No 5volts from ECU

[steveL]

Have just recently wired up my 1UZ using the LS400 wiring diagrams off lextreme. My engine is a 92 acording to the plug leads and some of the colours don't match but most of the pinouts are correct, I think. It has the 32/28/22/16 pin ECU.

The problem I have is there is no 5 volts available from the Vc pin (for the TPS or AFM)

Has anyone had this problem before, perhaps the diagrams are a little different for the earlier models and I need and extra power or ground connection?

 

[steveL]

I guess what I am asking is, does any one have alternative wiring diagrams for the 4 plug 32/28/22/16 ECU? any help would be great! thanks

 

[clint]

dunno if this is any help to you, mine is a 1990, different pin configuration, 26/16/22/26. but it needed 2 ign switched 12v+ feeds, and one pemanent 12v+ for the ecu memory.

 

[steveL]

Thanks Clint, I suspect that will be the case with mine also. The diagrams from lextreme for the 96 LS400 are close but different to my earlier 1992 engine. Has anyone wired up a 1992 engine with the 32/28/22/16 pin ecu?

 

[madmont]

I can email you diagrams for LS400

 

[gloverman]

I have done one and there where a few pins that were different from the early ones. Not sure if I still have diagrams. Is the ECU switching the main relay ok? Cheers

 

[steveL]

Hi Madmont, if you could email me the diagrams to: [email protected] that would be really great! thanks alot.

 

[steveL]

Hey Gloverman, I have used the 96 diagrams and I would say there where about a dozen pins that where different. the only problem is at the moment I don't know what the different pins should be connected to. When I switch the ignition on, I get 650mV from the VC terminal and no relays are being switched on cranking or otherwise?

 

[steveL]

Hi Thanks alot for the diagrams, however after inspection they are incorrect for my ECU. It seams I have a 1992 selsor engine, this uses the 34P, 22P, 16P and 28P ECU. anyone out there have the correct diagrams??

 

[sideshow]

if yr ecu is turning on then u should have the 5 volts

unless u got a cut harness then u need to double check all yr wiring

but if the ecu is powered up then u should have the 5 v
as the 5v circuit doesnt get touched if u have an uncut harness

so its either u havnt powered ecu correctly or wrong ecu or fried ecu

 

[steveL]

Hi Sideshow, you are quite right about my three options.
Wrong ECU: I believe the ECU is correct as it came with the engine and uncut loom and the part number matches the type and year of engine.

Fried ECU: it could quite well be, I don't know this as I have yet to locate a correct wiring diagram to determine if I have wired all the powers and grounds.

Havnt powered ecu correctly:I believe this is the most likely cause but until I locate the correct diagram or ECU pinout I am having trouble verifying this.

Can you help with a ECU pin out?

 

[sideshow]

sorry i stopped giving anyting out as they always end up on here
and due to afew things said on forums
all i can do is offer to wire up yr loom properly if u send it to me

i help out abit it all depends how much work i get thru forums
which is not much these days but diagrams i never hand out anyway they are my own hand writed ones but even so there are afew different types
do u have the 3rd and 4th plug on the harness which goes to the dash loom
this is most important to finding out which diagrams u need

 

[steveL]

Yes I have a complete loom that has the three plugs for the ECU I also sourced the 4th connector with a length of loom attached.

I have had toyota NZ verify that the ECU is from a 92 celsior, it has the 34,26,22,16 pin ECU #89661-50171. I gather this is a UCF11. It is similar to the 96 LS400 in that it uses the same plugs however this has paired injection and runs a karmen votex AFM as apposed to the hotair from the 96LS400.

I guess all I really need to know is the power and ground connections, if you or anyone else would be will to pass these on that would be very helpful!

 

[sideshow]

the prob u might run into is with the 4th plug since it didnt come with the ecu
how do u know if its right
so u cant go by wire colours

when i run into those probs i either find a matching ecu and loom at sss
since i work there or try power things up one at a time and find which wires do what this takes time and u need to know how the ecu all works

 

[steveL]

All the connectors are the same colour as the PCB header on the ECU. I don't need to know the colours of the wires just what pins go where. I have a fair idea of how the ecu operates just need to know power and ground pins.

Once I have the ECU powered up it will not be difficult to workout what goes where as I have traced most of the wires to sensors,actuators etc and have a fair idea of how the ecu works.