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33alfa33 · Alfa Arna Joined: 16 Jul 2003 Posts: 4

I have the usual type of problem with my Series 2's speedo. It has worked fine for a few months, but now is back to its old tricks. It will be working fine but then, for example, in bumper to bumper traffic (what a place for a 33!) it will not work after being stopped for 30 seconds or so. Then after the next stop and start, it wil be working again. Sometimes it will work after re-starting the car, sometimes it stops while driving if I hit a bump in the road. All pretty normal behavior, I know.

I get the feeling this may be because I was playing with some other wires near the brake fluid reservoir. There are two thick junction blocks here, one of which on my own car has had some wires cut and rejoined to bypass the block. An auto electrician did this a while ago to fix some burnt wires which were causing a problem with the headlights.

Do the speedo wires pass through either of these two blocks? If not, how can I identify them? Does anyone happen to know which colour the wires are?

Matt Stolton · Posted: Fri Nov 21, 2003 8:42 pm Post subject: Been there

There are two 12 way connectors by the brake servo/master. Thease are power for lights etc.

The one for the speedo can be traced from the top left (viewed from front of car looking towards boot) of the gearbox, where the electromagnetic pickup is, through the hole where the brake pipes go through to a sepreate connector around the brake servo.

This only has 2-3 connectors. One is the braided screen that surrounds the other two wires. The other two wires are coloured black and red (it is very like microphone cable, if you have seen that). Corrosion or faults are common here. I modified my connector to a male and female neutrix 3 pin XLR, as used on microphones, to stop water and crud getting into the connectors. However, I can solder, and have access to the connectors (I'm a sound engineer), so may not be the easiest of mods for normal people to do (I'm afraid I'm far from normal). Certainly worth doing though, if your solderings very good.
_________________
Regards

Matt

Ex Alfa 33 'GTA' (P4 with Knobs On)
Now cruising in a 166 3.2 Ti!!

Eddie W · Posted: Fri Nov 21, 2003 11:19 pm Post subject:

Matt's answer covers it well, however I recently had the same speedo problem and after checking that plug it still wouldn't work and I traced it to the plug on the back of the instruments. The same resistence problem can occur here.
NOW, A USEFUL BIT OF INFO. Trying to clean these contacts can be a bitch and if you scratch them clean it only seems to shorten the time between services. Recently daughters new cellphone started playing up and the specialists advised cleaning the batt contacts with NAIL POLISH REMOVER. Worked a treat! It also worked brilliantly on mine which was getting erratic to the point of replacement. I believe it is the answer to Alfa plug problems. A midnight raid on the better half's cosmetic stocks should see any of you guys set up for many years of Alfa electrics. This of course may not be news to some of you but it was a re
velation to me.
Regards Eddie
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A LITTLE FURTHER A LITTLE FASTER

Rob (Perth) · Guest

CONNECTIONS, CONNECTIONS, CONNECTIONS!

Totally agree with what the others have said. Pull apart the connectors in the scuttle compartment (where the brake master cylinder is) and do a cleaning job on the metal pins. Open all the connectors, not just the ones you think are supplying the instrument panel - they all develop corrosion and resistance over time. If you can get a fine file inside the connectors to clean the metal contacts it could solve the problem - even scraping with a screwdriver or penknife blade could do the trick. Also, using pliers, try to bend the female metal connectors so they will grip better on the other half when the connectors are pushed together again. Electrical switch cleaner (in an aerosol can) wouldn't do any harm either. Finally, to repel moisture in the future, a little squirt of WD40 on the connectors should help maintain good contact for quite some time.

The push-on connectors at the back of the instrument panel can be a real bitch. I eventually decided to solder (very carefully!) short fly leads onto the pins that I identified were sending the signals to the speedo, then I cut off the plastic connector and restored the electrical continuity using a screw terminal block. Doesn't look too pretty but at least I know it is making good contact and I can unscrew the wires in a jiffy if I need to.

Good luck with your endeavours. I'm sure you'll find the bad contact somewhere.

Cheers,

Rob

ZeNiTh-PbArM · Posted: Mon Nov 24, 2003 7:09 pm Post subject: re : speedo

hi

it looks like you got the same problem i had a while ago.
i traced the culprit to be the wiring behind the dash, the connector for speedo signal wears out and no amount of cleaning or contact tightening can improve things for more than two months.
i ended up making my own wiring between the sensor and the dash, with a shielded cable soldered directly on the soft eleectric card in the back of the dash. worked perfect for me, no troubles anymore.

regards,
zp