No Resistor?

[96TD2500]

I had my PMD replaced and they mounted it on the plastic cover over the engine. I've been having the same stalling I had before when it was still on the pump. They left the old PMD on the pump and I don't think they put another resistor in the new PMD. It should be in the new PMD's plug end?

Will the engine run the same with no resistor?

[john8662]

It will run w/o a resistor, but the computer will eventually default to the lowest value and set a code after so many key cycles.

The standard value for a vin F 6.5 is going to be a 5 or a 6

So, when they mounted the driver to the plastic cover, was there any heatsync or did they literally drill some holes in the cover and screw it to it?

[96TD2500]

Right to the plastic. There is the thin piece of metal in between. They pulled it only as far as the harness would reach and attached the new PMD. I know after plenty of research that it needs to be put further away than that, and that is my next order of business. But i have the new PMD off and see that there is no resistor inside the plug end. Then its off to get a extension harness and a big heatsink and mounting it somewhere cool. I have been reading on the site and the many places to put it. Now to decide.
Thanks for the help with the resistor question though...Now to get it all right again.

[More Power]

If your PMD/FSD isn't dead yet, it soon will be..... :( It needs to be mounted to something that can dissipate/conduct heat. A composite engine cover doesn't qualify....

Jim

[Hubert]

John can you explain that again please.

I am not sure about this but thought it went something like this

The resistor is only a calibration device for fuel output of the IP on the "test bench".
They are trying to fine tune this output. This FSD circuit has some resistance that varies due to mfg tolerances and the IP has some variations due to tolerances. So that: they compensate for all variability with 1 through 9 resistors 1-4 are to reduce fuel output 1 being most reduced 4 least reduced. Then # 5 is near neutral or no correction and 6 through 9 numbered resistors being to increase fuel output 6 least increased output and 9 the most. I did not think the ECM knows or monitors actual fuel output only duration of fuel solenoid open/close times. So this fuel calibration resistor kind of fools the FSD/ECM to correct open/close time to meter fuel to specific output. If this is correct how does the ECM know if resistor is there or not?? Unless open/close times are out of spec??? Seems like the resistance values go from 0 to ???? something ohms. Not sure about that but no resistor would be like 0 ohms ????

Now I question my remote mount resistance. Its been a good while but I don't remember seeing the resistor either and wondered about it. I have 72" of extended harness. Would the extra length line add just enough resistance for ECM not to think there was no resistor??? I have never heard that no resistor would set a code. I mounted mine similar to Kennedy tech tips on drivers fender. But it gets warm there too. It has lasted a good while. Next time will be somewhere upfront out of engine area. Lots of opinions about where to mount it. Seems like least favorite is on top of intake.

[JohnC]

The value of the reisitor is just a code that tells the PCM how the pump performed on the test bench. Once the PCM reads the resistor, it stores the value and never looks at it again, unless the value is somehow lost or TDC offset learn is commanded.

Based on the stored value, the PCM chooses a fuel map that gives the desired fuel rates for a given set of circumstances. The resistor has no "run time" influence on the system.

No resistor is "infinity ohms" which is outside the allowed range, hence the code is set.

[Turbine Doc]

also once it "learns" there is no resistor it won't run, you are running on the stored value

[Kennedy]

It amazes me the ideas some people (sounds like a shop in this case) come up with to save a buck and waste two more. I get so frustrated when I get calls looking for an FSD extension so a guy can mount their PMD to the firewall. IMHO, the FSD cooler is still the best device that I have found to help a PMD live. I don't know how many thousand of these I've sold, but it's a lot. While there have been failures, they are few and far between. The results are excellent, especially when compared to the number sold.

As for the resistor, it will be fine until the PCM sees it missing and sets a code:

http://www.kennedydiesel.com/detail.cfm?ID=135

[JohnC]

Just to clarify, if the PCM discovers no resistor, the code is set but the truck will continue to run, using some default value.

[Turbine Doc]

Not to start an argument but the learn I'm talking about is TDC offset learn, in several PMDs swapped in mine, and a couple of other trucks I played with, once TDC offset learn is initiated, and no resistor it would not start. (maybe the key difference is with TDC offset learn initiated) Kennedy 1st clued me to this had to try it just to see, also same reason why Steak Sauces "on the fly" fuel controller doesn't work.

[JohnC]

Not to start an argument but the learn I'm talking about is TDC offset learn, ... once TDC offset learn is initiated, and no resistor it would not start.

No argument here! Could be, I never had a reason to try that. What I meant is that if you install a new PMD and forget the resistor, and a year or so later the PCM looses the value and tries to read the resistor, it'll set a code but continue to start and run. (Of course, I never tried this either, but I've been told by others who did.)