Tacho Dies at 2,700rpm???

NickW · Post by **NickW** » Fri Jul 16, 2004 6:30 pm

Gents,

I have installed the EDIS part of the system and it works fine, rock steady 10deg BTDC.

However, my tacho dies at about 2,700rpm and drops to zero. If I drop the rev's then the tacho starts working again.

I used the diode kick-back circuit from the -ve of the two coils to the tacho.

I used two 1N4004's as suggested and a 1N5352B 15v Zener.

Is my diode circuit breaking down?

Any idea's please???

Thanks,

Nick.

Post by **brentp** » Thu Jul 22, 2004 12:05 am

Hard to say- you might want to temporarily try an aftermarket tach to see if it behaves differently...

Brent

NickW · Post by **NickW** » Mon Jul 26, 2004 11:01 pm

OK, I tried several zener's, but none of them worked.

Looking at the signals from my original coil and the signal from the Ford coilpack then it looks like the Ford coilpack is not supplying a clean enough signal for my tacho (tacho is by VOD, c1990).

However, the tacho output from the EDIS4 module, Pin 11 drives my tacho very well. The signal from the EDIS4 is a good clean square way, so this should drive any tacho that's designed to run off a traditional style coil.

I also tried my Omex rev limiter, but this would not work off the signal from the coilpack either.

Regards,

Nick.

Josh_b · Post by **Josh_b** » Tue Jul 27, 2004 12:50 am

my old smith tacho and a cheapo tim one work fine using the diodes method, also my armtech speedshift, a shiftlight/rev limiter work fine of the same diodes

NickW · Post by **NickW** » Tue Jul 27, 2004 9:36 am

Josh,

Not sure what the difference is?? It would be good to see a signal trace from a scope for the feed to you tacho to compare it to what I get. Don't suppose you have a scope handy?

BTW, what part of the UK are you in? I'm in West Midlands.

There are a couple of photo's of the signals I get here:
http://www.q253fdf.pwp.blueyonder.co.uk/2.html

Excuse the website, it was a quick 5min job.

Also, I'm not 100% sure about how I wired the diode circuit up, I'll do a drawing of my whole wiring harness and send you a copy (don't hold your breath) if you could compare it with yours for me?

Thanks,

Nick.

Josh_b · Post by **Josh_b** » Tue Jul 27, 2004 9:46 am

i live in bridgnorth, is that west midlandsy? if your not too far away i could drive over for you to scope my setup

Autosport Labs

Tacho Dies at 2,700rpm???

Tacho Dies at 2,700rpm???

Hard to say- you might want t

Sorted it!! - Sort of!!

odd that

Yup, don't understand it either??

no scope im afraid