M374llic4

I just got my car back today from a friends house. He is experienced at wiring, and the car had a sohc to dohc swap done. Car turns over but wont get fuel or spark. Would this be an ecu thing?

He did not really have much time to test other things as he works a lot and the car could not sit in his yard anymore because the state was going to fine him. So now I am going to take a look at some things tomorrow. What all could cause no fuel OR spark? I understand it could be 2 separate issues at once like fuel pump and ignition system, but I guess need to start at the easiest and most common things.

Thanks,

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96Turbo

sounds like the ecu isn't turning on. use a test light and make sure it is getting +12v on the pins that should have constant power, and most importantly make sure the switched power is on when you turn the key on

most likely the EGI relay isn't supplying power to your ecu to tell it to turn on. Another easy way to check is to see if the red LED on the ecu lights up when you turn on the key

lemme know what you find!

Schassis707

that problem sounds pretty hesitant, try checkin fuses, for all we know it could be a stupid fix such as that. If u find all fuses working, and the ECU does light up than start with basic tune up parts if needed(they are cheaper and whenever u are new owner of an engine it will be needed) check the ohm of the injectors and also check dizzy timing...I do want to know more of what u hear when trying to crank like the starter, injectors and other things, LMK

slidewaysmn

Check all your grounds....get a dvom/ohmeter and start checking all your sensor grounds at he sensor, so you'll need a wiring diagram, or fsm with pinouts.

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'95 Zenki
'85 Cressida

slidewaysmn

Cam angle sensor, and crank position mainly....then your main ecu.

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'95 Zenki
'85 Cressida

M374llic4

Hey guys, thanks for replys, sorry it took so long to reply. The car is not at my place so I can mess with it and test things. The ecu in fact was not turning on....when you turn the car on, it turns on when you turn the car OFF?

Any ideas?

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96Turbo

you gotta take a look at the relay labeled "EGI RELAY" under the hood. That's what turns on the ECU. I just got done rewiring mine because the ecu mysteriously stopped turning on.

If ur standing on the passenger side looking under the hood (facing fuse box) you will see a green 4 prong relay

The bottom 2 prongs are the "power side" that actually feeds power to the ecu.

The top 2 prongs are the "switch side" which is a low current signal from your ignition switch to flip the switch inside the relay and deliver power to the ecu.

It sounds like you have a problem on the switch side of the relay (since it does power up...just not when you want it to)

The switch just needs one side to ground, and the other to a switched +12v source.

What I did to fix my problem was to split the signal wire from the relay right next toit (fuel pump) so that it would switch on the ecu relay as well.

A test light or multimeter really helps with these things once you understand what the relay is trying to do

M374llic4

I am sorry, I forgot a piece of information. The ECU only works when I pop that relay off and jump the bottom 2 pins (2 closest to the fender, that are the ones closer together)

Once I do that THEN the ecu turns on when the ignition is off. I tried switching the relay to a different one, and same thing.

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M374llic4

I noticed today that when I unplug the ECU I get power on the 2 pins on the relay all the time, no matter if ignition is on or off. So I pulled out the harness to check the wiring on it.

I got it here at my desk. What things do you suggest I look for, besides obvious wires that may be mis matched? Anything in particular?

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