Smokin05 35 ohm MAP mod
01-21-2006, 02:54 PM
#61
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Originally Posted by Superduty
I think this mod was started by someone a few days ago trying to sell people information on a website for $25.
"Very similar to the 10k mod on the Powerstroke ICP."
No. Not even close.
The 10K mod on a Powerstroke fools the ECM into thinking the high pressure oil pressure is lower than what it actually is, effectively making the ECM command a higher oil pressure than what the engine usually runs at. Because of this the injectors operate at a higher oil pressure and deliver a bit more fuel.
This mod attempts to fool the ECM into thinking that there is more manifold pressure than what there actually is. As a result, *sometimes* the ECM will command the injectors to deliver more fuel than what they normally would.
HOWEVER, there are a couple problems:
a) there are two air pressure sensors on the ISBs. One in the intake manifold otherwise known as a MAP sensor (Manifold Absolute Pressure) and the other in the air intake pipe near the air filter. At startup, before the engine is running, the ECM compares the pressure it reads at the air intake with that of the MAP sensor. The two have to agree, otherwise the ECM sets a code and goes into a limp type mode where it estimates manifold pressure rather than using the actual manifold pressure.
b) The ECM will throttle back fuel delivery if it senses overboost. It isn't clear what exactly is being done with the resistor mentioned here. If it is used to change the pressure/voltage curve of the MAP sensor, it will send an over pressure signal to the ECM at high manifold pressures and the ECM will cut back the fuel accordingly. Thus the engine makes LESS power.
I don't understand why one would want either of these conditions to occur. The engine doesn't make more power. All it does is smoke if it is gotten to work at all.
Whoever thought of this mod didn't research it very well.
"Very similar to the 10k mod on the Powerstroke ICP."
No. Not even close.
The 10K mod on a Powerstroke fools the ECM into thinking the high pressure oil pressure is lower than what it actually is, effectively making the ECM command a higher oil pressure than what the engine usually runs at. Because of this the injectors operate at a higher oil pressure and deliver a bit more fuel.
This mod attempts to fool the ECM into thinking that there is more manifold pressure than what there actually is. As a result, *sometimes* the ECM will command the injectors to deliver more fuel than what they normally would.
HOWEVER, there are a couple problems:
a) there are two air pressure sensors on the ISBs. One in the intake manifold otherwise known as a MAP sensor (Manifold Absolute Pressure) and the other in the air intake pipe near the air filter. At startup, before the engine is running, the ECM compares the pressure it reads at the air intake with that of the MAP sensor. The two have to agree, otherwise the ECM sets a code and goes into a limp type mode where it estimates manifold pressure rather than using the actual manifold pressure.
b) The ECM will throttle back fuel delivery if it senses overboost. It isn't clear what exactly is being done with the resistor mentioned here. If it is used to change the pressure/voltage curve of the MAP sensor, it will send an over pressure signal to the ECM at high manifold pressures and the ECM will cut back the fuel accordingly. Thus the engine makes LESS power.
I don't understand why one would want either of these conditions to occur. The engine doesn't make more power. All it does is smoke if it is gotten to work at all.
Whoever thought of this mod didn't research it very well.
The ECM compares the battery temp sensor to the ambient air temp sensor (combo air temp/press sensor in airbox) at start up. I was not aware of a pressure sensor retionality check, but I can't confirm and SuperD has been right more times that I have been.
01-22-2006, 11:07 AM
#63
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Mikey thanks for the info....how do I plug up that pop off valve thingy!? I am just kidding!....check it out I got it ...I have not tried your way of grounding the zener YET.... however I did get the fuel mod working I said forget tapping the apps I made a bracket and attached it to the go pedal w/ a adjustable n.o. switch and when its closed the signal wire from the fuel sensor runs to a six position switch wired from position witch is open= no mod ...all the way from 3000 ohms to 1800 ohms on the other five positions....I at first had a adjustable pot to get the right resistance....however it still slips the clutch below 2600 ohms so I try to stay around 2700 ohms until I get the south bend G56 double disk installed .....it really does not smoke too much ether so I think the boost w/ the fuel is burning pretty good ....however I did get code P0069 (crappy code lost all kinds of power) I think it was ....a rationality code for the suction sensor in the air box....so I cleared it moved the sensor out of the box (like the k/n mod does) and it has not come back
btw my buddy came over w/ his 4 door short bed 4x4 AUTOMATIC w/ the k/n tube and filter mod and straight piped....and I let him two truck lengths behind me at 30 mph and floor it and I never got on my truck until he was well past me ...I caught right up to him AND went by his but! However I still hit the governor pretty quick!
btw my buddy came over w/ his 4 door short bed 4x4 AUTOMATIC w/ the k/n tube and filter mod and straight piped....and I let him two truck lengths behind me at 30 mph and floor it and I never got on my truck until he was well past me ...I caught right up to him AND went by his but! However I still hit the governor pretty quick!
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