The past week I've become increasingly suspect the tach was reading slow. Ear, eye, feel all telling me it wasn't right. A trip up and down the interstate today really did get my attention so I did a standing hard run of 1st and 2nd gear while keeping one eye on the tach. I'm guessing its off by half because I was at the end of the torque curve when the tach said I was 3000 but both the and my ear and "feel" tell me we were closing in on 6,000. So, any ideas how to troubleshoot? I am not familiar enough with how the tach actually reads so any nudge in the right direction is appreciated.
I had the same issue in my 88 328 and fixed it following the instructions of CliffBeer in that thread. Thanks to him for posting!
Only thing I would add is to get some sort of accurate tach instrument- photo tach or whatever - to set/adjust the car's tach rather than using a table re gearing/MPH/RPM. If you use gearing/MPH, you are assuming the speedo is accurate and at may not be PLUS if the tires are not the same outside diameter as the originals, that measurement will be off whether use the speedo or GPS for the MPH.
I don't know if this helps any, but here are the theoretical curves for the 328 with stock tire sizes -- I made this up when I was learning the nuances of the gearing. Among other things, one could use this to know how to do a perfect rev-matched downshift or upshift, but it will also help you sanity check how far off your tach is. Image Unavailable, Please Login
Have any good instructions on how to remove the tach? The process outlined looks pretty simple but not sure how difficult it is to get it out of the dash. If the CliffBeer instructions solve my issue I'll find a better way to get it dialed in. Right now the sanity check chart tells me my belief that it's 1/2 or less then actual RPM's is about right.
Common problem with these Veglia tachs, reading 1/2 engine speed. Send it off to one of the rebuilders.
I haven’t reviewed CillBeer’s notes before writing this so sorry if I’m restating anything obvious. To get it out, remove the steering wheel first. It’s only six Allen bolts. Then put a towel over the steering wheel hub. At the four corners of the instrument panel there are idiot lights. Gently pry them out and carefully thread their wires out - no need to disconnect anything - so that you can access the four screws holding the instrument panel in and then take out the instrument panel, tilting it down so you can then disconnect the wire harnesses behind it. I used a screwdriver with capture wires on the end to hold onto the screws but if they fall it’s fine, you can easily get them later. That does come in handy for putting them back though. Then take the whole instrument panel and put it on your bench or table and it’ll be obvious how to take the tach out per CliffBeer’s directions. Just be patient and it’ll all work out.
PS - you’ll have to do all this anyway if you send it out to be repaired so I figured while it was out I’d take a crack at it and it worked out fine and I saved myself $650 . . .
I started trying to work on this one today, and situation normal, it never is never "normal" Most of which I'll find a way through, possibly need a few plastic idiot light parts damaged in a prior removal of the dash. Did your capture wires on the screwdriver work for the larger screws on the bottom? the look longer / heavier. Magnetic screwdriver won't hold them at all, and want to make sure I can get them back in once I remove.
Having fun yet? Yes, the lower screws have bigger heads for some reason. Go ahead and unscrew them and let them fall. You’ll see when you take the instrument panel out that there’s a “tray” under there that catches them. The capture wires should work fine for getting them started when it’s time to put everything back. Or even some masking tape to hold them when you put them back which will easily tear free once the screw is started.
Thanks. I decided to pause to collect a couple things. - I don't have a screwdriver with the keeper wires so looking for one or another type of screw starter. - I now know at least 3 of the light inserts are broken from previous work and were sort of rigged in place or barely holding. I'll get those parts on hand (assuming i can find them). - Figured I'd get the LED bulbs for the instruments before I pull it all apart, might as well only do it once. Also found the speedo is loose, hope there isn't an issue there. So project short term postponed, but its still coming soon and I have a better feel for what i'm getting into.
Somewhere I saw a thread where replacement "keepers" for the dash lights were being remade by a FerrariChat vendor and they were more removable friendly. I can't find that thread now, can anyone provide name/company I can reach out to Monday?
