Hentai's 1992 Mazda Miata (15th)

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Fred
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Re: Hentai's 1992 Mazda Miata (15th)

Post by Fred »

Paste:

(11:20:03) Fred: ok, well, if there is a 2v drop across the 1k resistor then you have a 1.5k in the pull down where you should have 100k
(11:20:51) Fred: which could mean they don't turn on reliably
(11:21:11) Fred: so that's the first thing you should check and change
(11:21:25) Fred: and you may want to roll your dwell back at the same time, as they'll fully saturate with 12v applied
(11:22:03) Hentai: if I run my dwell back from 4.8 to 4 I get more noticeable missfires
(11:22:04) Fred: R103 R102 by the looks, make sure these are 100k not 1.5k
(11:22:09) Fred: well yeah...
(11:22:18) Fred: if those numbers are correct,, you're lucky it works at all
(11:22:33) Hentai: haha
(11:23:03) Hentai: so r104 and r105
(11:23:06) Hentai: 100k
(11:23:22) Fred: basically the input of the fet driver is super high impedance and presents almost no load to the cpu at all
(11:23:30) Fred: so seeing 2v across your 1k drive resistors is bad
(11:23:35) Fred: no no
(11:23:41) Fred: 104 and 105 should be 1k
(11:23:42) Fred: check that too
(11:23:43) Hentai: ok
(11:23:49) Fred: they could be 66k if the others are already 100k
(11:23:52) Fred: check all four
(11:24:28) Hentai: I will verify them all on the circuit paths
(11:24:30) Fred: once you have a solid 5v at the input of the driver, you will get a solid nominal 12v at the output assuming a good 12v feed
(11:25:02) Fred: if you still don't have 12v at the inner end of r100 and r101 then the feed is bad
(11:25:07) Fred: or the jumper wrong
(11:25:09) Fred: or no jumper
(11:25:30) Fred: do you have the link in the circle?
(11:25:38) Fred: and is it to the 12v side?
(11:25:50) Hentai: yeah 12v jumped
(11:25:57) Hentai: but I could accuratly check it at the time
(11:25:57) Fred: ok
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Re: Hentai's 1992 Mazda Miata (15th)

Post by DeuceEFI »

More than likely you don't have a 12v supply that is supposed to be connected to the IGN-12v input which supplies 12v to the JP1 and JP2 jumper block. Right now you are probably only feeding the ignitor driver with 5v from the MCU output. This would explain the 2v drop across the 1k resistor and the fact you are only seeing 2.2v to 2.4v on the output pin. There is an internal diode that connects from the gate input to the Vdd input, which would drop the 3v you see at the gate input by approximately 0.707v which would give you about 2.3v on the output pin.

Connect a 12v supply lead to the IGN-12v input near D3 in the LSD3 section of the PCB and then check to see that you have 12v at JP1 or JP2.

Cheers,
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Re: Hentai's 1992 Mazda Miata (15th)

Post by Hentai »

DeuceEFI wrote:More than likely you don't have a 12v supply that is supposed to be connected to the IGN-12v input which supplies 12v to the JP1 and JP2 jumper block. Right now you are probably only feeding the ignitor driver with 5v from the MCU output. This would explain the 2v drop across the 1k resistor and the fact you are only seeing 2.2v to 2.4v on the output pin. There is an internal diode that connects from the gate input to the Vdd input, which would drop the 3v you see at the gate input by approximately 0.707v which would give you about 2.3v on the output pin.

Connect a 12v supply lead to the IGN-12v input near D3 in the LSD3 section of the PCB and then check to see that you have 12v at JP1 or JP2.

Cheers,
I have 12v connected to ign-12v. I also read 12v at jp1 and jp2.

I will let the picture do the talking

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Hentai
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Re: Hentai's 1992 Mazda Miata (15th)

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Re: Hentai's 1992 Mazda Miata (15th)

Post by Hentai »

Perhaps the first actual working Variable vane turbo setups on FreeEMS.
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Re: Hentai's 1992 Mazda Miata (15th)

Post by Fred »

Hentai wrote:Perhaps the first actual working Variable vane turbo setups on FreeEMS.
Congratulations! :-)
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Re: Hentai's 1992 Mazda Miata (15th)

Post by m2cupcar »

Congrats! very cool
90 Miata | 302rwhp @ 6450rpm | 281rwftlbs @ 4800rpm | FE-dohc 2.0L turbo
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Re: Hentai's 1992 Mazda Miata (15th)

Post by Hentai »

Fun

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Re: Hentai's 1992 Mazda Miata (15th)

Post by Fred »

Ouch! :-(
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Re: Hentai's 1992 Mazda Miata (15th)

Post by Hentai »

Reinstalled stuff after repairs. If the turbo lets go again I'm going back to N\A for a while

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