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NA6 won't start, suspect CAS

 
Old 04-22-2019, 08:52 PM
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Default NA6 won't start, suspect CAS

I'm in need of a little advice. I have a 1.6l '89 eunos roadster, turboed with a DIYPNP and it's sat in a shipping container for most of the last six years, Last time I drove it was Feb '18 and it seems to have particularly suffered in the last year. I left the hood/bonnet down and it seems that a lot of moisture was trapped in the engine bay :\

Anyway, I tried starting it the other day and it cranks but won't fire. There's no spark and it doesn't look like the plugs are wet so looks like no fuel either. I suspect an issue with the CAS.

I hooked up tunerstudio and monitored the gauges while cranking, rpm stays at zero which I assume means that the MS is not getting a signal for engine speed but it would be great if someone can confirm that.

I unplugged the CAS and tested the cable, I'm getting GND, 12V, 11V, 0V (1.3Kohm to GND) when I expected GND, 12V, 5V, 5V (Untitled Document). Assuming this means that there is an issue with the wiring but unsure whether the DIYPNP changes anything?

Next steps will be to follow the wires to the ecu and test continuity and try bypassing the wires in the loom, followed by removing and testing the CAS if that doesn't work.

If anyone is able to offer any MS2 specific or tunerstudio diagnostics that I can do it would be much appreciated, it's close to 10 years since i built the DIYPNP and my memory's a bit hazy.

Last edited by giblets; 04-22-2019 at 09:32 PM.
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Old 04-22-2019, 10:13 PM
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This is gonna sound dumb but have you checked all fuses? What is the resistance for your ground circuits? 2 ohms or less on a ground wire is ideal. Is your timing belt broken? If the sensor isn't spinning then it obviously won't be working. Just random questions to throw out there.

Do you have a spare CAS to swap in or know anyone in the area who could either let you borrow one on use your CAS on their car to verify operation?
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Old 04-23-2019, 03:02 AM
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Cams are definitely moving.

I tested the wires from the ECU plug to the CAS plug and they're fine. Opened up the ECU and found this:

Since this cap is part of the 5V supply it likely explains the lack of 5V on the two CAS signal wires.
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Old 04-23-2019, 07:36 AM
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Originally Posted by giblets View Post
Cams are definitely moving.

I tested the wires from the ECU plug to the CAS plug and they're fine. Opened up the ECU and found this:

Since this cap is part of the 5V supply it likely explains the lack of 5V on the two CAS signal wires.
Should be an easy fix. Unless theres a hard short somewhere. Did it get any melted stuff anywhere else onto the board?
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