would it hurt the truck to go higher than the 22k resistor

 

i fear it would be too high of pressure, and cause rough running

 

I agree may ru rough but shouldn't hurt anything.

 

you can only go so much before the manual safety in the pump kicks the pressure off, 4k psi

 

you're going the wrong way! going with a higher resistance will lower the pressure on the fuel rail.... I have been running a modified 10K variable for about 2 years.. I used a 4K resistor and a 10K variable... I can adjust on the fly.. turned down I am about stock and turned up is awesome!!! DO NOT GO BELOW 4K RESISTOR!!! IF YOU GET TOO MUCH PRESSURE YOU CAN BLOW AN INJECTOR BOOT(S)...

I am an engineer and I really cannot stress enough about going lower than a 4K resistor... I have heard of a guy going as low as 2K but it wasnt very long before I heard he was installing new injectors , LOL

 

ya, that doesnt make sense...
If you have an unmodified truck, you have (essentially) no resistance where the resistor would go. how would having a smaller resistor be worse than a bigger one?

 

Ah whats an injector boot??

There are two ways to do a 10k mod. inline and bypass

Inline more resistance means more ICP pressure
Bypass is less resistance means more ICP pressure.

 

oh boy, electricity 101 again....lol

i'll try to explaing this one more time. in any electircal circuit your ideal is to have no resistance.
you have a fixed 5 volt signal being delivered to the sensor. if you add a resistor inline to any fixed voltage circuit then you will have a voltage drop across the resistor. in their design they force electricity to work harder to get across them.

in a normal circuit the signal would be amplified to cross the resistance. for example, in a starter circuit, the pcm's 5 volt signal is the battery, the icp sensor is the starter and the 10k mod is corrosion in the battery cables. the more 10k mods(corrosion) build up the more current will flow through the cables from the battery to overcome the corrosion. thus the voltage at the starter(icp sensor) will stay 12 volts until the cables melt from the excessive current being drawn from the batteries.

in the icp circuit this is not possible because it is a fixed 5 volts, the pcm will not deliver anymore than that intial 5 volt signal. therefore if you add a resistor inline before the icp sensor you will drop the available voltage going into the sensor. when you drop the available voltage you will inturn get a lower voltage going back to the pcm from the icp. doing the mod inline allows the sensor to still function as designed, it still reads the pressure and adjusts the signal accordingly.
doing the mod inline gives you better control of the mod and more adjustability.
the more resistance you add to the circuit the less voltage goes to the icp resulting in a proportionate increase in ipr. that is electicity 101, you cannot change ohms law.

doing the 10k the bypass way gives the current flow 2 paths of travel to take, electricity is lazy by nature, it will always take the easiest path back to its source. by doing the 10k mod the old way of jamming the resistor in back of the sensor gives the electricity 2 paths to take. this is why adding the larger resistors has less effect on the engine. as you increase the resistor size the electricity could care less, it will just bypass the resistor and travel through the icp sensor. whichever path has less resistance, sensor or mod, is the path the current will travel. depending on engine load and mod size depends on which path and when the electricity will travel through the sensor or the mod. its unpredictable and unstable to do the mod the bypass way.

 

Joe you were right on until that last sentence!

 

hey sounded good to me

 

the unpredictable and unstable part? not really, but i can see how you could have read it, the statement refers to how the voltage is constantly going from icp to resistor; back and forth depending on engine load, oil pressure and throttle. this is an unstable circuit as far as electricity is concerned, the resistor, for lack of a bette rword, is a short in the circuit. if you draw a simple diagram of the bypass method then you will see that the mod is shorting the icp sensor.

not short as most people would think, but in electrical terms it is a short, its an alternate path for voltage to flow that isnt in the intial design of the circuit. it allows electricity to take a path around the desired load and make its way back to the source. when the current takes this alternate path it takes away from the icp sensor and doesnt give as accurate a reference to the pcm as it could.

 

And the inline method does make the ICP signal accurate??? I don't think so. Thats the whole purpose of the mod no matter which way you do it. The point is to fool the PCM as to what the ICP is telling it. Both ways create the same result.

 

I am assuming by bypass you mean putting the resistor in parallel which is what I am refering to. My mod is NOT inline. and I have never had a problem with it. when it is cold outside I do turn it down for start up, just to make it easier on a cold engine, then turn it back up after it is running a few seconds. I usually run it about half way up for daily driving, but occasionally I turn it up at a stoplight to get the jump on some little fool in a rice burner with a fart pipe. its really fun when it is summer time and they have their windows down (which happens to be at exhaust pipe level) and I fill 'em full of black smoke, lol

 

A very nice clarification Joe!
I was unaware that with different methods the resistor change had different effects.

 

does a chip take the place of these fuel mods or would they add to a chipped truck?