Toyota 18R-G (808, NVRAM, USB)

Converting To Delco ECU From Carby Or Other Injection Systems
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Toyota 18R-G (808, NVRAM, USB)

Postby Steve M » Wed Apr 22, 2020 1:44 pm

Hi,

I have been having trouble getting my engine to start, and then to run if it does start. It was running ok before the problems started, which happened mid-drive.

Engine:
Toyota 18R-G (4 cylinder), 44mm Individual throttles, 310 Deg cams with oversize valves, 12.5:1 compression with 3.5mm oversize bores. Compression tested OK.
Distributor is 18R-G original electronic points - single pick-up reluctor and 4 tooth trigger, each tooth approx 1 to 1.5mm thick and ~4mm long.
808 ECM with NVRAM and USB comms running $12P
Camira Ignition module, loom and sensors.
Bosch 35lb/hr high impedence injectors.
AEM Wideband with gauge - wired into ECM

The engine was running for over 6 months more-or-less trouble free, then was unused for 6 months.
Problem started on the first drive back on the road. It developed an intermittent misfire, which got worse until the engine stopped completely.
Each misfire resulted in the tachometer dropping toward zero. Tunerpro registered misfires as either min RPM (400) or Max RPM (9600)
It had no spark during cranking, tunerpro registering 9600RPM, which is above spark-cut/rev limit, which could explain the lack of spark.
I adjusted my reluctor air gap (smaller) and it started, drove for about 100m then died so I put it on a trailer.
2 days later it started, drove to get petrol and then had to push it most of the way home.

Here is the list of things I've done in trying to get it running again:

VS commodore ABS sensor with 2-tooth trigger mounted to the harmonic balancer. Teeth ~5mm wide. Air gap - tried a few between 0.5-1.5mm.
- successful triggering at 10deg during cranking and when turning engine by hand. No start but occasional attempts to fire, sometime out the inlet side.
Started once but ran very poorly until it died, timing light indicated spark timing of approx 20deg After TDC, which was confusing.
While running, there was a large amount of raw fuel coming from the exhaust (white cloud, I don't think it was condensation. It looked more like an old diesel on a cold start)
- coil spark was sometimes strong individual pulses when battery fully charged, sometimes continuous sparking on the 3rd or fourth attempt to start.
- Changed to a 2 slot trigger wheel, also set to 10deg.
Both trigger wheels were tried with reversed polarity on the ABS sensor.
Also tried a few other static advances (0, -10, 20, 40, nothing started the engine)

Replaced ignition module (2nd hand spare)
Replaced coil (2nd hand spare)
Replaced ECM (2nd hand spare with same modifications for RT tuning and USB comms)
No improvement
Tunerpro shows 200RPM while cranking with spikes of 9600 everytime it tries to fire.

Removed entire engine wiring loom and tested continuity at all ECM pins. All tested ok.
The sparkplugs are getting wet with fuel, enough to flood, and the engine tries to fire occasionally.
I can hear the injectors activate when the spark is triggered.
I can hear the fuel pumps trigger with the spark also, and feel pressure in the fuel line increase when that happens.
I've now reinstalled the electronic points in the distributor, which trigger at a very small air-gap (<0.1mm) but appear ineffective at larger gaps.

Can someone help me?

I'd like to sort this out as I hate being beaten by electronic problems and I'm doing everything I can to not give-up on the DELCO system.
I'd really like to avoid spending $2000 plus on changing to Haltech or Microtech for something reliable.

Cheers, Steve
Last edited by Steve M on Tue Apr 28, 2020 10:13 pm, edited 2 times in total.

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Re: Toyota 18R-G (808, NVRAM, USB) - died, help please

Postby Holden202T » Wed Apr 22, 2020 2:06 pm

it sounds likesome sort of electrical interference if your getting spikes in the rpm trace...

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Re: Toyota 18R-G (808, NVRAM, USB) - died, help please

Postby Steve M » Wed Apr 22, 2020 3:20 pm

20200422_143057.jpg
Distributor pick-up

20200422_143018.jpg
ABS sensor wire

20200422_143036.jpg
Distributor plug


Sorry about the images being rotated 90degrees. I don't know why my phone did that.

The ABS sensor wire is short and goes directly to the Ignition module (disconnected in pics).

Would having numerous connectors between the pickup and the ignitor cause problems?

I am aware that the disconnected ABS sensor wire is resting next to the ignition module but nothing was working anyway so I don't think that is the problem.

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Re: Toyota 18R-G (808, NVRAM, USB) - died, help please

Postby antus » Wed Apr 22, 2020 3:37 pm

I dont understand where the abs sensor fits in to this picture, i'd expect the sensor in the distributor against the reluctor in to the bosch ignition module, or an abs sensor on a metal wheel with the trigger pattern going in to coilpacks and module. if it worked before I assume its right, but im not clear on that. I agree with Holden202T that it quite likely is high frequency ignition noise from somewhere else. Do you have a wideband heater controller there somewhere? or filtering capacitors on anything that could have died? or a bad ground connection?

or is the abs sensor interchangable with the distributor sensor?
Have you read the FAQ? For lots of information and links to significant threads see here: viewtopic.php?f=7&t=1396

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Re: Toyota 18R-G (808, NVRAM, USB) - died, help please

Postby Holden202T » Wed Apr 22, 2020 4:03 pm

yeah im a bit lost now too, are you saying that the distributor gets unplugged and then you plug the abs sensor wires in its place ?

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Re: Toyota 18R-G (808, NVRAM, USB) - died, help please

Postby Steve M » Wed Apr 22, 2020 4:06 pm

The ABS sensor is interchangeable with the distributor sensor. It was not there when the problem originally began.
It is triggered by a steel wheel (2 slot or 2 teeth depending on which I bolt on) on the front of the harmonic balancer when it is in use.
I installed it to see if it could be used in place of the distributor sensor, which I don't trust anymore.

I have a wideband controller integrated in my gauge in the centre console, approximately 500mm from the ECM.
The cable does run alongside the engine wiring harness as it exits the engine bay and enters the cabin, but not within 500mm of any ignition system components.

A capacitor exists, which was in the original wiring from the Camira. It seems to be on a 12v power line. It's capacitance is still accurate to its labelled value. I could not find reference to this capacitor in the wiring diagrams, but it is in the same part of the wiring loom as the ignition coil and the engine bay tachometer plug.

Original Camira grounds wires are bolted directly to the head. They have been disconnected, reconnected and continuity tested.

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Re: Toyota 18R-G (808, NVRAM, USB) - died, help please

Postby Steve M » Wed Apr 22, 2020 4:11 pm

1587535687368287725651.jpg
0.47uF capacitor

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Re: Toyota 18R-G (808, NVRAM, USB) - died, help please

Postby Steve M » Thu Apr 23, 2020 12:36 pm

Some extra thoughts.
At some stage in the past, a kill switch was added into the positive (pink) wire that goes from HEI module (+) to Ignition coil. This switch adds about 2m of unshielded wire into that line.

The ECM has only been seeing 12.4-13volts from battery voltage so I'm wondering if there might be something not right with the alternator or wiring (EA falcon alternator (3 years old).

Which wires should be shielded in the loom?

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Re: Toyota 18R-G (808, NVRAM, USB) - died, help please

Postby antus » Thu Apr 23, 2020 1:45 pm

the sensor wires from the trigger system to the ignition module should be shielded. the battery volts sound fine. How low do they drop while cranking in the logs? can you post up a log of cranking? the hei kill switch wire might be creating RFI, but if it was there before it doesnt seem like it'd be it.
Have you read the FAQ? For lots of information and links to significant threads see here: viewtopic.php?f=7&t=1396

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Re: Toyota 18R-G (808, NVRAM, USB) - died, help please

Postby delcowizzid » Thu Apr 23, 2020 2:44 pm

Yeah needs to be shielded or a twisted pair of wires not just parrellel 2 core
If Its Got Gas Or Ass Count Me In.if it cant be fixed with a hammer you have an electrical problem

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