10k mod

[shelby85]

ok i keep hearing about this 10k mod and also a 18k mod. what are they and do they help at all. what are the differances between the 10k and 18k. also how do you do it and what would you need to do it the right way. any help and step by step instructions would be great.

[Patrick Feeley]

If I remember correctly, the 10k mod is more for the OBS trucks while the 18k is for the SD trucks. They fool the PCM into thinking that the high pressure oil pressure is lower than it actually is (which then raises the real pressure in the rails). Here's the mod from "Steve Baz's pages" (in the Diesel FAQs here):

"10k Resistor Mod
A 10k ohm resistor will raise the injection oil pressure approximately 200 psi. Increased injection pressure will deliver more fuel and will deliver more fuel sooner. This increase in fuel deliver and advance will yield higher combustion temperature but your exhaust gas temperature will remain almost steady. Such an efficient burn has it's down side. It will cause an idle rougher than stock. It may also cause the production of nitrous oxides. Thermal efficiency is a function of the high(absolute)temperature divided by low(absolute)temperature. In other words, the higher the peak combustion temperature in comparison to the exhaust temperature the more efficient is your engine.

Parts Needed
digital volt ohm meter
10k ohm resistor (1/2 or 1 watt)
2 fine copper wires 4" length
black tape
Procedure
1 Solder wire on resistor
2 Identify injection pressure sensor (on front of driver side cylinder head)
3 Test for voltage with key on and engine off

IPS has 3 connections:
+4.97V
+0.003V
+Output
Turn key off!
Connect resistor between output and 0.003V (do not cut any factory wires)
Slide fine wires into plug and reassemble
Cover bare wires with tape


I used a 1 watt .05 rated 10K resister. Soldered a 3" piece of wire on each side of the resister slide heat shrink over the entire part of the resister and about 1" of wire. Leave about 1" of the wire soldered on inside the heat shrink and seal each end to be sure with electrical tape. Then I stripped the wire back 1" I pulled out of the wire 5 strands and cut the rest away. Looking at the connector it looks like 2 eyes and a mouth put 1 wire in the right eye and the other in the mouth Blue/stripe and grey/stripe wire. I put the plug back into the ICP about 20 time until the check engine light did not come back on. If the check engine light comes back on you still have a open circuit. Just push it into there harder or pull it a part and put in again until no Check Engine Light comes on. It will if your work if you keep putting it in the plug and it seats.

REMOVE BEFORE DEALER SERVICE"

Hope that helps! Cheers!

[shelby85]

thanx for the info on it does it work well with the idm mod or should i just do one or the other.

[Window&Door]

I'd like to know as well, TIA, fellas!

[94strokerace]

Window&Door, i see you are chipped. A tuner will do the same thing the 10k mod does. This would be redundant in your application perhaps.

shelby85, an idm mod makes the injector "quicker" electrically while the 10k raises icp and affects the injector mechanically.

Have you noticed that your engine has a little more zip when cold? Basically, the 10k mod fools the pcm and icp is elevated. Thats all. Dont forget to remove when troubleshooting if you go with this mod.

Imo, i would let a tuner decide how to cheat the pcm.

[shelby85]

does the edge tuner fool the injection preasure like other ones would

[94strokerace]

Im not sure about the off-the-shelf chips, but the custom tuners manipulate icp.

[Window&Door]

Thanks 94stroke. I like this forum

[ArrowHeadJim]

With the 10k mod the presure can go high enough to throw codes. You may also get the turbo presure high enough to throw an over boost code. If you search you can find a 10k mod with a series of diodes. That mode will allow the truck to idle with out the rumpity rump you could experience with some values of resistors. The diodes also allow small inputs from the throttle with out the oil preasure going up. But at partial throttle the preasure will rise and give better response at lower throttle settings. This mod also seems to affect the transmissons shifting. I run an ajustable version with a shut of switch. The affects on the transmission at high settings are not what I would call desireable. You have to also watch the exhaust temps as you are fooling the pcm into believing all is good in the injector department to a point. You can over boost and over preasure. So be careful and have fun. An easy test to see how it works is to use thin solid wire like wire wrap wire used in electronics. Attach to the resistor, insulate, and pull the IPC plug and tuck the assembly in to the appropriot contacts and reconnect the connector. Give it a test drive. Adjust to you likes. Or remove and toss it in the circular file.

[Scottyk]

Seems to me this mod would cause your mileage to go down the crapper, is that true?

[Larry S.]

Seems to me this mod would cause your mileage to go down the crapper, is that true?

Not necessarily. Many report an improvement in mileage. Theory is: higher pressure improves atomization of fuel. Right now I am running my version of the 10k with actually 7.5k, lower means more pressure, and an old Hypermax chip. My DP-Tuner chip is in for some program updates. On my last trip I made right at 20 mpg. BTW: my version of the 10k uses a transistor to control the turn on of the resistor and is adjustable. Works very good. With this old chip and my injectors the 7.5k can really be felt in the seat of my pants. If I had a bigger HPOP I could go even lower in resistance.

[ArrowHeadJim]

I actually though it would good to carry a couple of resistors all wired up. So if ya ran in to someone who asked about it, you could toss em a couple let em see for them self.

Larry
Do you have a schematic on your 10k version?

I used a series of diodes to create a knee in the signal. I think I used three silicon uinits. That way at idle and just off there is no affect. But as you add throttle the IPC signal will be affected. I also used a pair of resistors to create a divider and a pot so I could adjust it. I can go from little to alot of change. I also have a switch so I can take it out of circuit if needed.

Over boost and over pressure codes are easy to get. So I usually run it at about 1/4 to 1/3 it's range. It is fun to crank it though.

[Larry S.]

Do you have a schematic on your 10k version?

Jim,
Yes I do. Send a PM to me with your email address and I'll send a schematic.

FWIW: I looked at using diodes when first working with asmith, the originator of the 10k mod, but felt it didn't give me enough control of the turn on point. Your three diodes turn on between 1.5 and 1.8 volts, which is OK, but the shunting current of the added resistor is produced from the ICP viltage minus the diode drop which means the effective resistance is higher than the actual resistor value. That doesn't mean the diode method does not work. It just is more non linear than a switching method. With my transistor scheme I use a divider and the diode drop of the base emitter junction to set the turn on voltage. When the voltage reaches the turn on point the transistor begins to turn on and soon saturates which connects a resistor in parallel with the ICP output. I use a fixed resistor and a pot in the collector of the transistor to facilitate having a variable amount of shunting resistance. I also use a small resistance in the transistor's emitter to soften the switch characteristic which makes the transition very smooth. My prototypes had pots to control turn on voltage, shunt resistance, and turn on softening but after much trial I settled on a fixed turn on and softening value and only kept the shunt resistance pot. I also have a switch to turn the circuit "off". I tried selling these things and have a few satisfied customers but decided it wasn't worth the time and work to continue selling them. I still have enough parts to build a couple more but have no interest in building any. My eyesite is getting so bad I have difficulty soldering the board. I'll send a picture of a unit in my truck and the instruction packet I included with my units along with the schematic. It should work good with your split shot Cali truck.

[ArrowHeadJim]

Sent you a PM last night.