PMD Test

[Truckie117]

Hi
Does any one know how to test the PMD ? I recently mounted a new DTECH pmd on heat sink behind the bumper. Now my mechanic says the pmd may be bad? Can the resistor go bad and give bad readings it came with a # 9 I replaced the 9 with a #5. which did not help my throttle problem. Any help would be appreciated.
Thanks
Truckie117

[JohnC]

What is the symptom?

Not much the resistor can do to cause real problems.

[DmaxMaverick]

The resistor can cause issues with the PCM. The worst that will happen is the SES will come on (with the accompanying DTC) and fueling will reduce/increase (depending on where it was, before) to a default level. No other running issues or limp mode will happen. Nothing. The resistor is only a fine tuning key to accommodate individual pump calibration, and accepts a rather broad range before the PCM complains. In almost all cases, a #5 resistor will never cause issues, of any kind. However, a relocated PMD harness to pump ground lead can.


If you have a suspected bad PMD, there is a test. This test is 100% effective with older Stanadyne PMD's. Test reliability with more recent Stanadyne and aftermarket PMD's is not known at this time.

1. Remove PMD from the injection pump (leave it on the pump, if the pump is shot, and drain all fuel from it).
2. Locate yourself and the PMD near a large body of water. Preferably a deep lake, or an ocean.
3. Throw said PMD as far as you can into the large body of water.
4. If it floats, it's good. (If you are optimistic, you may wish to bring a boat for retrieval, but you probably won't need it.)

[JohnC]

.. If it floats, it's good...

In New England that's known as the "Salem Witch Test". ;)
100% reliable at weeding out witches (and bad PMD's).

[Artworks]

I would check the harness. I had a couple extension harnesses that were no good ( EDAM)
I have a Kennedy Diesel one on a Dtech infront of battery and a PMDCable & Dtech system in / bumper behind the lic. plate.

[Truckie117]

Thanks for the reply's guy's
I'm thinking of doing that with the whole truck. But the green police will probably arrest me!
Hmm but that means I get 3 hots and a cot free dental and free medical. Nah!
thanks for the info and laugh.
I have a j kennedy extension new dtech pmd and the ground is still on pump my guess is the pump has had it 100k on it.
Thanks
Truckie117