smokin05

oh yeah I also would agree w/ your typical ohm load on inputs statement...but for some reason they did these different ...I was very suppressed....like on the ford ...10k ohms would do the trick and bleed off the signal feedback on the fuel pressure sensor...these are much lower impendence devices we are using 35ohm .25watt ...like I said I was surprised to see it took this many milliamps to make it work..... Still (5v-.5v) =4.5v*35=about 157ma for a sec or two (assuming the engine would go into a vacuum) at 1.6v ....this would not even light up one l.e.d. so its not like it’s going to smoke something

Superduty

"Still (5v-.5v) =4.5v*35=about 157ma "

No.

Ohms law V=IR. I=V/R You've got I = V*R. That is wrong.

Should be (5-0.5) = 4.5V/35 = 128 ma.

smokin05

am sorry your right i was looking at my notes after i posted that and relized what i had done...my bad so if you understand what i am doing w/ this then check this out if i put one 5.1v zener diode "in-line" between the sensor and ecm the 25 ohm jumper at the sensor instead of 35 ohm ....this gets you up to 2.2v or so ...now thats too much...you'll get a code but the zener is knocking off .5v back to the ecm...so now were back to 2.2-.5 = 1.7v that the ecm sees but ....remember me saying the ecm wants to see 3.8v at WOT so now it sees that voltage when your really holding a steady 3.8+.5= 4.3v at the sensor....that is why the amplifer you mentoned would not work alone superduty..Cause it will cut your boost on top end too soon...before even normal levels

smokin05

Let me have your thoughts? You seem to understand what I am doing...and I respect your concern for the sensor honestly


ps i am cuttin and pastin from word so i get the ol spelo cheko

04ctd

here ya go:
http://toolbar.google.com/?promo=mor-tb-en

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this does sound like an interesting mod. keep telling us what results you are seeing.

smokin05

Well I have already done it...and a couple more ... but it makes the truck run good...but i have said this before i dont drive this thing much. Its a toy I have another truck I am working on gauges now...so i can comment on what else it might be doing...(that i dont know about)...i dont feel that the map mod runs the exhaust temps up much at all... but it really needs a nice shot of fuel and i figured that out too ...and its slips the dog mess out of that G56 clutch @ 3/4 pedel , however thats definately added to the exhaust temps... in a major way i assume and that scares me .....So I am not playing with it too much on the fuel side until I get about 4 good gauges...boost, fuel, pyro, lift pump pressure.

gatf4

Great post guys, keep it up

Why not run a toggle switch in the cab, connected to the resistor jumper circiut so you can turn it on/off at will? That might be harder with the diode installed?

350005

Been reading this thread, sounds like an electrical battle. Personally, I think it is much ado about nothing. All that "smoke" coming from the tail pipe is nothing but wasted fuel. Horsepower is not made with wasted fuel. Optimum fuel/air ratio creates the most heat. Heat turns the turbo...not smoke. Air into the engine is key....but you can only stuff so much of that in there... More fuel at full load will give more HP. You might reduce turbo lag a minute amount...but is it really worth all the JERRY riggin ????

CarolinaThunder

Ok so uhhh what exactly do I have to do to get this extra amount of smoke?

hmmm...How about a step by step instruction for an idiot that knows nothing technical about electrical.

MikeyB

Smokin05 circuit is a voltage divider. Vout = 5v(R2/R1+R2). R1 is the pullup resistor and R2 is the MAP sensor (variable).

MikeyB

MikeyB

Smokin,
Have thought about this circuit for the MAP mod? It's a zener clamping at 3.9v. Close enough to the 3.8v you recorded.
A note on the resistor value, if the value is below 110 ohms a 1w zener will be needed.
BTW, the DTR stamp at the bottom of the pic covers the ground reference on the zener.



MikeyB

smokin05

mikey I have not tried to wire it that way... but I might!...I wired a zener "in-line" all this did was knock off half a volt there are other elements I might have used but this zener is a 5.1v however ....what I liked about it was rather that clipping all the voltage...I am just knocking off a half. the real cool thing is remember the ecm has to see the change in voltage ....unlike fords ecm...also it will still see the spike in pressure and back the fuel up still to prevent too much boost if I totally clipped it would think the truck was able to get the boost up... what the ecm is looking for simply works like this...

an increase in the apps signal is an increase in fuel in relation to apps signal and map signal...example wot....the ecm would fuel the engine boost would rise to 4v and then the ecm back the fuel up to 3.8v where the ecm likes to see it at WOT the ecm is looking to see more boost than it wants and just slightly trim the fuel....if I clip it the ecm would never see the top end voltage change....not sure what it would do but I can bet it would set a code after a few min of trying to reach that upper limit.....however it might be worth a try

In the morning I will try to finish the fuel mod.....this one is a little more tricky cause there is no dang idle validation switch like a ford has! And you CAN NOT increase fuel pressure at idle on the dodge w/ the three event injection idle mess! ....got to master the apps!

MikeyB

Smokin,
The zener in my circuit drawing clamps the voltage at 3.9v, and will not allow the voltage to go higher than that. Also note, you might have to experiment with different value zeners, some actually clamp at a lower voltage than specified, so you might have to use a higher value zener to find one that clamps right voltage level, example, having to use a 4.3v or 4.7v zener. Test on a bench before installing.
Here are some p/n's to try.
All are 1w zeners.

3.9v - 1N4730
4.3v - 1N4731
4.7v - 1N4732

As for the fuel mod, are you raising the rail pressure? If so be very careful, and don't exceed 27k psi. In fact, I wouldn't exceed 24-25k psi. Make sure you have a VOM hooked up to the rail pressure sensor and monitor the voltage, and use the values that I posted earlier in this thread.

Good luck

MikeyB

smokin05

I understood the circuit you drew...mikey I think I would work but I am going to check on the ecms reaction to not seeing the spike in boost and then being able to trim the fuel back...see if we clamp it at 3.9v the ecm will think we never made full turbo speed? it wants to see the 1.2v go to 4.0v then trim to 3.8v but....then again it may work really awesome I already built a voltage regulator circuit so I will try to ground the zeners on the bench and see what one actually clams at 3.9v ....I really appreciate your help

I will be careful w/ the rail pressure... however I never got your voltage output/pressure chart....its no big deal I think I can find on the net ...but if you have it handy send it to me texasvalveman@yahoo.com

MikeyB

Here it is.

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

Just be careful and don't exceed the 27k max. May pop the pressure relief valve and it's a $400 item.

MikeyB