Basic Engine Conversion Question For The Is200

[evilonion.com]

Hi all, i have a bog standard is200 which generally i really like.

Handles well, got a 'bit' of poke but im just used to more power.

I went from having an aristo 3.0TT to the is200 2.0 n/a and im getting bored.

I've been reading so many threads on engine conversions but many skip past the finer details, i know we all like our projects to be unique but at the same time its the small details that let others advance into engine conversions also.

I looked into the LS400 v8 conversion but it just seems to much work, fitting it, sourcing the adapters, getting the manual box, then struggling to wire everything in.

A few members of a drift forum pointed me in the direction of the 1uzgte which is cheap enough and available in manual so fitting should be a lot easier... set of custom mounts, custom prop etc etc

but each and every conversion comes to a bit of a wall... wiring.... everyone tells me the is200 runs an ecu called multiplexing, which runs everything, and that its a nightmare to work with. If i go with a standalone ecu upgrade such as link etc, does this remove the need for the origional ecu altogether? or do i have to link the two together?

My only reason for asking is several builds people have come up with the questiona about getting the standalone ecu to work with the multiplexing etc.

if i can get past the basic wiring questions then it will make everything a lot easier as i can source the parts quite easily, and fitting things isnt much of a hassle. I have local copmpanies that can fabricate thiings and im no begginer with a spanner, but unfortunatly wiring isnt my forte...

i would however like to push into having a larger turbo engine in the is200.

Sadly if i cant source the information im likely going to have to sell and buy a different turbo car, but id prefere not to as ive become quite attached to the is200 :D

[sparkystav]

I run a link on my engine.

and yes you still need the standard ecu running as well to run the speedo, fuel gauge, aircon, and pretty much everything else.

My mappper fitted it and i'll be perfectly honest ive no idea how he did it but he's a bloody genius because the fuel gauge and everything works perfectly. unlike other conversions in the past using standalone ecus

[evilonion.com]

yeah i was reading your thread as well mate.

ive been signed up here ages, just not stopped reading lol.

so basically i will need to trick the standard ecu into thinking the engine is still running in order to get an accurate reading from thinngs? if anyone knows... can this be done by adding a voltage feed to the ecu to make it seem like the origional engine is there?

If i can figure out how to keep the original ecu running accuratly then ill be able to fit pretty much any engine.

[sparkystav]

Yeah thats right mate, figure it out and you can fit any engine with the right engineering. how to do it though is a complete mystery to me.

[ibby]

yeah i was reading your thread as well mate.

ive been signed up here ages, just not stopped reading lol.

so basically i will need to trick the standard ecu into thinking the engine is still running in order to get an accurate reading from thinngs? if anyone knows... can this be done by adding a voltage feed to the ecu to make it seem like the origional engine is there?

If i can figure out how to keep the original ecu running accuratly then ill be able to fit pretty much any engine.

Its not just as simple adding voltage into the ecu on the wires,

the voltage maybe a pulse, ie from the crank sensor.

Hence why sparky has a secondary ecu installed which does the engine mangment, I am near 100% sure that the guy who wired his engine up had to feed the lexus ecu with someinformation, just to keep it quite

If you remove the Lexus ecu, then it will require you to find an aftermarket ecu which does all the correct functions, - I dont know of a multiplexing ecu that has this capability (the last time I looked was about 3 years ago).

Personally, what ever engine conversion you go down the line of, it could be worth paying someone who has prior knowledge of the wiring, rather then doing a botch job which probably will cost you more to get right in the first place.

Ovbiously if you dont want your speedo, and other functions, leave it disconnected

[evilonion.com]

ok i see, well im planning to keep the origional ecu there so that i can still run the electrics in the car...

so basically i would need to get the sensors from the 1jz engine to the lexus ecu wired in so the right signals etc are sent?

I have a sparky that can work on the project, id just like to educate myself as much as possible, ive learnt quite a bit the last couple of years about mechanics and im quite confident when it comes to working on the main parts of the car. i striped and rebuilt my 200sx and worked on various other projects over the years, just never got my head around electrics... which is needed with the lexus lol.

is there any information on the web about what the ecu controls on the is200?

ive been told that just about everything electrical on the is runs through the ecu...

[Yeldarb]

The only real nightmare on my conversion was getting the rev counter to work properly, the Lex is 6cyl and my engine is 4 cyl so it was under reading by 1/3. Apart from that they sorted out the electrics without much of a problem. Other things have had to be modified post completion but everything is fine now!!