For the love of a tractor engine: The life and times of the 18R-G

[Omegaman]

At this stage its good to know that i have pretty much wired it in right.
Javal, thanks for looking over the diagrams.
once i change the coil/ballast...in should start. well theres really no other reason it shouldn't.
everything else checks out. well Maybe the replacement alternator which is now a 85amp one...

[Javal]

At this stage its good to know that i have pretty much wired it in right.
Javal, thanks for looking over the diagrams.
once i change the coil/ballast...in should start. well theres really no other reason it shouldn't.
everything else checks out. well Maybe the replacement alternator which is now a 85amp one...

Heh, no worries mate. Elec, wiring and diagnosis work are 90% of what I do these days. The wiring itself for these engines is super basic, it's just making sure all the actual components (eg igniter, AFM etc) are working properly which can be the tricky bit. Like I say, you could have a bad igniter - or the wrong kind of igniter - I know of at least two different types which look almost the same from that era. Earlier ones (which suit 18RGEU) can be had from RA60's etc, but later ones which from things like 4AGE's and very late model RT142's which use the IGt and IGf wires to send and recieve ignition timing info from the ECU are not suitable.

The 85A alternator is a great upgrade and as a bonus it's quite easy to do, but maybe get it running first

[Omegaman]

current standings....
Replaced coil and resistor. I now have spark at coil and at spark plugs.
Injectors still aren't pulsing. there's constant power at the resister, so im assuming that the ECU is not triggering the earth.
Is that about right. Or does that mean there is an earth, but on all the time.

[Javal]

current standings....
Replaced coil and resistor. I now have spark at coil and at spark plugs.
Injectors still aren't pulsing. there's constant power at the resister, so im assuming that the ECU is not triggering the earth.
Is that about right. Or does that mean there is an earth, but on all the time.

Good news that you've got spark. Usually if you have spark but no injector pulse, it'll fire up on the cold start injector and then die straight away. If you are running a cold start injector that is. If you're not running one, it's packed up or the switch for it has had it, you should spray a bit of carby cleaner down the manifold and see if it kicks, just for fun.

When you checked if you had an injector pulse, did you just hook your test light up across one injector plug, give it a crank and see if it pulsed? The test lamp didn't light up at all I take it?

Just to be sure it is the ground trigger from the ECU you're missing, you could just switch the key on and go between the power wire on the injector plug and a known good ground. Test lamp should light up. Now you KNOW it's the ground trigger that's missing.

In that case i'd check continuity (resistance) down the IG wire between the -ve side of the coil and the ECU connector.
If that is OK then check the continuity between the ECU connector pins Eo1 and Eo2 and ground.
If that is OK then check the continuity between the ECU connector pins #10 and #20 and the appropriate pins on the injector plugs.

[Omegaman]

Good news that you've got spark. Usually if you have spark but no injector pulse, it'll fire up on the cold start injector and then die straight away. If you are running a cold start injector that is. If you're not running one, it's packed up or the switch for it has had it, you should spray a bit of carby cleaner down the manifold and see if it kicks, just for fun.

When you checked if you had an injector pulse, did you just hook your test light up across one injector plug, give it a crank and see if it pulsed? The test lamp didn't light up at all I take it?

Just to be sure it is the ground trigger from the ECU you're missing, you could just switch the key on and go between the power wire on the injector plug and a known good ground. Test lamp should light up. Now you KNOW it's the ground trigger that's missing.

In that case i'd check continuity (resistance) down the IG wire between the -ve side of the coil and the ECU connector.
If that is OK then check the continuity between the ECU connector pins Eo1 and Eo2 and ground.
If that is OK then check the continuity between the ECU connector pins #10 and #20 and the appropriate pins on the injector plugs.

1. yes i'm running cold inj. seems to be wired up correctly. have continuity with starter wire and earth.
no carb cleaner to try to have fun..soz...

2. checked pulse with node light and probe light. It did not light up on cranking.

3. when ign ON. prob light shows power at both wires per inj plug and on all plugs... is this normal?
should the power show only one or both and the ECU/coil earths the other at cranking?

4. there is continuity at all points -ve to ECu
ecu to Eo1/Eo2 and ecu #10 & #20, so all good there.

just the injector plug power looks weird, depending on what the ECU does with earthing.

i have earthed the ECU, the ign relay so im not sure what else to check... aaaaaaahhhhhhhhhhhh

[Javal]

Unplug all the injectors and then re-check, I've had it before where I get power on both sides of the injector plugs unless they're all unplugged. Try that first.

[Omegaman]

I unplugged them. turn on ignition an rechecked. same deal, power on all.
Im now going to try another rgeu ECU, to check if problem with old one.
I need to add wires onto the new one as I have no plug that suits it. which I've done, now just to poke bare wire into old harness plug.
see how that goes.....
im out of ideas and I be t yr getting close to being out of ideas.....

edit. after trying the 2nd ECU, it seems I can get the injectors to pulse.
it hasn't starte d yet, but I know it wants too. im getting all the right signals that she wants to thrill me.
will check the plugs and get some auto sta rt spray.
Javal, or anyone...would you have a ecu plug to sell?
it seems the same as yr ECU, 1 plug for all, the ecu even has the VF wire & the OT wire for 2nd Oxy sensor, which my old one does not.
seems to be a sin gle 21 pin plug.

giving up for the ay...im spent........

[Omegaman]

p.s if some of the words previous post are highlighted in red and Caps.
dont press them. it seems to have been added as adds.

edit again. put back the older std ECU.
And guess what, she coughed and sputtered, then actually started...Yes she started.
Advanced dizzy a bit and she smoothed out nicely...But..after idling a bit, died..
Over and over after that, she came to life and then died.

Javal, if yr wiring diagram is ok. with no issues, i will re-wire my harness the same as yours.
what do you think?

[RA35GT]

Does the fuel pump continue to run?

Is it the fuel or ignition cutting out?

[Omegaman]

it is an ignition thing. the pumps and everything cuts out.
no run on, just dies all at once.
tomorrow I will hack my harness and re-wire it. i'm over it...again.

[Javal]

Alright, I'm going to try and address each point individually so forgive me if the formatting is a bit of a trainwreck.

I unplugged them. turn on ignition an rechecked. same deal, power on all.

This is throwing up a few alarm bells. If the injectors are all unplugged you should definitely NOT have power on both sides of the plug. Having power on both sides is normal if you have even one of them plugged in, but unplugged the ground side should be a dead circuit. I'd be unplugging them all and then checking if you have power at #10 and #20 at the ECU connector. If so, you may have a short to power on that wire.

Im now going to try another rgeu ECU, to check if problem with old one.
I need to add wires onto the new one as I have no plug that suits it. which I've done, now just to poke bare wire into old harness plug.
see how that goes.....
im out of ideas and I be t yr getting close to being out of ideas.....

Not even close

edit. after trying the 2nd ECU, it seems I can get the injectors to pulse.
it hasn't starte d yet, but I know it wants too. im getting all the right signals that she wants to thrill me.
will check the plugs and get some auto sta rt spray.
Javal, or anyone...would you have a ecu plug to sell?
it seems the same as yr ECU, 1 plug for all, the ecu even has the VF wire & the OT wire for 2nd Oxy sensor, which my old one does not.
seems to be a sin gle 21 pin plug.

Righto, good that you can get the injectors to pulse (and fire up as you say later) with a second ECU, but because she started with the original one, I don't think that's your problem. Soldier on with your original ECU for now.

giving up for the ay...im spent........

Help yourself to a few diagnostic ales. Always good after troubleshooting to stop it rattling around your head all night.

edit again. put back the older std ECU.
And guess what, she coughed and sputtered, then actually started...Yes she started.
Advanced dizzy a bit and she smoothed out nicely...But..after idling a bit, died..
Over and over after that, she came to life and then died.

So it smoothly idled? Awesome! Are we talking for 10-15 seconds or 1-2 minutes? That's a huge step right there mate. Congrats on at least getting it running for a bit.

Javal, if yr wiring diagram is ok. with no issues, i will re-wire my harness the same as yours.
what do you think?

Your harness is already fundamentally the same as mine, those wiring diagrams, while drawn slightly differently, are in actuality identical in layout and function. While you may have an issue with your harness, it's not in how it's wired.

it is an ignition thing. the pumps and everything cuts out.
no run on, just dies all at once.
tomorrow I will hack my harness and re-wire it. i'm over it...again.

Don't pull the harness apart just yet. I'd suggest finding what it is that kills, if you can work that out you can fix it a lot easier. Divide and conquer, y'know?

Here's a few things you could do before you go tearing your harness and subsequently your hair out -

I'd highly recommend unscrewing the four screws on the top plate of your ECU case and making sure the pinouts are correct for how you've wired it. The names are printed on the PCB next to their pins. Super easy to do and it's always good to be sure you've got everything right. My ECU is a two plug type for an RX60 Cressida so I wasn't sure where any of my pins were going to be, so I had to do that to make sure I stuck the right wire in the right hole

Now, I don't really know whether you've got a problem with your EFI setup on the ignition side of things or the injection side, but let's isolate. Again: Divide, isolate and conquer. So, when it's not running or has cut out on you, spray some carby clean / start-ya-bastard and see if it'll fire up for a moment. If it kicks, your ignition side is fine. If it's dead as a doornail then your ignition system may not be working and your injection side may not even be coming to the party (remember, no ignition = no injection on an 18RGEU).

Work that one out first, but i'm still kinda concerned with this power-on-both-side-of-the-injector-plugs-when-all-of-them-are-unplugged business. Power on both sides of the circuit is totally normal when you've got all of them bar one or two plugged in, but with all of them unplugged it should be a dead circuit as I mentioned earlier, and again I think I said before that if this is the case, check the #10 / #20 pins at the ECU for power, possible short to power etc etc. All of that is assuming that you DO have an injection side fault, it may well be ignition related.

Also check if the plugs are fouled up. That may stop it from starting.

[Omegaman]

ok, you have convinced me not to hack up my harness.
my sleep habits are screwed, trying to figure this out.
yr idea to open the ecu is a good one. i opened the newer ecu, to add the wires. But did not re-check my current one.

I will re-check the power to injectors, the continuity was correct on all 4 & for each wire.

she idled for a few seconds. it really feels that theres no voltage through the system to keep it running.
i powered the pumps to battery and they continued to pump even after it shut down.
in saying that, i does suggest a ign wire is not receiving 12v when on.

[Omegaman]

question, on my diagram 2.
would and should i get the same result if i connect the Ign wire (ign +VE) at either the ign system (on when key is on)
or to the +coil.
If the same result, would there be a preference EG ign wire under dash?????

[RA35GT]

Depends, if it uses a ballast resistor then the coil + won't be at 12V while running.

[Omegaman]

yes it does use a ballast resistor.
I did know it drops down voltage when running, but wasn't sure at what point in the wiring sequence.

cheers