Resistor in an aftermarket PMD?

[rcull]

I have a Dorman PMD, do I move the resistor from my Stanadyne to the Dorman or does the aftermarket PMD run without a resistor?

Thanks

[DmaxMaverick]

You would have to confirm that with Dorman, as it depends on which technology series they are copying or sourcing, and it may depend on the time you sourced it, and when your supplier sourced it. However, looking at what they have to offer at this time, the driver has the resistor relief in the connector, so I would say yes, the resistor is required, IF your driver also has the relief. The drivers I've seen that didn't require a resistor did not have the relief, and if a resistor was installed, the connector would not fully close. That's a lot of words for a maybe, but I think you'll be safe with it. The worse that may happen is the PCM will complain if you get it wrong, and it's a simple correction.

[rcull]

You would have to confirm that with Dorman, as it depends on which technology series they are copying or sourcing, and it may depend on the time you sourced it, and when your supplier sourced it. However, looking at what they have to offer at this time, the driver has the resistor relief in the connector, so I would say yes, the resistor is required, IF your driver also has the relief. The drivers I've seen that didn't require a resistor did not have the relief, and if a resistor was installed, the connector would not fully close. That's a lot of words for a maybe, but I think you'll be safe with it. The worse that may happen is the PCM will complain if you get it wrong, and it's a simple correction.

Thanks, sounds reasonable. You would think that if the technology used in the Dorman PMD did not require the resistor, there would be a sign in the plug not seating properly. I will attempt the install with that in mind, and if there is a question I will contact Dorman.

[DmaxMaverick]

I don't think I'd waste too many brain cells on it. If it has the relief (the slot is shaped like the resistor card), install the resistor. If it doesn't, don't. If the PCM complains, remove the resistor, or install it. I don't have much confidence in whatever Dorman might have to say, but I could be wrong. I've heard a lot of negative about Dorman's quality and fitment, but personally, I've not seen it. I've used a lot of their products over the years, and while I wouldn't consider them high performance, all have been at least minimally acceptable. That's not an endorsement for the brand, but only what I've experienced. As far as PMD's go, I'd source them in other ways. From what I can tell, Dorman, and many aftermarket options, have only copied the original, flawed, driver. More recent iterations have shown to be much more reliable. Flight Systems, Stanadyne (new, gray), and D-Tech drivers come to mind. The new Stanadyne driver requires a new harness adapter or (simple) modification, but seems to be much better than their original version, which is why we're having this pleasant conversation.

[rcull]

I tried installing the resistor and it does fit, BUT the plug will not seat properly, SO it is installed without a resistor, and the plug fits nicely.

Thanks,

[JohnC]

That's interesting, because, the resistor has absolutely nothing to do with the PMD. The PMD is just a convenient place to put it. The value of the resistor tells the PCM about the pump's delivery characteristics, and hence which fuel map to use. Historically, the resistor goes with the pump.

The PCM doesn't as a matter of course check the resistor value, so, you can change the PMD, ditch the resistor, and the PCM will continue to use the value last programmed, perhaps for months or years. Should you command the TDC offset learn process, it will try to read the value, and, if there is no resistor it will set a DTC, 56 I believe. If after years of use, the code never sets, then the PMD must have a resistor built in, most likely something close to a #5 in value.

[More Power]

That's interesting, because, the resistor has absolutely nothing to do with the PMD. The PMD is just a convenient place to put it. The value of the resistor tells the PCM about the pump's delivery characteristics, and hence which fuel map to use. Historically, the resistor goes with the pump.

The PCM doesn't as a matter of course check the resistor value, so, you can change the PMD, ditch the resistor, and the PCM will continue to use the value last programmed, perhaps for months or years. Should you command the TDC offset learn process, it will try to read the value, and, if there is no resistor it will set a DTC, 56 I believe. If after years of use, the code never sets, then the PMD must have a resistor built in, most likely something close to a #5 in value.

I was going through the boxes of parts for our Blazer project the other day, and found the "FSD Cooler" that I originally installed on this engine back in 2000 or thereabouts... (when we owned it the first time). I looked inside the electrical connector on the mounted PMD/FSD (a black Stanadyne module) and saw that it didn't have a resistor... I have a box with several resistor packs in it that I accumulated twenty years ago, so whatever shakes out I've got it covered. Interesting also is that daughter found a brand new black Stanadyne module in the Blazer's center console. Jim