VVTi UZ into 1st Gen SC400 Project

[spdrcr771]

I went and dyno'd today @ MVP motorsports. My numbers are in my sig. Looks like I was correct when I thought, I had lost alittle torque w/the S&S but great on the HP. Not thread jacking just sharing HP info with your new vvt-i build. By the way have you found your shifter assembly yet. I havent been looking down here for any 98-00 SC's, but I will if your running out of options/junkyards.

 

[stevechumo]

252 rwhp is impressive considering it's not even a SC430. The torque is a little lower than the hp. Umh! If you put on cams and a good ECU that can tune timing, you'll get to 300 rwhp and probably bump up the torque.

 

[spf_lexus]

Those are good numbers. Congrats on those specs spdrcr771. I ordered my shift assembly thursday from a dismantler based out of Georgia, managed to grab it for $100 w/o the wood trim. Still need d-shaft but that should be it. I'm a little skeptical about ordering used parts out of state and if the correct part arrives i will place a 2nd order for the d-shaft. Lex found me a throttle cable and I should have that next week. Today im spending fathers day installing a stereo in my dads supercharged tacoma and installing my MB quart components into the SC.

 

[spdrcr771]

^^^^^ Damn thats cheep for the assembly w/wood too. Nice components, those ought to sound great. What size are they. I have old Infinity cappa components 5.25 mounted inside the door speaker boxes. Got the cross over & speaker to fit in there. I want to upgrade to those 6.5 adaptor plates off ebay, go w/JL zr650 component. Sounds like you got almost all the parts on there way. Your almost there.

 

[spdrcr771]

252 rwhp is impressive considering it's not even a SC430. The torque is a little lower than the hp. Umh! If you put on cams and a good ECU that can tune timing, you'll get to 300 rwhp and probably bump up the torque.

thats also in a 100 degree heat shop w/just a fan goin. so should be better in colder temp.

 

[spf_lexus]

Nice components, those ought to sound great. What size are they

I have 2 sets of MB quart Q's. 4'' up front in the stock enclosures (stock nakamichi boxes are EXTREMELY well designed) and a set of 6.5" Q's for the rear deck. I plan to make fiberglass speaker boxes that will hang down from the rear deck and into the trunk. I found that the 4" MB's with stock enclosures sounded MUCH better than the 6.5" MB's crammed into the same boxes.

 

[JBrady]

Nice numbers!

That said what RPM range was tested? The 4.3 peaks at 3400rpm at 320 in the SC430 and that rpm range may be hard to get with a dynojet and the stock tranny. The 400 tq peak is 310 at 4000rpm which is probably around the same as the 4.3 at that RPM. The headers should not have hurt the tq but you did state that you have a custom H pipe system of what? size?

I would actually like to see the torque curve with a stock Y pipe. Rock-a-lex over at CL made 282rwhp and 306rwtq on a GS400 with the headers, tune, intake and the stock Y pipe. That stock Y is a great torque maker and is not the restriction most think it is by looking at it.

 

[spdrcr771]

Well I dont think that this pic is good enough but here it is. Jbrady your right I was hitting the throttle about 3400-3500 to keep it from down shifting.

 

[spf_lexus]

So I installed the throttle cable, made sure the transmission shift arm was moved to park, all fluids topped off, timing double checked, and i my first start attempt failed. I turn the key to "start" and I get nothing from the starter.. but I can tell there is a major electrical drain because if I hold the key for a few seconds at "start" the fans will slowly start to die. This tells me the current is being directed to something but not the starter. Im thinking the security system is the cause. The 98+ has transponder keys that work with the ECU and i obviously only have the 92' key. I have been told that the security system can be bypassed by whats involved? Does the ECU need a reflash? Resistors? Maybe some wiring changes? The only electrical mods i'v done to the car is a battery relocation and my electric fan, of which I used a relay instead of simple ignition splice.

Aside from that I was thinking maybe the ECU requires a signal for the neutral safety only from the 99' shifter assembly and not the 92 shifter assembly.

The only person I have heard of that has sucessfully done this swap used every single part off a 98' including the transponder key so it doesnt really help me much.

 

[spf_lexus]

Can anyone post a wiring diagram of the 1992 sc400 mechanical ignition switch? I need to identify the "start" position positive wire so I can bypass it to the starter relay.

 

[cribbj]

Here you go Sean. It's a diagram for a '93, but it should be the same.

If you're looking for current drain, first confirm that's the problem by putting a clamp on DC ammeter on the main battery cable. If you have more than a few milliamps without the key in the ignition, then you definitely have a current drain/leak somewhere.

Then start pulling fuses until you find the one(s) that cause the current to drop.

If you just want to see if the car will turnover manually, I'd suggest pulling the starter relay altogether, then put a momentary contact start switch, or an alligator jumper on pins 3 & 5 of the relay socket as shown on the attached diagram. If you use a jumper, just be ready for the engine to turn over as soon as you've jumped these contacts. Regardless whether it turns over this way or not, it's not going to start until the master fuel injection relay gets energised by the ECU, and there are a number of preconditions necessary to make that happen.

BTW, be very careful where you put your start switch, or jumper. DO NOT short out pins 1 & 2, as these are the coil pins. A couple of Supra buddies got mixed up between 1 & 2 and 3 & 5, and accidentally shorted 1 & 2 and it fried the ECU.

 

[spf_lexus]

Thanks for the fast reply + diagram John. I was hoping to keep everything as is, just jump the starter relay to the start position wire instead of doing this inside the relay. This way I dont have to worry about the close proximity to the other relay pins and I can rely on my key for security reasons. Is AM1 the "ON" position and AM2 the "start" key position?

 

[spf_lexus]

Cribbj

If I can get the starter firing up, what will hold the ECU back from starting as well? I didn't think swapping setups would be so in depth.


What if I bought a used body harness for the 99 sc400? Its the only part thats not 1998 on this car.

 

[cribbj]

Thanks for the fast reply + diagram John. I was hoping to keep everything as is, just jump the starter relay to the start position wire instead of doing this inside the relay. This way I dont have to worry about the close proximity to the other relay pins and I can rely on my key for security reasons. Is AM1 the "ON" position and AM2 the "start" key position?

The starter switch has two separate stacks (think of it as two separate rotary switches on a common shaft). One is AM1 which is for the starter circuit itself, and the other is AM2 which powers most of the rest of the engine and the accessories in the car. Manufacturers do it this way so that most of the accessory electronics are "not" powered up in the "Start" position, to avoid damage during the huge current surge of starting, and its resulting voltage drop, sometimes down to 8-10 volts.

BTW, that diagram doesn't show all the contacts on the starter switch; only the ones that concern the starting & ignition circuit. If you want to see them all, PM me your email and I'll send you the Overall Electrical diagram, which shows everything. It's nearly a megabyte in size, which is too large to post here.

 

[cribbj]

Cribbj

If I can get the starter firing up, what will hold the ECU back from starting as well? I didn't think swapping setups would be so in depth.


What if I bought a used body harness for the 99 sc400? Its the only part thats not 1998 on this car.

It can be a bit intimidating if you've never worked through the logic of how all this works. But just slog your way through it, and keep studying the schematics, and it'll finally come to you. That, and ringing it all out is a great way to learn.

The ECU has to be happy for the start conditions, and once it is, it will send a +12v MREL signal out on pin 24A that energises the EFI Main Relay. Once this relay is energised, all the injectors get a constant +12v on one side, and the ECU provides a return when it's time to fire.

So one thing you can check, after you've sorted out your current drain problem, is whether the EFI Main Relay is pulling in when the engine is cranking. If it's not, then the ECU isn't happy.

 

[spf_lexus]

The drain I am referring to is only under "starting key position" and I get a very slight dimming of cluster lights and an audible change to the electric fan. All current comes back to both when I drop from "start" to "ON". I am thinking the starter is grounding off the amperage that the starter normally uses because of a transponder issue/security circuit.


Sorry about drilling the same Q's over and over but what current am I looking for at the EFI main relay? And at what pin?

Thanks

 

[sideshow]

its most prob a black wire or black/white
test it with test light
99& of toyotas have black/white wire for start sig to inhibitor
and black wire from the inhibitor to starter relay

what wiring have u swapped
maybe u underestimated the enormaty of wiring it properly
u need to wire the vvvti harness to match the 92 harness
and if the vvti ecu has security
u should be able to tell this if the immobiliser ecu wiring is in the ecu wiring
anyway there is no way to bypass security on a toyota so basically if u have security u have to do this as i know of no other way around it

u need a matching set of ecu and immobiliser ecu and transponder key and transpionder key reader i have done about 20 late model toyota deisel motos with security and i have to wire everythbing to do with security

if u have missing bits then yr stuffed ther eis ways around it but its expensive
by the time u buy new immob ecu and key reader and key

u might as well go by an aftermarket ecu

 

[sideshow]

wiring is not a easy as everyone on here makes it sound like heheheheh

 

[Lextreme II]

Here you go.. http://www.lextreme.com/dx-starter.html

Get the power from the KEY (START POSITION) and jump it to the relay... see link above......

 

[spf_lexus]

Well after doing some research on getting this up and running its looking like this one might be another possible failed project like LS470. Even if I get the starter to crank, I need to match transpoonder keys as well as the body control units to run the transmission and this means the entire body harness and then I need to pray all this cash is going to lead to a running engine.


My only option is my adaptronic standalone and even then the e420c cant handle VVTi functions so im totally screwed. Best bet is to buy an AEM full standalone or the adaptronic super ecu and start all over. This is a major major letdown.



If anyone has specific knowledge on how to bypass the entire system i'm all ears.