troykinsjz

What year model ls400? Same as rhe sc400?

187

Pretty obd2 specific question. I'm getting rid of the maf to clean up the bay with a new intake. The maf temp resistance is about 2800 ohms where the hks vpc guide says to install a 1200 ohm resistor in its place. The hks temp probe itself reads 1400 ohms and the same temp as the maf. Should I tap the hks into the maf?

I'm pretty sure the car likes to see temperature variance, but I can't really find a graph for the temp/resistance relationship.

Ali SC3

iTrader: (10)

I would install the hks temp probe, since the HKS goes through its own chip, use the temp resistance that it wants to see. I dont like doing the resistor either. the ecu isn't super sensitive to air temp, but it does like to see when its hot or cold. with a resistor, it will only be reading hot or running temp all the time, so it will run a little "off" until it warms up if that makes sense.

don't tap into the maf cause that is what you are trying to get rid of. I have always used the AEM intake temp sensor with the jdm ecu which is basically like the GM one, so its not super sensitive to the exact value I have never had to get a toyota temp sensor. I think the hks temp probe into the hks vpc is the safest bet, and it will probably have the right output to the ecu to match what the vpc is doing.

187

Okay, I'll tap the vpc into the maf plug and see how it reacts.

I'm just worried the 1400 ohms will be to low making the ecu think the air is hotter than it is, but 1200 is even lower so. If it comes down to it I could easily install a toyota IAT, it seems like every brand uses different resistances.

Ali SC3

iTrader: (10)

it should be fine, just try not to put the sensor somewhere where it will heatsoak alot.

scblackout

iTrader: (2)

Rather confused... so, if going with usdm obdii ecu + mapecu2 into sc300, do I actually need to purchase a supra tt obd2 maf? I get that normally it is an obvious yes, but by adding the mapecu2 am I not 'replacing' the maf with the mapecu? I also understand that I need to add a tt map sensor, that should be right?

If I do have to use a tt maf, how is everyone adding it into their cold site piping as most of the kits (i.e. boost logic) are 2.5" pipes vs the 3" maf?

Ali SC3

iTrader: (10)

if you get the map ecu then you do not need to have the maf.
you also need the tt map sensor yes.

map ecu and a tt map sensor and also you will need an air intake temp sensor.

187

Well I spliced the temp connection into the maf connector, but it game me a CEL for some reason. It's within a normal range for the ecu to be okay with. Is it possible to be reversed when its just measuring resistance?

Fixed some good sized boost leaks while I was in the area along with a new 02 sensor and some other lighting goods.

Studiogeek

iTrader: (6)

Just in case this info helps anyone make a decision.
My car ran perfectly every single day with the TT ECU Mod.
Since I went AEM, my car has NOT run perfect on any single day and I have thrown thousands of dollars at it. I have a whole stack of parts ready to go in and more dyno time ahead.

So far, the better setup was the TT ECU. If you have a bug up your *** for a standalone like I did, go for it but it does not always wind up being an upgrade after the loads of coin you spent.

troykinsjz

Thanks mate ! Im in aus and our prices are bull****.
And my jza80 is a jdm one.
Has map sensor
Ive just repinned for coil on plug (it bypasses the ignigter)

Im going ffp so trying to figure out the iacv the jdm NA one has it

So by my understanding i have to make a flange, weld it to the ffp and add this to it

scblackout

iTrader: (2)

It was the info from Ali and your build thread that convinced me to try the TT ECU Mod in the first place. I was surprised when i saw in your thread that you were changing setups as your TT setup seemed virtually perfect. Wish you luck as your current situation doesn't sound much fun.

Studiogeek

iTrader: (6)

Yeah, it was perfect. I believe i will get there but It will take some time and effort. I should have just tried to safely max out the TT mod.

Ali SC3

iTrader: (10)

You sure you got the right ground? I think you want to use pin *4* not the other one they are different. but try swapping them even if not. your connector should be the same as the one in this picture.


Your being a JDM model is by far the easiest. if you were not going coil on plug there wouldnt be much wiring at all.

You are holding the non turbo idle valve I think. what you want is this one
off a 1uzfe, see how the bottom has a large flange and the 2 bolt holes.


Thanks for the tt ecu mod praise, I feel the same way it always seemed to work once you wired it up. I also know how you feel about the standalone, I just pulled out the tt ecu to try an aem ems I bought from a respected moderator on SF only to find out that it does not turn on my stock fuel pump ecu, something is bad on it but they never knew cause they had 12v relays installed for 3 pumps, so I have to now wire up a fuel pump relay and bypass the fuel ecu, yay extra work.

I also tried to order a 3.5 bar map sensor and they give me a connector with pins... no wires attached. So after ruining 1 of the 3 pins, I ended up ordering a wire harness on ebay, and now waiting on that. I am sure the car will not run correctly for some other reason but I wanted to give the aem another shot since I drive my car alot less now.

The TT ecu mod will always be my go to though when everything else fails or when you just have had enough standalone drama, so I have a feeling I will be back at some point. It is usually the starting point for any of my na-t projects when I need them to run properly 100% of the time.

Ali SC3

iTrader: (10)

Nice, is that the greddy style intake for the gte? did you modify it or does it line up well after you cut the runners, looks very interesting.

Yours is JDM so its already wired up to pin 62, you do not need to move it. Just unplug the na map sensor and plug in the tt map sensor. your intake temp sensor is already wired up also. unplug na ecu and plug in tt ecu, and looks like you already wired up the coils, so you should be good to go double check the coil order on some old manual diagrams its backwards for pins 52-57.

187

I only had the two pins for the temp in the maf plug. I know one was brown can't recall the other but I'll try swapping them and see if anything happens. I wouldn't be surprised if that was it being that obd2 makes everything extra fun.