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  • Factory lift pump & After market lift pumps Caution !

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    The subject matter has been discussed for years and all diesel enthusiasts/owners know how important it is to maintain proper levels of fuel pressure via the "transfer pump" or Lift Pump for reliable operation. There are many requirements that each owner/operator may wish to achieve in replacing the OE Carter or perhaps making an aftermarket selection. Notably, most have  had the rude awakening of a failed VP44 following the failure of the Lift Pump in a too late scenario. The cost of a VP44 compared to the Factory (Carter) Lift Pump is considerable and many of us have learned the hard way.

     

    The general consensus among the vast majority is to eliminate the factory OE Carter pump and invest in a robust Class 8 aftermarket system. There are several companies that offer such devices with different performance levels and packaging. Many, come complete with new 1/2" fuel lines, mounting structures, fuel fittings and electrical control harnesses. Some companies offer more modest devices with a budgetary aspect at minimum level. All of this becomes apparent when a conscientious owner/operator begins the research to purchase a new device or system. I for one have stopped reading "Lift Pump" threads because it's so very painful...and I've already seen so many stories of the same old blah blah blah! No, I am not being insensitive to a fellow CTD owner's plight...after all, this is most likely a "new to Diesels" type person. The post is reaching out to the "experienced" diesel enthusiasts for suggestions and perhaps constructive feed-back, prior to making that large investment. Confidence from fellow CTD owners in what they may have purchased or installed goes a long way with the new guy or lady looking for an answer.

     

    For just a moment allow me a little latitude...Oh God! Not another Lift Pump story :rolleyes:...Yes but, not what you might think. This will drill-down in a different manor so, please bare with me. :neutral:

     

    The factory OE "Carter" is such a little peanut-whistle why did Dodge do this? The fact is, as many know quite well, the decision was Daimler Chrysler who dictated to Cummins to provide the complete CTD engine package as a drop-in module. Carter's specifications states that, "this pump is to be located within 18 inches of the fuel supply"...it's sad to know these details greatly after the fact. This detail was covered 20 years ago on nearly every diesel website worldwide. This led to the unfortunate degradation of the Carter transfer pumps reputation.

     

    In actuality, the Carter LP (lift pump) has excellent design characteristics!

     

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        At first glance the appearance seems a bit "puny" but, let's look at some of the "not so apparent features"... First of all, Carter is a very large world-wide company who provide a vast selection of produced articles. They also provide excellent technical documentation regarding the application of their products in numerous industrial devices, automotive, marine and aeronautical systems or platforms. Electro-mechanical pumps of this nature, are just a single product that they produce... In our application, CTD's are at first, supplied copious amounts of diesel fuel at acceptable levels to operate the engine and provide flow-through for critical cooling of the VP44 in return to the fuel tank. This is "how" the designed system was to perform. :rolleyes:

     

    We know as experienced CTD owners that this was not always the case. Many of us know the error of mounting this little well designed pump nearly 10 feet forward of the fuel supply (not to specification of Carter Inc.) and ask this little pump to draw fuel through a small 1/4" line and....force the liquid through "banjo-bolt" fittings as delivery to the VP44? Wow...it's an unreasonable expectation for an electro mechanical pump, that most likely, costs less than $20 to produce in the Philippines. :duh: None the less, how many of us have had the occasional chat with a CTD owner (who knows nothing) that tells you they purchased the 2nd Gen new, he has 187K miles and has NEVER replaced the VP44 (he doesn't know what a VP44 is...you just taught him the word) and NO...he has never put a fuel pump into his truck! Yeah ! You know what I'm talking about ! How can this be ? Well...I guess some folks are a lot more lucky than I am... heck...this guy doesn't even know about 2 Stroke for lubricity,... credit our GodFather @Mopar1973Man 

     

     

    This photo is well known as a starting point. Also, a depiction of what Cummins had to do to appease Daimler Chrysler's request of a "drop in module" CTD

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    Okay...what is "a well designed pump"... even if it is not mounted correctly?

     

    At Carter, where they have been doing this longer than any of our familiar after-market LP suppliers... please note:

     

    1... A fully enclosed hermetically sealed electro-machanical  device that allows the liquid fuel to act as a cooling medium and fully immerses the active armature of the 12 volt DC motor to never exceed the temperature of the supplied liquid (diesel fuel)...because it is "airless" (hermetically sealed) there is no ignition to cause flammability. It's liquid cooled !

     

    2... The entire body or "encapsulation" as hermetic, provides absolute closure or isolation of the motor-brushes as they kiss the surface of the armature in run condition. This is very important as a DC (direct current) motor with carbon pile brushes act as a wild uncontrolled sparking noise source generator !!! 

    This is a normal phenomena of any analog DC brushed motor. A given manufacturer of brushed DC motors, depending on purpose, will take steps to "silence" the electrical (RF noise generation)...the term "purpose" needs clarification... "if the motor is a "CCS" continuous commercial service (runs all the time) then, additional electronic filtering or "shunting" of the armature must be provided.

     

    3... Carter Inc. employs RF Engineers (BSEE graduates minimum) to accomplish technical requirements when contracted specifications are to be adhered to for final product production. An expensive platform in any industrial production would have a string of engineers along with design engineers specking' components or assemblies that will be encapsulated within the finalized product. This occurred in "our" beloved CTD's with electro mechanical LP's....the Carter is "RF quiet" for continuous run condition. 

     

    Let's examine the electronic terminals of the Carter LP

     

    1050224.jpg.ae2ca33a3733fb423d14c83563d3032c.jpgNote: The plastic weather-guard assembly directly attached to the full metal housing that contains the + & - 12 volt DC !

    4... This connection point provides the direct current to power this LP. I wish you to fully understand what you're looking at. As viewed you'll note "both Plus+ and -minus" is provided at this connection point. You must also NOTE, the + and - are arriving directly from a single "pair" connection of both + & - .... I know you'll think I'm stating things "twice" and I want you to know this is an attempt to be a "balanced" feed. The housing of the pump is fully DC grounded when it is attached to the mounting bracket. In a "balanced" feed the "minus" or "negative" is NOT directly at chassis ground...it is merely + and - of the source (12 volts DC in our case) the body of the pump IS directly grounded but, the "source" is isolated from the pump body. Put your Ohm meter on either terminal and touch the pump body....there is NO direct DC continuity in a "balanced" source. This is a sexy way of making things very "quiet" electronically. Professional audio studios are fully balanced systems using "Cannon" connectors with three terminals. One is "plus" Two is "minus" and Three is "shield ground"....hence, balanced and NO Hum or Static noise. (Hey...those guys at Carter make a quiet pump...it's wimpy but, damn quiet)

     

    Okay...now let us examine what is going on internally on the back side of the connection point.

     

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        A careful surgery, with hack-saw in hand, to remove the hermetically sealed body cover and expose the multi-octave filter or "shunting" design of this Carter LP. The double sided epoxy circuit board with modern surface-mount chip capacitors is excellent. This board is located directly at the input of the 12 volt source with virtually zero component lead length (surface mount) to provide shunting of the make and break contact that the brushes are doing directly at the armature when in "run" condition. This DC motor is virtually by-passed or shunted for any RF noise or "spiking" all the way passed 450 MHz!  NOTE ! I did say "spiking" or should I say... "ripple"... this is a source of nasty "ripple" directly connected to the entire 12 volt DC rail of our beloved CTD's

    Quality engineering of analog DC motors remove such garbage before it is introduced to devices such as aircraft, fighter jets, military assault platforms, nuclear submarines and civilian automobiles.

     

    There are many preferred after market suppliers of fuel pumps or systems available and many are quite note worthy when it applies to providing solid reliable fuel flow.

     

    maxresdefault.jpg.26252839fca770e5a09305c22d942fa4.jpgMany of these platforms exceed the requirements in "fuel flow" for the average diesel enthusiast. Sometimes choices are made because the owner has future plans of building enhanced performance characteristics. Some choose additional GPM for the insurance of added cooling by the "return flow" system design. All of the after market manufacturers of the upper end platforms do this with ease and price the devices accordingly.

     

    Caution in selecting any device that may cause unknown after effects in any mobile platform. The CTD 2nd Gen, is something I've looked at carefully for many years and I've made concerted efforts to correct some electrical over sites for the betterment of these noble platforms. I too have made large investments and the after market LP selections are not cheap. I was exceptionally disturbed when I successfully installed an after market LP system. The extreme effort to correctly and cleanly install the system along with all the cool JIC fittings and complete the project with pride that someone may examine my work was all accomplished. Then I shortly discovered the absolute short comings of my nearly $900 investment. I blamed myself for not test operating the device on a test bench and viewing the horrendous RF interference HASH that took out everything from 500 KHz (just below the commercial broadcast band) to well above 500 MHz.

     

    Is this important to you?... It is and perhaps it has not become apparent by the way such broadband RF interference manifests itself within a closed stand alone 12 volt system. To make these statements to you, the reader, let me be clear, I use and own a Hewlett Packard 8921A Digital RF test device, at $24,000.00 ...one must be "a fully certifiable crazy idiot" to have this along with a Tektronix  200 MHz 4 channel scope...and someone asked..."Do you need such instruments to look at $25.00 DC motors"...no but, I'm fully confident in my findings.:wink:

     

    Let's take a look at the much enhanced DC motor of an after market LP...it is irrelevant as to the manufacturer...they are all the same.a864e95f.jpg.da7040b1197f92ae0a81860f58fc7ea5.jpg

    This is an initial basic disassembly procedure that needs to be performed. It's very easy to accomplish.

     

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    Once you have the cookie opened you'll be able to view the end-plate where the carbon brushes reside in their respective holders. Many of these devices and earlier models vary by design in physical form but, they are all the same in regard to an end-plate with brush tube holders.

     

    Here is the end-plate removed from a different LP unit and we can see the very minimal by-pass engineering of a single .47 Mfd mylar capacitor directly across the two brushes. Note, the lead length.

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         This is typical of an inexpensive analog DC motor...I'll estimate the average wholesale cost of this to be somewhere around $10 to $15 US dollars. It would vary greatly, according to quantity buying levels. The only capacitor seen here is barley a by-pass or shunt...I'd prefer to call this a carbon brush protector. As the armature spins in normal operation, the "make" and "break" of the brushes riding against the armature where "flame" occurs...this cap is merely removing or dampening the "spark" and aiding brush-life longevity. At .47 Mfd it's really only helping at the lowest frequencies to roll off the RF spiking, also with long leads, transversing the distance between the two brushes does not help with the higher frequencies of this wild free-running spark-gap transmitter. This is a far cry from the excellent by-passing techniques incorporated into the wimpy little Carter device. :cry:

     

    Let us take a look at the fix procedure to begin " RF silencing" one of these very substantial LP platforms. We can't be as effective as the fully closed hermetically sealed package but, with careful effort you can knock this "ripple hash" down by 40db or better in just this simple step.

     

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    The procedure above depicts a simple "drill and tap" technique using small machine thread hardware. 6/32 or 10/32 should suffice. You can use what ever hardware is available in your junk box as long as it is small enough to fit into the limited working space. Purchasing a small tap and companion drill at your local hardware store to match your "screw-thread pitch" is very low in cost. The skill required to do this is modest, just take your time and carefully hand-cut your threads gently. The cast aluminum end-caps are very easy to drill and tap. NO 9% IPA's should be consumed prior to drilling! Keep your hole straight :stuned: and pay attention to the "depth" of your drill. With the armature removed you can "eye-in" an approximate location for the mounting hole to accommodate the miniature "lug"...this is where you make an accurate decision of the "angle" for the lug's contact arm to avoid contact with a spinning armature in "run-mode". You must also consider component "lead length"...keep this EXTREMELY short...it will be like working on a Swiss watch in confined space.

    NOTE: You must loctite your threads! This procedure is introducing component count within a very critical area...errors in loose components will be catastrophic !!! You will make NO errors here! :smart:

     

    Sorry...my photo is fuzzy. The photo below is zoomed-out for examination of component placement within the end-cap structure. It is tight but, it is precise and highly efficient.

    This depicts component selection: two each .1 Mfd silver Mica 100 volt dipped packages. I happened to have these in my junk box and standard miniature ceramic caps would also suffice.

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    This completes the "critical" internal modification to initially "RF silence" the armature brush contact event point.

     

    I buy electronic components/parts from DigiKey or Mouser...these two capacitors will set you back about 30 cents each...your shipping cost will be ten bucks! Boy...I miss those cheesy little Radio Shacks. It was so convenient to buy little things like this for little money within my own community. Times have certainly changed. :(

    Now, carefully reassemble your enhanced LP device and mount it into it's operational nest on the vehicle.

     

    The photo below is the final step in this procedure. Again, this shunt capacitor is a .1 Mfd Orange drop package rated at 100 volts. I do prefer this package  over standard Ceramic disks under the hood within engine compartments due to heat stress. These maintain tolerance over an extremely wide temperature range.

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    The shortest leads possible, again, is the goal...the lead is directly connected to the relay socket where the 12 volts DC is connected through the relay contacts, that when "closed", provides DC excitation to the LP. I could have made these leads shorter but, I utilized the present ground on the firewall for convenience.

     

    Insert the relay back into the socket.

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    This now completes the entire procedure. The monetary expenditure amounts to less than $1.00 for the capacitors. The time involved is substantial.

     

    The $689.00 plus dollar, advanced LP platforms available should have arrived fully prepared for trouble free installation and operation. The design engineering staff at Dailmer Chrysler would have never introduced an uncontrolled CCS constant run DC motor device into their platforms at any level. Cummins also, would have never allowed a DC pump without qualification standards to be specified for any production platform. The factory OE Lift Pump from Carter is a very under powered volumetric unit and their is no debating that short coming however: electronically it's design is superior in every aspect. The entire hermetically sealed housing acts as a complete Faraday Shield to fully encapsulate all electromagnetic static fields of force. It is a "dead silent" RF void device!

     

     

    This is just an example...all of the after market companies tout their prowess in delivering liquid fuel at astounding levels of performance, be it a stock engine or perhaps an extremely high horse powered competition street killing monster. None of them provide a civilized RF silenced DC motor to prevent "other" electronic automotive control elements from being harmed when operated within the confined structure of the vehicle. Note: not one bit of verbiage regarding the actual DC motor that powers the device! But, it pumps fluid like heck!

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     I so dearly appreciate the flow factors, the filter systems, the mounting structures and comprehensive packages to alleviate all the short comings of my dismal factory transfer pump issues. Knowing well, that I'll never allow my one thousand dollar plus VP44 from ever being fuel starved again, by selecting an aftermarket LP system...only to realize afterwards, that the introduction of this major investment into my vehicle is now causing electronic issues, else where, within the vehicle!

     

    The expensive sound systems, vehicle speed sensing systems, erratic operation of TC lock-unlock, cruse control abnormalities, and radio communications equipment. All of these things at one time operated without error, you enjoyed the accurate trouble free aspects of your prized motor vehicle, then...something happened!

     

    Being cautious about adding any electronic implement into a trusted vehicle is always prudent. Asking the right questions before hand is always best practice. This information applies to ALL Vehicles regardless of manufacturer Ford, Chevy or Dodge.

     

    This article is following additional postings on this web-site...Mike Nelson @Mopar1973Man and Nick @Me78569are struggling to keep this small and independent site operational. I am not affiliated with any supplier or manufacturer...I am a contributing customer who appreciates the time proven and solid information/guidance these two men  provide to the diesel community.

     

    I humbly share this knowledge with the CTD fraternity with enthusiasm, for the improvement of our platforms...may I ask a very small favor...if you find the information on this site of value could you please consider making a one dollar donation to the site to keep the lights on :pray:  

     

    Thank you, Respectfully,

    W-T 

     

     

     

     

     

     

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