Nistune Forums

sorry my bad about the enrichment related to fuel temp. must have been something else I was thinking of

Hello,

That's exactly what I experienced ... it starts with 20C and rises to 80C.
Trouble is I exactly followed the manual for the modification, and soldered the 2k resistor were it should be.

Zuikkis wrote:

Torque wrote: If there is a 'short' shouldn't the voltage be 0 volt?
And if the sensor is not connected 5 volt?

If there is a short to 0V or 5V, Nistune doesn't show the actual measured value, instead it shows this "emulated" temperature that starts from something like 20C and rises slowly to 80C..

Anyway, I think Eric is correct in that fuel temp only affects the P-REG valve, which is not present in RB25DET, anyway. Just disable the DTC and don't worry about it.

Hmmm. This is most strange. I've now tried this mod a couple of times on the bench and it worked perfectly. I'll re-check but maybe there are ECU differences. Seems weird though.

If we can't come to an answer for this I'll remove the fuel temp resistor part from the manual as I don't have the information to do anything else.

PL

Hello,

Yes ... it's kinda strange.
Please double check .. if it really works(ed) with the 2k and does not creep up the scale later on.

According the the Z32 manual the resistor should be around 2k.
Lower values mean higher temperatures.

I am 110% sure I did the soldering right.

I measured the pin against sensor ground after and it was around 800 ohms.
Matt confirmed this value as correct.

How long does it take before it starts creeping up?

PL

4-10 secs

>> Hmmm. This is most strange. I've now tried this mod a couple of times on the bench and it worked perfectly.

I'm using a variable resistor so I can set it to anything I want and this works fine for me also.
On the bench and in the car....

> I am 110% sure I did the soldering right.

Maybe there's something wrong with the ECU you are using ?

We are getting the same issue here. Z32 going into an R33 GTST, modded for direct plug in. Fuel temp starts at 25 degrees then ramps to 80 over a few minutes. The ECU goes into knock mode while driving normally.

I have tried many different resistors and cannot get rid of the FUEL TEMP code.

Seems to be ECU related since I remember sam (drdrfit) having the same problem with two different ECUs in the same vehicle

One was fine and the other had fuel temp code issues. He also mentioned about knock sensitivity being too high also. There I suggested turning off the knock feedback flag in the maps

I could live with the fuel temp going through the roof.

But I could not tolerate dysfunctional knock sensing on a Skyline.

How do I check in Nistune that there is knock detected?

crans wrote:We are getting the same issue here. Z32 going into an R33 GTST, modded for direct plug in. Fuel temp starts at 25 degrees then ramps to 80 over a few minutes. The ECU goes into knock mode while driving normally.

I have tried many different resistors and cannot get rid of the FUEL TEMP code.

Hi Crans,
What is your ECU number?


All in all I believe in logical explanations.
I am having a hard time believing that some ECUs work, and others do not.

Cheers,
Andrew

Timing would get pulled back if it is detecting knocking (deviate from the maps) or switch to knock map

Only on a few vehicles so far

Best way to check is set your knock map to about 10 degrees or similar lower so you suddenly feel the difference when it switches maps

If I do a trace or log (knock count) knock wouldn't show up?
And if the ECU knows about knock events, would it be possible to have this displayed in Nistune?

Matt wrote:Timing would get pulled back if it is detecting knocking (deviate from the maps) or switch to knock map

Only on a few vehicles so far

Best way to check is set your knock map to about 10 degrees or similar lower so you suddenly feel the difference when it switches maps

I ran some tests with the knock warning panel up, it does not detect knock but still goes to the knock map.

Could the ECU be monitoring fuel temp and switch to knock maps over a certain limit, like it would if 'guessing' the fuel temps? (ramping from 25-80 degrees)

Hi Crans,

I think the fuel temperature has only an impact on the fuel pressure.

How did you realize that the ECU is in knock mode?

And what is your ECU-Number??

What resistor values did you test?