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-   -   Spark at Ignition point 2 but not on cranking? (https://www.miataturbo.net/megasquirt-18/spark-ignition-point-2-but-not-cranking-43126/)

DMRider_10 01-21-2010 12:57 PM

Spark at Ignition point 2 but not on cranking?
 
Trying to start a friends car for the first time with MS. Its mechanically stock. But, the car has had a big overhall recently with a engine bay respray etc, so everything was out bar the actual block.

The MS has run my car in the past fine, and has been tested on a jimstim last weekend, all was fine with it.

Now, when turning to ignition point 2, every plug fires (the startup "pop"), but when cranking none do?

Ive seached through every ignition problem thread I can find but nothing has the answer.

Are there any voltages etc I can check on the ignitor/coil?

With ignition to point 2, CAS plug wires read

Yello/white : 0v
White: 5.83v
Red/white: 12v
Black (earth): 0v

Car is a 1991

Thanks

richyvrlimited 01-21-2010 04:22 PM

Sounds like a faulty CAS or more likely a fault in the wiring to the CAS.

When you crank does the MS see RPM?

Braineack 01-21-2010 04:32 PM

do you see rpms when cranking?

DMRider_10 01-22-2010 02:28 AM

No, no rpm's in MT/dash when cranking?

p51hellfire 01-22-2010 02:31 AM

ignitor or cas my guess..... did you do a firm ware burn with the ignitor plugged in???

DMRider_10 01-22-2010 05:04 AM

No, and he has 2 spare igniters which we have also tried, so its looking to be CAS related

DMRider_10 01-22-2010 05:05 AM

What should the voltages be at the CAS plug with ignition on, and at cranking?

Thanks

Ben 01-22-2010 10:26 AM

If the MS is not reading RPM, the likely suspects are:
*bad wiring--likely due to recent engine bay work
*bad CAS

DMRider_10 01-22-2010 11:31 AM

Hes already tried a different CAS, so that rules that out.

Braineack 01-22-2010 11:32 AM

how do the tach input mods look?

DMRider_10 01-22-2010 12:54 PM

As per the How-to thread on here

DMRider_10 01-22-2010 12:58 PM

One thing I did notice, not sure if theres any relevance or not, when the ignition is turned on, both outer LEDs come on. If you then crank the engine, the one nearest the outer of the board dims? If you then stop cranking (back to just ignition) then the LED goes back to full brightness but the 2nd time you crank it it stays at full brightness?

If will do the dimming thing every first try at cranking?

richyvrlimited 01-22-2010 03:44 PM

The MS is fine mate it checked out a'ok on the JimStim

get Dan continuity checking wires ;)

CRAIGO 01-22-2010 08:09 PM

Is this the white car?

He's had the whole loom out from what I could gather and also performed a wire tuck in the engine bay IIRC. I've another multi-meter if you want to half the fault finding time? :eek:

RCraig 01-22-2010 10:22 PM

When I first built my MS for some reason I had grounded the shielding loom around the CAS signal wire to pin #2 on the DB37 connector like the diagram shows in the DIY MS thread. Not sure if I understood it correctly.

This caused no rpm signal to show in megatune and car would not start. When I cut off the shielding going to pin 2 it started right up.

DMRider_10 01-25-2010 04:14 PM

Ok I hold my hands up!

When following the 1990 standalone wiring guide, wiring up his car for him, IAC1 should be connected to a yel/blue stock wire.........I had it connected to a blue/yel wire..........which I believe is the power steering pressure switch.....


Oops! Thanks for the help everyone. Changed that wire over and it started :)

His rev counter aint working but thats bound to be the igniter

Braineack 01-25-2010 04:15 PM

standalone with cops?

DMRider_10 01-25-2010 05:02 PM

Just plain 1990 standalone, stock Ignition system. Why you ask?

richyvrlimited 01-25-2010 07:01 PM

COPS don't always have the tacho out, or if they do it needs to be wired up properly.

Good stuff fixing it matey!


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