pins 6 and 3.

 

[macleanflood]

You going to disassemble the pump assembly and replace the pump, maybe the regulator...or are you planning on buying a complete assembly?

I've done my pump and regulator. Good write up in resources section.

-Mac

 

[jeff6times7]

You going to disassemble the pump assembly and replace the pump, maybe the regulator...or are you planning on buying a complete assembly?

I've done my pump and regulator. Good write up in resources section.

-Mac

Autozone has a Delphi DFG1353 on hand. I'd rather not try to rebuild any part of the assembly.

 

[B1Toad]

Don't throw away your old stuff. After careful research I decided the best, most dependable replacement was going to be installing a new Bosch pump in my existing assembly. I also had to round up the correct pickup screen and a separate regulator. All this took up time and cost substantially more than a box store replacement but I am confident it was the right choice especially given all the complaints of box store pump failures. The original Bosch lasted 23 years. If your Delphi gives you troubles at least you will have your old parts ready to rebuild and swap in.

 

[jeff6times7]

Don't throw away your old stuff. After careful research I decided the best, most dependable replacement was going to be installing a new Bosch pump in my existing assembly. I also had to round up the correct pickup screen and a separate regulator. All this took up time and cost substantially more than a box store replacement but I am confident it was the right choice especially given all the complaints of box store pump failures. The original Bosch lasted 23 years. If your Delphi gives you troubles at least you will have your old parts ready to rebuild and swap in.

 

[jeff6times7]

Good news. The fuel pump is ok. I finally figured out how to bypass the fuel pump relay. I jump pin 3 (12 V) to pin 5, which engages the fuel pump. When I jumped those two, the pump went to work.

Bad news. I have no idea why the computer is not sending a signal to the fuel pump relay. I tested the fuel pump relay and it's ok.

I removed the fuel pump relay and put 12V to pin 1 and connected pin 2 to ground. That caused the relay to operate and do exactly what it was designed to do: make pins 3 and 5 and break pins 3 and 4.

Someone earlier mentioned the auto shutdown relay could be interfering and that I was supposed to reset that circuit. I switched the ignition on for 2 seconds and then switch it off. Then repeat that 14 more times. I did just that and it changed nothing.

What is the next step in this diagnosis?

 

[Jerry Bransford]

Does the tachometer needle rise up any while you're cranking the engine? The tach needle rising up or not rising up is often a very good clue to whether the CPS (crankshaft position sensor) is working or not.

 

[jeff6times7]

Does the tachometer needle rise up any while you're cranking the engine? The tach needle rising up or not rising up is often a very good clue to whether the CPS (crankshaft position sensor) is working or not.

The tachometer need does not move at all during cranking. But then I also noticed that the battery voltage meter on the dash is at zero too.

 

[jeff6times7]

The tachometer needle does not move at all during cranking. But then I also noticed that the battery voltage meter on the dash is at zero too. Got plenty of good life in the battery. There's 12V at the battery's posts. Cranking hasn't slowed down yet so I believe the battery's not at fault.

 

[jeff6times7]

I was about to ship my PCM off to Mark at wranglerfix so he could remove/disable its SKIM function. I disconnected the battery. Then I touched the rightmost connector on the PCM. It fell off.

Yes, it fell off.

So, I put it back on. And then I pulled a little bit. It fell off again.

Then I daisy-chained two zip ties together, went around the back of the PCM, and pulled the zip ties snug on the front of the PCM connector. Then I did the same to the other two.

The $*%@* thing started up better than it ever did. No idiot lights on the dash. Nothing but a purring motor.

Note to future self: when things go south under the hood, be amazed by nothing. Nothing.

 

[macleanflood]

My rear O2 sensor plug is zip tied together. So are half my coil on plug connectors on my 2001 V-10. Twenty year old plastic connectors suck.

Glad you "fixed" it!

Any thoughts on locating new connectors, depining yours?

-Mac

 

[jeff6times7]

My rear O2 sensor plug is zip tied together. So are half my coil on plug connectors on my 2001 V-10. Twenty year old plastic connectors suck.

Glad you "fixed" it!

Any thoughts on locating new connectors, depining yours?

-Mac

Interesting. Glad you asked. If you know how to do it, I'd be very happy to listen.

I should be fearful of zip ties and connectors that aren't 100% up to snuff. There are two ways I could proceed. One is to ignore the technical debt until it bites me again in the future. The other is to find some way to fix them now. The latter is new territory for me because the only older car I had, a 2000 Infinity QX4, I traded for a 2015 Nissan 5 years ago.

This 2002 is a PR (Personal Record) for me. I thought it would be easier and I should've known better.

 

[macleanflood]

Big question is what's broken...is it the wiring harness connector or the ECU?

Got any pictures of the face of each connector?

I know others know where to source these connectors. Hopefully they'll chime in.

-Mac

 

[jeff6times7]

Big question is what's broken...is it the wiring harness connector or the ECU?

Got any pictures of the face of each connector?

I know others know where to source these connectors. Hopefully they'll chime in.

-Mac

Here are pictures related to the PCM in question. There are no known problems with connector #2 (all.jpeg). The other attached pictures are numbered according to the connector number labels in all.jpeg.

 

[Jerry Bransford]

I was about to ship my PCM off to Mark at wranglerfix so he could remove/disable its SKIM function. I disconnected the battery. Then I touched the rightmost connector on the PCM. It fell off.

Yes, it fell off.

So, I put it back on. And then I pulled a little bit. It fell off again.

Then I daisy-chained two zip ties together, went around the back of the PCM, and pulled the zip ties snug on the front of the PCM connector. Then I did the same to the other two.

The $*%@* thing started up better than it ever did. No idiot lights on the dash. Nothing but a purring motor.

Note to future self: when things go south under the hood, be amazed by nothing. Nothing.

I did the same zip-tie thing on my previous TJ's PCM, it works well.

 

[jeff6times7]

I did the same zip-tie thing on my previous TJ's PCM, it works well.

If the zip ties don't have to be replaced too often and the work to replace the broken connectors is too time consuming and error prone, then I might just live with the zip ties.

 

[Jerry Bransford]

If the zip ties don't have to be replaced too often and the work to replace the broken connectors is too time consuming and error prone, then I might just live with the zip ties.

Nylon zip ties have a good long life, not so much with plastic zip ties. But even plastic zip ties hold up long enough to be fine for most of us.

 

[jeff6times7]

Just as an aside have you checked for spark? You went straight to fuel from a quick read through of the thread. Before going through the effort I would prefer to rule out anything from the computer preventing cranking or disabling startup. Check for spark and even ignition with some starter fluid sprayed in the throttle body. If you have spark and/or ignition with starter fluid then I'd say you are on the right track, but if you have no spark possible another issue computer/sensor related tripping the ASD circuit.

I eventually did check for spark and there was none. I don't recall where I mentioned that fact but it was probably just before I started considering a problem with the crankshaft position sensor. Soon after I started down that path, someone mentioned SKIM. That's when I saw the amber idiot light on the dash and soon after that found the PCM connector that was loose. The only profound thing I can say at this point is that looks can be deceiving. What looked like a normally connected PCM turned out not to be true.

 

[MutantNinjaTJ]

Hey man, I like your style, never give up attitude. That what it takes to be a TJ owner, but for me, that's part of the "game" of ownership.