Wiring Diagrams for LS400 Engine swaps

[Tonyd]

Guys,

As some of you may know I'm building two Cobra replicas with LS400's providing engines and gearboxes.

Having equipped myself with the excellent wiring diagrams available through this site and buoyed up by the sage advice and encouragement of Lextreme members I went forth into the freezing cold garage this evening to see if I can make sense of the diagrams and start to wire one of the beauties up in the completed chassis in which it sits.

However it quickly became apparent that the two engines I have ( one 1990 and the other 1993) have different plug and pin arrangements on their respective ECU's both of which in turn show no relation to the wiring diagrams I already have.

The 1990 ECU has sockets with two rows of pins, three sockets grouped together and then one seperate socket, whilst the 1993 ECU has smaller square sockets, all four in one row with four rows of pins in each socket. I did take some piccies but I need to shrink the file size.

The 90 ECU pin configueration is 26 16 22 26, whilst the 93 ECU has 34 22 16 28. Has anyone got the wiring diagrams that relate to the ECU's I have? If so copies of them would come in very useful indeed.

Also if I ask my Lexus dealer quoting the ECU part and serial number will they be able to give me the wiring diagram for the exact cars my engine and boxes came from? ( I do doubt this, bearing in mind they were unable to date the engines from the engine number).

I have the engine and gearbox loom complete as it comes through the bulkhead with the plugs on it. I do not however have the fourth plug ( 26 pin in the 90 ECU and 28 pin in the 93 ECU) that was fitted from the cabin side of the vehicle. Can anyone tell me what inputs I need to put into this plug ( I'm planning on getting said plug from a friendly Lexus breakers ).

I bought the engines and gearboxes complete and unsplit from the breakers but they were already out of the vehicles so I hope I got most of whats needed to run the ECU's barring the fourth plug.

Any help gratefully received....I'm now off to get a hot toddy as my gas heater in the garage broke today as well......

Cheers,

Tony

 

[MacroP]

Guys,



I have the engine and gearbox loom complete as it comes through the bulkhead with the plugs on it. I do not however have the fourth plug ( 26 pin in the 90 ECU and 28 pin in the 93 ECU) that was fitted from the cabin side of the vehicle. Can anyone tell me what inputs I need to put into this plug ( I'm planning on getting said plug from a friendly Lexus breakers ).

Cheers,

Tony

These non engine plugs will carry info from the dash cluster(like speed) also they carry the ignition and starting signals, fuel pump control plus others. So yeah, they are very important.
Did the engine come out of local UK LS400's or did they come from import Celsiors(Japanese LS400). Give me the part numbers off the ECU's also from the trannies too. The transmission has a small plate at the rear on the right side. It will be something like 35000-xxxxx or so. I can then tell you the approximate year and model they came from.

 

[Tonyd]

Wiring Issues.

Hi Macro,

The engines and boxes came from UK reg'd, specification and supplied LS400's, so getting the ages and market specs isnt a problem. I have tried to correlate the wiring codes and the pins off each ECu without success, there are 15 wires in one and 17 wires in the other ( ie no colours shared) that do not match between both the ECU's and engine plugs and therefore I think there must have been a change in the wiring loom between 90 and 93 that coincided with the change in ECU plug configeration.

For anyone whose interested the code numbers on the ECU's are

1990 ECU part number 89661- 50050 175000-2933 12v FG 0-388

1993 ECU part number 89661-50160 175000-5213 12v FV 0-564

Again any help or clarification on the wiring issues would be greatly appreciated.

Happy Xmas and a Great New Year btw

Cheers,

Tony

 

[Cobber]

Tonyd,

I am at about the same stage, I have what I belive to be a 1990 ls400. I also have the fourth plug missing but I think it mainly goes to the ABS and traction ECU. The following wiring pdf's 1uzfe EEC/ECU parts 1 & 2 from the tech section seem to match my wiring but I have a different ECU part number to you.

Are you running the Auto?

I am running a manual box so I will need to trick the neutral switch.

No problems with heating the shed here although an airconditioner may be a good addition.

 

[JZK25]

There is a battery power and fuel pump control in that plug that you will need. They are fairly generic *** plugs so you could get one from another vehicle.

 

[madmont]

If you would like me to email you a scan from the manual of the 1990 ls400 ecu and ect wiring diagrams pm me

 

[sideshow]

hey cobber

the 4th plug powers up the ecu and does other stuff for auto

its all bullshit about tricking the ecu for when running auto

i have never come across this and ive done 20 to 30 1uzs

i have shitloads of plugs lying around to suit nearly every toyota ecu

ill be in perth in a month or so for work

 

[Tonyd]

Wiring ECu's

Tonyd,

I am at about the same stage, I have what I belive to be a 1990 ls400. I also have the fourth plug missing but I think it mainly goes to the ABS and traction ECU. The following wiring pdf's 1uzfe EEC/ECU parts 1 & 2 from the tech section seem to match my wiring but I have a different ECU part number to you.

Are you running the Auto?

I am running a manual box so I will need to trick the neutral switch.

No problems with heating the shed here although an airconditioner may be a good addition.

Hi Cobber,

Yes it looks like yours is a 1990 LS 400 as it looks just like one of the ECus I've got which is from a 1990 LS400 over here. I see that you are missing the 4th plug also, so as it seems to be important I'll get if from a Lexus breaker over here.

I'm running the standard auto box in both Cobras for the moment so hopefully the wiring should be relatively straightforward once I get my head around the issues.

Just got back from Xmas away and theres snow on the ground and its just below freezing outside so I wont be in the garage for a day or so......must get that gas fired blower going again !!

Cheers,

Tony

 

[Cobber]

Thanks for the input guys,

I hope we all had a good Christmas break and ate way too much of everything.

I can see now that pin 26 on the fourth plug is BATT and pin 6 is FPR. So that's all I need to use on that plug?

"its all bullshit about tricking the ecu for when running auto"

Sideshow did you mean manual? I'm confused now, it does'nt take much.

As for tricking the ECU I belive it just needs to have a power signal from the ignition to pin 14 NSW 0f the 22 pin plug?
Please tell me I'm on the right track.

Sideshow when you are in Perth call in for a cold beer if you have time.

If anyone has a spare 26 pin plug I would be interestd.

 

[sideshow]

yes for manuals

nsw is a start signal to the ecu before the inhibitor

i have never had to trick the ecu for anything

and no one has ever proven to me that u need to trick the ecu

 

[Cobber]

OK,

Pencil paper and a 6 pack last night and I extrapolated this out of the excelent work done for the crown by Zuffen, Kdog, 34ford and thegiantomato.

For the LS 400 / Celsior ECU Manual transmission & single speed fuel pump set up the wires requred to be used are the following.

Plug 1 (26 pin)
E01 Pin 13
E02 Pin 26

Plug 2 (16 Pin)
None

Plug 3 (22 Pin)
IGN+ Pin 1
+B Pin 12
+B1 Pin13
NSW Pin 14
E2 Pin 18
E1 Pin 22

Plug 4 (26 Pin)
M-REL Pin 4
W Engine check light Pin 5
FPR Pin 6
BATT+ Pin 26

Two things I am not sure I have correct are the engine check light and the NSW. I bow to the knowledgable others to check my scribble and let me know where I have gone wrong with my homework.

 

[MacroP]

At first glance, to me, I see a few little dramas. The LS400 setup is very similar to the Soarer setup where as the Crown ECU connections quite abit bit.

The NSW on the tranny is wired between a starter fuse and the starter relay control. The starter fuse is fed from the main engine fuse via the ignition barrel(starting contacts). The NSW input to the ECU is tapped into the connection between the actual Neutral Start Switch and the starter relay(control). I guess this is to tell the ECU that the tranny is in neutral or park. By bridging the actual switch does two things - It allows the engine to be cranked anytime and tells the ECU the tranny is in park or neutral.

There should also be a STA signal (to the ECU) from the starter relay to tell the ECU that the engine is cranking.

The FPR signal on the LS400/SC400 should not exist. Instead there is FPC(fuel pump control) which is an output and DI(?) which I think is an input. These engine have a fuel pump ECU( hence no relay and low speed resistor) where as, I think, the crown setup does not. I suspect the crown uses the older Toyota setup with the fuel pump running all the time(with resistor is series) and a fuel pump relay(driven form the FPR output) that bypasses the resistor to allow the fuel pump to run at full speed.

The FPC output is 3 stage voltage output (between 1 and 5 volts i think)from the engine ECU to the fuel ECU to give a 3 speed range to the pump. There's a Toyota document floating around showing how it works. The DI signal is feedback to the engine ECU so it knows the fuel ECU is actually working. I think the easist way to setup this up is to have the pump running
all the time the ignition is on, via a relay of course. Not the safest way but the easiest.

As for the Check engine lamp, it is wired between the meter fuse and the ECU input which is labelled on the ECU as 'W'. You'll need to find where that input is though.

This webpage has a wealth of info on how Toyota engine systems work. The pages here cover plenty of systems that the 1UZ has.

http://www.autoshop101.com/autoshop15.html

Non of this might be correct though

EDIT: You'll also need to find a way to power up the injector(via a fuse 30A?) and the ignition (igniters and coils)componets. The ECU does not supply power to these items it merely controls them. The feeds for these are in the engine bay on the engine loom. On my Soarer loom the feed for the injectors and igntion system is to a 8 pin connector on the loom. This connector is roughly where the igniter and starter motor(and NSW) connectors are (front LHS). Maybe in a different positon for the LS400 loom though.

 

[sideshow]

i sell tachometric relays that will work of the small toyota tacho signal

these can be used to run the fuel pump when there is an rpm signal just incase

you have a bad accident and the fuel pump stays running

the ones i buy are ones fitted to alot of race cars

 

[MacroP]

i sell tachometric relays that will work of the small toyota tacho signal

these can be used to run the fuel pump when there is an rpm signal just incase

you have a bad accident and the fuel pump stays running

the ones i buy are ones fitted to alot of race cars

That's awesome, I been wondering if such an item exists. If it's off the tacho signal then I guess I could mount one of these above the glovebox near my fuel pump relay(kich panel) as the tacho signal goes past here too(to the cluster).

Could you PM me a price and availability of said item please.

EDIT: Is this the type relay that causes the fuel pump to run(and prime the fuel system) for a couple of seconds when the igntion key is first turned on(without starting) in some cars, namely in my old VQ(5L EFI) statesman?.

 

[Cobber]

Fuel pump
The drawings I have for the LS 400 / Celsior show a 2 stage fuel pump fed from FPR Pin 6 plug 4. There is an FC on the ECU that appears to control the slow speed for the fuel pump.
There must be two versions? one with two speed and one with a seperate ecu for the fuel pump?

I do like the idea of the tacho switched relay to control the fuel pump.

STA is this an input or an output? It looks to me that this goes to the cold start injector? Does it also need a signal from the starter relay trigger wire from the ignition switch?
Please confirm.

Engine check light It looks like the Engine check light is in the right place.
What faults trigger this light?

NSW Pin 14 plug 3 needs to get +12v all the time the ignition is on to simulate neutral position? if so it looks like its in the right place.
Please confirm.

I don't want to let all the smoke out of the box because as we all know when you let the smoke out you can't put it back in.

 

[Cobber]

Ok, more beer and it is all starting to make sense.
Correct me if I am wrong and I'm sure you will.

STA is an input to the ECU from the ignition start position to tell the ECU that the engine is being cranked and also trips the cold start injector time delay relay?

Stuff the FCR & FC on the ECU and use the master relay to pull in the fuel relay. As above I do like the idea of the tacho controled relay and will be getting one of those little buggers when it's going.

NSW Pin 14 plug 3 needs to get +12v all the time the ignition is on to simulate neutral position? if so it looks like its in the right place.
Please confirm.

Thanks for the link below MacroP I don't need to ask about the charge circuit now.

Below is modified drawing for marking.

 

[MacroP]

Looks like you'rer on a winner there.

I found some info today at work about those fuel pump tacho relays. Bosch make a unit that is triggered from the switched negative of the coil. Its a seven pin device that has similar terminal numbering to a standard relay(30,85 etc etc) but with the addition of a few extra terminals for the rpm input, constant power and ignition +. It came standard on 6cyl VK commodores with EFI(Bosch J-Tronic EFI) so should be found easily. The relay can drive the fuel pump directly apparently though a another high current relay couldn't hurt. It turns the pump on for a few seconds(ign on, no start) to prime the fuel and then opens again until it sees a rpm input whilst cranking. It might not work with the tacho signal output from the 1UZ igniter but should work off the coil output from the igniter.

Sideshow mentioned his unit works from the tacho signal, so it's probably a different unit altogether. The Bosch unit is around 100 bucks brand new though there would be plenty of wrecking VK's around.

 

[sideshow]

my unit does exactly the same thing
when it gets ignition it turns on pump for 2 seconds

then when it gets an rpm signal it runs the pump

my unit only costs 50 bucks new

when i said tacho signal well its an rpm signal from any source

the holden ones might need a strong rpm signal since it gets it from the neg coil

i have afew different types of these relays

one that can handle a weak signal like the ig- signal on a toyota

or ones that can handle a strong signal from the neg coil

 

[Tonyd]

Hi Guys,

Thanks for the info. I'll have to extrapolate the info above for the 1990 engine and ECU ( many thanks Cobber) and match it to the 1993 engine and ECU I've installed into the first Cobra chassis. I know its a bit strange using the younger engine of the two first but it was the easiest to throw into the chassis.

I'm sure that with a few hours poring over the circuit diagrams with the soldering iron and heatshrink wire wrap I'll be able to get the engines and gearboxes working correctly.

Any more tips or thoughts please keep 'em coming.

Cheers,

Tony

 

[Cobber]

If you have the wiring diagrams the pin identifiers should match up I gues.

Drink plenty of beer.