International Customers - Chevy GM Stanadyne mechanical aka manual injection pump model DB2-4911 completely remanufactured upgraded and warranted by SSDiesel Supply TM, a trusted name in 6.5TD solutions. All wear parts replaced whether they test bad or not, including the head. Fits all 1992-1993 GM 6.5 Turbo Diesels in C/K pick-ups, Suburbans, G vans (Express and Savana), with a mechanical injection pump. Compare price only to those remans replacing the head assy with a new upgraded head. Most rebuilders leave the head if tests ok and can offer cheaper.
We will never cut corners. The head on these pumps has a tendancy to warp with heat and is the #1 source of failure, and if not replaced/upgraded, is just destined to fail. We replace the head everytime with new upgraded Stanadyne heads that solve the warpage problem.
A core deposit of $500 will be required, due to the rarity of this pump. Symptoms of failure include hard starting when hot (common head warpage problem) Poor mileage, rough running, heavy smoke, loss of power.
The mechanical pump can be easily adjusted for more power with the turn of a screw and an EGT gauge. With purchase, upon request, I will furnish detailed instructions on how to adjust for more power if you already have a 4' exhaust and EGT & Boost gauges. I recommend our Haynes Manual ssd-330 if your first time replacing a pump for the basics.
Then if you have any further questions, please use the contact page on the website for tech support. Gaskets not included and sold separately as p/n ssd-306A.
Related Information:. by Neil Beadle photos courtesy of Peter Bierman The Stanadyne DB2 rotary distributor pump has a single pumping element that feeds all injectors. The high pressure pumping action is carried out in a single barrel, which houses two opposing plungers operated by two rollers. These plungers are pushed together by a cam ring with internal lobes acting on the rollers and it is this action that pressurizes the fuel.
The number of lobes on the cam ring corresponds to the number of cylinders in the engine, so each thrust of the plungers by a pair of cam lobes results in a pulse of fuel to one particular cylinder injector. The injection pump controls fuel delivery by:. accurately metering the fuel as demanded by the operator.
automatically pressurizing the fuel to match the injector pop off pressure to open the nozzles. delivering the pulses of fuel in the required firing order. controlling injection timing Injection Pump Operation Fuel enters the pump inlet under lift pump pressure from the fuel filter, where a vane type transfer pump further pressurizes it.
From the transfer pump, the fuel is then routed to three separate places:. Some is sent to the automatic advance mechanism. Some fuel goes through a vent wire assembly to the housing reservoir and then out of the check valve return fitting to the fuel tank. Most of the fuel is sent to the metering valve. The metering valve is actuated by the throttle lever at all engine speeds above idle and by the governor linkage, when the engine is at idle or maximum speed. The metering valve flows a measured fuel quantity into the center of the hydraulic head where the distributor rotor is turning and from there the fuel goes to the center of the rotor, which has two inlets at one end and an outlet at the other end.
As the rotor spins, the inlets line up with ports in the hydraulic head and fuel is forced out into the pumping chamber. The pumping chamber consists of two sets of rollers, shoes, and plungers, which rotate inside a cam ring. The cam ring has lobes for each injector on the inside.
The force of the fuel entering the pumping chamber, along with the centrifugal force generated by the spinning rotor, moves the plungers apart. The plungers move outward a by an amount directly proportional to the volume of fuel passed by the metering valve. As the rotor turns, the cam ring lobes, squeeze the rollers together, which in turn push in the rollers.
As the plungers are pushed together, they pressurize fuel until the injectors nozzles open at their preset pop pressure. The fuel at injection pressure is forced back along the center passage of the rotor and into the discharge port and released when the discharge port lines up with a injector line outlet in the hydraulic head. As the single discharge port rotates with the rotor it lines up with each of the hydraulic head injector line outlets in a sequence matching the engine’s firing order. Each injector outlet is connected to an injector nozzle by a high-pressure line.
The injector pump varies the rate and quantity of fuel delivered to the nozzles as demanded by the throttle and/or governor. The DB2’s Components and Functions Vent Wire Assembly. The vent wire assembly controls the amount of fuel returned to the fuel tank from the injection pump, and is located in a short passageway behind the metering valve bore. Excess fuel from the transfer pump flows past the vent wire, carrying any air which might have entered the transfer pump. After the excess fuel passes through the vent assembly, it goes to the governor compartment and then back the pump through the return line. The vent wire’s size controls the amount of fuel that enters the return line.
So if the amount of return fuel doesn’t meet specification, the vent wire can be swapped for one of a different size. A delivery valve, in the center of the distributor rotor, assists the injector nozzles to rapidly reseat and prevents anatomized fuel from dribbling into the precombustion chambers. Pressurized fuel from the pumping chamber forces the delivery valve plunger slightly out of its bore so fuel flows past the plunger and then out the discharge port. When fuel pressure drops, the delivery valve plunger immediately reseats, causing a rapid drop in injection line pressure. There are three timing advance mechanisms on the fuel injection pump:. An automatic advance system.
A mechanical light load advance. The housing pressure cold advance solenoid.
The automatic advance mechanism advances and retards the start of fuel delivery. This mechanism starts working as the engine speed increases to ensure that the injector nozzle opens just before the piston reaches top dead center, when compression is at its highest point. Otherwise fuel wouldn’t be injected before the piston had started moving downward on it’s power stroke. The mechanism comprises a power piston, servo valve, servo spring, servo piston and a cam advance pin. The cam advance pin connects the advance mechanism to the cam ring. When the power piston moves, it rotates the cam ring so that fuel is delivered earlier.
Housing pressure and transfer pump pressure behind the power piston influence the action of the servo piston. When the engine is cranking, the fuel behind the servo piston is at housing pressure, and the power piston is seated against the housing.
As the engine speed increases, transfer pressure rises and the subsequent increase in transfer pump pressure forces fuel into a chamber behind the power piston. When transfer pressure in chamber behind the power piston exceeds housing pressure, the servo piston acts against the servo spring, and the power piston pushes the cam advance pin which rotates the cam ring in the opposite direction to the distributor rotor’s rotation and so the rollers contact the cam lobes earlier and injection timing is advanced.
Dodge Dakota Chilton Repair Manual - Vehicle Maintenance, Part Number: 20500 Vehicle Specific Chilton Repair Manual - Vehicle Maintenance. Use the form. Haynes repair manuals review. Haynes Repair Manuals Dodge Durango, 00-03 & Dakota Pick-ups, 00-04. Chilton's Dodge Durango/Dakota 2001-04 Repair Manual. November 11, 2017.
When engine speed decreases, transfer pressure drops, the cam ring rotates in the other direction retarding injection timing. A light load advance mechanism provides advance when the engine is operating at low speed or under light load, when the transfer pressure is too low to move the advance piston. The light load advance is actuated by an external face cam and rocker lever assembly when the throttle shaft rotates (on the 6.2L and 6.5L engines, this mechanism is on the passenger side of the pump). The lower end of the rocker lever pushes on the end of the servo advance plunger. As the throttle shaft rotates, the face cam pushes on the rocker lever using a “see-saw” action, which depresses the servo plunger and advances the timing through the power plunger’s linkage to the cam ring. At a predetermined angle, the face cam flattens out, so that additional throttle movement does not affect the servo. After the light load advance mechanism ceases to act on the servo plunger, advance action is regulated by transfer pump pressure.
The housing pressure cold advance solenoid is one of three solenoids that affect the operation of the injection pump. The solenoid makes it easier to start a cold engine by reducing housing fuel pressure in the advance mechanism. The HPCA solenoid is located under the fuel return outlet, under the pump housing cover. It is activated by the coolant temperature switch, which is mounted on the rear of the passenger side cylinder head. When coolant temperature is low the temperature switch is closed, energizing the solenoid (rear pump terminal connected with a green wire), which lifts the check ball off its seat in the return outlet. This reduces housing pressure to near zero, so that the transfer pump pressure behind the power advance piston can easily advance the cam ring.
In addition to the housing pressure cold advance solenoid, there is a fuel shut-off solenoid (front terminal connected with a pink wire) located inside the pump housing cover that stops the engine by cutting off the fuel flow. The fuel shut-off solenoid moves the governor linkage, which in turn rotates the metering valve. When the ignition is off, the solenoid is no longer energized and the return spring pulls the shut-off rack to the “OFF” position, which through the governor linkage rotates the metering valve to cut off fuel.
The minimum/maximum engine speed governor, located under the governor cover maintains idle speeds under varying engine loads and limits the maximum speed of the engine. The governor assembly comprises weights, the governor arm, low idle spring, idle spring guide, main governor spring, main governor spring guide, and the guide stud. The governor weights are rotated by the drive shaft. Their centrifugal force controls the metering valve at minimum and maximum engine speeds. At idle speed, the governor weights don’t exert much force, so the spring on the governor keeps the metering valve nearly closed. At high engine speeds, the centrifugal force of the governor weights moves a pivot arm, compressing the spring, and rotating the metering valve to an almost closed position.
At engine speeds other than idle or maximum, the driver directly controls the metering valve through the accelerator/throttle linkage. At those engine speeds the force of the governor weights and the governor spring tension are balanced, so that neither can influence the metering valve.
A pressure regulator protects the transfer pump from excessive output pressure caused by high engine speeds or because of a restricted fuel return line. When the valve is closed during normal operation, the valve spring holds the piston forward, blocking the regulating slot in the valve thus rendering it inactive.
As output pressure increases, the valve opens. High-pressure fuel pushes the valve piston, which compresses the spring. If the pressure is high enough to overcome the spring’s force, the piston will be pushed back, uncovering the regulating slot in the valve.
This will allow fuel to flow back to the input side of the pump, thus relieving output pressure. A viscosity-compensating device maintains the constant fuel pressure, so that fuels with differing viscosity levels due to composition or temperature may be used. The compensator is part of the design of the pressure regulator mechanism. GLOSSARY HPCA: High Pressure Cold Advance; this mechanism advances the timing by about 6 degrees to compensate for the slower burning injected diesel charge until the engine warms up to around 125F. Sources: Tags:, Sunday, October 11th, 2009 at 17:37.,.
feed.
If it doesn't work you're not out much. If it does you saved a bundle and learned something in the process. I do gas station service work.
I have to go out of my way to make simple jobs appear difficult and complicated. If people knew how easy a lot of stuff was I'd be in the welfare line. I paid a guy $900.00 bucks for rebuild a pump and injectors. He tried twice. Took it somewhere else and paid them to fix it right for a fraction of the cost.
Just cause you're paying a lot of money to get something done doesn't mean anything. John is a special person that has had a lot of varied experience.
He and I have always had a difference of opinion about who should attempt to rebuild/patch up a Roosa Master pump. Guess that is the perfectionist coming out of me. I have always been one that has to do it exactly right, but that is just who I am. If you are looking for perfection or have a pump that needs more than just a reseal, it needs to go to someone who has had years of experience after having factory training like John and I have had.
And even then, it can be a challenge. Only the most experienced can tell by looking if a part should or should not be replaced for for a long service life. Even simple things like the transfer pump blade springs or delivery valves can be ready to fail or knowing how to check for the presence of water having gone through the pump. I remember a CB pump that came through the diesel room that gave me fits back in the 70s. It simply would not settle down on the tractor, nor would it on the test stand. The first thing I checked was the air seperator for blockage. To make a long story short, there was a shiny sliver of steel in the bleed hole that made it appear the hole was empty.
Only found it when I tried to to run a pin punch through it. Not saying you can't do it, for I,too, have torn apart pumps on the tailage of a pickup truck,even in corn fields. The most memorable was a brand new 4320 at the Indiana State Fair.
The dealer I worked for wanted to use it as a pull back tractor on the tractor pull strip and to also pull it as a demonstration. First 4320 I had ever seen as it had just been released from Deere that day, I pulled it apart, removed the shims and set the pump wide open. Talk about a new model making a show,it did.lol. Good luck and go for it. You won't learn Any younger.
We also had many issues with the CDC and early CBC pumps also. I guess that's why they had so many updates - until they were discontinued. That all being said, there are many still around, with very high hours, still working fine. It's too bad somebody hasn't picked up the slack and made some repair parts for them. About being a perfectionist- there's nothing wrong with that. But, sending a pump to a certified pump shop does not guarantee such perfection. Any job is only as good as the person doing the work.
Most pump shops do do NOT upgrade the plastic weight-dampener rings in DB and JDB pumps unless specifically asked to do so. That if far from what I'd call 'perfection.' On cars and trucks, they have to - I guess because someone 'dead on the road' is apt to complain more. I don't claim that anybody can fix one. Nor would I claim anybody can repair a starter motor, wire a tractor, rebuild an engine, etc. Some cannot even change a spark plug without getting into trouble. Somebody who is a skilled mechanic should not fear working on an injection pump any more then many other mechanical component.
There is NO magic involved. Main difference is - the service/repair informations is kept a bit more 'secret' then for other things. If you've got a pump that can be fixed with less then $40 in parts, then investing $10 in tools, and $50 in a tech manual - is a worthwhile investment - as compared to sending to a shop that will sometimes charge $700 for the exact same work on a flat-rate basis.
Some people who like working on equipment also like learning new things - which also has a value. Nothing special about it except that repair info is not always easy to find. No more complicated then some carburetors.
Ever have to fix a GM Quadrajet?? No special equipment is needed as long as you have the tractor on-site. Test stands for these pumps are only needed when all you have it the pump, and no engine or tractor to run it on. Stanadyne injection pump is basically just a high-pressure piston pump coupled to a low pressure rotary vane pump, with some controls added. That along with a distributor that sends the fuel charge to one cylinder at a time. On a few applications (depending on tractor make) one special wrench is needed that cost around $8.
Other then that, no special tools or measuring devices needed. Just about all Deere and Allis Chalmer's spec pumps need the wrench. Also some Oliver, Case and Ford aps. Keep in mind that these pumps rarely get 'rebuilt.'
I think that word is mis-used. The pumps get resealed, patched up, calibration checked, and most major parts used over again - as is. They are NOT renewed in anyway. I suspect that most negative comments you're going to hear about working on these pumps are from people that have never done it. The 'kit' you mention costs around $12. All that provides is all the rubber parts, i.e. O-rings, seals, and governor dampening ring.
Roosa Master Injector Pumps Manual
It allows you to reseal the pump and renew the governor ring. If you find any other parts worn, they have to be ordered one by one.
I.e., there is no such thing as a true 'rebuild kit.' Again, the word 'rebuild' is misused. When you rebuild an engine, all major moving parts are renewed in some way.
Not so with a fuel injection pump. Most so-called 'rebuilds' get less then $40 in new parts stuck in. A typical Stanadne/Roosamaster DB or JDB pump can be repaired while sitting on the tailgate of your pickup truck, out in the woods, if you're careful. I've done many with nothing more then some clean rags, diesel fuel, and compressed air. No special measuring tools needed either.
All fits of parts are checked by appearance and feel - not with any measuring devices. Main max fuel setting, if you feel needs to be checked, it done with a common 2' micrometer. Timing advance can be adjusted with the pump on a running engine - with a timing light, or a $6 plastic timing window. In all due respect, JDemaris, unless he knows what every part does and why, in other words, unless he knows the theory behind the workings of the pump, he will not be able to do anything but replace parts. Unfortunately that is not going to get the job done. Also if it needs pump vanes or maybe new gov weights (they do wear so they don't advance correctly) you are not going to get all this in a rebuild kit for the price that has been quoted on here.
The whole head could be bad then what? Think he has the training to see that? Sometimes the only way to know whether certain parts ar out too far is to assemble it and test stand it. If certain specs cannot be met or met without throwing off other specs then you need to replace some parts that you couldn't detect visually.
I rebuilt these at a stanadyne authorized center for quite a while and there is only one guy in our state that can get them close without test stand and he has 40 yrs experience and learned how by the test stand FIRST until it was second nature and knew by what the engine told him. This poster might better take it and get it done right.
Stanadyne Fuel Injection Pump Diagram
About all the amateur is going to be able to do is dissassemble, clean and replace crumbled weight retainer ring. He won't know what else to even look for.