Hey everyone, new paying member here, having issues with my truck and looking for some guidance. My truck is an 01 24v HO. I have had zero drivability issues since purchasing it about seven years ago until yesterday. Driving down the road as per normal when the engine just suddenly shuts off. I coasted it to the side of the road noticing the check engine light was on so immediatley cycled the key to view codes. I was met with P0230, P1688 and P1689. Luckily I was semi close to my shop so had some good Samaritans help me push it the rest of the way there. The truck is a crank but no fire scenario. I first turned the key on and confirmed the lift pump started and primed. I then bumped the key to allow the lift pump to run and opened the schrader on the injection pump inlet. Fuel was present and spraying out as I have always seen when bleeding after a new filter install. I then started checking the lift pump and injection pump circuits with some strange results. Pin 2, component side of lift pump to ground showed open limit on my ohm meter. Pin 2, harness side of lift pump showed the same result. Spent some time messing with that to make sure I was getting good connection to the block when testing, no change in results. In frustration I moved on to the injection pump. Confirmed voltage on injection pump connector of 12.5 volts. Removed ECM connector and resistance tested pin 13 (Datalink +) to the ground pin on injection pump connector aswell as battery ground. Both results from this were also open limit on my ohm meter.... At this point I was starting to doubt my meter, checked resistance from injection pump connector ground to battery negative, .6 ohms so meter was functioning. Am I looking at a severed harness? Where should I go from here? I am just assuming the meter saying open limit on all of these circuits would mean the wires are damaged / broken. It seems unlikely to me that they would all fail at the same time but I guess stranger things have happened.

 

Hopefully all of the wisdom here can help me figure this out!

Ohm test the following wires from ECM to fuel injection pump (FIP):

• ECM pin 23 to FIP pin 1--- 0 ohms 
• ECM pin 13 to FIP pin 2---0 ohms
• ECM pin 30 to FIP pin 6---0 ohms
• ECM pin 30 to ground---0 ohms

If open circuit is detected repair wires or clean ground.    

 

 

Do you have a stock lift pump or an aftermarket pump with a relay?   If stock pump, is it in the tank or on the left side of the block? the grounding point, G107, for the lift pump is on the left side of the block next to the starter motor.

 

 

I'll give these a test after work today and post the results. 

 

The truck has an OEM style lift pump on the side of the block. I was given maintenance records and receipts when I bought the truck and the lift pump had been replaced but it appears to just be an OEM style replacement unit. When I am checking pin30 to ground are we just testing it to any ground point on the truck? Battery negative even?

 

2 minutes ago, Basranabread said:

When I am checking pin30 to ground are we just testing it to any ground point on the truck? Battery negative even?

Testing to the battery ground is best but any clean grounding point will do to start with.

1 minute ago, IBMobile said:

Testing to the battery ground is best but any clean grounding point will do to start with.

Okay, will do. Not sure if this info gives any indication but the only thing strange I noticed with the truck prior to this was the alarm randomly went off twice with no trigger. Would sound and then would turn itself off after about 30 seconds. This happened two times that I know of in the week prior to my current issue. Just made me wonder about wiring gremlins.

As IBMobile has instructed, all grounds need to be serviced for cleanliness to insure continuity at ground level.

 

As for the intermittent anomaly of your security system being activated, be aware it is an "RF" receiver that decodes the key-fob's data. In rare instances depending on the location of your vehicle at the time of occurrence you may be in the proximity of strong RF fields emanating from commercial sources. Micro-wave links at 2.4 Ghz near airports and cellular relay installations combined in specific concentrated areas can induce RF mixing as "image frequencies" (or birdies) removed from the fundamental primary frequencies to create the "mix" where the onboard RF receiver becomes vulnerable to the extraneous RF mix and trigger a false alarm. I've experienced this near Boeing Field near Seattle Washington at a hotel parking lot overnight.

 

Depending on "where" this occurred, can you recall any unusual antenna towers or micro-wave dishes within 300 to 500 meters distance from your vehicle? Has there been an assembly of RF radiation installations erected in your vicinity when this abnormality occurred? 

 

Your sense of detail in noting this occurrence, along with what your drive ability failure has brought to you, may or may not be connected however; ground connections are a key starting point to alleviate "wiring gremlins" as a foremost starting point.

 

I know you're new to the forum, and time to assemble a signature would allow us to see any modifications you might have incorporated into your platform...that being said, are you able to monitor fuel pressure from the transfer pump to the VP-44?

 

W-T         

11 hours ago, Basranabread said:

I was met with P0230, P1688 and P1689

 

As for the P1688... Basically the VP44 is dead...

 

At this point the rest of the codes don't count because the PSG unit on the injection pump is shot. I would consider the replacement of the injection pump to insure you have a good PSG unit and don't cheap out. Make sure to buy a pump from a certified Bosch rebuilder or dealer that sells certified Bosh pumps. Like @dieselautopower is the go to spot for a VP44. 

 

Also I would highly suggest W-T ground wire mod being that the P1688 is typically from the AC noise issues and bad ground wiring on ECM and VP44. 

 

 

I suggest doing a VP hot wire test to verify if the VP44 is dead or not. If VP starts then VP is good, if no start then VP is dead.  Below is the link on how to do it.

 

https://mopar1973man.com/cummins/articles.html/24-valve-2nd-generation_50/51_engine/59_fuel/hotwire-test-vp44-r615/?tab=comments#comment-87

 

 

Still in all if there is a P1688 code that is not clearing hot wire test won't do much being the PSG unit is damaged. Can't fire fuel if the PSG is brain dead. 

2 hours ago, W-T said:

As IBMobile has instructed, all grounds need to be serviced for cleanliness to insure continuity at ground level.

 

As for the intermittent anomaly of your security system being activated, be aware it is an "RF" receiver that decodes the key-fob's data. In rare instances depending on the location of your vehicle at the time of occurrence you may be in the proximity of strong RF fields emanating from commercial sources. Micro-wave links at 2.4 Ghz near airports and cellular relay installations combined in specific concentrated areas can induce RF mixing as "image frequencies" (or birdies) removed from the fundamental primary frequencies to create the "mix" where the onboard RF receiver becomes vulnerable to the extraneous RF mix and trigger a false alarm. I've experienced this near Boeing Field near Seattle Washington at a hotel parking lot overnight.

 

Depending on "where" this occurred, can you recall any unusual antenna towers or micro-wave dishes within 300 to 500 meters distance from your vehicle? Has there been an assembly of RF radiation installations erected in your vicinity when this abnormality occurred? 

 

Your sense of detail in noting this occurrence, along with what your drive ability failure has brought to you, may or may not be connected however; ground connections are a key starting point to alleviate "wiring gremlins" as a foremost starting point.

 

I know you're new to the forum, and time to assemble a signature would allow us to see any modifications you might have incorporated into your platform...that being said, are you able to monitor fuel pressure from the transfer pump to the VP-44?

 

W-T         

 

I live in a pretty rural area so no antenna towers etc near by. Have only had the alarm falsely trigger with the truck sitting in my driveway which I thought and still think was extremely strange.

 

I will update a signature for you guys but as of right now, my truck is completely stock besides a level and 35's. I do not have a fuel pressure gauge on the truck or have one I can use on the test port currently. I can get ahold of one if necessary though.

 

2 hours ago, Mopar1973Man said:

 

As for the P1688... Basically the VP44 is dead...

 

At this point the rest of the codes don't count because the PSG unit on the injection pump is shot. I would consider the replacement of the injection pump to insure you have a good PSG unit and don't cheap out. Make sure to buy a pump from a certified Bosch rebuilder or dealer that sells certified Bosh pumps. Like @dieselautopower is the go to spot for a VP44. 

 

Also I would highly suggest W-T ground wire mod being that the P1688 is typically from the AC noise issues and bad ground wiring on ECM and VP44. 

 

 

 

So what you are saying is if 1688 is present then 0230 and 1689 will show up just as a result? There is no chance 1688 could appear due to losing connection with the injection pump caused by a wiring issue? I'm not against changing the vp44 just want to be 100% sure before spending the money. I will also look into that ground wire mod, thanks for linking that!

1 hour ago, Mopar1973Man said:

Still in all if there is a P1688 code that is not clearing hot wire test won't do much being the PSG unit is damaged. Can't fire fuel if the PSG is brain dead. 

 

I haven't attempted to clear any of the codes but can do so this evening. The truck basically died, I rolled it to my shop, messed a bit with it the next day and that's where it sits. Would you recommend clearing codes with a scanner and then seeing if they do come back in this case? 

Sometimes pouring cold water over the IP can temporarily fix it. If that is the case then the pump is definitely bad.

Ok Riley, your rural location generally rules out a harsh RF environment and further close inspection of key grounding locations could contribute to an intermittent triggering of the security system.

 

In abstract situations a poor ground that isn't absolute can cause issues where the minute corrosion can act as a diode at the molecular junction contact point, this in turn, can act as a high frequency rectifier similar to a "crystal radio" receiver and rectify very low level RF generation and act as the culprit in extraneous RF generation. The current flow in such a generation can be in the pico-amps level and induce unwanted electrical behavior in surrounding sensitive electronic devices. The fix...clean and burnish all DC grounding points with diligence.

 

An old primary rule discovered and documented by Mike @Mopar1973Man is the important aspect of monitoring fuel pressure in the transfer delivery system. This assures ample volume under idle and WOT conditions to cool and lubricate the VP-44...it is imperative to monitor fuel pressure and prevent it from dropping below 15 PSI at all times.

 

Also, Mike educated all of us regarding diesel fuel lubricity in regard to the 2nd Gens being produced during the "low sulfur" diesel fuel era and I'm sure Canada followed along when the diesel fuel became "Ultra low sulfur" refinement. This caused an extreme lack of lubricity in order for the VP-44 to survive. The quiet fix we all use is doping our fuel with two-stroke low ash TCW-3. Only one ounce per gallon restores the protective lubricity of the diesel fuel and improves the scarification aspects to the metal pump components within the VP-44

 

I believe these two aspects and suggestions, will provide longevity to your 2nd Gen platform once it's back in running condition. Your 7 years of trouble free operation is exceptional considering many owner/operators overlooked these two key issues and lost the service of the VP-44 early. I too, lost mine at 74K miles in only 3 years of operation. I now monitor fuel pressure and dope my fuel religiously. VP-44's are not cheap.

 

I'll let Mike expand on the P1688 code that indicates error at the PSG unit attached to the head of the VP-44

 

The "test" run that @IBMobilelinked is an excellent hot-wire test and can help evaluate the possible hard failure of the PSG board. It would be a relief just to get it running at idle.

 

W-T

 

 

1 hour ago, Basranabread said:

So what you are saying is if 1688 is present then 0230 and 1689 will show up just as a result?

No.

 

The P1688 means the VP44 PSG is no longer functional. 

The P1689 means the PSG is unable to communicate because a of the P1688 code

The P0230 means the voltage / current of the lift pump is out of range. Lift pump is most likely bad or wiring issue.

 

Hey guys, Sorry for leaving this dead in the water for so long. Sold my shop property which caused the truck to be tucked away and ignored until now. I did the hotwire test and the pump is confirmed dead. So now I have some questions about injection pump options. I took a look at DAP and they seem like a strong option. The only other one I am considering would be a Blue Chip. When comparing the premium upgraded vp44 from Blue Chip  to the 2 year warranty version from DAP the only difference I can see that is apparent from the descriptions is that the Blue Chip version has a steel sleeve in the housing where DAP is aluminum?  It seems there isn't much else that differs in the pumps. Both use new electronics and both have Bosch upgrades / updates to the internals. Does this justify the $1000 price increase for the Blue Chip? I'm also going to pair this with an AirDog Raptor 150Gph lift pump, is there a fuel pressure indicator light set up that isn't 5psi? I'd be much more comfortable with the light coming on around 10psi but can't seem to find anyone that makes this. I'm not a big fan of mounting a gauge in my truck, I like the clean, OEM as possible, look so an inconspicuous indicator light would be best for me.

 

Also plan on throwing a steering box in the truck, was planning on doing a redhead unit but since I'm already asking for your input I figured I would see if anyone has a different opinion or better option on that as well.

Edited December 19, 20222 yr by Basranabread

A small-engine oil pressure switch at your desired pressure would do the trick. But then what action do you take when the light is on, when it could be 9.5 PSI, or could be negative PSIG.

 

Could use two pressure switches on a tee, one at 5 PSIG, one at 10.

3 minutes ago, LorenS said:

A small-engine oil pressure switch at your desired pressure would do the trick. But then what action do you take when the light is on, when it could be 9.5 PSI, or could be negative PSIG.

 

Could use two pressure switches on a tee, one at 5 PSIG, one at 10.

My feeling is that if I'm seeing the light come on at 10psi, I'm already below the recommended supply pressure of 13psi on DAP's website. I can see that and identify what the issue is, whether it be the pump getting weak or something else. With a 150Gph pump, and the truck otherwise stock, I don't really see the need to monitor a gauge constantly. My reasoning is If the light ever turns on I'll just know to replace the lift pump before damage is done.

Look for a adjustable Hobbs switch. About 9 years ago I found one at Summit Racing but I dont remember the number. The one that I got as I remember it was adjustable from 8 to 16 pounds and I set mine to turn on at 10 and off at 12 @ pound ( dead band ) .

I have tried several engine oil pressure switches, but they don't last.  The high frequency pulses from the VP44 destroy them in a relatively short period of time, even with a snubber.  The longest lasting one lasted for about a year.  I installed the switch in the photo below one year ago this month (10,000 miles ago).  So far, I like this one  the best.  It comes with 3 terminals - common, normally closed, and normally open.  It is adjustable (a winner here) and comes preset at about 10 psi.  I also like this one so far, mainly because it is still working!

 

 

 

 

 

 

I am posting the following information because I think you have not purchased your AirDog Raptor 150Gph lift pump, yet.  I think that lift pump volume is way overkill for your application.

 

After years of thorough research I have found at least two groups of people who have installed a flow meter in the return flow line between the VP44 and the fuel tank and test drove their trucks under many different operating conditions.  I have done my own fuel return flow testing  of the VP44, as well,  In fact, I even went one step further and disabled the lift pump and routed a hose around it.  The return flow from the VP44 remained unchanged.  I drove the truck for 30 miles under all kinds of throttle applications.  It drove no different than it did with an operational lift pump.  

 

All of our test results have come to the same conclusion - lift pump pressure has no bearing on the volume and pressure of fuel flowing inside the VP44, or how much fuel is returning to the tank from the VP44.  We have all learned that it is the VP44 internal fixed displacement vane pump that provides the fuel flow for the operational and cooling needs of the VP44 injection pump.  The lift pump does not provide this.  However, the lift pump does provide a flow of fuel greater than the volume required by the VP44.  As long as there is a positive pressure at the inlet of the VP44, the fuel supply required will have been met, even under the most demanding VP44 operating conditions.

 

How a fluid under pressure and flow behaves is much like how electricity behaves.  In electricity you have the following:.

 

*   Electromotive force (electrical pressure) measured in volts.

*   Electron flow (current) measured in amperes

*   Resistance to electron flow (resistance) measured in ohms

 

So you have pressure, flow, and resistance

 

In fluids you have the following:

 

*   Pressure - usually measured in pounds per square inch (psi)

*   Flow - usually measured in gallons per minute (gpm) or gallons per hour (gph)

*   Resistance -something restricting the flow of fluid - also usually measured in pounds per square inch (psi)

 

Again, you have pressure, flow, and resistance

 

When working with electricity, we have relatively inexpensive meters to measure voltage, amperes, and ohms (electrical pressure, current, and resistance).  We use these meters responsibly to measure the appropriate property of electricity to draw responsible conclusions.  Would you modify an electrical system based on one gauge - a voltage gauge - and not consider the current flow or the resistance of electrical loads?  Probably not.

 

When working with fluids, the only inexpensive measuring device is a pressure gauge.  Flow meters are very expensive and can be difficult to install.  So, we usually end up with only a pressure gauge as a tool to diagnose a fluid flow problem.  Without a solid understanding of the physics of fluid under pressure, flow, and resistance, diagnosing a fluid flow related problem with only a pressure gauge can be difficult.  Misunderstandings of how things operate can easily occur.

 

Now, we get to our VP44 fuel system with a pressure gauge and ONLY a pressure gauge.  No flow meter in conjunction with other pressure gauges to evaluate a complex operating fuel system.  Nope.  Just one pressure gauge location for over 20 years of VP44 operation with many folks making decisions and drawing conclusions based on the reading from that pressure gauge without even considering fuel flow and the resistance to fuel flow.  Even worse - not even considering that there is another fixed displacement feed pump in series within the same circuit (the fixed displacement vane pump inside the VP44).

 

On 6/20/2022 at 1:54 PM, W-T said:

An old primary rule discovered and documented by Mike @Mopar1973Man is the important aspect of monitoring fuel pressure in the transfer delivery system. This assures ample volume under idle and WOT conditions to cool and lubricate the VP-44...it is imperative to monitor fuel pressure and prevent it from dropping below 15 PSI at all times.

 

 

This is only my opinion, of course, but I completely disagree with the "it is imperative to monitor fuel pressure and prevent it from dropping below 15 PSI at all times." part of that statement.  Similar statements have appeared over the years on this site stating that the VP44 could be harmed by having fuel pressure fall below 14 or 15 psi.  This is simply not true.  It has also been stated on this site that when fuel pressure falls below 14 psi, there is no fuel from the VP44 returning to the tank, so no VP44 cooling.  Again, simply not true.

 

On 6/20/2022 at 1:54 PM, W-T said:

I too, lost mine at 74K miles in only 3 years of operation

 

W-T, my original VP44 failed at 64,000 miles and was replaced under warranty at 87,000 miles.  The warranty also covered the "fix" at the time, which was to install a relayed in-tank lift pump modification.  Before I took the truck in for repairs, I had already heard of the horror stories of faulty lift pumps taking out the VP44.  Of course, at the time I believed them - why shouldn't I?  So, I strapped a fuel gauge onto the driver side wiper arm and drove the truck back and forth to work for a week (250 miles).  The lift pump pressure stayed between 12 psi (idle) and 7 psi (WOT) one hundred per cent of the time.  Hmmm.

 

After the repairs the truck drove much better.  The very next day I strapped the same fuel gauge onto the wiper arm again and went for a drive.  6 psi at idle and 3 psi at 2000 rpm wide open throttle.  Hmmmm..., again.  I went back to the dealer and talked directly to the mechanic - a very knowledgeable guy.  He said that those low readings are normal but he readily stated the he did not understand why this was the direction Chrysler decided to go.  I told him not to worry about it because with my background in fluid power, I figured that as long as there was always a positive pressure at the inlet of the VP44, the VP44 would be happy, so I would be happy.

 

I have currently logged 283,000 miles on this re-manufactured VP44. I used the in-tank lift pump for 160,000 miles (6 psi at idle, 3 psi WOT).  According to a lot of information from this site, this VP44 should have been killed in short order.  I elected to replace the in-tank lift pump (still working fine) with a used frame-mounted FASS (65 gph, I think) on the frame rail just in case of an in-tank lift pump failure.  The used FASS lift pump shows 12 psi at idle and 6 psi at 2000 rpm WOT (with a mild tune on the Smarty S03). That lift pump is still being used and has logged over 120,000 miles.  So, in conclusion my re-manufactured VP44 has never seen over 12 psi...., ever.  Just for the record, I use no fuel additives nor any two-stroke oil. 

 

So...., @Basranabread, if I haven't bored you to death by now, the pressure switch in the photo can easily be adjusted to suit your needs.  I adjusted mine to turn off the warning light quickly after the engine has started.  I didn't set it at a specific pressure.  In one way you can make it behave similar to a gauge.  Set the gauge at a fuel pressure that would make the warning light come on under a heavy throttle at a specific rpm of your choice.  Then when you drive your truck under those conditions, the light will begin to flicker when the fuel pressure nears your setting.

 

@W-Tand @Mopar1973Man, I mean no disrespect to either of you.  Both of you have provided information many times that has helped me resolve problems or, in many cases, has provided me information to make my truck a nicer vehicle to operate.  So I thank you both for that.

 

- John

 

 

 

 

 

 

Hey John, I did review your post on Monday this week however; I've been so busy I hadn't had the chance to digest and respond appropriately to your very well thought out contribution in this subject matter.

 

The history of the 2nd Gen platforms have been mauled over for twenty years now and the "tribal knowledge" many of the participants have gleaned has come at the price of success and failures of others. The care and feeding of the VP44 became a focus point in much of the earlier years due to the method DaimlerChrysler elected to transfer fuel to the working VP44.

 

TDR, Turbo Diesel Register had a large following at the time and their printed magazine had many comprehensive articles on various subjects revolving around the VP44. With outraged customers who purchased a 2nd Gen platform to experience Injection Pump failures at fairly early intervals, typically less than 100K miles, the frustrations with dealerships grew to alarming levels. I'm not referring to the "wire tap" roll-coal enthusiasts who blatantly voided their factory warranty with stealth-cap wire tap modifications or worse, being it is a totally visual modification, easily discoverable by novice dealership technicians. It reminds me of the Seinfeld episode with the "Soup Nazi" NO SOUP FOR YOU...or No Warranty for You.

 

I wish I had the time to thumb through all my early TDR magazines to find the actual articles where the information came from the actual manufacturers of the related components and the arguments between Cummins, Daimler Chrysler and Carter (the OE transfer pump) manufacturers. This is why I made reference to "tribal knowledge" having gone back in time twenty plus years...I know these things but, I don't recall how I came to know the details.

 

I'll attempt to parlay some basic recollections of small but, important data that Carter stipulated regarding their recommendation to "pump placement" or location. Carter told Cummins the transfer pump is to be located within 24 inches of the fuel supply reservoir. This is printed documentation that arrives with each pump in the box, brand new.

 

Daimler Chrysler told Cummins NO, we want the entire Engine as a "drop in module" with fuel supply devices attached as an assembly.

 

I don't wish to beat a dead horse here...but, I think this maybe a key point where all of this buffoonery began and still, to this day, misconceptions prevail.

 

I truly appreciate the prowess of the obviously advanced Diesel mechanics or technicians who have contributed their findings or discoveries in various forums. Also, it is interesting to note the "technical excellence" across the web forums varies according to Joundra of a given site. I believe this site has merit and the historical talent that has made valuable contributions over time, can not be discounted. 

 

My background has a few eclectic sojourns in various industrial environments. It has allowed me to dabble as an inquisitive nerd over a vast selection of endeavors for personal satisfaction and household support. The last 30 plus years, as a "slang term" I was referred to as a "pump-man" and worked in the field of Fluid Management. I've worked with and repaired nearly every pump configuration imaginable on this planet. Double action displacement, single action, gear rotor, vane and diaphragm, Plural component hot and cold, just, to mention a few. The liquid products being pumped or manipulated, varied from light weight volatiles, heavy mastics, intumescent coatings, residential and industrial coatings, sporting event field striping, Interstate, Highway and city street line striping ect...ect... yeah, I know....boring stuff but, the Space Shuttle heat-shield Tile adhesive plural component project was out of this world. Sorry, not trying to over power the subject...just highlighting a foundational background.

 

I had the pleasure of providing operational maintenance and repair seminars to large and small organizations with mechanically inclined shop employees. The primary aspect of focus was to stress the importance of never allowing the pump to run dry. Never, "Dry Stroke Your Pump" for the shear fact that the liquid nature of the vehicle, regardless of it's chemical composition is the "lubricating" shield between working mated surfaces. Repair or refurbishment of a given pump that has been inadvertently "dry stroked" for even fractional amounts of time cause immediate damage and hinders the operational longevity of the internal components. This is much more prevalent in a "high pressure" scenario with "thin bodied" liquid materials and leads to additional operational cost factors. In our case, an on the road failure is always a stress filled event that could or should be avoided through disciplines as a diesel engine owner/operator.

 

The aspect of lubricity in diesel fuel and how it is formulated is a worth while subject all it's own. I hadn't paid much attention and gleaned some very important knowledge from @Mopar1973Manin our early correspondence . It also included the important aspect of liquid flow volume to enhance cooling of the high pressure VP44's internal components to enhance longevity over thousands of repeated heat soak cycles. 

 

I took the time yesterday to call @dieselautopowerand spoke with Lenny about the changes that have occurred with Bosch and the VP44 re-manufacturing details. His background knowledge is outstanding and he brought several aspects to my attention that needed clarification. It appears Bosch, did indeed, make some critical changes in materials used in construction. Most notably, the sleeve, previously made from aluminum (sheeesh) is now an alloy steel sleeve...yeah no brainier here...along with many enhanced internal working components. He also informed me the PSG circuit board control device has been enhanced for longevity. The changes that Lenny referred to, have most definitely made an impact on how long these pumps will remain fully operational. He assured me the failures they are seeing now, are almost exclusively electronic related failures and internal part wear or failure has become quite rare in comparison. This alone, may very well, take the aspect of doping fuel with one ounce (per gallon) of TCW-3 two-stroke to a lesser degree of urgency. I don't believe anyone would debate the aspect of our 2nd Gen CTD's being produced during the "low sulfur" formulation and the cautionary note we all took when Ultra Low Sulfur fuel was introduced. With Mike M1973M enlightening the forum with Scarification principles and standards, the fix of providing lost lubricity became a standard practice for myself and many others. It just seemed to be good common sense.

 

The volume or flow through quench, of the fuel, to enhance or 'strip off" heat, through liquid exchange is nothing new, I believe most new fuel injected vehicles are all dumping more fuel back into the tank as a full circulatory system than ever before. If it's for cooling purposes, I don't know for sure, perhaps it's just volume for that occasional WOT and avoids fuel starvation in all conditions. I touched this subject with Lenny at DAP in regard to the principle of heat dispersion through flow-volume and he guided my thoughts around "heat cycles" before failure. Bosch has made changes to the electronics of the PSG circuit board with "heat cycle" periods being the main focus and to gain longevity. I was curious as to what Bosch might have done at component level but, Lenny assured me, Bosch keeps such information as proprietary and won't divulge the intricate details. However, heat is the negative aspect for run failure in nearly every electromechanical device over a period of time.

 

Close inspection of how Bosch cast the housing with regard to how the PSG circuit board is embedded in it's mounting location to shed heat from the surrounding structure is not how I would have engineered it. Being that fuel flowing during run time is one aspect, the heat-soak after shut down is the issue Bosch was most certainly addressing.

The board is all surface mount components and the composition of the small capacitors on the board are most likely standard ceramic with standard heat coefficients...they'd last a life time in a tabletop clock radio in your bedroom but, in this environment of heat-soak I'd have elected to place Tantalum caps as a superior component in high heat environments. Cost wise... ceramics are 5 cents, Tantalum are 18 cents.

 

The shut down of a CTD in July in Phoenix  Arizona after a hard pull or run on the Interstate is the worst case scenario for that little circuit board to just sit there and cook...as I pointed out to Lenny at DAP there is a way of providing cool-down to the PSG after shut down with a Pelter Junction device.

 

I purposed my fix as a timed circuit to provide DC for 20 minuets and then terminate the cycle. The Pelter Junction is a fascinating device that operates at a fairly low current consumption and once you provide 12 volts DC to the device (shaped like a flat faced playing card) that is in direct contact with the circuit board, one side of the Pelter Junction becomes very cold and the other side is hot...this becomes a solid state heat sink or heat inducer, depending on what side you are working with. The aspect of getting it nested within the cavity of the mounting location within the VP44 will be a small challenge. It could be activated on start up of the CTD and have a simple timer like a 555 controlling the "after shut down" timing interval to scavenge the "heat soak" in a reasonable time interval. The little control could have a knob to adjust the length of time the device operates.

 

I do regret using the term Imperative, I do realize there is a balance when conveying a message or thought...my habit of getting a bunch of rowdy blue collar butt-cracks to pay attention during a seminar so the owner or Boss is happier with their new $60,000.00 device.... because the "guys" know how to trouble shoot and fix it.

 

This subject of lubricity and additional fuel flow has certainly been tossed around for twenty plus years. The enthusiasts who partake and share findings is a main reason for my interest and participation. John, your findings and documentation are always of great interest to me, besides, your a pump man!

 

So @Basranabread...my apologies for semi hijacking your thread with peripheral data.

 

Only @IBMobile remained focused to directly assist this member.

 

On closing my rant...if anyone can procure a Bosch flow-bench, and allow me to use it, (oh heck, just give it to me) I'll build VP44's that you'll only purchase once.

 

You know...the CTD is a pump, feeding a pump that feeds a pump...gosh it's a pump mans NIRVANA !

 

Merry Christmas

W-T

 

 

 

 

   

 

 

 

 

 

 

 

 

 

   

 

 

 

       

 

 

 

 

                   

Thank you both Tractorman and W-T for your well thought out posts above. I'm still breathing LOL!

Awesome amount of information in the previous posts, thank you @W-Tand @Tractorman, I really appreciate it and also supplied the answers I was looking for. 

 

@TractormanI did end up purchasing the 150gph pump. I do realize it is overkill for my current application but do not plan to keep the truck stock forever and saw no harm with putting an "overkill" pump in it right now. I also went with the 2 year warranty DAP vp44 and red head steering gear. 

 

Now this brings me to my next issue that has me scratching my head. I finished the install of all of this the night before last. All went well, truck primed and fired up as it should. On my maiden voyage after about an hour of normal driving I decided to get on the loud pedal a bit. When I did I thought to myself "seems down on power up high" so I now curiously continued driving normally. Shortly after I got into it again and noticed the truck hiccup like it was starving for fuel. Got off of it immediatley and then rolled back into throttle very lightly. The truck hiccuped again and continued to do so anything over 1/4 throttle. I pulled over and jumped out to look at the gauge installed on the Raptor lift pump. 0psi is what it read! I turned the truck off immediatley and checked the fuse to the pump. All was good, I bumped the starter to run the pump and the pump ran but very loud (sounded like cavitation) and gauge stayed at 0psi. I repeated this three or four times until the pump finally decided to build pressure once again but remained noisy. I then limped the truck home to inspect further and when I did I noticed fuel dripping off of the pump. The 4 bolts holding the pressure regulator on the side of the pump were finger loose and fuel was coming out around the regulator. I tightened these and it appeared to seal up. I then started the truck and the pump remained noisy but was reading pressure on the gauge. I then shut the truck off and bumped the key to run the pump and it continued to sound like it was cavitating but there was pressure on the gauge. I ended up pulling everything apart pre pump to check for air leaks or restriction to no avail. I then fired the pump several times in a row and about the 4th time it became quiet sounding like it should. Then primed it a couple more times and it started cavitating again. While it was cavitating this time I opened the fuel bowl drain. It pushed fuel out no problem and after closing it the pump has been quiet. I have contacted airdog about this and they would like a video of the noise the pump is making. I cannot get it to do it again since I cracked the fuel bowl and I'm not convinced it is solved since it was doing it intermittently. I am now paranoid to drive the truck and potentially hurt my brand new vp44. Could it be possible that the leaking regulator allowed an airlock into the system and me cracking the fuel bowl drain purged it? Could the loose regulator also have caused my initial pressure loss aswell? My brain is melting trying to make sense of the complete loss of pressure paired now with an intermittent cavitation sound from the pump that I cannot replicate after simply opening my fuel bowl drain during diagnosis 🤯. Any input would be greatly appreciated!