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4G63 Throttle Body question.

Foetoid

Member
Joined
Jan 9, 2017
Messages
5
Location
Nambour
Hey everyone, longtime reader from Qld, Australia, first time poster. I have been extraordinarily lucky in my vehicular endeavors recently. I managed to aquire basically my dream car for only $2500. It's a 1985 Mitsubishi Cordia GSR, 1G 4G63 DOHC 2L turbo swap, front-mount cooler, Microtech LTX-8 ECU, retrimmed interior, Ford Blood Orange, its beautiful. But...it also makes 45hp, at the wheels.

That's not a typo. The guy who put it on the dyno said it's running way too rich and the timing is so far out it's hilarious. But before i can get a tune done, i need to replace the throttle body i broke. I over-tightened the idle control switch and broke the thread off the side of it. Finding one of these TB, especially off the 1990 HG Galant with the built-in unremoveable FIAV, is basically impossible. I've searched online and every wreckers i can find within 300km, and after speaking with the guy up at a local performance shop who himself loves and specializes in the 4G63, he recommended getting an aftermarket replacement.

After some research i stumbled accross the S90 Pro TB: click

Now given my engine is the Cyclone intake with the 60mm TB, should this one bolt straight on? I can't take the FIAV off my current one so i've been told getting a deletion plate to remove it completely is ideal. It wasn't plugged in anyway thanks likely to the aftermarket ECU. Does this sound right?

My current idle adjusting screw thingy (serious WTF is it called) that no longer screws into the side of the throttle body had a little tag on the end for a wire that went back into the firewall. I assume this was some sort of closed-throttle sensor for the ECU. This new one i'm looking to get doesn't have that is that ok?

With this new TB installed, does the ECU need a retune or should it work well as a simple bolt-on replacement?

Prepare for incoming car porn pics. Some of these you may want to hide your children or those sensitive to awful power curves and glowing headers. Enjoy!









 

89Mirageman

Well-known member
Joined
Jul 5, 2006
Messages
2,502
Location
Stantonsburg, NC
I might be wrong so maybe some others can chime in. Pretty sure you can get a 2g dsm TPS since its a 4 wire unit with the closed throttle switch built in and just reuse that TB.
 

transparentdsm

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Joined
Jul 27, 2011
Messages
3,690
Location
Cherry Hill, NJ
if your going to tune it, get DSMlink and just simulate the idle switch through the TPS.. ive done it a bunch. makes things easy when you delete the FIAV and the IAC, all those wires can disappear. this is also how it needs to be done to run the S90 TB you speak of.
 
Last edited:

Foetoid

Member
Joined
Jan 9, 2017
Messages
5
Location
Nambour
Ahhh i see. So what exactly is DSMLink? And does this mean i need the 2G TPS as previously mentioned? Mine's definitely a 3-wire TPS so that solves that mystery.

Does this mean that realistically i can just get the 2G TPS and reuse my old TB? And if so, how do i get it to work with the 2G TPS?

Can i simply take the 3 wires from my current TPS and the wire that went from the idle switch and put them into a 4-wire 2G TPS?

And will DSMLink work with my Microtech LTX-8? Or will the Microtech suffice alone?
 
Last edited:

AllanL

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Joined
Aug 4, 2008
Messages
294
Location
NV
Quote:

Does this mean that realistically i can just get the 2G TPS and reuse my old TB? And if so, how do i get it to work with the 2G TPS?

Can i simply take the 3 wires from my current TPS and the wire that went from the idle switch and put them into a 4-wire 2G TPS?




Basically yes.

But you need to replace the 1G idle swtch with some kind of bolt or stopper. Without this stopper, the throttle plate is binding to the housing.

This is why the 1G switch adjustment procedure says to tighten the idle switch 15/16" more after continuity of the switch to ground is present.

The 15/16" adjustment is to prevent the plate from binding to the housing

click

click

click
 
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Foetoid

Member
Joined
Jan 9, 2017
Messages
5
Location
Nambour
Does the plug that went into the 1G TPS have room for me to somehow insert the idle switch wire so it'll just plug straight in?
 

bazeng

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Joined
Feb 6, 2003
Messages
2,520
Location
Melbourne, Australia
Quoting Foetoid:
Ahhh i see. So what exactly is DSMLink? And does this mean i need the 2G TPS as previously mentioned? Mine's definitely a 3-wire TPS so that solves that mystery.

Does this mean that realistically i can just get the 2G TPS and reuse my old TB? And if so, how do i get it to work with the 2G TPS?

Can i simply take the 3 wires from my current TPS and the wire that went from the idle switch and put them into a 4-wire 2G TPS?

And will DSMLink work with my Microtech LTX-8? Or will the Microtech suffice alone?





A few things to note here.
1. Microfiche ltx8. Unsure if you know but from memory, the microtech ecu's don't have enough outputs to support a Mitsubishi idle controller.. This means your idle is either running off a single non factory idle valve or no idle control at all.

Mitsu use 3 methods of idle control. 1 is the Base idle screw. 2 is the cold start fast idle (wax). 3 is the stepper motor.

I would say you don't have 3. Only 1 and 2. 2 pending your water line routing. If connected to your heater hose lines then you probably have it still. Unless it has been blocked with a plate.

So, your idle stop is also probably not used if you have a microtech. Microtech would be using your tps only.

I'm not sure what function the stock ecu activates with the Idle switch. I know the automatic tcu needs this input for some reason. Anybody know?

So, the s90 will not be your solution. Whatever was causing your tuning issues is not your tb. As for the tuning, if you have ign timing issues and your tuner cannot fix it, then what is the tuners purpose?

Unless you were only paying for a dyno run and the tuner had no time...

If you need a tb. Message me. I'm in Mel and have a few.
 

bazeng

Well-known member
Joined
Feb 6, 2003
Messages
2,520
Location
Melbourne, Australia
Oh, and the s90 tb requires enlarging your intake manifold tb hole to match the s90 bore size.

Will also require recalibration of your tps. The s90 also lacks the Idle stop via sw. Must be from tps as mentioned above. And your tb elbow you currently have needs to be modified. It takes a direct hose instead of the mitsu tb elbow.
 
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