Let me go try that.
u mean, place a jumper wire between pins 1 and 3?

Correct. Disconnect the harness from the sensor and jump 1 and 3.

Also thought while out mowing the grass that since your sensors have three wires and one of them is power and one is ground you should be getting some sort of signal out when the engine is cranked as long as they are getting power and ground. There is some sort of processing going on inside the sensor to maybe clean up signals and such... there just should be a measurable change.

 

Juro, what are you using to load test wires? Do you have a spare headlight you can use. We can do this very quickly and get to the bottom of it. Step by step just follow the path of current flow to the PCM. Remove the ASD relay and insert the headlamp between hot side of relay (pins 57 and 58) and the other side to ground. If the headlight lights up nice with key on, do the same at pin 6 (dk grn/or wire) of the PCM relay. Wiggle wiring and see if headlamp changes at all.

 

The orange wire shows about 2.2 volts for reference voltage on both cam & crank sensors. Shows same at PCM, so low reference voltage not due to voltage drop. should be 8.0 volts with ign key on.

Went back and looked at your first post again for clues... Does this happen with the sensors connected or disconnected? Is it the same for both PCMs? If it is the same with sensors disconnected and both PCM's then it's down to a wiring issue somewhere. Can you remove that pin from the PCM connector and test the output of the PCM without the wire. If it stays at 2.2 with the sensors disconnected and different PCMs I would take a closer look at your power and ground pins of your PCM connector... there may be hidden damage inside that's causing the issue. What else does the 8 volt wire go to? Maybe disconnect anything else connected to it and see if anything changes then.

Correct. Disconnect the harness from the sensor and jump 1 and 3.

After rechecking the diagrams I may have been wrong in my thinking. I believe the gauge is grounded through the sensor housing due to how it is drawn and this test will still give you some clues, but may not be the best idea in the event of a ground issue.

My guess now is since the crank and cam sensors aren't getting the 8 volts they need then they aren't sending a signal back to the PCM which may be where your whole problem lies. I'm not familiar with what harness connectors Dodge uses or how exactly to remove pins without seeing them, but there should be information somewhere online to guide you. If you could get a close up of the connector itself I may be able to point you in the right direction. It may be possible there is a weak or corroded crimp on a pin the connector (another problem that has burned me in the past). If you can get a hold of another PCM connector maybe make up some test leads you can change out with the original wire long enough to test individual circuits... I have a whole tool box drawer at work full of old harness connectors for that exact purpose.

Also looked at your pictures from the code reader... Usually an error saying something is high has to do with ground problems. It's not getting pulled down to a level the PCM expects to see due to a weak ground or bad connection. Sensors generally have a working range somewhere between the highest and lowest voltage it can produce, but if it is at the highest or lowest the PCM takes it as a fault. Jump 1 and 2 on your coolant temp sensor connector and see if the coolant sensor code changes or goes away. If it does then I would assume the sensor ground is good... if not take another look at it.

 

I know you've probably checked power and grounds more than you want to by now, but they can be some of the hardest problems to track down. Everything will work until you put the right load on the circuit and then things get out of hand. I just had an issue last week with a ground that is fresh in my head which is why I probably keep leaning towards a ground issue. It would also explain the 2.2 instead of 8 volts due to the regulator not working the way it should if nothing else is shorted and pulling it down.

The fact that you are able to read codes would suggest the PCM is at least operational enough to recognize it has problems... Just have to keep digging.

 

Sorry for my delay, my car is outside & rain has been bad this week.

 

Correct. Disconnect the harness from the sensor and jump 1 and 3.

Hi,
Today i performed the test of jumping the two leads on the wire harness connector to the coolant temp sensor.
My temp gauge did indeed peg out at highest reading. The needle just popped from bottom to top.
This while ignition switch in run position.
Is this good or bad?

 

Another thought... what happens when you connect pins 1 and 3 on your coolant temp sensor connector? I should make the dash gauge peg on the hot side if I'm reading the diagram right. That may tell you if you have a sensor ground issue.

See uploaded file.

 

Hi,
Today i performed the test of jumping the two leads on the wire harness connector to the coolant temp sensor.
My temp gauge did indeed peg out at highest reading. The needle just popped from bottom to top.
This while ignition switch in run position.
Is this good or bad?

Was starting to wonder if you really gave up or something.

That is what you should expect to see and eliminates my thought of a ground issue in that particular part of the circuit. Do you have a wiring diagram of the throttle position sensor?

Did you find anything with the 8 volt circuit yet? I'm thinking at the moment that is your biggest problem. Next after that would be the P0123 code. Do you have a diagram for it? If you jump the right pins in that connector it should make the code change to either a low fault or go away. If the code is saying what I think it is it may not pulse your injectors. Most EFI engines have programming in place that if you hold the pedal to the floor while starting it won't add anymore fuel until it starts. It's meant to "clear out" then engine in case it somehow floods itself much like doing the same with a carburetor if you pump it too much and flood the engine.

Keep us posted. I love these kinds of problems, but without being actually there to see everything for myself it takes a bit to process and come up with different things to try.

 

sorry, i have a hour long commute to my job, it drains me.

Do you have a wiring diagram of the throttle position sensor?.

See uploaded file.

Did you find anything with the 8 volt circuit yet? I'm thinking at the moment that is your biggest problem.

tomorrow i will test for the 8 volt reference & give update. Never saw it before, all i ever got was 2.2 volts on that orange wire.

Next after that would be the P0123 code. Do you have a diagram for it?

not sure what u mean? this?
http://www.dtcsearch.com/P0123/
P0123 - Generic
Type Powertrain - Fuel and Air Metering - ISO/SAE Controlled
Description
Throttle/Pedal Position Sensor/Switch "A" Circuit High

P0123 - Chrysler
Type Powertrain - Fuel and Air Metering - ISO/SAE Controlled
Description
TP Sensor Circuit High Input Conditions

Cause
Key on, then the test started and the PCM detected a TP sensor input of more than 4.5v for 704ms Refer to Mini Test and the code repair chart for details to test TP sensor, its related circuits and the PCM

 

First thing I would be checking ,is Crank sensor signal at the ECU. I use a cheap DSO138 Dig Oscilloscope. Picture of my Mazda 323 Crank sensor at cranking speed. No signal, no spark or injector pulses. Fuel pump relays are normaly run for a few seconds by the ECU then look for Crank pulses or ign pulses to keep the relay energized..

View attachment 160647

https://www.ebay.com/itm/142642969949

Also this tool arrived, so i will give update tomorrow.

EDIT: the nine volt power supply was not shipped with it.
oh well, may as well return it.
EDIT #2: using a 12V power supply from my external hard drive, & it
seems to work for now.
EDIT #3: my new tool is a counterfeit, oh well. Hope it works.

Debe, what settings did u use? I assume u connect positive clip to Crank sensor signal at the ECU or PCM, & negative to ground?

 

tomorrow i will test for the 8 volt reference & give update. Never saw it before, all i ever got was 2.2 volts on that orange wire.

I'm starting to wonder if that may be due to a bad connection in either your power or ground pins in your harness that you still haven't caught. Does that 8 volts go to any other sensors that what is shown in the crank / cam diagram? Maybe another sensor that is shorted and trying to use more power than the PCM can supply?

On the throttle sensor you should have 5 volts on pin 3, probably .5 to 1 volt on pin 2, and 0 volts (ground) on pin 1 with it connected using the section you hilighted. With it disconnected the only change should be on pin 2 since it's your return signal. Try jumping pins 1 and 2 together and see if the code switches to a circuit low type code. If it does then you either have a bad TPS or it has more than 5 volts on pin 3. If it doesn't change then it's either a bad ground still or a break in the sensor return wire somewhere. Maybe try unplugging other sensors (starting with the ones in that diagram) and see if anything changes.

If I'm asking about things you've already covered somewhere I apologize... I kind of have a plan of how I would go about troubleshooting and I need to follow it to comprehend it all.

Good luck

 

Debe, what settings did u use? I assume u connect positive clip to Crank sensor signal at the ECU or PCM, & negative to ground? Yes, if you are using the supplied lead with clips. Set top LH switch to AC next one down 1V bottom one to 5V, Time to 10ms & Auto. Check to see if the sensor actualy gives a signal at the sensor first.

 

Today i got no spark once again. No fuel pump humming sound.

All i did was disconnected the negative on the battery, and then i disconnected the harness from the PCM.
The purpose was to test the two PCMs that i purchased a few weeks ago. Because i spent $170.00. Then
I put the old PCM back on, still nothing.

Before i did any of this, i started up and ran the engine for a minute. Most beautiful start ever, too.
Yesterday i ran the engine for fifteen minutes or so, after installing the cooling system, to test for leaks.
But it would not start at first attempt, i cranked it like crazy. Spark and fuel was good. Then an hour later
I tried again, and it started up easy.

So now i really need to find this short to ground. Also, my multimeter died, so waiting for new one. I want to re-perform what i did a week ago.

 

I'm starting to wonder if that may be due to a bad connection in either your power or ground pins in your harness that you still haven't caught. Does that 8 volts go to any other sensors that what is shown in the crank / cam diagram? Maybe another sensor that is shorted and trying to use more power than the PCM can supply?

see file "8 eight volt reference all sensors." The Vehicle Speed Sensor connector is unplugged, as the Vehicle Speed Sensor broke off.
maybe i should wrap it, it could be touching ground.

On the throttle sensor you should have 5 volts on pin 3, probably .5 to 1 volt on pin 2, and 0 volts (ground) on pin 1 with it connected using the section you hilighted. With it disconnected the only change should be on pin 2 since it's your return signal. Try jumping pins 1 and 2 together and see if the code switches to a circuit low type code. If it does then you either have a bad TPS or it has more than 5 volts on pin 3. If it doesn't change then it's either a bad ground still or a break in the sensor return wire somewhere. Maybe try unplugging other sensors (starting with the ones in that diagram) and see if anything changes.

let me try that.

 

Today my new multimeter arrived, so resume testing.

The Sensor Ground, or black & blue wire, has zero continuity with either the PCM ground or battery ground.
Sensor Ground was tested at both the PCM & the Ccamshaft Sensor.
This is abnormal?

Also i repeated what i did last time to make it work, but got nothing. Relay did not respond.
Zero continuity between the orange wire & the black & blue wire.

 

It sounds like your best bet is to start back tracing the harness from your cam sensor to the PCM. I'm guessing both the orange wires and black and blue wires of the sensors all come back and connect to a single orange wire and single black and blue wire that to goes to the PCM. Once you find those points cut off the heat shrink and make sure they are not corroded and falling apart. Do your checks again at those points and see what you find.

 

The only other thing I can think of keep checking grounds. Have tried to measure a voltage drop between your battery ground and other ground points? It's not doing enough strange stuff to be in the main, but maybe a ground from a central point to your PCM could use another look.

Today I did that, got difference of zero volts between battery & PCM ground.
Also see uploaded files. All PCM ground PINs, #10,47, & 50, tested for proven continuity or near zero ohms
between the PCM & both battery & PCM grounds. Sensor ground PIN #43 tested for no continuity. That seems bad to me.
All tests performed with ignition switch in both on & off positions.

 

Juro, what are you using to load test wires? Do you have a spare headlight you can use. We can do this very quickly and get to the bottom of it. Step by step just follow the path of current flow to the PCM. Remove the ASD relay and insert the headlamp between hot side of relay (pins 57 and 58) and the other side to ground. If the headlight lights up nice with key on, do the same at pin 6 (dk grn/or wire) of the PCM relay. Wiggle wiring and see if headlamp changes at all.

Today i did this test; my light bulb lit up and stayed steady when I wiggled the wiring with my hand.
But this test worked on for the fuel relay, and the light bulb stayed dark for the ASD relay, because
the grounds go only to the PCM.

see two uploaded files.

 

Today I did that, got difference of zero volts between battery & PCM ground.
Also see uploaded files. All PCM ground PINs, #10,47, & 50, tested for proven continuity or near zero ohms
between the PCM & both battery & PCM grounds. Sensor ground PIN #43 tested for no continuity. That seems bad to me.
All tests performed with ignition switch in both on & off positions.

I'll agree it is strange. Have you tried using your sensor ground as a ground for your test light? I know it doesn't make sense, but sometimes who knows. It pegged the temp gauge which is essentially the same thing.

Did you get 8 volts yet? I checked your pin charts and found an orange wire (#72) that goes to the vapor canister pump switch driver which I'm thinking would correlate with the evap code I saw earler. Have you looked into that at all? It doesn't specify a voltage in the chart, but I'm hoping since it's also orange that it's also supposed to be 8 volts and unplugging the pump will cure it... or it may just be something else not getting power.

I lost track... does the fuel pump relay turn on when you turn on the key? I remember the ASD not working still, but I'm thinking that won't turn on until you sort out the other problems first. It is a shut down relay which would normally shut the engine power off in the event of a problem if needed.

 

https://forums.neons.org/viewtopic.php?f=1&t=420568&start=40

Circuit K4 20BK/LB is the ground supplied internally by the PCM for the MAP sensor. DO NOT apply 12v to this circuit at any time or you risk damaging the circuit in the ECM.

This is how you can test the circuit to the sensor With the connector disconnected from the map sensor or you can use a poke probe through the insulation and leave it connected. Use a Digital Multimeter set to Volts DC put the black lead on the black with light blue stripe wire then touch the red lead of the DMM to battery positive. If you see 11-12 volts you know you have a ground all the way thru the ECM. If it does not show 11-12 volts on the DMM then there is an open fault in either the wiring to Pin 43, a problem with the connector and that pin, or an open fault internally in the ECM.

does it share ground with battery ground and other ground points, & is that normal?

the cam sensor, crank sensor, & VSS all use Circuit K4 20BK/LB for ground, correct?

Circuit K4 20BK/LB is a ground through the computer. It is shared with other sensors yes. You can identify it by the circuit label on any pinout in the FSM as K4 20BK/LB . this is for 97-99s and it probably also is valid for 96s. 95s however had a different ECM pinout if I remember. Yes ultimately it is battery ground however it is a filtered ground that is not designed to take 12V. It's filtered inside the ECM/PCM to prevent noises on the '12v' ground from interfering with the signal of a sensor.

If the test I wrote out before does not come up with 11-12 volts it will be a no run issue. Again DO NOT use a test light connected to 12v positive to test K4 20BK/LB or you are extremely likely to damage the PCM.