Electrical Q's

[johntramp]

Hey, I am wiring up a new engine, and have been getting some info from this thread, viewtopic.php?t=44442&start=20 but instead of hijacking it anymore I decided to start a separate one.

I am trying to wire up the starter relay at the moment, but the coil from the relay does not have an earth. Should this go directly to the ground? Because the wire which it connects to from the fuse box goes off into the loom somewhere and it has a very weak ground. Should I splice that wire to the ground?

Cheers

[johntramp]

ok, maybe i didnt make myself too clear.

This is how a starter relay works, right?



In my car the coil does not have a ground connected to it. Is there any reason I should not soilder a wire to the bottom of the fuse box and connect one to it?

Cheers

[wde_bdy]

If that is the starter solenoid, it earths through the body of the starter so check you have enough earths to the engine block and gearbox. If it has a separate relay then it will need to be earthed, no need to go to the fuse box just wire to any part of the body.

Callum

[johntramp]

This is the relay which is in the fuse box, switching from the ignition to the starter solenoid.

I drew this picture so it could be wrong... I want to know if what I think is right actually is.

thanks

[wde_bdy]

Generally there won't be a relay, thats what the starter solenoid is for. What model car?

Callum

[johntramp]

20v 4age -> AE85.

There is a relay in the fuse box and there is also the starter solenoid.

[johntramp]

Q2/ Should BATT and B+ be running off the same +12v ?

Does it matter if they are?

[sergei]

BATT should run constant 12v, usually through 15A fuse, it is there for ECU memory.
B+ should be switched on when ignition key is on the "ON" position.

[sergei]

Generally starters are wired directly, but some times when the clutch start switch is present they have relay... Can you measure resistance of the earth pin you are talking about when somebody (or brick) is pressing in the clutch? Thats if you have that button...

[johntramp]

There is no clutch button (well not in my car anyway).

I am putting a blacktop 4age (ae111) into my AE85. I am using the AE111 engine loom/fusebox etc. but the starter motor I am using is from the 3au which the car came with, because I am using a RWD gearbox/flywheel etc.

Does it not sound right that the AE111 comes with a relay for the starter motor in the fuse box? - A big purple one.

So from what I have read there is no harm in running the STA wire from the ignition straight to the starter motor, aswell as to the ECU?


Hopefully if all goes well I will be able to start the car tomorrow

Cheers

[sergei]

I don't remember any starter relays on blacktops, but I could be wrong,I wired one into AE82 a year ago and reused AE82 fuse box, so there was no relay, I just fed STA to ECU and to starter, if there was relay what is the point of having fat wires in first place?

[johntramp]

well I wired the STA to the ecu and to the starter motor. The car cranks but does not fire. I have not checked for spark yet but I assume there isn't. Where abouts should I be looking to find the problem? Cheers

[matt dunn]

I don't remember any starter relays on blacktops, but I could be wrong,I wired one into AE82 a year ago and reused AE82 fuse box, so there was no relay, I just fed STA to ECU and to starter, if there was relay what is the point of having fat wires in first place?

the silver top AE101's have them, and pretty sure the GZE's had them too.

I would guess that the blacktop also have them.

[sergei]

I went through wiring diagrams of all AE8x-9x and ST16x-18x and only ST185(Export) had starter relay, which was wired in series with Circuit open relay and connected to STA pin in ECU. So according to this you should get the ~100Ohm (second coil of circuit opening relay). But what I found interested that in parallel of the second coil on ciruit opening relay was connected the clutch switch. In this case STA input on ECU should be low active.

[sergei]

Yes AE101 has starter relay (grey, on left strut). But when I was doing AE111 20v into AE82, we took the whole lot off the AE111, everything off the firewall and there was no starter relay, also when I did splice the AE111 loom with AE82 loom it did not had starter relay either (otherwise I would remeber it wiring or chucking away if it was present on AE111 loom, unless it was in the fuse box).

[johntramp]

from the 4A-GE 20Valve Black Top Manual









Q. What is an H-Fuse ?

From the same manual this is what it is suggesting with my EFI problems.
"Check H-fuse, fuse, fusible link and ignition switch"

[johntramp]

ok, so far I have checked everything on this EFI Check Procedure chart.
The only thing which failed is the voltage at the injectors' pins, which all had 0 volts.

BTW, I am wiring a blacktop 4age into an AE85.



So this is FI-22;



I have checked the Main FL and the 15A AM2 fuse and they are both working fine. So then it goes on to the ignition switch. Is there something I should have spliced from there aswell as STA into the loom to connect it to the injectors?

Otherwise where should I be looking next to get this engine running?

Cheers

[sergei]

check on the loom if you have any unconnected Black-Red wires, it seems to me that your injectors do not have power feedings them.
If you find the disconnected Black-Red wire, with power and loom disconneted from ECU (and fuse box) measure resistance between injector wires and that wire, you should get 13Ohm on every injector.
As far as I remeber there are 2 plugs sticking out on ECU side besides the ECU plugs from black-top loom, look if you can find that wire there, if not there, than it should be on the fuse box side...

[johntramp]

Cheers, I will have a look and let you know what I find.

[johntramp]

I could not find any black/red wire, only a red/black one. Here are a couple of photos of what I am working with, if it helps at all.



ecuend.jpg
Here are all the plugs on the ECU's end of the loom. - The three on the right being where the ECU plugs in.

fusebox.jpg
This is the back of the fusebox. I couldn't find the wire you are talking about here either

redblack.jpg
And this is the red/black wire which I found. This has a ~750 Ohm resistance to the ground and nothing to the injector's wires. I dont think this has anything to do with my problem tho.