the resistor just puts the pump within factory specs due to fluctuating tolerances when they are made, if i remember right when the computer actually resets(something like 50 key cycles), the default setting with no resistor is like a 5.

 

After reading this forum for a while, there is really no pattern with running PMD without resistor. All I have read is that in some truck, owners come here with no start condition (limping mode with new PMD), turns out they don't have resistor. It does not do it right away when you change PMD after the old one went bad but after sometimes. So nobody never correlates it to no resistor unless the owner told us there is no resistor. Then when the resistor is in, it starts right away.

My guess is it depends on the year of the truck being OBD-I or OBD-II. Even within the same type, there are some variation.

 

After reading this forum for a while, there is really no pattern with running PMD without resistor. All I have read is that in some truck, owners come here with no start condition (limping mode with new PMD), turns out they don't have resistor. It does not do it right away when you change PMD after the old one went bad but after sometimes. So nobody never correlates it to no resistor unless the owner told us there is no resistor. Then when the resistor is in, it starts right away.

My guess is it depends on the year of the truck being OBD-I or OBD-II. Even within the same type, there are some variation.

I have to agree. A quick search will show this. A number of older posts, however, indicate OBD-I will default to #1 and OBD-II just won't run. That is, of course, after 50 Ko-Ko cycles or a TDC relearn. However, there are examples that don't follow that pattern. DTC's also seem to be common.

 

Thanks for the replies guys.

 

Where do I get the resistor with the highest value?

 

Internet or local parts store possibly. I picked mine up at Advance but they had to order it. I think it came in a kit with a 5 and a 9.

 

I have owned my 96 for 1.5 years and it through a P1218 after the year and a half which is pump calibration when I checked the resistor I found it had none. Have experienced a no start but it was a blown ECM fuse and I think that blew do to shorted out lift pump.

 

Never saw a truck the won't run without a resistor. It just tweaks the fuel just a cc or so. Not enough to make it not run.

 

Amazon has them if you are into that... Amazon.com: Dorman 904-107 Tuning Calibration Resistor for Chevrolet/GMC PMD No.5 and No.9: Automotive

 

So what makes the price vary between $5 and $45 each? Not much to em.

 

Cheap China made ones are junk. Some fall apart when you try to take them out.

 

Silly question from a novice ... does running without resistor make the engine a little bit more ... marbly sounding ??

 

No. The resistor allows a Minuscule adjustment to Fuel IP. It would not be anything noticeable..

 

Don't know. I would not think if all it changes is the fuel it would make much difference but maybe the fuel change effects the timing and I think that makes a difference in the sound.

 

94 K2500 suburban 4x4 auto
power sucks while under load or up hill like foot to floor on 5 percent grade can only go 50 no load on back or in suburban was told to check and get PMD w/#9 resistor it is mounted to bumper

 

^ I'll bet you have a fuel delivery problem