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Discussion Starter #1
Just had my 91 cluster rebuilt by Palo Alto Speedo (total cost close to $700).
Everything is working, but I noticed that the tach needle seems bouncy.
I'll have to post a video of what it looks like, but based on other videos I've seen, I don't think this is normal.
I'm sure PA Speedo will correct it, if in fact there is a problem, but now I have to pull the darn thing again.
 

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Maybe before removing the gauge cluster check the electrical connections? I believe the tach gets a signal from a wire at the coil - I'd make sure those connections are clean & snug. And like many things Alfa - make sure there are good ground connections. Our Series 3 Spider has a gang of black wires under a screw at the extreme left side under the dash.
 

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wow, 700 bucks. I didn't realise prices were so high these days.

no wonder I smiled when my tech friend asked me 100 to do mine (came back perfect and no bouncing).......;)

but yes, first check and clean the brown/white wire on the coil negative
then the connection 133b on the passenger fender.
rev counter dzm tacho wire connector2.jpg

If those are OK, then it can only be in the monopod itself.
(perhaps it got a knock in the post on the way back to you, as PA would have tested it before sending it out)
 

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OK, then you need to return it.
Tach needle should not bounce, at all, it is very smooth
 

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On a 91 rev counter is electronic? If still cable I thought they all bounced?

Pete
 

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I mean, I see some jitter there, but I wouldn't call that bounce, per se. Not clear that it's a problem.

Seems like maybe your idle RPMs are high or your tach is reading high at idle, BTW. It's possible they calibrated it at the high end and it's off at the low end, I suppose. Or I could just be wrong.
 

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Looking and listening to your video I don't think it's your tach. Your idle is about 400 rpm high and it sounds like you have a little bit of a miss. That wil cause your tach to bounce. Listening to it it sounds like a good tune up is needed (maybe it's just the way it sounds on youtube) but your idle is definitely high. Should be somehwere between 700 and 800 rpm depending on how accurate your tach is.
I recently had the same issue with the idle and it was an airleak from a hose that had a very small split in it. Once the hose was replaced it now purrs like a kitten

Ventura Alfa
 

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huh?
that itsy bitsy little bounce is nothing to worry about.

I though you meant it bounced all over the place.

yes, your idle should be closer to 850/900
but check that with a proper meter as it is not really adjustable on the S4....(some good DMMs can also test rpm)

Maybe clean the IAV again and check the big rubber grommet into which it fits
 
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