legacycentral bbs

SOLVED.

Cliff Notes:

Changed cam and crank sensor. I also updated the design to the new ones, see caution below.


I converted to the new style (sensor + harness) crank and cam sensors using the pigtail from the old sensors and soldering the matching plug on the sensor end. The crank and cam plugs are NOT the same.

CAUTION:

The 95+ changed the polarity of the crank sensor from the 90-94 ones. If you match white-white, red-black, it swaps the Signal (+) and Signal (-) wires. I had it wired up backwards and it would barely idle with 2 cylinders, was dumping fuel, and had the no trigger on 2 channels.

Swapped the pins, idles like butter. Has a small stumble on throttle tip-in, but I haven't let it warm-up (no lower rad hose yet).

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Original Post


I'm working on the last lead, but other than that, I'm out of ideas.

91 SS, EJ20G from 92 Legacy RS, and a K8 JECS ECU. I don't know if this is correct for the engine, but I assume it is since my 92 diagram matched and it has intercooler pump control.

Engine harness: EJ20G
Car harness: EJ22T

EDIT: I know this might be confusing, but I made a conversion harness to go from the EJ20G engine harness to EJ22T car without hacking the car harness. I have double checked the harness pins and locations and confirmed continuity, so I have ruled that out.

Runnning COP from RS Legacy including OE 4-channel ignitor and coils. All stock motor. AWIC setup.

It's a no-start condition, but I have confirmed spark, fuel at the rail (and if I pulse the injector manually with a ground jumper).

- 12V at the injectors with KOEO.
- Good ground at B125 Pins 25 and 24.
- 12V at ECU from injectors
- Injectors ~10 ohm.
- NO codes in ECU (including injector circuits)

I run my JECScan, but it has to use 91-94 NA ECU values as it doesn't have mine defined. I get realistic values for temp, system voltage, TPS, and ignition timing, but I can't confirm. I see injector pulse width is ~38mV, but the injectors do NOTHING.

I don't want to write off this ECU since EVERYTHING else works, so I'm double checking the cam/crank wires since someone had been monkeying around with the ECU harness before I got it, so I can't confirm it the cam/crank are in the correct locations. Car previously had another EJ20G ECU, but it was from a later STi.

According to my diagrams, the cam/crank pin locations should be the same between EJ22T and early EJ20G ECUs, so I shouldn't have a problem. But I don't have my oscilloscope to confirm waveform output.

Can I still have spark without injector pulse?

Thanks as always!

Hi,
I don't have any answers, but in my EJ20G thread the K8 ECU isn't listed. Although I thought the EJ20G's should all work, there may be some exceptions.
Rob (RobTune) mentions it HERE.
GL,
TD

Thanks for the link!

I found out on birtyolbc.co.nz, that the K8 supposedly comes from a gen 1 TW, 5MT EJ20G. So I'm glad that's solved.

I also got my hands on a set of 'noid lights and hooked up the only easily available injector (cyl 1) and at first, it didn't want to blink. Then it was blinking regularly.

But now I get the VERY occasional backfire from the exhaust (just a single pop) when I release the key.

I've even taken jumper cables to ground the ECU to the battery and engine ground to the battery to supplement the grounds.

If fuel and spark are there and good then it's got to be a timing issue of when all that comes together. I wish I had some more info for you but it sounds like you've looked over things pretty thoroughly.

Update:

I doubled checked the timing (as I was out of ideas and Josh had the same thought), but it was bang on. I put a new t-belt on it before dropping in.

How ever, I did swap out the cam sensor with my unknown spare, and it ALMOST spun up to stay running. Swapped back, and it now runs at about 300 RPM, almost sounds like it's on 1 or 2 cylinders. Still no codes.

I think it might be a weak crank sensor. I tried to "energize" it with my rare-earth magnet, an it seemed to make starting-up easier, but still did NOT want to rev up or stay running.

Do you have a spare crank sensor you could try?

Legacy777 wrote:Do you have a spare crank sensor you could try?

I do not, but I do have a spare cam sensor. I'll probably borrow the connector and try it.

Update: it's a spark issue. All injectors are pulsing consistently, but I'm getting a 1-in-20 firing of coils on cylinders 2 and 3.

The problem comes from the ECU only triggering the ignitor. When it does trigger 2 and 3, the engine coughs and tries to start. I've even disconnected the ignitor to check the ECU trigger exclusively, and it's not triggering 2 nor 3 like 1 and 4.

I'm heading to the yard to grab a 95+ crank sensor and make a conversion harness to put the crank signal question to bed.

Otherwise, I've got 2 dead ignitor drivers in the ECU. So.... Anyone have a spare K8 (or similar) ECU?

Edit: checked timing; bang on. Checked cam and crank sprockets; flawless.

The plot thickens. Is the crank sprocket good and has all its teeth? I'm assuming yes, but never hurts to double check.

Check the engine harness ground on the back of the intake, mine had the same issues and I tried everything u have as well, and Good ol Josh said to check the ground. Mine was loose, played havoc with my spark and fuel timing. Doesn't hurt to check.
Josh knows all!!

Update:

Put a brand-new crank sensor in (95+ style), with my conversion harness. Harness has zero resistance and is pinned correctly.

I also grabbed the cam, am working on conversion harness for that one too.

And I'll double check the intake grounds, but when I check the grounds AT the ECU plug, I get perfect conductivity to ground (and the ECU only grounds at the intake, according to the FSM).

What were you using as your reference ground (neg terminal of the battery) to check continuity?

SOLVED.

New-style cam and crank sensor, conversion harness.

After more head scratching, pulled the pinout for 95 EJ22E, discovered the pins are swapped for Signal (+) and Signal (-) at the ECU/harness plug. Swapped the pins at the connector for the sensor, idles like butter and fires on half a turn.

Also found out why it had a bad miss. I had two stuck injectors (sitting for years would do that), but a solvent bath and a harness for manually pulsing the injector cleaned them right up.

Legacy777 wrote:What were you using as your reference ground (neg terminal of the battery) to check continuity?

I was using the negative and then double checked with the intake grounds.

Well glad you got it solved!

Good find! That's good information.