1994-2002 Electronic GM 6.5 Stanadyne Injection Pump - Reman 5521

HDiesel Remanufactured Stanadyne Diesel Fuel Injection Pump for 1994-2002 Electronic GM 6.5L Trucks, Vans, & H1 Hummers DS4831-5521

Stanadyne 05221S  DS4831-5521

These are remanufactured injection pumps buit by Huckstorf Diesel. Huckstorf Diesel is an authorized Stanadyne dealer, and we have the ability to rebuild these pumps in house. We are seeing the effects of the high mileage being accumulated on these engines, and in most cases it makes more sense to buy a new assembly than replace all the necessary parts needed to rebuild a used pump to new standards.  But now with the high cost of new pumps we reconsidered.  These new pumps include a new updated gray Pump Mounted Driver (PMD) and new Encoder Sensors for added durability and reliability.

This pump is a direct replacement for the following pump numbers;

• DS4831-5942
• DS4831-5459
• DS4831-5521
• DS4831-5288
• DS4831-5067

In 1994 there were pumps produced with tag number DS4031-5068.  This pump is not compatible with the 5068 pump.

This pump comes with a one year warranty. Restrictions do apply. 

Core is required.

Core Charge Instructions

Click on the drop down list to see the price of the remanufactured injection pump with the core charge applied. To avoid paying the core charges a matching, acceptable, core must be received prior to the exchange being sent out; otherwise we will charge you for the core and refund you the full core price if an acceptable core is received within thirty days of purchase.

In 1992 General Motors replaced the 6.2L diesel engine with the 6.5L engine.  The engine was designed to be a more powerful version of the 6.2 and met emission standards required for half-ton trucks.  In 2001 the 6.5 was replaced by the 6.6L Duramax engine in light and medium trucks and starting in 2003 in vans.  The 6.5 is still being used in some AM General applications, mainly for the military.  The piston stroke was lengthened to achieve the extra cubic inches.  Machining the bore further into the block caused a lack of material between the main cap bolt holes and the cylinder walls.  The main bearing web in the block was prone to cracking.  That made these engines poor candidates for big performance upgrades.  The Duramax engine is much more capable of making power levels that matched or exceeded the Ford and Dodge diesel offerings.   Horsepower numbers for the 6.5L started at 180 HP @ 3400 rpm and peaked at 315 HP @ 3200 rpm.  Torque ranged from 360 lb-ft @ 1700 rpm to 530 lb-ft @ 1800 rpm. 

There are several GM 6.5 liter diesel engine production options. The Turbocharged L56, (VIN "S") was used in most light duty 3/4 ton (2500) Heavy duty 3/4 ton and 1 ton trucks used the Turbocharged L65 (VIN "F") engine. The L56 is emissions controlled with EGR and catalytic converters. The L65 engine has no EGR, and has no catalytic converter. There is a soot trap on L65 engines that is often mistaken for a catalytic converter. The L49 (VIN "P") and L57 are both naturally aspirated engines. L57 is listed as HO or Heavy Duty. Additional RPO codes are LQM (175HP) and LQN (190HP).

Changes were made by GM to the 6.5 in their light trucks for emissions or reliability improvement. The 1992-1993 model years used a 6.5-specific Stanadyne DB-2 mechanical injection pump. GM replaced the DB-2 with the electronic throttle DS-4 in 1994-2000 vehicles.  The DS style pump used a pump mounted driver known as the PMD.  The PMD is an electrical solenoid that drives a plunger solenoid inside the injection pump.  These PMD’s have had reliability issues that still persist after many revisions.   In mid-1996 GM implemented a redesigned engine cooling system incorporating twin non bypass-blocking thermostats and a 130 GPM water pump. This improved the flow through the block by 70-75% and flow to the radiator 7%.

Through the years there were many different variations in the 6.5 diesel injection pumps.  The engine application codes were based off the Truck Style, Model Designation, and if the engine was equipped with or without a turbocharger. 

This pump will work on the following applications.  Due to minor differences this pump may not be a direct supersession, but will work properly.  If you want your pump built to a specific model code, Huckstorf Diesel will be happy to do that for you.  If you want to have your pump customized for a performance application we can do that also.  Give us a call and we can discuss your options!

GM 6.2 & 6.5 Diesel Engine Application Codes

Truck Styles

C, R = 2 Wheel Drive
K, V = 4 Wheel Drive
G = Van
P = Recreational Vehicle, Motor Home, Step Van
D, CUCV = Military (Commercial Utility Cargo Vehicle)
HMMWV = Military (High Mobility Multi Wheeled Vehicle)

Starting with the 1988 model year, the C/K designation was changed to the R/V designation with the body style change.

Model Designations

LD = Light Duty (with EGR)
HD = Heavy Duty
SD = Super Duty (6.5 – 15,000 GVW)
ALT = Altitude
CAL – California Only

Other Designations

N/A = Naturally Aspirated
Turbo = Turbo Charged
1.2 cSt = Low viscosity fuel compatible (Military)

GM Part Numbers

12561307S
19209059S 

See the wide variety of 1982-2000 GM 6.2 & 6.5 diesel performance, repair, and maintenance parts offered by Huckstorf Diesel both online here, and in person at Wisconsin’s premier diesel repair, performance, and installation center located just outside of Milwaukee Wisconsin in Franklin WI.