Tachometer not working with 123 Ignition

[Darren SV]

Today I installed a 123 ignition into my 1800ES and got the car to start for the first time in 21 years. Yea!

I realised that tachometer is not working. The normal distributor uses connects to the coil via the tachometer. The 123 wiring diagram does not allow for this.

How can I hook up my tachometer?

Please help.

Darren

[123GT-AMAZON]

Originally Posted by Darren SV

Today I installed a 123 ignition into my 1800ES and got the car to start for the first time in 21 years. Yea!

I realised that tachometer is not working. The normal distributor uses connects to the coil via the tachometer. The 123 wiring diagram does not allow for this.

How can I hook up my tachometer?

Please help.

Darren

Hi. Darren

You have to bi pass the standard wiring I believe rons website has the wiring diagram and full instructions to get round this issue

Brb will nab link ....... EDIT no home button off link at rons website so I did a search on here

Kind regards
Robert.w

[123GT-AMAZON]

Hi ya found some info ....

Originally Posted by ClassicVolvoShop

I do not at all see, why it shouldn't work just as usual.. ??

I admit that I have only looked on the 123ignition website for the first time today - and found the installation PDF for the B18/20 unit.

In the manual - there's a BLACK wire that's surposed to go on the - (minus/ground) terminal on the coil.

The accessorie rev. counters uses this ground connection to count - so why not just cut the BLACK wire and throw in between the rev. counter (usually WHITE) wires??..

Have I missed something?

Added:
According to wirring diagrams for the 1800 series - the rev. counter is put in between the WHITE cable from "-" (ground/minus) to the distributor.
According to the 123ignition manual, the 123ignition distributor and the coil is to be connected by a BLACK cable/wire.

As far as I see, the 123ignition does not require any special "terms" for the BLACK wire - so solution is simple: Cut the BLACK wire - and reconnect it with the "old" WHITE wires (going in/out and through firewall).

I see no reason for any "modifications"??..


Final edit:

Search for 1800S on the 123igitinion's own forum (!!)

http://www.123ignition.nl/forum/read...=740#reply_740

As said - loop the BLACK wire with the "old" WHITE wires.

[Darren SV]

Great diagrams. It is perfect. Thanks a lot for your help.
I can't wait to get to the garage today to work on it. I hope to drive it around the garage.

I do need to slow down the idle. I can only see 1 screw for this - the throttle linkage screw.

[ESMAN]

Hi,
Do not use that adjuster. Idle is set by an air bleed screw. Below the air input pipe at the front of the manifold is a big nut with a large grub screw in it. Loosen the nut slightly and adjust the screw with a screwdriver to set the idle.
I have also fitted 123 several years ago and found instructions for rev counter with it. I had no problems that I can recall.

[Ron Kwas]

Darren;

Inductive link coupled 1800 Tach is known not to work with 1-2-3Ign conversion**. If it's not indicating at all (suggesting insufficient trigger voltage) you might just try two or even three turns on the sensing primary to increase this, if you can fit wire through sensing loop. See: http://www.sw-em.com/Smith's%20Tachometer.htm

To decrease idle, adjust linkage screw, also check Aux Air Regulator (See: http://volvo1800pictures.com/documen...lt_tracing.pdf Page 2.33 ) and associated hoses for a vacuum leak.

Good Hunting from Connecticut!

** Forum; I'm no expert on 1-2-3Ign conversion, but if someone with that conversion installed in an 1800 or 122 (and access to a shop with an ignition scope), can supply an oscilloscope shot of Ign Coil Primary Waveform, I would evaluate and make suggestions (if possible) on how to get OE Tach to play with it...main questions I am trying to answer is: How is Magnitude of voltage pulse, which occurs when Points open vs. when Transistor Switch within electronic module opens, different? Also, does 1-2-3Ign provide single or MSD (Multiple Spark Discharge)?

[Derek UK]

Noting the somewhat negative comments on the other 123 ignition thread I offer this from the 123 site.

Will my tachometer (RPM meter) work with a 123ignition distributor?
Yes, by far most of the tachometers work in combination with a 123ignition.
RVI type tachometers manufactured by the Smiths Company, will not work properly though.

We have found two companies that offer solutions to this problem. They use the existing rev counter and replace the electronics with another printed circuit board.
In the UK this is done by JDO-instruments ( www.jdo1.com ), and from the Netherlands
this is done by CASU-Utrecht ( www.casu.nl )

[Ron Kwas]

Derek;

Thanks for confirmation. Non-compatibility is what I understood also...but that's the superficial, non-technical answer...sometimes, we can apply some good engineering and come up with a solution...that's why I asked the question in previous post...I'm trying to understand circuit and functional differences between OE and 1-2-3Ign systems.

When I spoke to Nisonger in the US, I was told cost of an Volvo Tach OE simple rebuild is $225 (and that this result is not compatible with electronic ignition conversions)... a rebuild with conversion to make it additionally compatible with electronic ignitions is $325: http://www.nisonger.com/index.htm I have no further details or practical experience with this option.

Cheers

[Darren SV]

Thanks for all your help.

Update:
The car is running. It needs tuning for sure.
I got the tach (rev counter) to work. I just hooked it inline onto the black cable from the 123 distributor to the negative on the coil.

It is idling about 1500. It was idling about 2500 to 3000 before I adjusted it.

I slowed it down by turning the distributor a little bit (so the advance is out by 10 degrees - which my manual says it should be set to) and by unscrewing the idle screw at the end of the throttle cable. If I unscrew it any more, it runs very rough.
What should the idle be on my ES?
Any tips on how to better adjust it?

I just remembered I have a screw directly under the front of the manifold. (see pic - screw bottom right - note: this not my manifold). Is this an idle adjust screw also? I will try it tomorrow.

Thanks.

[c1800]

yes, the bottom right hand screw in the picture is the idle adjustment. the adjustment on the cable end is the throttle stop screw and is not to be used to adjust the idle. there is a procedure for setting the throttle stop screw which should be done prior to setting the idle adjustment.