Code P0088... bad rattle after replacing everything

[Supa]

Ok... so here's the LATEST update... the saga continues! (sigh) Hoping I'm not boring you... maybe someone has insight after the end of all of this?

We got a remanufactured CP3 pump from what appeared to be a smaller American rebuilding family owned business... followed the steps in the service manual... and it turns out the pump leaked right down the seam in the middle... probably a bad o-ring of some kind. Pretty bad leak (steady drip stream and the truck wouldn't start). So we put the old one back in and could at least drive the truck again. Returned the cp3 pump...

We ordered another remanufactured CP3 pump from Thoroughbred Diesel, installed it, and this time the truck started and seemed to be maybe a little quieter... still the same P0088 code (high pressure at the fuel rail) and still the loud injector knocking sound. AND the fuel pressure relief valve is REALLY HOT... too hot to touch... which has been the case since the day we bought the truck.. No leaks thankfully. At the end of the day we were really bummed, we just thought that after all the research and trial-and-error we've done this would be the one winning trick... but no. Oh, and while I was putting the drive belt back on I realized that the belt tensioner was really worn and had a few sharp edges and missing bits from one of the wheels... so went out and bought a new tensioner and drive belt. Put that on and it seemed like our AC got a little colder... (sweet)

So then a few days later we're towing my 25' boat across town (maybe 4k lbs max) and I see some smoke from under the hood and pull over right away. The drive belt snapped! It seemed to me like the A/C compressor seized and caused the drive belt to break. Got towed to my mechanic and waited until he had time to diagnose and fix... yes indeed the A/C compressor had seized so he put in a Denso replacement and new drive belt and recharged the A/C. At least the truck ran again... and the AC was even colder.

In summary... at this point we're like $4k into fixing the P0088 error code (reman injectors, new fuel injector tubes, reman cp3 pump, new FCA, new fuel pressure relief valve, new fuel temperature sensor, FASS lift pump... we even spent half an hour cleaning the battery terminals and making sure all the ground bolts were nice and tight... but nothing helped...

To make matters worse, we were driving across town yesterday and noticed that the knocking sound was getting louder and louder by the minute. I pulled over and verified that it was indeed coming from the fuel pump/rail area. At this point the sound was maybe the loudest noise I've ever heard from an engine so thankfully we were a few blocks from the Dodge dealer so we dropped it off there for a diagnosis. They said they will get back to us Monday (tomorrow).

We're really hoping the bad/dirty fuel issue that caused all of this in the first place didn't somehow create a bigger engine issue. Could it be that one of the sensors we replaced could have been broken by contaminated fuel or too much high pressure? Or maybe if fuel was leaking from the rail (from the previous owner) it would drop over the ECM and could have shorted the connection to the FCA? It does kind of feel like there had been fuel dripping over the ECM in the past... or brake fluid?

All this feels a bit like the movie Christine... and the truck was possessed somehow...? we just want to get it to run smoothly again... please! lol

Anyway, thanks in advance for any insight or suggestions. We appreciate you guys.

 

[Tuesdak]

Stop driving it until it's fixed. Rent something if you have to have a truck. The high pressure "fuel leak" where something is getting really really hot can ruin the lube in the diesel fuel. This can ruin other fuel injection parts including blowing an injector that takes the engine out in seconds. Maybe the knock is a limp mode. Maybe it's pre-ignition from an injector leak attempting to melt a piston.

There should be a few good diesel shops in the area that are but a short tow away. Dealer is one thing, but, a good diesel shop IMO is better than a dealer that wants to throw parts at it. The online reviews are worth reading like I mentioned about the fuel injection fraud co. or ask on here about your area.

I double down my advice if you are a mechanic or have one in the family as my experience is these are the worst for pushing minor problems into expensive failures from refusal to use the hook. "It only has to make it 2 miles to work/home/the store with no oil in whatever system..." Just saying.

 

[p-Bar]

I second the no drive policy. Fix it before you "grenade" it.

 

[sag2]

Until you confirm with a scan tool the set vs. desired rail pressure you are just going to keep throwing parts at it. The diagnostic for that code is very straight forward. It appears it should be either the FCA or the pump, but you have replaced both.

 

[Ozymandias]

Maybe the wiring to the FCA is broken.

 

[Supa]

Thanks for your feedback, much appreciated!!

We are no longer driving the truck. We are still waiting to hear back from the dealer. If they don't give us some good news, we did finally get the numbers for a couple diesel mechanics in the area and will see if someone can help further with a scan tool.

The FCA wiring goes directly to the ECM and those wires seem ok, but maybe I should remove the ECM and check/clean the connectors at least.

 

[Ozymandias]

Any news here?

 

[Supa]

Funny you should ask... after over 2 weeks at the dealership they just gave us a status update about 30 minutes ago! Not good news either... Still that code P0088 (high pressure at the fuel rail) and their lead diesel tech has tested more things and even had Chrysler corporate try and help remotely. They said they are compiling a list of things they have tested for us to review so we can decide how we'd like to proceed. At this point they are guess-timating it may be a bigger engine issue as there is a slight misfire in one cylinder which points to internal damage. They said they were going to cap our billable time at around 4 hours but that the tech put in many more hours than that troubleshooting. The dealership service rep has been great overall considering everything, but that still doesn't change the fact that no real progress was made and we gotta pay close to $500. Oh, and on top of that it seems the flex plate bolts came loose and the threads are damaged so it needs a new flex plate and torque converter too... their quote $5k!

It's a real bummer to think of all the time and money we put in and we're dealing with an almost total-loss at this point.

We did get the numbers of a couple local diesel mechanics so it's possible we could reach out to them to have them see the tests the dealer performed and between that and their own scan-tool maybe they can think of more "outside of the box" solutions? But it's getting really hard to think of throwing more money into our truck at this point... we probably have $15k and a hundred hours into it already.

Anyway, we're definitely open to any thoughts y'all have. Thanks again!

 

[Supa]

So one more update from the dealer when we picked up the truck.

Fuel pressure hitting 21k psi. Swapped a known working FCA but no change.

Since cylinder 4 had a bad miss they capped the injector but there was no change. They flashed the PCM with the newest software but no change.

They wanted to do more tests of the (new/reman) fuel injection pump to make sure it is working (check return amount and high pressure) at an additional cost.

They also suggested to have a compression test done at a cost of around $650...

At this point they are leaning towards a crack in the cylinder block or some internal damage (or less likely the reman injection pump could be defective).

Anyway, that's all I got for now. Suggestions would be appreciated if anyone can think of anything else. Thanks!

 

[Ozymandias]

We had piston rings go out, could it be that?
Anyhow that's are no good news at all.

But all of this don't explain why your rail pressure is all the time up to max limit. At idle you want to see around 6K and then rising with throttle.

Im sure the dealer checked for continuity of the FCA from Sensor to ECM, that's basic test.

 

[AH64ID]

As Ozy mentioned it's not a mechanical issue within the block that is creating 21K psi.

If the FCA is good then the FCA is being told to generate 21K psi... even if the pump is bad the FCA should be able to limit flow to reduce pressure.

The FCA needs voltage to reduce pressure so I would guess there is a wiring issue that's keeping full voltage from going to the FCA, it's the only thing that makes sense at this point.

 

[Supa]

Thanks for chiming in further guys! The dealer did write a note that says "FCA - good. Manual add power and ground - no"... and the service rep explained that they did give it direct power and ground to see if that changed anything but no. One of my thoughts a month or so ago was to send the ECM to a provider that re-flashes or "fixes" possible issues just in case that was it... but the dealer reflashed it without any issues (or changes for that matter). It does have some old wiring that has been covered in grime and signs of past leaks that ate through some of the conduit/wrapper but after my countless times running through the wire harnesses I haven't found anything that makes me think there is something actually broken.

Well first things first, gotta figure out how we're going to get the flex plate and torque converter fixed... definitely not going to give the dealer $5k to do that job. Wish us luck!

Thanks!

 

[Ozymandias]

There are many good converters out.
Me myself I'm using a BD Diesel Converter, single Disc.
Perfectly happy with it.
I'd say you should get away with 2K for a good converter, a flex plate, and the install I shop.

 

[cerberusiam]

A "good" converter is about $850. If you get a billet cover the updated 4 mil flex plate is like $150 if you shop around. Blue Loctite on the threads when you install the flex plate to TC and you are good for a lot of power and time. A good mechanic can r&R that in 4-6 hours. That should give a comparable price to look for.

SOMETHING is demanding that rail pressure to go high, my question is what is the ECM commanding for pressure?

 

[Supa]

Well we ordered the flexplate and torque converter and bolts... we're not trying to do any substantial power upgrades so went with the ThoroughbredDiesel reman TC and a flexplate that sounds better than stock... including shipping about $1100 to Hawaii. Hoping we can find a decent mechanic to do the install, got our hands full on too many other projects at the moment.

As for the high rail pressure, my gut says that it's some "small" thing... and it seems strange the dealer wasn't able to pinpoint it considering they have all the right tech tools.

 

[Ozymandias]

I'd have spent a little more for the upgraded converter. It's so much better to drive.