Hard to find noise -- clinking and clanking

WWDiesel · **Posted:** Fri Apr 29, 2022 3:24 am

You cannot use a gasoline intank fuel pump, the pressure is way to high. You must use a low pressure fuel pump like the ones for Dodge diesel trucks.
Read this:

Quote:

Being the CP3 is a constant displacement pump means that it you can't hook just any supply pump up to it. Whereas some injection pumps can tolerate a large difference in flow rates to/through it with relatively little pressure change, the CP3 cannot. If you try to push too much fuel through the CP3 (supply pressure), the discharge pressure will skyrocket to very unsafe levels and the rail pressure will increase accordingly way beyond design pressure. There are no internal pressure relief valves in the CP3, only a direct feed to the internal supply pump. Conversely, if there isn't enough flow to it, the pressure will drop and the internal supply pump will create a vacuum in an attempt to supply itself enough volume of fuel.

Supplying the CP3

Users should never pump fuel to a CP3 at a high pressure. Because it has a built-in supply pump, the CP3 only needs to be supplied at a low pressure OR VACUUM and it will handle supplying the pumping chambers from there. Whereas previous pumps had to be somewhat pressurized, the CP3 handles its own pressurization.

Conversely, users do have to worry about getting enough fuel to the CP3. Remember the COFV? It prioritizes the flow and when there isn't enough fuel to the CP3, it shuts off internal lubrication and cooling flow. This is very bad news for the longevity of the CP3. Diesel fuel viscosity and lubricity falls dramatically with an increase in temperature. Hot fuel within the CP3 is bad.

Basically, one needs to get enough fuel from the tank to the CP3 inlet to keep the CP3 well fed, yet but never over pressure it when doing so.

layback40 · **Posted:** Fri Apr 29, 2022 7:46 pm

CaptainDean wrote:

layback40,

I watched a few videos on polishing fuel and one of them described the algae in fuel as bugs. I might still have the old filter set aside. Thanks for the advise.

Dean.

Yes it is an algae that grows.
There are plenty of pictures on the net of the black goo that grows.
When you cut open your filter, if the media is black, you have an infestation.
Many with machinery that sits idle for part of the year look for it before their work season starts.
Most diesel sold contains an additive to prevent its growth. It depletes over time.
That is why its recommended to only purchase diesel from a place that has a high throughput of diesel.
Once you get bugs (algae) in your tank, it can be hard to get rid of it.
Your cleaning should do the trick.
Its the pockets & dead spots in the tank/fuel system that can be a problem.
Good Luck!!

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 693

Thanks WWDiesel and layback40,

layback40: Thanks for the elaboration on killing the Algae "bugs". I'll slosh some of the cocktail-treated fuel all around inside the tank and even lay it down upside down for an hour. I got a new fuel pump (Edelbrock for diesel) and the fuel filter arrived from Amazon. I'm ready to polish some fuel tomorrow.

The Edelbrock diesel fuel pump delivers 4-7 PSI output. I see there are two gasoline versions; one that delivers 4-7 PSI, and one delivers 2-3½ PSI.

WWDiesel: The book says the gear driven fuel lift pump within the high pressure fuel pump is capable of drawing 20 inches of vacuum. They don't say that it's 20 inches of Hg (Mercury) or Diesel or H2O (Water). A Google search brought up a site claiming 20 inches vacuum is 9.8 PSI... ...which must mean 9.8 PSIV. (Not sure whether a negative sign is required on PSIV units.)

So, it sounds like making sure the fuel line is capable of withstanding 10 PSIV and all the connections are solid. ...and no connections are the typical "fuel line connector" style. A simple hose on a metal line should be best. This is worthy of draining the tank and checking the connections and wiring.

Dean.

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 693

I added two types of Diesel fuel system cleaners and polished the fuel. Built a simple stand with a filter w/water separator and a pump. I let electric pump run for 3 hours while exchanging 38 GPH. The fuel looked very nice even from the start; no water or debris collected in the separator.

Still, the engine intermittently misses and tries to stall but only under load. I'm starting to think this is an electrical problem. The engine idles perfectly, and runs good while running the RPM up in neutral. Occasionally the tachometer goes to zero for an instant even though the engine is turning. Even put it in gear and held the brake and stepped on the gas; it ran fine while not moving. Soon as I get onto the road, it tries to stall then recovers.

I'm stumped.

[Edit] I'm starting to remember a previous time when this vehicle would drive in reverse perfectly, but would stall and shut down the engine as soon as I applied even a small amount of accelerator pressure. Happened to be at my favorite mechanic so I left it with him. He couldn't figure it out, so he called Chrysler Troubleshooter. They finally found (according to the mechanic) a ground that was not connected. They said it had to do with the Transmission Control Module.

Today, after looking in the schematics and reading about the TCM, I see there is a Torque Control wire from ECM to TCM. I'm also wondering if performing the Quick Learn on the transmission via TCM is worth while.

Dug out my iCarScan OBD-II scanner and downloaded the EZDiag program. Logged in and got the program to come up. It's late now so tomorrow I will plug'r in and see what happens.

Dean.

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 693

CaptainDean wrote:

I added two types of Diesel fuel system cleaners and polished the fuel. Built a simple stand with a filter w/water separator and a pump. I let electric pump run for 3 hours while exchanging 38 GPH. The fuel looked very nice even from the start; no water or debris collected in the separator.

Still, the engine intermittently misses and tries to stall but only under load. I'm starting to think this is an electrical problem. The engine idles perfectly, and runs good while running the RPM up in neutral. Occasionally the tachometer goes to zero for an instant even though the engine is turning. Even put it in gear and held the brake and stepped on the gas; it ran fine while not moving. Soon as I get onto the road, it tries to stall then recovers.

I'm stumped.

[Edit] I'm starting to remember a previous time when this vehicle would drive in reverse perfectly, but would stall and shut down the engine as soon as I applied even a small amount of accelerator pressure. Happened to be at my favorite mechanic so I left it with him. He couldn't figure it out, so he called Chrysler Troubleshooter. They finally found (according to the mechanic) a ground that was not connected. They said it had to do with the Transmission Control Module.

Today, after looking in the schematics and reading about the TCM, I see there is a Torque Control wire from ECM to TCM. I'm also wondering if performing the Quick Learn on the transmission via TCM is worth while.

Dug out my iCarScan OBD-II scanner and downloaded the EZDiag program. Logged in and got the program to come up. It's late now so tomorrow I will plug'r in and see what happens.

Dean.

Plugged the iCarScan into the OBD-II port and got a light. Started the Android phone and got the program. Discovered that the money I spent 4 years ago has expired - after 1 year. I'm hesitant to spend more money when I don't know what I'm getting. :dizzy:

Anyway, it won't start at all anymore at all. :furious:

Read the codes and I get P0304 and P1140 which both seem to point at EGR, which is removed. I'm stumped again. :dizzy:

Dean.

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 693

Ok, I got it going again. Checked the Fuel Pressure Solenoid again at the goddamnedbackend of the fuel rail. It is allowing fuel out of the port at the back when I think it's not supposed to (during cranking). I'm still not certain about it's operation, but I *think* the solenoid is supposed to hold the valve closed during cranking in order to make the most fuel pressure possible at start up. After cranking the solenoid releases and the valve operates with only spring tension to regulate 23,000 pounds of fuel pressure.

I suspected it was dirty so I clicked the starter about 10 times just to exercise that valve. Then it started. But it failed to start again. Time to knuckle down and buy a new one.

Dean.

WWDiesel · **Posted:** Sun May 01, 2022 10:13 pm

CaptainDean wrote:

Ok, I got it going again. Checked the Fuel Pressure Solenoid again at the goddamnedbackend of the fuel rail. It is allowing fuel out of the port at the back when I think it's not supposed to (during cranking). I'm still not certain about it's operation, but I *think* the solenoid is supposed to hold the valve closed during cranking in order to make the most fuel pressure possible at start up. After cranking the solenoid releases and the valve operates with only spring tension to regulate 23,000 pounds of fuel pressure.
I suspected it was dirty so I clicked the starter about 10 times just to exercise that valve. Then it started. But it failed to start again. Time to knuckle down and buy a new one.
Dean.

Being able to read fuel rail pressure (from fuel rail pressure sensor) with a scanner while cranking the engine would provide you with a lot of information on the status of the fuel rail solenoid. :wink:

14 - 86 FUEL INJECTION - 2.8L DIESEL FSM wrote:

Fuel Rail Pressure Solenoid OPERATION:
High pressure which is present in the fuel rail flows to the ball seat of the pressure solenoid (Fig. 19). The specified pressure required by the system is built up in the rail by the fuel pressure solenoid building up a magnetic force which corresponds to this specific pressure by means of a control current from the Electronic Control Module (ECM) (Fig. 19).
This magnetic force equals a certain outlet cross section at the ball seat of the valve. The rail pressure is altered as a result of the quantity of fuel which flows off (Fig. 19). The current fuel pressure is signaled by the fuel rail pressure sensor to the engine control module (ECM). The controlled fuel flows back along the return fuel line, into the tank.
In a de-energized state, the fuel pressure solenoid is closed as the spring force presses the ball into the ball seat (Fig. 19). When driving, the fuel pressure solenoid is constantly open (Fig. 19). When engine is started, the fuel pressure solenoid is held closed by magnetic force (Fig. 19). When driving, the pressure of the fluid counteracts the magnetic force of the coil and the slight spring force (Fig. 19).

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 693

Thanks WWDiesel,

That write-up of the pressure control in the fuel rail is great. Thank you for digging that up. My description was somewhat right, however the write-up says energizing of the fuel pressure solenoid is through controlled current. My original understanding was simply on or off.

I measured 4.4 ohms when checking the fuel pressure solenoid through the ECM connector. If controlled by 5Vdc, then the max current is 1.13 amps to close the solenoid valve. The ECM probably doesn't need to produce that much current in a properly seating solenoid valve. I wonder if the seat becomes eroded after many years of operation while allowing fuel to "sip" by.

I wish VM Motori would have made the hard high pressure line connect at the back end of the fuel rail, and the fuel pressure solenoid at the front end. The fuel system would have been 'self bleeding' and easy to access. Hmmm, the Cam position sensor could have been placed that way too. ...and the injectors could have been turned around as well.

One thing the Italians made right is the beer bottle sanitizing device. Google: Italian Bottle Rinser.

Dean.

WWDiesel · **Posted:** Mon May 02, 2022 1:08 pm

If like most other electrically controlled devices on this engine by the ECM, the power supply (5v) would be constant and the ECM would modulate the ground side of the coil in the solenoid to induce the magnetic force to open the valve. Since the solenoid is forced closed by spring pressure when at rest (engine starting), if it is leaking by and not sealing off properly, this would account for low fuel rail pressure issues during startup. You may simply have something under the seat not allowing it close fully? As you can see in the pictures below, there is a very small sealing surface for the plunger to actually seal against so any small amount of debris that were to get hung under that plunger could cause problems.

I remember one member who actually removed the solenoid, cleaned it and reinstalled it with success. I know they say in the FSM if you remove it, it must be replaced with a new unit, but might be worth a try??? See pictures below of one taken apart.

Another thought; with the solenoid unplugged, would be to ground one side of the solenoid to a good ground and then provide it with 5v supply from the BR/OR wire with a jumper on the other side of the solenoid while spinning the engine over with the starter to provide full fuel flow through the rail. This should force the solenoid 100% open electrically and maybe flush any debris out from under the seat of the plunger into the fuel return system???
--------(5v) (ground-)----------

This statement in the FSM could be the key?

Quote:

The tip of the fuel pressure solenoid uses a knife edge, for metal to metal sealing. The knife edge actually deforms the metal in the fuel rail in order to seal the surfaces. The solenoid must be replaced when ever it is removed from the rail. The solenoid controls and maintains the rail pressure constant along with a control current transmitted by the engine control module (ECM)

Pictures of Fuel Rail & Fuel Rail Pressure Solenoid seating surfaces with Solenoid removed & disassembled:

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 693

14 - 86 FUEL INJECTION - 2.8L DIESEL FSM wrote:

Fuel Rail Pressure Solenoid OPERATION:
High pressure which is present in the fuel rail flows to the ball seat of the pressure solenoid (Fig. 19). The specified pressure required by the system is built up in the rail by the fuel pressure solenoid building up a magnetic force which corresponds to this specific pressure by means of a control current from the Electronic Control Module (ECM) (Fig. 19).
This magnetic force equals a certain outlet cross section at the ball seat of the valve. The rail pressure is altered as a result of the quantity of fuel which flows off (Fig. 19). The current fuel pressure is signaled by the fuel rail pressure sensor to the engine control module (ECM). The controlled fuel flows back along the return fuel line, into the tank.
In a de-energized state, the fuel pressure solenoid is closed as the spring force presses the ball into the ball seat (Fig. 19). When driving, the fuel pressure solenoid is constantly open (Fig. 19). When engine is started, the fuel pressure solenoid is held closed by magnetic force (Fig. 19). When driving, the pressure of the fluid counteracts the magnetic force of the coil and the slight spring force (Fig. 19).

This write-up gives conflicting information. Check out the different colors of text. I think the violet text should read: When driving, the fuel pressure solenoid valve is SLIGHTLY open to prevent over pressurizing the fuel rail

Dean.

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 693

I succumbed and ordered a new Fuel Pressure Solenoid valve from IDParts. This will give me a chance to remove mine and clean it. If it doesn't work afterward, then at least I won't be stuck anyplace. I'm expecting to find junk from the interior of the pump, the hard fuel lines, and the fuel rail that got removed by the fuel cleaners.

Ordered a new Fuel Pressure Sender as well.

Dean.

WWDiesel · **Posted:** Tue May 03, 2022 2:23 am

I agree on the mistakes, but certainly not the only ones we have found in the FSM.

Note: Another one I found, there is NO wiring schematic in the 05 manual for the MAP (Intake pressure & temperature) sensor or the air inlet pressure sensor on the air box even though they list and show the connector pinouts for both of them. They do have the schematics for both of them in the 06 FSM.
Go figure...

As to the operation of the fuel pressure solenoid, after rereading it a few more times, it sounds like the fuel solenoid is closed at rest by spring force for startup and after engine starting fuel pressure overcomes the spring pressure with assistance from the magnetic force provided by the ECM to control rail pressure like a bleed off valve. The ECM varies the amount magnetic force based on feedback from the fuel rail pressure sensor. How do you think it operates?
Very interesting little piece of hardware and how it operates! But I totally agree, the FSM description is not very clear and somewhat contradictory in places.

Quote:

OPERATION
High pressure which is present in the fuel rail flows to the ball seat of the pressure solenoid (Fig. 19). The specified pressure required by the system is built up in the rail by the fuel pressure solenoid building up a magnetic force which corresponds to this specific pressure by means of a control current from the Electronic Control Module (ECM) (Fig. 19). This magnetic force equals a certain outlet cross section at the ball seat of the valve. The rail pressure is altered as a result of the quantity of fuel which flows off (Fig. 19). The current fuel pressure is signaled by the fuel rail pressure sensor to the engine control module (ECM). The controlled fuel flows back along the return fuel line, into the tank.
In a de-energized state, the fuel pressure solenoid is closed as the spring force presses the ball into the ball seat (Fig. 19). When driving, the fuel pressure solenoid is constantly open (Fig. 19). When engine is started, the fuel pressure solenoid is held closed by magnetic force (Fig. 19). When driving, the pressure of the fluid counteracts the magnetic force of the coil and the slight spring force (Fig. 19).

I think the text in violet above is incorrect! I think it is held closed by spring force at rest, not by magnetic force...magnetic force helps vary its opening amount. :banghead:

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 693

As much as I don't like cutting into the Fuel Pressure Solenoid wire, I am tempted to connect an Amp Meter in series with it. I am impressed with [stinking] Chrysler in that nearly every wire from the ECM to the engine sensors & solenoids are straight wires, and not going through any extra connectors. Adding a connection in the Fuel Pressure Solenoid wire sends a little chill down my spine.

Dean.

WWDiesel · **Posted:** Tue May 03, 2022 10:28 pm

CaptainDean wrote:

As much as I don't like cutting into the Fuel Pressure Solenoid wire, I am tempted to connect an Amp Meter in series with it. I am impressed with [stinking] Chrysler in that nearly every wire from the ECM to the engine sensors & solenoids are straight wires, and not going through any extra connectors. Adding a connection in the Fuel Pressure Solenoid wire sends a little chill down my spine.

Dean.

I totally concur with your thoughts on operation; that is the way I had it figured to operate as well. Even though we both agree the FSM is a little off in some of their description of operation.

As for probing the wires, why not just simply back probe the wires to see what the voltage is reading? This would at least tell you what the ECM is telling the solenoid to do based on the amount of ground current it is applying against the 5v supply and you won't have to cut any wires. I would think that during starting phase, you should see close to the full 5v at the sensor.
Just a thought! :idea:

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 693

WWDiesel wrote:

As for probing the wires, why not just simply back probe the wires to see what the voltage is reading? This would at least tell you what the ECM is telling the solenoid to do based on the amount of ground current it is applying against the 5v supply and you won't have to cut any wires. I would think that during starting phase, you should see close to the full 5v at the sensor.
Just a thought! :idea:

I like your thought and I like non-destructive testing. I already know the resistance of the solenoid coil (4.4 ohms) and the voltmeter will tell me the voltage. Ohm's law will tell me the amperage. (I = e/r) ...or for non-technical types: Volts divided by Ohms = Amps.

Dean.

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 693

CaptainDean wrote:

I already know the resistance of the solenoid coil (4.4 ohms) and the voltmeter will tell me the voltage. Ohm's law will tell me the amperage. (I = e/r) ...or for non-technical types: Volts divided by Ohms = Amps.
Dean.

If I was an engineer for solenoids, I would be able to calculate the strength of the magnetic force to counteract the fuel pressure to maintain fuel rail pressure.

For example, if the resistance of the solenoid coil was not 4.4 ohms, but instead 5 ohms, and the voltage is 5 volts, then 5 volts/5 ohms=1 amp. 1 amp of current could be calculated into strength of magnetic force. The ECM could translate the fuel pressure sensor output into a predictable solenoid amperage. Cool, eh?

Well, I'm not an engineer for solenoids, so all I can figure out is the basic theory.

Dean. (Couldn't sleep so I drank a glass of make-me-smart rum.)

WWDiesel · **Posted:** Thu May 05, 2022 3:15 am

If we could map the solenoid applied voltage (ECM variable ground) and resulting amperage to generate the magnetic field in the solenoid vs the actual rail pressure, we could draw/graph an XY curve to show the relationships over the operating range.
An interesting thought...

layback40 · **Posted:** Thu May 05, 2022 9:22 pm

CaptainDean wrote:

WWDiesel wrote:

As for probing the wires, why not just simply back probe the wires to see what the voltage is reading? This would at least tell you what the ECM is telling the solenoid to do based on the amount of ground current it is applying against the 5v supply and you won't have to cut any wires. I would think that during starting phase, you should see close to the full 5v at the sensor.
Just a thought! :idea:

I like your thought and I like non-destructive testing. I already know the resistance of the solenoid coil (4.4 ohms) and the voltmeter will tell me the voltage. Ohm's law will tell me the amperage. (I = e/r) ...or for non-technical types: Volts divided by Ohms = Amps.

Dean.

You are forgetting Dean/WWD that you are not dealing with a straight ohmic device. Its a coil so you need to consider it as an inductive device & so the current will be determined by that.

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 693

layback40 wrote:

You are forgetting Dean/WWD that you are not dealing with a straight ohmic device. Its a coil so you need to consider it as an inductive device & so the current will be determined by that.

Thanks layback40, that's a good reminder.

Coils ARE interesting devices, they can be used to induce voltage and/or current and/or magnetism into another inductive device (transformer) or ferrous metal, they can smooth a desired range of frequencies (choke), can generate an electromagnet force (solenoid/electromagnet), and more. Coils can also be a receiving device in all those same manners.

Motors are made of coils and are also influenced by Electromotive Force (EMF). EMF causes the counteractive current in the motor coils to reduce input current once the magnetic armature is spinning -- by inducing magnetic energy back into the coils (windings). Coils can also make heat, such as in Induction Cooking.

In our circumstance, the coil is being used as an electromagnet to apply force against the fuel pressure in the fuel rail. There are no moving or rotating magnets or magnetic fields immediately near the solenoid so it should not be greatly affected by counter EMF. However, if there is an AC component to the current energizing the solenoid, then the rising and falling magnetic field being generated by the solenoid will have some affect on the current.

Just for fun, take a magnet (off the refrigerator) and drop it down through 3 pipes. A steel pipe, a copper pipe, a PVC pipe. It will act differently in each one. It will immediately click to the side of the steel pipe, it will drop slowly through a copper pipe, it will drop straight through a PVC pipe. The falling magnet causes counter EMF in the copper pipe which slows the fall of the magnet.

Sorry to be a Know-It-All. I've spent 50 years in electronics.

Dean.

WWDiesel · **Posted:** Fri May 06, 2022 2:40 am

The coil windings in the solenoid is a fixed coil, so it does not move and there is no variable other than the amount of current passing through the coil which is controlled by the ECM to generate the desired amount of magnetic flux or force on the moveable plunger in this case to overcome the spring pressure against the movable plunger to control the amount of fuel dumped to the return system.
So the coil windings in the solenoid would be a non-variable resistance (ohms) and the only thing changing or variable would be the applied voltage and thus the amperage. :wink:

Hard to find noise -- clinking and clanking

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