Chevy/GMC 6.2L and 6.5LDiscussion of Chevy and GMC Trucks with 6.2L and 6.5L Diesel Engines
I was wondering if anyone has changed out there stock #5 pmd resistor for the #9 resistor? Is there any noticeable power increase. I was thinking on getting one but didnt want to just throw away my money if theres no increase.... JOIN NOW TO REMOVE TRACER
I was wondering if anyone has changed out there stock #5 pmd resistor for the #9 resistor? Is there any noticeable power increase. I was thinking on getting one but didnt want to just throw away my money if theres no increase.
I never have noticed a difference between the two. If I have the pmd off and have a #9 or need a new resistor I would go with a #9 but I would not waste the time or money changing from a #5 if what you have is working.
Driving with your foot on the pedel I don't notice any diference at all, but on cruise control on long steep hills I do see a diference with a #9.The #5 will drop a KPH or 2 pulling on cruise, but the #9 maintains the same speed with no drop at all. This is noticed on hills I frequently drive, not random thoughts.
The first PMD had a # 9 , then I replaced it with a new PMD and a #5, this is when I noticed the drop of a couple KPH, nothing to worry about. I changed the PMD and resistor to a #9 and the truck pulls the same hills on cruise with no drop at all again.
I would not change resistors unless I planed to pull heavy loads a lot, and pull long steep hills.
The #9 does not make the truck a neck breaker.
heres my 1 cent #9. I relocated my PMD inside the cab of my 3500 van. My used PMD had no resistor so I used a sewing needle to pierce holes through wires and with a couple of wraps and a pinch for a poormans crimp, and bingo. I used an 82k which measured in at 80.2k, anything between 79.8k-81.4k is a #9. Heres an idea, splice a resistor in either wire in seires with the installed #5, a 62k should do it for a #9. I also read it takes 50 starts for the comp to read this new value. Im just glad it runs.
That is one way to do it I guess, but since you are OBD-II it is running on the stored original value whatever that was which is why it stayed running without any resistor in it, for the PCM to recognize a #9 or # anything is in the harness or in FSD cavity, IMO it is a FSD once removed off the IP no longer a PMD.
Had it been commanded to do a TDCO learn the PCM would have self learned the resistor was missing giving you a resistor fault code, resulting in a no start condition. In order to take advantage now of the #9 marginal gains you have to teach the PCM you have a #9 in there, hopefully you hit enough wires in the harness it won't give you a no start condition once you do the learn, also what you have is really a "cold junction" and not the best electrical connectivity prone to fail.
There is a "individual" has his own let me be kind "unique" website think of a table condiment you put on meat, that says he has for sale a variable fuel rate controller that lets you adjust fuel on the fly, bovine scatology as "Stormin Norman" said back in the day, just to prove a point the PCM does not read real time the PMD/FSD resistor value I removed mine ran that way for over a year, did a TDCO learn reset after making a timing change (forgetting I was running sans resistor) got the resistor fault code and a no start condition.
I reinstalled the resistor I had been carrying in center console commanded the TDCO learn again "taught" the resistors value to the PCM and it fired right back up.
Iv'e never checked it myself but on OBD-Is I've been told that 50 "warm up cycles" (which is start ECT thru 170F ECT) are required to learn a new resistor value or learn the resistor is missing; if missing PCM, I'm told PCM then defaults to a null #5 (0 mm/3) fuel added or subtracted to the fuel delivered at test stand calibration speed 1500rpm which would equal 3000 of vehicle rpm delivery rate.
This is where one has to be in engine rpm to see full effect of a resistor delivery change, provided the rest of the IP is capable of full fuel delivery and no internal wear in the IP is present reducing max fuel, and one also has to have a program change to request maximum fuel. F PCMs stock new 65-76 mm/3 delivery, S PCMs (emission vehicles) 56-63 mm/3.
DS4 is physically limited to about 92 mm/3 if one has the right programming to request that and sustain it, chasing the extra 1-2 mm/3 with a resistor swap is just that a chase; because a stock PCM will cut back any fuel it does not want or need you have to be at WOT to get a momentary bump to max fuel with stock programming.
Last edited by Turbine Doc; 10-09-2012 at 11:19 PM.
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