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

[Javal]

Oh, in addition to the other stuff I asked, does anyone know how necessary the 2nd oxygen sensor is when using a factory 18RGEU computer?

[Omegaman]

struggling to sort this car out for the appreciation day event.
O_man, how do I check the impediences? I checked the resistor and found number 4 cylinder not firing due to loose connector.

I know I need to adjust timing, but it seems there is still no power.
Fuel seems rich, even after warm up.

My dizzy shows way over 50 on the dwell, but its a electronic dizzy which was re built due to a bent shaft.
I will see if it can be adjusted.

I spent most of the day soldering any suss wires.
Any help will be appreciated.

edit, vid now attached

[wa5]

Just bought an 81 Hilux... with the mighty 18R...




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[ra_28]

Hey Omegaman, Can't watch the video it's private?

[Omegaman]

just fixed it. thanks

[Javal]

Whelp, that's running really rich. I'd see what the cause of that is first, put a fresh set of plugs in it, set the timing and reassess.

[RA35GT]

Oh, in addition to the other stuff I asked, does anyone know how necessary the 2nd oxygen sensor is when using a factory 18RGEU computer?

I'm running without the second oxygen sensor and get 9.2L/100km

[Omegaman]

I'm running without the second oxygen sensor and get 9.2L/100km

I have a wideband 2nd O2 sensor. As much as it lets you see your AFR's. No adjustment on the std ECU can be made.
I was going the use Emanage Blue and see if fuel adjustments can be made, also change injectors, but ditched the idea for now.
the only adjustment you can make and maybe use the sensor and a AFR gauge, would be, AFM adjustment, maybe manipulate one of the sensors on the thermostate housing.
So performance may change, therefore gauge fuel and engine.

[o_man_ra23]

Omegaman, check the air flow meter also, make sure it is moving freely and gives a changing signal full range.

The impedance of the coil (I was talking ignition coil) is checked by putting an ohmmeter (multimeter set to ohms) across the primary coil (the two smaller studs), and the secondary coil (negative small stud and the output to the dizzy). The checks should be done at operating temperature (apply 12 volts to the coil until it warms up, or run the car for a bit).

Primary impedance should be between 3.3 and 4.3 ohms. Secondary resistance should be between 7,500 and 10,000 ohms. This is from the Haynes Celica GT (US) manual - 8R-C and 18R-C engines. It also gives a dwell angle 50 to 54 degrees.

Your reluctor air gap should be 0.2 to 0.4mm

[Omegaman]

O_man, 2 things. I think your on the right track.
1. being the imp on the primary coil is 3.45 there abouts, but the reading on the secondary is 5.8. if im measuring correctly.
I measured the 2 points on the ballist resister> (spell Chk).

2. by the video i'll put up soon. injectors 3 and 4 are not firing.
I have power on all wires out of the injector box thingy, also power on one wire on each of the injector plugs. But still 3 & 4 not firing.
I had adjusted the dwell, but now at 41. Ooops.

Does the resister on the coil deteriorate to show less olms and could this affect the injectors?
I have one more day on Thursday to figure this out, then register on sat, then hopefully drive it to appreciation day on sunday.
As far as spark plugs go. there black, due to being too rich, gave them a clean and re-gapped them to 0.75mm. The timing was set at TDC, but I can't get a good reading due to the idle being so erratic.

[o_man_ra23]

The coil impedances are not measured with the ballast resistor. Ideally you should disconnect everything off the coil and use the three connections on there. So you want to measure between the + and - pins (primary), and between the - pin and the distributor outlet (secondary). The ballast resistor should also have an impedance (measure with it disconnected too), can't remember what it is. What the ballast resistor does, is it drops the primary voltage from 14.4 (which comes out of your alternator) to 12. This is the reason there is a bypass wire going from the starter circuit, as your alternator is not running when cranking, thus you need all the volts you can get during this time.

If your injectors aren't firing, but you are getting voltage, then disconnect the injectors and the computer, short the injector pins on the harness side, apply voltage (turn the ignition to ON) and check for voltage on the injector pins of the computer harness. These should see full battery voltage.

It may also be that your injectors are stuck in the on position. Pull the fuel rail, apply pressure (turn on the fuel pumps), and see if there is any fuel coming out (you will need a bucket). This would cause an extremely rich mixture.

[Javal]

Like this. Sorry for the small picture.

Also while the injectors are unplugged and you are doing the testing that oman suggested, better check the resistance across the injector windings to make sure the injectors themselves aren't open circuit.

[Pagie84a]

erg

My original early build, required a cat for engineering purposes. Since that car is gone, I put all the gear on a new one. To remove the cat now means I need to change the rear or front of the exhaust. So guttering the cat would be easiest.
I also recall the rules saying that a 76-77 car and up requires a cat. Also that the engine since being originally from an 82-84 model car, needs a cat. This is all to do with unleaded fuel.

Is there anything to stop you from banging up a piece of pipe with a flange one each end and bolting it in in place of

[Omegaman]

Seems the coil is the problem. Watch this Vid and see if you agree.
But as i asked before, would this cause 2 injectors not to fire?

I'll have to test the injectors during the week.

[Javal]

Short answer - no.

The coil thing is a bit funny but it could be your self ranging multimeter (it is self ranging, yeah?) playing funnybuggers. I mean if your coil has a short across the primary windings, it wouldn't develop a field. Also, short circuit - blown fuse, there would be no spark, no running at all. So yeah. I suspect that's your multimeter being a bit funny.

Diagnosing a problem over the internet is never easy, best way to start is to confirm the fault and to do some proper testing - confirm that your fault is a no-fire condition on cylinders 3 and 4 and that it is definitely an injector problem. I mean even with the sound quality of the video, it should be sounding like a dying subaru if it's only firing on two cylinders. Easiest way to verify this is simply pull the spark plug leads on each cylinder one at a time. Any large deviation in idle speed indicates that cylinder is firing. No deviation indicates no fire.

From there - if it's definitely a no-fire on 3+4 - then we have to go hunting for the cause - The injectors seem to be everybody's prime suspect, after reading your build thread I kind of understand why, it seems you've had or thought using about a half dozen different sets. First confirm the supporting electronics - power on one terminal, continuity to the ECU injector drivers on the other. You can do both at once using a noid light, that will confirm injector pulse as well. Then confirm the injector windings are not open.

ALSO, some food for thought, if it the 18RGEU ECU uses two injector driver circuits, #10 does cyl 1+2, #20 does cyl 3+4. So if the #20 wire to the ECU is open, you'll have no fire on cylinders 3 and 4.


Also to be questioned is whether your piggyback setup has ever run the engine properly in it's current guise, because no injector operation on two cylinders and 10:1 AFRs at idle don't exactly go hand in hand.


If your problem is not a no-fire condition on cylinders 3 and 4 then your search for your missing horses is going to get a little bit trickier. Again whether the piggyback setup has ever run the engine properly in it's current guise. If so, what has been changed since it did? I mean from doing some quick reading about it, the emanage blue just operates like a conventional piggyback, skewing the factory sensor inputs. If that is the case then why are we getting 10:1 AFR's at idle?

Anyway. Answering some of these questions raised would be a good start.