Hard to find noise -- clinking and clanking

lfhoward · **Posted:** Mon May 23, 2022 8:29 am

Fingers crossed this does the trick!

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 694

lfhoward wrote:

Fingers crossed this does the trick!

Thanks Ifhoward,

Unfortunately, this has not done the trick. The engine still cuts out above 1300 or 1500 etc -- I'm thinking the fuel pressure sender is bad or flaky. Maybe just the connector. I'll look into that after work today. Measuring the voltage on that connector should tell me something.

I have a new one on the table.

Dean.

lfhoward · **Posted:** Tue May 24, 2022 1:59 pm

Bummer. I guess sitting for 4 years is not good for automotive components with seals, etc. Hope you get it sorted soon so you can start enjoying your CRD again!

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 694

Ifhoward, I've always known that the sound of silence is also the sound of things breaking. Our vehicles are much happier running down the road.

Today I measured the Fuel Pressure Sender on the fuel rail. It read: 0.56Vdc at key ON, then 1.2 at engine start and 2.7 at 1300 RPM. That's when the engine starts cutting out.

Changed the Fuel Pressure Sender anyway and the new one read: 0.62Vdc at key ON, then 1.4 at engine start, and 2.9 at 1300 with the engine cutting out. This tells me the fuel pump and fuel rail are good, along with the associated sensors and solenoids.

I'm really stumped on this one. It's had plenty of time to run the water out of the filter, high pressure pump, and hard lines. But yet it stumbles at 1300 RPM. I think it's time to make and appointment with my favorite mechanic and let him do some magic on it. The path to the shop is all downhill and all surface streets, no highways. It will idle it's way to the shop, and maybe even clear up along the way. Burns me up to have to give up.

Dean.

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 694

Talked with my favorite mechanic today. He reminded me that dirty injectors would make a diesel run as I described: Idles fine but starves going to higher RPMs.

So, next step is to clean my injectors. Anybody done that before? I suppose an ultrasonic cleaner is in my future.

I have cleaned Cummins 5.9 mechanical injectors, and these tips look the same. Should be able to remove the tip, clear and chemically clean the tips, then reassemble in an ultra clean environment.

Dean.

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 694

Pulled the injectors today after work. One had a ball of carbon hanging from the tip, but it fell off before I could photograph it.

This is the image directly after pulling them. Don't know what that is on #2, but it's not on there anymore either. I'll clean them tomorrow or Saturday and post more pictures then.

Dean.

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 694

Cleaned the injector tips and interiors today, and they didn't really need it. All tips shot in 5 directions quite well.

Here is a YouTube video about cleaning injectors that resemble ours quite well, with two small differences.
Adorian E Bismarck "How to clean diesel injector and clogged holes"
https://www.youtube.com/watch?v=guYFnOMlR_k
1) His are mechanical injectors from a 1.9 Turbo Diesel, but he didn't say what make.
2) There is one additional small (tiny) part that is not covered in his video that our injectors have.

My injectors come apart with a large crescent wrench and a 15mm box wrench. Only unscrew the tip, don't take apart the rest of the injector. I did shoot brake cleaner up through the main part of the injector and it came out the supply fitting. Then followed it with a shot of light oil just to rinse out the brake cleaner.

Take notice of these tiny parts, especially the smallest little spacer. I almost lost it in the weaves of my shop cloth. (Not shown. This picture has the parts on a paper shop towel.) It's about 3/32nds inch in diameter and about 1/16th inch thick.

To reassemble, first spray off the assemblies with Brake Parts cleaner to remove all debris. These parts fit together metal to metal and have to make a tight seal. Next, dribble some light oil on the parts just to make them a little sticky. Locate the tinyist part (a spacer) and place it atop the plunger.

Tip this coupling over onto the tiny spacer and the end of the piston. Then continue to follow the instructions in the video (above) to reassemble the injector.

After all this effort, the engine still only revs to 1300 RPM and starts to stumble. The only part left to change is the High Pressure Fuel pump. A new one is around $1700 - $2100, a re-manufactured one is about $800, a used one is about $400, and a rebuild kit of seals is from $65 to $120.

Because of all the huge effort to install the HP fuel pump, it seems worth while to get a new or remanufactured pump. Otherwise, I don't know what I'm getting.

Dean.

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 694

CaptainDean wrote:

Because of all the huge effort to install the HP fuel pump, it seems worth while to get a new or remanufactured pump. Otherwise, I don't know what I'm getting.Dean.

I've just been looking at YouTube University videos of rebuilding the CP3 Fuel Injection Pump for our CRDs and it seems very simple. There is a trio of special tools but they're just clamps with simple tabs to pull the pistons away from the central "off-center" rotary shaft. Those would be very simple to make, especially since they would only be needed once.

This looks like the route I'm going to take. Saving a thousand dollars is a good incentive to learn something new.

Dean.

layback40 · **Posted:** Wed Jun 01, 2022 1:39 am

CaptainDean wrote:

Because of all the huge effort to install the HP fuel pump, it seems worth while to get a new or remanufactured pump. Otherwise, I don't know what I'm getting.Dean.

I've just been looking at YouTube University videos of rebuilding the CP3 Fuel Injection Pump for our CRDs and it seems very simple. There is a trio of special tools but they're just clamps with simple tabs to pull the pistons away from the central "off-center" rotary shaft. Those would be very simple to make, especially since they would only be needed once.

This looks like the route I'm going to take. Saving a thousand dollars is a good incentive to learn something new.

Dean.

I am watching your work intently Dean.
My 2006 has an issue & others have told me its the CP3 or actually the pressure control.
I think there is an internal piston device that recycles fuel around the lift pump to reduce the supply pressure to the pumping pistons.
If it doesnt seal properly or sticks from varnish in its bore there is a problem.
It sounded like there is a spring & the solenoid puts fluid pressure against it to cause more fuel to recycle & so reduce the supply pressure to the HP part of the pump.
Has the You Tube videos any information about this?
I learned a lot from a tutorial in a pdf that was on this site.
You could have a play with the one on your spare engine first or swap it into you good engine.

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 694

Hey layback40! Good to hear from you again.

Thanks for following my posts, I do it half as a diary and half as community interest & participation.

Been talking with WWDiesel via PM and he reminded me of the Fuel Pressure Regulator solenoid valve on the high pressure pump as a possible cause to my whole mess. So I've got one on order now through Amazon $69 (thanks to WWDiesel sniffing it out). I'll find out Sunday because it's supposed to arrive on Saturday.

That solenoid valve is one that took some abuse while I was troubleshooting. I applied full 12v directly from the battery not realizing the ECM controls are only 5v AND pulsewidth modulated. I heard it clank open and closed like an old tractor on/off fuel valve. I probably did some damage.

I thought about swapping-in the regulator valve from the other engine, but since this is a difficult place to work, I'd like to only do it once this year. Certainly changing the regulator valve is far easier than changing the entire pump.

The more I looked at YouTube, the more I found. None of the videos were about troubleshooting the engine to reveal the pump as a cause, but many videos were about rebuilding it. You have to watch each one to get all the details. Each video expresses different ideas about a rebuild. By the time you've seen a bunch, then you get a pretty good education about the pump.

The CP3 pump is an excellent boiler plate for many diesel engines. One could certainly find Plunger and Bucket parts for a 3.0L or higher pump to place in our 2.8L pump.

Lots of info out there !

Dean.

layback40 · **Posted:** Wed Jun 01, 2022 4:55 am

I swapped the solenoid on mine. Its not that hard.
The 3 holding bolts have torxs heads.
Putting them back without dropping them never to be seen again is harder.
I placed a piece of thin tie wire around them while getting them started so they didnt fall.
My interpretation of how it works is that there is a control piston inside the pump.
The solenoid just adjusts the pressure on the piston, a little like in a hydraulic system like auto trans had before elec control.
Its that piston that sticks & caused issues. Mine at the moment is good to about 1500rpm & then it soon dies.
If I am quick I can turn the key off & on quickly & it restarts.
If I put my foot down it blows a lot of black smoke & dies.
It needs starter fluid to start.

layback40 · **Posted:** Thu Jun 02, 2022 12:31 am

Dean,
A few tips to removing CP3 while engine in car.
1/its difficult.
2/ Probably best to remove throttle body to make some room. It should allow you to get the CP# out of where its hiding.
3/remove alternator as well.
4/ loosen nut on pully of CP3 before pulling timing belt etc off.
5. removing vacuum pipe & fuel lines including HP rail line helps, more room.

Took me 2 hrs to get it out of my 2007 that already had radiator etc out.
Probably will take 1/2 a day to get out of a fully assembled car.
May do that tomorrow depending on weather.

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 694

Thanks for the Regulator Valve removal info. I have had to teach myself to bide my time while working on the Jeep. 1/8th of a wrench turn here and there, etc.

You like to wrap the tool and screw with wire, I like to stuff a small scrap of paper in the screw head to stick the screw onto the screwdriver. Almost always works, and I don't care if the paper falls into a hidden place.

Dean.

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 694

layback40 wrote:

I think there is an internal piston device that recycles fuel around the lift pump to reduce the supply pressure to the pumping pistons...

...It sounded like there is a spring & the solenoid puts fluid pressure against it to cause more fuel to recycle & so reduce the supply pressure to the HP part of the pump.

Has the You Tube videos any information about this?

Our pump is controlled electronically by the ECM by only manipulating the Fuel Pressure Regulator valve. There are a bunch of calculations the computer makes to determine how far to open the Regulator Valve on the High Pressure Fuel Pump. It takes information from the air temperature sensor (air density), fuel temperature sensor (fuel density), the fuel rail pressure sensor (pressure), torque from the transmission (demand), and accelerator petal position (command), and maybe more. The ECM sends a continuous train of pulses to the Regulator Valve causing it to open a certain amount.

The width of the pulses determine the amount the regulator valve opens. This valve sends fuel back to the tank when closed, or into the pump when open, and a variation of both when partially open or closed.

The fuel that gets into the pump either barely feeds the (plunger & bucket) pumps (3 of them), or generously feeds the the pumps, or some variation in between. The pumps just pump, there is no variation on their stroke length. All 3 pumps feed fuel to a single output that goes to the fuel rail. Thus, fuel pressure is supplied & maintained in the fuel rail.

The injectors are controlled by trains of pulses from the ECM that also vary in pulsewidth. The ECM determines how long of a spray shot goes into the cylinders and at what time.

Dean.

layback40 · **Posted:** Thu Jun 02, 2022 4:38 am

CaptainDean wrote:

layback40 wrote:

I think there is an internal piston device that recycles fuel around the lift pump to reduce the supply pressure to the pumping pistons...

...It sounded like there is a spring & the solenoid puts fluid pressure against it to cause more fuel to recycle & so reduce the supply pressure to the HP part of the pump.

Has the You Tube videos any information about this?

Our pump is controlled electronically by the ECM by only manipulating the Fuel Pressure Regulator valve. There are a bunch of calculations the computer makes to determine how far to open the Regulator Valve on the High Pressure Fuel Pump. It takes information from the air temperature sensor (air density), fuel temperature sensor (fuel density), the fuel rail pressure sensor (pressure), torque from the transmission (demand), and accelerator petal position (command), and maybe more. The ECM sends a continuous train of pulses to the Regulator Valve causing it to open a certain amount.

The width of the pulses determine the amount the regulator valve opens. This valve sends fuel back to the tank when closed, or into the pump when open, and a variation of both when partially open or closed.

The fuel that gets into the pump either barely feeds the (plunger & bucket) pumps (3 of them), or generously feeds the the pumps, or some variation in between. The pumps just pump, there is no variation on their stroke length. All 3 pumps feed fuel to a single output that goes to the fuel rail. Thus, fuel pressure is supplied & maintained in the fuel rail.

The injectors are controlled by trains of pulses from the ECM that also vary in pulsewidth. The ECM determines how long of a spray shot goes into the cylinders and at what time.

Dean.

The way the device works is in the LP part of the pump there is a mechanical valve that is normally shut when shut down or starting.
This results in no LP fuel being recycled to the fuel feed to the LP pump and so maximum feed pressure to the plungers & buckets.
When the rail pressure gets high (running), the solenoid on the CP3 provides pressure to the valve to overcome the spring force & allow fuel to recycle to the LP pump feed.
This reduces the LP pump output that is the feed to the 3 HP plunger & buckets, so reducing the output pressure from the HP part of the pump.
The valve is shut via spring force & opened via LP fuel pressure from the solenoid. The fuel rail pressure is controlled by variation of the supply (suction) pressure to the HP part (plungers & buckets) of the pump.
This suction starving is the way the rail pressure is controlled.
The signal you talk of is what controls the solenoid. The only direct control on the fuel rail pressure is the valve that you showed in a previous post at the end of the rail that only opens if there is grossly excessive fuel rail pressure.

I have had it in my hand today.
I now suspect that the pistons in mine are not working well enough (wear) to provide the needed rail pressure.
I will know more when I get the bad pump out, tomorrow if the weather is kind.
The spring valve is near the solenoid and fuel supply pipe & can be unscrewed with the pump out.
The valve cant be unscrewed while the pump is in place though.

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 694

I think you are talking about how the pump works inside, and I am talking about how the ECM controls the pressure.

There are about a dozen videos showing how to disassemble and reassemble the pump. Each had a slant toward a particular aspect of the pump. Watching all or most would provide a full rounded set of criteria to examine and repair your own pump.

Dean.

WWDiesel · **Posted:** Thu Jun 02, 2022 12:49 pm

Below is a good cut-a-way drawing of the CP3 that shows its internal & external components.

Dean, one item you did not mention in your writeup of how the CP3 functions is the Cascade/Overflow Valve which plays a very important and vital role in the overall operation and protection of the injection pump internals. This valve is pure mechanical in operation (no wires), and serves three functions all of which could affect final injection pump output (rail) pressure if it is malfunctioning or defective.

Quote:

Cascade/Overflow Valve
on side/top of CP3 injection pump. (See drawing)
Regulates lubrication to internal parts of the injection pump and regulates the fuel pressure to the fuel quantity solenoid valve on the back of CP3 injection pump. Also, controls the amount of fuel being returning to the fuel tank via the fuel return line.
Fuel is fed to the FQS (Fuel Quantity Solenoid) via the cascade overflow valve located on the side of the pump. The cascade overflow valve's (COFV) sole purpose is to prioritize the fuel flow between the pump itself (i.e. feed the FQS), then flow excess fuel to the lubrication flows to cool and lubricate the pump and finally divert any excess flow above that to the return line back to the fuel tank. (Bosch Part No.: F00N200798)

layback40 · **Posted:** Thu Jun 02, 2022 8:03 pm

CaptainDean wrote:

I think you are talking about how the pump works inside, and I am talking about how the ECM controls the pressure.

There are about a dozen videos showing how to disassemble and reassemble the pump. Each had a slant toward a particular aspect of the pump. Watching all or most would provide a full rounded set of criteria to examine and repair your own pump.

Dean.

Yes, I am talking about how the pressure control works internally. There is a pdf tutorial about that explains it.

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 694

layback40 wrote:

I have had it in my hand today.
I now suspect that the pistons in mine are not working well enough (wear) to provide the needed rail pressure.
I will know more when I get the bad pump out, tomorrow if the weather is kind.
The spring valve is near the solenoid and fuel supply pipe & can be unscrewed with the pump out.
The valve cant be unscrewed while the pump is in place though.

Here is a YouTube University video about refreshing the CP3 pump. You might want to slow the Playback speed to get the whole effect of the video details.
https://www.youtube.com/watch?v=-G3mwbu_-ys

Dean.

CaptainDean · **Joined:** Thu Oct 05, 2017 2:22 am **Posts:** 694

Our Liberty vehicles are really nice, but I loathe all the wiring. So, I have wondered how to get rid of the ECM for this engine. Now while searching through all the CP3 videos, there are some videos regaling "dump your CP4 for a CP3". This led me to the Linear pumps. The mounting looks the same, the crankshaft pulley and the fuel pump pulley seem to be 2:1 ratio... ...I wonder if a nice little 4-pumper linear pump for a ~2.8L would bolt onto this engine? There must be mechanical injectors that will fit. And hard lines could be fabricated by a worthy shop.

This model is not a direct bolt-up, but there must be some that are...

Has anyone done that? Need to trade the fancy electronic accelerator pedal for a mechanical pedal with a push-pull cable and return spring.

I can just imagine going on a wire pulling frenzy and reducing the weight of this vehicle by 100 pounds. [Drool]

Dean.

Hard to find noise -- clinking and clanking

Who is online