HOW TO tamper with the fuel temp sensor like KERMA

Is it possible to do the IAT mod in addition to the Evry mod? I know the Evry mod uses pins 3 & 2, and according to Kerma, the IAT sensor uses pin 2.

I believe that is a common ground. If that is true, then there won't be a problem.

Joeviocoe said:

Im gonna try this mod but there has been too much confusion here.
Kerma posted:
And to put a 2.2k ohm resistor in series (inline) with ONE of the wires for each sensor. But people are getting CEL codes if they choose the IAT pin 1 (brown/blue) wire. And non-starts when using pin 4 (brown/blue) on the FTS.

Why?

Cause:http://www.geocities.com/tech4tdi/pages/map.html
Pin 1 is the ground wire for the MAP/IAT sensor. People forget that it is a shared sensor. So if you put a resistor on pin 1 (brown/blue) for the IAT sensor, not only do you lower the temp reading, but you also mess up the "Manifold Pressure" reading (MAP).

I don't have a wiring diagram for the Fuel Temp Sensor (FTS) but I think it is safe to say that the FTS harness has more than just a temp sensor. So which one do you think the ground is? Probably the (brown/blue) again right?

This is what Rub87 was saying about not cutting the ground wire.

Click to expand...

I am not too sure that pin 2 is the ground. Not trying to say you're wrong, but if it were just a ground then why would it be necessary for something like the Evry mod? Just a guess.

I am trying to understand if performing the mod on the IAT sensor will undo what the Evry mod attempts to do. The Evry mod, as I understand it, bridges pin 2 and pin 3. So why would anyone want to throw a resistor in pin 2 if they are first trying to bridge it to another wire? Are you supposed throw the resistor in after the bridge? Has anyone successfully done both the IAT mod and the Evry mod and the Fuel Temp mod?

If anyone has any information to help correct any/all of my faulty logic that would be also be greatly appreciated.

I think the EVRY mod is a more extreme way of fooling the temp sensor, a resistor in line in the fuel temp mod will set it so that fuel temp never goes above xx degrees, the evry mod pushes it to the extreme.

Well, that really didn't answer my question, but thanks...

Another question: I know that if you throw a 18k resistor in-line with the fuel sensor you can achieve a two degree timing advance. Would you still get a two degree advance if you used a lower rated resistor (i.e. a 10k or 5k or 2.2k)?

bump!

Evry on PD engines fools fuel temp. Evry on VP will fool the quantity adjuster position sensor feedback signal so that the pump thinks its fueling less than it actually is.

hatemi said:

Evry on PD engines fools fuel temp. Evry on VP will fool the quantity adjuster position sensor feedback signal so that the pump thinks its fueling less than it actually is.

Click to expand...

is there any benefit to raising the fuel temp on a PD- or any down side
cheers Nic p.s.if Gilligan's still there how does he pick up his pension?

Is VP the equivalent of ALH here in the US?

Cheshire,

Haven't you heard of Direct Deposit?

VP is ALH AGR etc.

Raising the actual fuel temp is bad on all of our engines. Raising the fuel temp reading that ecu sees will increase fueling and that is EVRY mod for PD engines in essence. Or was it coolant temp... Cant remember anymore

surely it's fuel temp readings

GgOTi said:

Is VP the equivalent of ALH here in the US?

Cheshire,

Haven't you heard of Direct Deposit?

Click to expand...

didn't realise there was an ATM machine on there

So, has it been determined if one could use this in conjunction with an every mod?

I would need :

- 2.2k ohm resistor in pin 7 (yellow/blue) on fuel pump harness
- 1k ohm in IAT TEMP wire on on fuel pump harness

This will achieve LOWER reported feul temp and LOWER reported Air Temp, and with my VERY mod, I can intruduce a varied amount of resistance (via on/off switch and potentiometer) with no problems?

The IAT temp mod is done on the map sensor wires. The resistor goes in line with the wire, basically making the temp never go above a certain number, as that sensor gives temp by varying resistance.

The fuel temp mod is done the same way. When the temp is hot, the inj pump retards timing for NOx emissions purposes, which causes more smoke and inefficiency.

KERMA said:

Here is a table with the different resistances at various degrees C in case you want to try different resistance values:

C Ohms

0 5000-6500
10 3350-4400
20 2250-3000
30 1500-2000
40 900-1400
50 700-950
60 530-675
80 275-375
100 150-230

This table is the same for IAT and fuel temp.

Click to expand...

Would a 2.2k resistor in the fuel line sensor be enough to keep the timing from becoming retarded when the fuel gets warmer than about 20º C? Or to put it another way: At what fuel temperature will the ECU begin to retard the timing?

I don't know exactly, I believe it to be around 70 or so... that is why this mod is advised for those with veggie oil conversions as they run fuel temps around coolant temp. 2.2k ohm resistor inline would make it so that the highest temp the sensor reads is 20 C, which is even below ambient on a hot day! Some people have said it increases timing for part throttle too, but it wasn't conclusive. Nowadays I don't run the mod as I have a fuel cooler, and my fuel temps never go above 45C.

Just did the KFC Mod on the 1996 Passat. I used a 15k ohm resistor on pin 7 and across the air intake wires. my scanguage II now says -6 on the intake temp.

So if I get it right, we are trying to fool the ECU in thinking the WVO is colder thatn it actually is. What happens when you are burning regular Diesel fuel?

Cheers

It will read lower. For example, I run a really moderate 2000 Ohm resistor so that the MAX temp that the sensor can read around 30 Celsius. WVO runs at almost 100C which is so high that the ecu gives very late timing (?? Deg ATDC). So lets say with my resistor, your fuel is at 100C, the fuel pump sensor is at lets say 200 Ohms. The 2000 ohms plus the 200 Ohms in series ends up adding to 2200 , which corresponds to around 25 Celsius. If lets say we used normal diesel that has a temp of 60C, that would be 600+2000=2600 Ohms which is going to give the ECU a lower reading, like 20 C.
Some people go more extreme and use resistors that correspond to 0 C etc. I don't think that is a good idea, because then you need to modify the IAT sensor which I don't think is a good idea as hotter air is less dense, so we should let the ecu manage this. For the fuel, as Kerma and others have seen, it really is bad that the ECU pulls back timing on hot fuel. I don't think that the miniscule amount of heat that the fuel brings into the cylinder makes up for how much the ECU pulls back timing!

C Ohms
0 5000-6500
10 3350-4400
20 2250-3000
30 1500-2000
40 900-1400
50 700-950
60 530-675
80 275-375
100 150-230

Fair enough... But what about winter. Up here in the winter we'll get -30C. I understand the WVO stays warm but the diesel will be in the -'s. Will this mod have a weird effect when driving on diesel in the winter?



Thx

No, because as the temperature drops lower, the resistor added has less of an effect.
Example: at 50C 800+2000=2800 , a huge change from 800
at 0C 6000+2000=8000 , smaller change from 6000.
Basically it changes the curve of the sensor to max out at a lower temp, so the ECU never sees the fuel hotter than 30C or so (in my case)

Not bad thank you.

But now, is this mod as necessary as some claim is it for running WVO?

yes because the ecu pulls back timing (runs retarded injection) w wvo which is run hot like 90C..
late timing means less complete burn
stock sensor- wvo runs quieter because of the late timing

I was thinking, if I replace straight the temperature sensor in the pump with fixed resistor, would that be ok to fool the ECU real fuel temperature?

Hi

I know this is an old thread but if running the KFC mod on non heated diesel fuel (even on say a 95 degree day with a half tank of fuel ) would this mod do anything at all or does it really only come into play with extra hot fuel alone ( like heated veggie oil).

At part throttle on diesel even in summer would there be any mpg gains due to fooling the ecu into thinking the fuel Is cooler ? ( I typically never run a tank lower than 1/4 remaining so maybe my fuel never gets hot enough to make a difference?).

Thanks

Andrew

This seemed to do nothing for my car, but it did make the CEL come on.

I read on this thread long time ago and I never did it cause I was waiting for good results, now i came across this thread again, it is something easy to do although i got fuel cooler on both of my alh cars, is it worth it?

If you only alter the fuel temp sensor circuit you will get a CEL, guaranteed. I think if you also alter the IAT circuit you won't get a CEL, but I never messed with that. I did have my fuel temp sensor mod set up on a switch so I could set my timing correctly after timing belt changes, setting the switch to "cold fuel" made no appreciable difference in anything, and the CEL always came on when I flipped that switch. I just had the switch set up right next to the injection pump...

Thxs for your input, I imagine that after installing external fuel cooler and FMIC in my ALH, I got to disregard these 2 mods, that's what I'm gathering unless I'd like to have a cel and probably will be an overkill doing these mods as well.

MAXRPM said:

Thxs for your input, I imagine that after installing external fuel cooler and FMIC in my ALH, I got to disregard these 2 mods, that's what I'm gathering unless I'd like to have a cel and probably will be an overkill doing these mods as well.

Click to expand...

HI,

Since you did actual physical cooler mods to decrease fuel temp and IAT (something I may have to do before it gets too hot because I put an 11 MM pump on without aux cooler).... did you notice any increase in performance vs stock?

Was fuel mileage (of course assuming you drive the same way as before the cooling mods) / throttle response improved?

Thanks

Andrew