Change crd timing with 2.5 kohms resistance

vgpwr · **Posted:** Mon Jun 22, 2009 9:58 pm

Advancing the timing will...
Decrease exhaust temperature
Increase cylinder temperatures/pressures
Increase fuel economy (yes, economy is better)
Increase your output of NOx (a pollutant)
Decrease your output of Hydrocarbons (a pollutant)
Increase the amount of black smoke at peak torque

The IAT sensor measures the temperature of the intake manifold. The ECM uses this sensor reading to set injection timing and adjust the air-fuel ratio. If the fuel mileage and power output of you engine seem low, some owners have found improvement in EGT, fuel economy, and power after cleaning carbon from the IAT sensor in at the rear of the intage manifold.
On CRD the IAT is combined with the pressure sensor Bosch 0 281 002 845 and have 4 contacts
pin 1= ground
pin 2= NTC resistor temperature sensor
pin 3= 5+Volts
pin 4= pressor output signal

I use scan tool to read the intake air temperature
in normal condition at 60 mi/hre iat = 160 F
with 2.5 kohms resistance on pine 2 , iat = 50 F

By fooling temperature probe, the ECM advancing the timing
From 26mpg, i jump to 30mpg on my last tank

More results to come.
Vgpwr

flash7210 · **Posted:** Tue Jun 23, 2009 7:36 am

So the resistor is wired in series with pin 2?
This is interesting. I'd like to see some more long term tests.

I installed a similar gas-saving device on my old '92 F150.
I didn't know too much about it and figured for $20 it was worth a try.
It plugged into one of the wires on the IAT. I can only assume it was some
sort of resistor.
Did it work? MPG went from from 14 to 14.5. Big friggin deal. :roll:

linewarbr · **Posted:** Tue Jun 23, 2009 8:23 am

Yeah, that whole "fooling the sensors" thing. Let us know how that turns out.

vegiH · **Posted:** Tue Jun 23, 2009 9:49 am

same technology as my edge trailjammer on setting #2,and yes it does all of the above......H

CATCRD · **Posted:** Tue Jun 23, 2009 12:20 pm

vegiH wrote:

same technology as my edge trailjammer on setting #2,and yes it does all of the above......H

160ºF manifold air temp seems high. Does your Jeep still have EGR enabled?

vegiH · **Posted:** Tue Jun 23, 2009 12:32 pm

SEGR equipped,and no kitty.I also must add that I run WVO 99% of the time so it needs advanced timing for correct detonation.WVO runs cooler than #2,and with the segr I have noticed some higher temps,but doesn't seem too high,Currently 27MPG around town 32MPG hiway.Any input greatly appreciated.

flash7210 · **Posted:** Wed Jun 24, 2009 7:12 am

Questions:
How did you come up with 2.5K for the resistor?
Why not 3K? 4K?
How does resistance corrolate to temp reading?
Why not try to fool the boost sensor?
Why not fool the ECU into thinking boost was a little low, thus adjusting
the turbo for more boost? (I dont know if it works that way, just thinkin)

vgpwr · **Posted:** Wed Jun 24, 2009 9:47 am

http://www.ontronic.com/products/doc/Sensors_mapt.pdf

Yes the 2.5Kohms is wired in serie with pin 2
My first test was with 5kohms, the intake temperature drop from 160F to 30F and the engine sound like a Dodge Cummin 96….so 2.5 was my next choice.
Fuel economie is my first target.
My CRD had F37 and Fcv butterfly removed

flash7210 · **Posted:** Wed Jun 24, 2009 11:53 am

Sweet! Thanks for the data sheet.

Ok, so resistance decreases as temp increases.
(higher resistance = lower temp read)

Pressure is a measurement of voltage output.
5v = high pressure
1v = low pressure
A diode in series at pin 4 could provide a ~0.5v drop. But I'm not sure if
that would produce the desired effect.
May just turn on the CEL.

Dawgbyte1975 · **Posted:** Thu Jun 25, 2009 3:00 pm

VGpwr, any new reports? Also, what about adding the resistor inline with the fuel sensor so the engine doesn't derate after fuel temps go up. I know my crd gets real sluggish when its hot and I've driven for a while.

flash7210 · **Posted:** Thu Jun 25, 2009 3:09 pm

Dawgbyte1975 wrote:

VGpwr, any new reports? Also, what about adding the resistor inline with the fuel sensor so the engine doesn't derate after fuel temps go up. I know my crd gets real sluggish when its hot and I've driven for a while.

Fuel temp sensor?
Have you unplugged the fuel heater?

If hot fuel is causing sluggish performance, a fuel cooler would work a lot better.

warp2diesel · **Posted:** Thu Jun 25, 2009 8:04 pm

flash7210 wrote:

Dawgbyte1975 wrote:

VGpwr, any new reports? Also, what about adding the resistor inline with the fuel sensor so the engine doesn't derate after fuel temps go up. I know my crd gets real sluggish when its hot and I've driven for a while.

Fuel temp sensor?
Have you unplugged the fuel heater?

If hot fuel is causing sluggish performance, a fuel cooler would work a lot better.

X2 on Fuel Cooler!

vgpwr · **Posted:** Sun Jun 28, 2009 8:17 pm

Dawgbyte1975 wrote:

VGpwr, any new reports? Also, what about adding the resistor inline with the fuel sensor so the engine doesn't derate after fuel temps go up. I know my crd gets real sluggish when its hot and I've driven for a while.

Report for Vgpwr mod

Last 500 miles = 38 MPG [/size]! (I never have that before)
Test done on Highway with cruise controle 60mph 1800rpm 35psi tire, no wind flat ground

No CEL !

geordi · **Posted:** Sun Jun 28, 2009 9:46 pm

Is that number what the EVIC is reporting, or the actual calculated fuel based on gallons actually put in, and miles driven?

B/c I have to call BS on that number without some numbers. I'm not discounting that there might be an improvement, but fully a 30% jump? Not unless it was sitting on a trailer for those miles.

CRDMiller · **Posted:** Sun Jun 28, 2009 10:03 pm

Lately I've been seeing bigger claims in mpg, like, 33-36+ So i dont know.

My odo is off and my speedo is off and for all i know my tach is off and sometimes i get 22 gals on E/w fuel light and sometimes only 17 so hell. I have no clue what my mpg is :P

My first tank was "hand calculated" at 17 mpg and i got rid of the cat and ehm'd and orm'd and i got 24 mpg, and i've been between "what i figure" is about 24-29 mpg. I've done a bunch of stuff between here and there, but it's always in that range. I think it's my commute, it's 10 miles of sub 50 mph up hill both ways kind of mountain driving. I did net "22" mpg from san diego to memphis in december or so, but, who the hell really knows. I know evic is inaccurate but i think i'm going to get one just to get a consistently inaccurate number for once. I also typically get at least 20 miles of low 4 per tank plus another 20 of 4pt to get to the nice trails so i'm sure that's not helping.

Anyway i'd solder a freeking resister and a diode or whatever the heck to my sensor in a heartbeat if i could pull down 38 mpg and not explode my inter cooler, or melt my turbo.

And the part about it sounding like a cummins, well, see if you cant find a better way to make me try something, ya hear?

stoutdog · **Posted:** Sun Jun 28, 2009 10:23 pm

A 10 mpg boost from tricking the sensors? Yeaaaa, I'm going to need some better numbers...

nursecosmo · **Posted:** Mon Jun 29, 2009 1:07 am

I'm gonna have to add to this one by saying that a 30% increase in MPG is almost certainly possible by increasing the timing. It is standard practice on the older P-pumped Cumins engines to set the timing to 17 degrees or more for huge performance gains. All of the pulling tractors have very advanced timing. I've done it on old volkswagons with great results. We have all known that this little engine is capable of far greater MPG. I asked one of the ECU tunners about whether timing advancement was used in their tune, but was not given an answer. It is common knowlege that the emissions regulations require auto manufacturers to program their diesel engine fuel curves for well below the most efficient timings simply to decrease NOx. Most 07 and newer engines even require a post combustion injection. The down side to the power gains achivied is that it creates a linear increase in cylinder pressure and engine stress or even blown head gaskets. I have wanted a way to achive exactly this effect ever since I bought my Jeep.

flash7210 · **Posted:** Mon Jun 29, 2009 7:23 am

Well, this thread has inspired me to create a "5 stage tuner switch."
I went to radio shack and got a 6 position rotary switch and some resistors.
Its all soldered together, just need to install on sensor.

Position 0- no resistor
1- 700ohms
2- 1260
3- 1940
4- 2500
5- 3180

I'll post pics when its done.

vgpwr · **Posted:** Mon Jun 29, 2009 9:07 am

My results are calculated from the fuel I put in the tank.

I don't try to sell anything, my mod cost nothing and take 5 minutes to do.

30% fuel economy for 5 cents invest... is a good payback!

Vgpwr

RJM · **Posted:** Mon Jun 29, 2009 9:43 am

B/c I have to call BS on that number without some numbers. I'm not discounting that there might be an improvement, but fully a 30% jump? Not unless it was sitting on a trailer for those miles.[/quote]

I notice vgpwr is in Montreal, the imperial gallon is larger than US gallon.
I get 30-33mpg with #2 highway driving no problem. So the numbers are in the range.

Change crd timing with 2.5 kohms resistance

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