Tach with EDIS

For discussing how to choose sensors and create a wiring harness for all Bowling and Grippo versions of the MegaSquirt® EFI controller.
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Artie777
MegaSquirt Newbie
Posts: 4
Joined: Thu Oct 01, 2009 6:54 pm

Tach with EDIS

Post by Artie777 »

Hi,

I have a BMW 318i (4cyl), and I use EDIS to control the spark and MegaSquirt-II EMS System - SMD PCB3.57 to tune it. I was postponing wiring my tachometer for awhile. When I started, neither of two ways described in the manuals are working.

First way was to run the IDM output (pin 2 on the EDIS module) to the tach input.
Result was: the tach would jump for a second when cranking the car and would stay at zero the rest of the time.

Second way:
Image
Result was: The tach would operate as it should at idle, but whenever I accelerate, my rpm will go up, tach will drop to zero and stay there.

Did I do something wrong or does my tach need something else?

Thanks
Image
http://www.subaru-tech.com/ life begins at 30psi/ in boost we trust
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8974Ollie
Helpful Squirter
Posts: 82
Joined: Tue Oct 13, 2009 4:35 pm

Re: Tach with EDIS

Post by 8974Ollie »

I would think you should only need to connect one coil to the tach.
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Artie777
MegaSquirt Newbie
Posts: 4
Joined: Thu Oct 01, 2009 6:54 pm

Re: Tach with EDIS

Post by Artie777 »

Interesting, would pin 2 be an output of one coil already, the first way I described in my post?
Image
http://www.subaru-tech.com/ life begins at 30psi/ in boost we trust
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Artie777
MegaSquirt Newbie
Posts: 4
Joined: Thu Oct 01, 2009 6:54 pm

Re: Tach with EDIS

Post by Artie777 »

Anyone?
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http://www.subaru-tech.com/ life begins at 30psi/ in boost we trust
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Philip Lochner
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Location: South Africa
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Re: Tach with EDIS

Post by Philip Lochner »

Did you try running the PIP signal also to the tach? My Jag is happy with that...

Elsewhere I saw a 1KOhm resistor being added to the tach gauge input going either to 12V or ground (cant remember which) but I would try ground first.

R12 needs to be at least 3300Ohm otherwise the pip signal is pulled down. (does not reach full 12V peak to peak).
Best regards
Philip
'74 Jensen Interceptor Mk3 (MS-2 EFI, GPIO + GM 4L60e)
'80 Jaguar XJS 5.3L V12* (MS-2 EFI + dual EDIS-6)
and about 10 others.
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Artie777
MegaSquirt Newbie
Posts: 4
Joined: Thu Oct 01, 2009 6:54 pm

Re: Tach with EDIS

Post by Artie777 »

Philip Lochner wrote:Did you try running the PIP signal also to the tach? My Jag is happy with that...

Elsewhere I saw a 1KOhm resistor being added to the tach gauge input going either to 12V or ground (cant remember which) but I would try ground first.

R12 needs to be at least 3300Ohm otherwise the pip signal is pulled down. (does not reach full 12V peak to peak).
I tried to resistor and it did not help. No change except rpm start to read lower.
Image
http://www.subaru-tech.com/ life begins at 30psi/ in boost we trust
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