tacho going crazy

Anthiron The Baja Rejuvenation Begins

4,936 posts · joined Oct 2003 · 5 May 2008, 5:06 pm

#644288

my car hasnt been running at an ideal standard lately.

and ive noticed that recently the tacho seems to skip up and down in rythym from 0 to engine speed up and down up and down and so on. usually only till around 2000rpm when i behaves normally. sometimes is does it and sometimes not. is this the tacho wire earthing? stuck points?

i did put in new plugs which were one stage colder than my old plugs as they had none of the ones i wanted and changed the points and condensor. would this affect it at all?

engine is idling lower than normal and is more sluggish from cold start etc than normal. also sometimes hesitates on accelleration.

i recently started a post on a problem is was having with the engine stalling at random. which i think was the idle cut of solinoid flicking on and off while driving. i have since fixed the connection and blown out the idle jet to be sure. it was after this that the idle dropped.

any ideas would be great

thanks
Nicko

62/60 model bug eye baja bug, (Full Build in Progress)
1974 Chevrolet Luv
1970 MK2 Ford Cortina GT
1979 Yamaha RX125 Two Stroke tracker project.
2004 Harley Davidson Sportster XL Custom

Joel Now containing 100\% E-Wang

9,368 posts · joined Feb 2006 · 5 May 2008, 5:24 pm

#644290

how old are ur plug wires?

if the tacho wire shorts out anywhere u'll no cos the engine will stop dead
makes for a good kill switch- grounding the tacho wire somewhere hidden

Anthiron The Baja Rejuvenation Begins

4,936 posts · joined Oct 2003 · 5 May 2008, 5:46 pm

#644296

just figured out the pulsation is when my indicators are on, so i should be able to fix that pretty easy.

plug wires are high quality items that i had made for my car about 2 years ago.

62/60 model bug eye baja bug, (Full Build in Progress)
1974 Chevrolet Luv
1970 MK2 Ford Cortina GT
1979 Yamaha RX125 Two Stroke tracker project.
2004 Harley Davidson Sportster XL Custom

vw54 Administrator Always Waiting 4 Friday

16,723 posts · joined Aug 2002 · 5 May 2008, 6:00 pm

#644305

check the earthing or the wiring and make sure its good

Some Tachos require the pulse lead to be looped to act as a dampener
( i dont understand the jiggory of electronics ) but i remember i had a VDO tacho a lot of years ago and there was a special insulated plastic block on the back and fitting instructions stating a loop was required in the pulse wire

I read it on FACEBOOK so it must be true

http://forums.aussieveedubbers.com/viewtopic.php?tid=91278&page=1#pid848630

http://forums.aussieveedubbers.com/viewtopic.php?tid=63561&page=1#pid624099

http://forums.aussieveedubbers.com/viewtopic.php?tid=4832&page=1#pid452603

http://forums.aussieveedubbers.com/viewtopic.php?tid=60650&page=1#pid574409

Joel Now containing 100\% E-Wang

9,368 posts · joined Feb 2006 · 5 May 2008, 7:02 pm

#644317

some of the newer tachos are real shits about working in old cars with points cos there all mainly only fitted to computer controlled EFI cars these days

my splitfire tach refuses to work with points but is fine when i have my pertronix in
ive heard the trick with this is an inline diode
but if its only with the indicators on its something else
where abouts are u getting power for the tacho?

Anthiron The Baja Rejuvenation Begins

4,936 posts · joined Oct 2003 · 8 May 2008, 10:01 am

#644864

if i run the tacho with constant power will it drain the battery slowly when the engine isnt on or is this ok to do?

62/60 model bug eye baja bug, (Full Build in Progress)
1974 Chevrolet Luv
1970 MK2 Ford Cortina GT
1979 Yamaha RX125 Two Stroke tracker project.
2004 Harley Davidson Sportster XL Custom

General_Failure Use your head, don't abuse it!

1,036 posts · joined Jun 2004 · 8 May 2008, 10:28 am

#644872

I await hearing a resolution on this.

Years back when I made a digital tacho kit from Dick Smith or Jaycar, I tried to use it on the S beetle but it was just totally berzerk. The revs were all over the place. But when I tested it on the van it worked perfectly. Never understood that one.

DUB74L, would using the tacho wire as a killswitch damage anything? I'm just asking because it seems like a great way to fit one.
I can also fit a no-start switch to my van if I want. Because it used to be an auto it still has the interlock wiring, just plugged together so it can start. A switch in there and no starter either 🙂

If at first you don't succeed. Build, build again.
Vehicle: 1975 Special order delivery walkthrough panel based LCA pop-top camper. Motor: Nippon 1.8L Single port Wasserboxer, Transmission: 3 rib 002.

68AutoBug Beetle Restorer - Experience over 138\% - YIKES --

11,654 posts · joined Aug 2002 · 8 May 2008, 11:19 am

#644879

Anthiron wrote:my car hasnt been running at an ideal standard lately.

i did put in new plugs which were one stage colder than my old plugs as they had none of the ones i wanted and changed the points and condensor. would this affect it at all?
thanks
Nicko

this happens to many people who don't go to a VW Shop for spares
ALL VW shops stock the standard VW spark plugs and other electrical items

The auto shops aren't interested in stocking parts for 30 year old cars...

Lee

- Helping keep Air Cooled VWs on the road - location: SCONE in the Upper Hunter Valley - Northern NSW 320 kms NNW of SYDNEY---