VS Tachometer bounces around

I recently purchased a 2003 VS and I have noticed that at about 50 mph, the tachometer bounces from about 3500 to 4500 rpm and sometimes from lower to higher rpm. I don't notice a change in the note of the engine or that the engine is missing. Any ideas?

Thanks, Rich

Some work and some don't...

Points?

Mine has protronics ad still does it a little...

First thing to check is loose or corroded wires. I had a poor connection cause that behavior once.

RICH MY 2000 VS DID THE SAME THING I NOW HAVE A 08 VS THAT WHEN I FIRST GOT THE CAR THE TACH WOULD FAIL COMPLETLY IN A VERY SHORT TIME VS REPLACED THE TACH TWICE STILL PROBLEMS FINALY THEY RE-ENGINEERED THE TACK USING 914 PARTS NO MORE PROBLEMS !!! CALL HORACE AT VS HE CAN HELP GOOD LUCK DAN

Neither the Chinese nor Brazillian replica tach are high quality. That said even the OEM German VDO ones could jump --- especially with electronic ignitions. Here's fix from VDO site - for $2 or so it worth a try. I believe diode filters out reverse impulses smoothing out the reading. (I had added (well, my dad did it) a Delco Capacitive Discharge system years ago to my '72 914 and had to do this to keep the VDO tach stable).

Will VDO tachs work with points ignition or Pertronix?
Answer: Yes, with diode in line on the signal lead. Instructions are as follows:
Purchase a diode #1N4005 from a local electronics store such as Radio Shack or Circuit City. Cut both ends of the diode so each is approximately 3/4

I've had 2 failed tachs on my 2007 speedster from Vintage and I'm waiting on Kirk to get it replaced. I tried the diode solution and it didn't do a thing on my car. Also, as I recall, the wiring is different on a VS car than on a CMC. I had to put the diode at the coil rather than at the tach. Never the less, for less than a buck, its worth a try.
Troy

My experience was different---I had the same erratic jumping around tach and swapped it out with Kirk a year ago for a new one. So far the replacement works perfectly.

I should add that Kirk's customer service has always been just outstanding. Good advice, good parts and prompt responses every time.

Tnanks Kirk!---Jack

Jack.
I'm glad you had a good experience getting your Vintage tach replaced for a good one. Like I mentioned, I have had three failed tachs (I said 2, buts its actually 3; none lasted more than a few months) and I'm waiting for Kirk to do something about this one. In my last email from him, several months ago, he said I was on his list for a replacement when he gets a new source for reliable tachs. In the past 3 weeks, I have emailed him twice with a possible proposal to solve the problem, but he has not responded. It's possible that he is on vacation or something, because he is usually very responsive and this is not like him, especially for a realtively minor issue like this.
Obviously, I know I can call, but should I have to? I'll give it another week, because I know he reads the list and maybe he just got busy and forgot to respond to my emails.
Troy

Troy---sorry that you had bad luck with replacement tachs. I got mine replaced over ayear ago and it has worked perfectly ever since.

There is a place in Hollywierd, CA that will rebuild a tach and they come out perfect--do a search here and you'll see that place. If mine ever goes out again I'll send mine there.

Good luck!---Jack

Jack! Where did you get it replaced? North Hollywood Speedo?

Barry---no I didn't send it to Hollywood instruments, Kirk replaced iot.

If it goes out again I would send it to Hollywood though.

I believe they put new "works" in it.---Jack

Barry,
I had the same erratic needle bounce problem with my tach and now have it at North Hollywood Speedometers. Mine is a chinese unit and will have the German VDO guts installed for around $180. Will let you know how it works when I get it back. Was quoted a week turnaround.
Norbert

I did just like Norbert a few years ago after replacing the tach twice on my 2004 VS. It wasn't working when I got the car new delivered straight from the VS shop; Kirk replaced it with one that worked for a while and later died. I then sent it to North Hollywood Speedometers to get the VDO retrofit. At the time I paid $160 and it hasn't bothered me since.

I guess I need to follow up on my 8/10 post. Received my tach within 10 days as promised with new VDO internals and calibrated. Needle steady, no bouncing or jumping. Should have done this 8 months ago.
Norbert

Just need to update here that I did finally get my new tach from Kirk and it seems to be working just fine.

UPDATE

I installed a Pertronix electronic ignition module in my 009 distributor last weekend and my tach no longer bounces.

Isn't THAT interesting..........

What used to be in your distributor, points or an electronic module??

009 with new points, rotor and cap.