smokin05

18 psig is pretty close though its about .125v per pound of boost @ the manifold......why does everyone hate on me i made the 10k mod off the chain w/ a six position switch in my last ford...but 10k is fule only and the ford 7.3 does not use a crazy two or three event idel...so it would sound really cool at 3.9 k (full race drag car!) however if u do this to a NEW cummins it will TRY TO BLOW UP!! however i am looking to tap into some kinda idle valadation circut somewhere w/ a relay to trick this out ...ill keep you haters and not haters informed

peace

Superduty

"why does everyone hate on me"

Nobody hates you.

But I think people should understand what they are doing to their $5K-10K engine when they are doing this.

"it would sound really cool at 3.9 k (full race drag car!)"

There are recent posts and a poll about the effects of boxes (increased rail pressure) having bad effects on injectors. The Cummins isn't a Ford. The Ford high pressure oil rail ran stock pressures of 2700 PSI. The rail on the Cummins runs at 23,000 PSI stock. Take the pressure too high and you'll crack an injector body and fill your crankcase with fuel.

smokin05

the apps it what took the place of the idel valadation circut switch! mounted on the pedel in the fords...and i am checking to to it right now...basicly from the drawing it looks this a feed back to the ecm for the pedel position i am gonna have more time this weekend to figure it out it looks like a simple self balancing electical circut...however very low voltage and very high impendence(not good for tapping into for a relay coil)..i have not even checked it out yet ...just looking at a drawing i got from the dodge bodybuilder web site...bythe way superduty i told my buddies about your truck.....i have to say i really admire your work...if you could get a allison behind that cummins in the fords...i belive you would have the best truck evermade! i would buy one!

Lary Ellis (Top)

Lets not get personal here guys... keep it on a friendly level please

smokin05

all it does is throw the diesel early see as soon as the motor really makes the boost the sensor output quickly goes over 1.6v so the resistors it not doing anything at all the motor is running bone stock its just a take off turbo lag trick but i have other secrets that do much more and i will tell more when i know more...i need some really good gauges and a really heavy trailer and lots of open road to perfect the level two and three i am trying tio do something cool for everyone ( i hope)

4x4not

Are you still here?

I am still convinced you have no idea what is really going on and you just started hooking up resistors after you got ahold of the FSM wiring diagrams.

04ctd

Superduty, I thought the sensor behind the filter was just an IAT (Intake Air Temperature) like on a gasser?

Is it really a Pressure Sensor?

because the K&N FIPK mounts it off the side. (pic in my gallery maybe)
I was assuming if it mounts it out of the air stream, then it is not cooled by the air flow over it?

smokin05

it is pressure and temp made by motorola i checked it out ! read the wiring diagrams too they reflect the same things too

smokin05

wait what is that k&n thingy got to go w/ the intake map/temp sensor?

smokin05

the sensor i am talking about is on the other side of the engine from your air filter.....but that filter by the way looks pretty sharp! is that the cold air stuff i hear people talking about?

smokin05

4x4not....you always got something to say ...so i was looking over your pics to see what you drive...you know the guy thing! what kinda guage is that and where can i check one out? how much was it if you dont mind me asking? looks cool

Superduty

"I thought the sensor behind the filter was just an IAT (Intake Air Temperature) like on a gasser?"

It is a 4 wire device, does both presssure and temp. 05 shop manual, page 8W-30-35.

ECM uses this to figure out when to throttle back the turbo to prevent overspeed. Like at high altitudes, in thin air. Or dirty air filter. (pre turbo air pressure is less.)

"look 35ohms from the hot yellow/pink tracer 5v wire to the solid blue signal wire on the four wire map/temp sensor"

You have to be very careful with what you are doing here. That pink/yellow wire also feeds the rail pressure sensor its 5 volts. 35 ohms is a small resistor that will allow a lot of current to flow. (5V/35ohms = 0.142A) That doesn't sound like much, but the ECM is expecting only a few tens of ma on the sensor load, so you might be pulling down the 5V supply line.

If you wanted to do this right, you'd feed the MAP sensor into an opamp and change the gain a bit and feed that to the ECM.

The way you've done it, you've taken the sensor output, which isn't designed to drive big loads and put a 35ohm pullup to 5V on it. If the manifold pressure ever goes to a vacuum and the sensor output drops to say 1 or 0 volts, there is going to be 142 ma going through the sensor output and I'm pretty sure that will burn it out.

smokin05

i agree and yes i agree your right superduty !

MikeyB

Smokin05,
You need to put a VOM on the 5v source and make sure the voltage doesn't sag, especially under no or low boost conditions. You could build a little 5v regulator so the 5v coming from the ECM is not touched.
Also be very careful with playing with the rail pressure, you could over do it and pop the high pressure relief valve. Hook a VOM to the fuel pressure sensor on the rail and monitor the voltage. Here's a base line for a stock system.
0 psi = .50 volts
5801 psi = 1.39 volts
10153 psi = 2.06 volts
14504 psi = 2.72 volts
20305 psi = 3.61 volts
23206 psi = 4.06 volts
26107 psi = 4.50 volts
26700 psi = 4.56 volts

MikeyB

DmaxEter

I hate to break it to everyone here, but what Smokin05 is taking about works. Its a very simple circuit to manipulate safely. I guess people are just scared about messing with the wiring and possibly burnning up something. I dont personally like the increasing of rail pressure because I have seen injector bodies crack due to this. The MAP mod he is speaking of works and works great. It will literally cost you about $2 and a little time. It is a modified mod that the powerjoke guys are and have been running. On my powerjoke I didnt even have the MAP plugged it. It has a series of resistors that plugged in in its place and made the ECM fuel off idle as if it had 22 psi of boost. It did not hurt anything. It makes more low end power and all but elliminates turbo lag. It will smoke under heavy acceleration until boost catches up but it does not take long. Smokin05, Keep it up.
Whats the difference between doing this mod and buying a box that does it?
About $200 dollars.
Will they offer help if you burn your motor up?? NO.
You dont have to cut any wires. Come on guys, dont be scared of them.
These are basic circuits and basic wiring. If you have never delt with this type stuff then I can understand questioning it. If you have, then you know its simple easy circuitry.