The PMD (pump mounted driver) or also known as a FSD (fuel system driver), has been a major problem for Chevy / GMC 6.5L diesel owners since its introduction on the 1994 6.5L electronically controlled DS4 fuel injection pump. The PMD is a solenoid pack that builds up heat and uses the injection pump and the fuel running through it to absorb that heat. The injection pump is in the valley of the engine between the cylinder heads and the heat produced by the engine is also absorbed into the injection pump. In some situations the fuel going through the pump cannot adequately remove the heat to keep the PMD functional. Once the engine begins showing symptoms of stalling, hesitating, most likely the PMD is failing and the problems will only get worse. Many times we hear from customers that their 6.5 stalls while driving, much like you turned the key off. Or, we here that the 6.5 will not start hot. For example you drive to the store and the engine is warm. Turn off the truck while you shop and then when you go to leave it will not start. This is a hot soak condition.
What happens to the PMD is the circuit board inside cracks and separates when hot. When the PMD cools off the contact inside is made again and will allow the engine to run. All GM 6.5L engines need a PMD Cooler! Mounting the cooler to the intake manifold works well for most people, but for those who want even more cooling an extension cable is available to relocate the cooler onto the fender or even further away from the heat in front of the radiator.
Tests show that when using the PMD Cooler, PMD temperatures will drop anywhere from 32° to 81° Fahrenheit depending on driving conditions. These temperature drops will seriously increase the life of the PMD and can save you money from towing and costly repairs. The PMD Cooler easily mounts to the intake manifold of your engine within reach of the wiring harness plug for the PMD. Installation is quick, simple and does not require any modifications or special tools. Purchase a new PMD and instead of installing it back onto the pump where the heat is, use a PMD Cooler and move the PMD out of that heat zone. The savings in the labor time it takes to mount a new PMD onto the injection pump will more than pay for the cost of the PMD Cooler, plus the PMD will last much longer! The PMD Cooler kit comes with everything needed to mount a PMD to the intake manifold. Don't pay for a pump replacement when the PMD may be all you need!
New Upgraded Pump Mounted Drivers
There is good news for GM 6.5L engine owners! Technology has advanced in the PMD area and there are now choices for replacement Pump Mounted Drivers.
Stanadyne is the maker of the injection pump and has come out with an updated version of the PMD. Stanadyne has termed their new DS Pump Mounted Driver as "Bullet-Proof ", since they incorporated a series of new features for added durability and reliability.
Stanadyne PMD Kit Number 35976, includes new PMD, pump wiring harness, heat transfer pad, and four mounting screws. Remote mount cooler and extension harness sold separately.
Note: Since Stanadyne changed the connector between the wiring harness and the PMD, the harness must be changed or modified on the injection pump when installing this PMD. The Stanadyne PMD kit includes this pump harness. (The pump harness is not the same as the extension harness we have listed below.)
Flight Systems is an aftermarket diesel product company. Flight Systems Electronics Group tackled the problem with the original PMD and manufactured a Pump Mounted Driver (PMD) that would handle the high temperature environment that was causing problems. FSEG has earned outstanding supplier awards from NASA, automotive manufactures, and original equipment manufacturers. Exacting standards have been a hallmark of FSEG for more than 30 years. What they created was an outstanding product that holds up great! The DTech unit is a direct bolt in replacement for the original. DTech PMD's have a One Year 50,000 mile warranty.
The injection pump fuel delivery is fine-tuned with a resistor in the PMD. The resistors range in number from one to nine. The number nine will deliver the highest fuel delivery. If no resistor is used, the pump will default to the number five. We recommend using the number nine resistor to give you that little extra performance.
Gray PMD Resistors
Stanadyne changed the connector between the wiring harness and the PMD when they updated their PMD. Use this resistor with the new gray colored Stanadyne PMD's.
Black PMD Resistors
Use this resistor with any black colored Stanadyne or DTech PMD's.
Note: This resistor can be used with the grey PMD by simply clipping the ends along the dotted lines shown below.
PMD Extension Harness
Short PMD extension harnesses are now available. They are great if your factory harness is just a little too short because it is wrapped around a fuel line. Or, if you want to adapt your black style end to the updated grey style without modifying your harness simply purchase the gray version. These measure nine inches long from end to end and give you eight inches of extension.
Long PMD Extension Harness
This harness extends the factory wiring harness between the injection pump and a remote mounted pump mounted driver 40 or 72 inches. If you choose to remote mount the cooler in another place besides the intake manifold, these are the harness that will allow you to do that.
Now available with the black original style end or the new Stanadyne gray connector. Simply choose the color that matches the PMD you are using.
Thank you for your help, it was much appreciated. I have received the new pmd and it seems to be working fine. It gets frustrating for this is pmd number 8 in less than 2 years. But your business was a breathe of fresh air, more helpful than Stanadyne. Thank you again, and from here on out Huckstorf Diesel is my business to go to! Thank you and have a god day.
Recieved a FSD and heatsink from you Friday. Thanks for pre-installing the resistor, the super fast shipment, and the quality of your product. A+ Worked great!