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Smiths tacho query


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Posted

Anyone know DIP switch settings that work for Zetec 1800?  Set mine as per manual and Smiths instructions

1 off

2 off

3 on

4 off

5 on

6 off

but at SVA the tester thought it was reading twice normal ie. was idling at 1800rpm.  I've tried different combinations and ...

1 off

2 on

3 on

4 off

5 on

6 off

.... shows idle speed as about 900 rpm, and sounds right.  But this is the setting for a 6 cylinder engine - there were only 4 last time I looked!

Anyone had a similar experience who can confirm settings they are using?

Thanks,

Tony

Posted

Tony

Without checking back to stuff I wrote down, which is at home, I can't help you with the dip switch settings but I do recall eaxactly the same thing. If I called it a 6-cylinder engine (or may have been 8, can't  remember) I got a reasonable idle figure. But this seemed stupid so I talked it over with Mark at WF and in the end, set dip switches as per Smiths instructions for 4-cylinder and twiddled the pot (under a rubber grommet thingy) to give an idle of 1000 rpm. It's still set at this though from the RR session at NMS it's still over-reading a bit but the variation changes with revs and it's on the safe side as far as over-revving it is concerned.

HTH

Kerry

Posted

Kerry,

Yes, calling it a 6-cyl is what I've done, as you say this doesn't make much sense - I think I'll fiddle with the pot until the idle sounds good.

Waiting for certificate of newness from WF before I can register the thing ... and the sun's shining!

Cheers,

Tony

Posted

Oddly enough I thought mine was double what it should be but haven't had time to sort it out yet found this link which may help. So I'll be interested to hear how you get on

http://www.caigauge.com/tachofit.htm

Posted

Thanks,

This link reads just the same as the instructions that came with the tacho.

Tony

Posted

Thinking about this :down: the Tacho gets fed from the ECU and and this is a wasted spark system (zetec) so you get an extra spark on the exhaust stroke so does this mean that you get a pulse per spark from the ECU feeding the tacho. If it was set to 8 cylinders instead of 4 that might work!!!

Anyone else got a better theory??

Posted

Tried 8 - cylinder setting - gave very low rpm reading, 6 is the only one that sounds right without touching the calibration pot.

Tony

Posted

I had put a post on this subject in techie talk. Mine has not read right since I put it in. The idle is fine, but as you rev it seems to under read by a long way.

I'm going to have another look today hopefully so I'll report back if I get anywhere.

Posted

I found that the only way I could get mine to read accurately was to use easymap to view the actual revs, hold the engine at 2000rpm, then turn the pot on the back of the rev counter until it read 2000rpm also (This assumes the dip switches are set right of course)

Paul

Posted

This is exactly what I did yesterday. The instructions also say to do this while selecting a 'mid-range' rpm. I selected about 2800 rpm and set it to that.

Now the idle reads a little high (more towards 1000rpm), and the general reading is not that accurate (+/-10%'ish).

DS settings as per instructions 00I0I0

How accurate should a tacho be???

Posted

Thanks guys,

Presumably 'easymap' is a program you run from a laptop?  My last build was a 1700 x/flow in 1989 so I'm not up to speed (no pun ...) with matters electronic.  Can anyone advise what's required to run easymap as I'd like to have a play and get the tacho somewhere near correct.

Tony

Posted

Hi Tony,

Yes easimap is a windows application, you hook it up via a serial cable between computer and ECU and it reports all sorts of useful stuff including RPM (I think from the crank position sensor). Apparently you need a special lead to hook computer to ECU, I haven't tried a standard serial cable so I can't comment, perhaps someone else can advise. If not, SBD sell them or you're not that far away from me if you wish to borrow mine.

Flappa - mine's also out by ~10%. I came to the conclusion that it was about as good as it was going to get though :(

Cheers,

Paul

Posted

Thanks for the link Paul,

If I can get the software and my daughter's laptop I may be in touch re. the comms cable.  I'm in Solihull near B'ham airport.

Tony

Posted

Tony,

Maybe you could calibrate it against a timing strobe?  I have a cheapo one from Halfords (Gunsons?) which you are welcome to borrow.  It has a dial on it which I seem to recall you turn until the flashing LED stays lit, then you can read off your engine idle rpm from that.

It may not be the most accurate method but it may be good enough to get the tacho about right.

All the above is from memory as I haven't used it for a while, but I think that would work.  Let me know if you want to borrow it...

Cheers,

Steve.

Posted

Cheers Steve,

I'll give it a go.

On the road at last then - bringing it into work?

Back to work now  .....

Tony

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