How do you do the 10k mod,I have a 97 7.3

 

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Thanks man lots of help..I done did that but I was just askin if yall know some different ways to do it cuz I think theres different ways.

 

This modification is pretty simple as it's just a resistor wired into the truck's engine wiring harness. HOW you attach the resistor is VERY important. Wire taps (Scotch Locks) are a BAD idea as are any methods that don't involve solder or sealing. These engines vibrate A LOT so anything that isn't secure WILL come loose over time and you certainly don't want any moisture or contaminants finding their way into the conductor portion of the harness or you'll be chasing electrical gremlins in short order.

To understand WHY this modification is made, you have to understand what the injection control pressure sensor does, how it works, and how its output effects the PCM's operation. The ICP sensor is there to tell the PCM the ACTUAL pressure that is created by the high pressure oil pump. The PCM is programmed to maintain certain pressures depending on the inputs of other sensors and operator demand. The ICP sensor is a variable resistance sensor. The PCM sends out 5 volts to the sensor and a ground. The third wire is there to return voltage back to the PCM. The voltage will vary depending on pressure in the HPO rail. Higher return voltage means that the pressure is higher and conversely, lower voltage means that the pressure is lower.

Now, there are two ways to do this modification. You can wire in a resistor in parallel with the injection control pressure sensor or you can wire it in series. Understanding Ohm's Law will help immensely with following the things I'm talking about. The first versions of this modification were designed to be wired in parallel with the sensor. This setup used a resistor that was used as a shunt to bypass some of the ICP voltage to ground; effectively lowering the signal voltage going back to the PCM. Remember the relationship of voltage/pressure. The latest versions of this modification simply involve putting a resistor in series with the sensor signal wire. This in itself lowers the signal voltage back to the PCM.

You may ask yourself, "Why do we want to lower the voltage that the PCM is seeing coming from the ICP sensor?". Well, if you recall, the PCM is programmed to maintain a specific injection pressure based on a few things. Lowering the voltage that the PCM is "seeing", will cause the PCM to try correcting the pressure "problem" (even though there isn't a problem) by raising the injection pressure (by raising the injection pressure regulator duty cycle) until the desired value is reached. The more one "fools" the PCM input, the greater the artificial rise in injection pressure.

Back to the circuitry part of this....

If you wire in parallel, you will need a very high resistance (10K Ohm for instance) and the lower you go, the higher the actual pressure will become.

If you wire in series, you need a low resistance (i.e. 10 Ohm) and the higher you go, the higher the actual pressure will be.

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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"