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Old 05-04-2014, 05:32 PM   #1
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Default Misfire Cyl 2&3, CAS the culprit?

So I got my head back, and installed it over the weekend. Car runs better, but still not quite where it should be.

Idling at around 1000/1100, the engine was audibly misfiring, so we started disconnecting COPS to find the culprit. Right back to Cyl 2&3. Pulling the COP on either one had no noticeable effect on the idle, but plugging it back in, the engine note rose very slightly. So, 2&3 were doing something.

Took a timing light and ran it across all the cops on their own, and checked for the synchronicity of the light output. At first it looked like 2&3 were the ones that were dropping signal (We'd already swapped the COPS out to test them, and the problem followed the cylinders). We re-checked 1&4 and found out that they were dropping signal at about the same time as the misfire.

To double check the wiring, we ran a wire from the ECU Loom and cut/tapped it to the #2&3 signal wire for the COPS. Same problem.

That leaves only two possible scenarios (please correct me if I'm wrong)...

Either the ECU is stumbling on triggering the COPS (unlikely in my opinion, I have a high faith in Reverant's work... and yes, the ECU is setup for 2.3ms dwell on toyota COPS)

Or, the CAS is screwed up...

As luck would have it, I'm sitting on an NB Cam Cover in paint right now, as well as a Protege trigger wheel, some NB cam gears, and all the sensors from a '99 NB.

If I'm recalling what I read correctly, I have to splice the Crank Pulse to the white wire on the CAS Loom, and the Cam Pulse to the Blue-Yellow, and setup Megasquirt for a dual trigger setup?
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Old 05-04-2014, 05:43 PM   #2
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Any chance TunerStudio came up with a weird/unexpected difference report and you chose to send the current TS settings to the ECU?
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Old 05-04-2014, 07:09 PM   #3
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Quote:
Originally Posted by Reverant View Post
Any chance TunerStudio came up with a weird/unexpected difference report and you chose to send the current TS









settings to the ECU?
trigger angle offset +0.10deg

cranking advance +4 instead of +8

afterstart enrich tables modified

controller auth 0 instead of +5

pretty much it. some veal table changes, but no hard settings changes. (didnt switch to maf instead of ait or anything like that...)
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Old 05-08-2014, 12:48 PM   #4
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Composite logger is your friend.

An even better friend is Dimitris - his service is second to none and I have no doubt he'll be proactive in helping.

If the ECU turns out alright I'd be scoping all the feeds (inc 0v) at the coils.
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Old 05-08-2014, 02:20 PM   #5
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yeah, I'd look at the composite log (or regular logs) to see if this is cam sync loss.
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Old 05-12-2014, 02:39 PM   #6
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Originally Posted by Braineack View Post
yeah, I'd look at the composite log (or regular logs) to see if this is cam sync loss.
Ok, I've pulled logs from Saturday. The composite log is a fairly long duration one, and the standard log is a shorter pull. Misfire is active during both settings. Composite log was taken primarily while letting the engine idle.

I've had a look at it, and you can see the pulse separation on the crank is off, but not sure if that's a result of the ignition failure, or a cause of it.

Saturday I re-ran the ground wires; the black one typically on the cam cover was run to the intake manifold, the LC-1 grounds were run to the central ground point, and I re-ran a new ground strap tapped to the right side of the engine. This log is pulled after I went through all that.
Attached Files
File Type: zip misfire cl.zip (305.4 KB, 9 views)
File Type: zip 2014-05-10_13.34.43.zip (270.7 KB, 10 views)
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