Fixed - A32 Cefiro RPM intermittent problem

[12savefuel]

UPDATED 28 Jul 2013 Fixed - A32 Cefiro RPM intermittent problem

Hey guys just want to share, I had internittant rpm meter problem where the meter would read Max rpm past 8000rpm or flying around everywhere or it would over read. At time at start it would read ok during idle or low rpm then start to go crazy. If it was a meter problem usually the meter would be dead, since it would read ok sometimes that would lead be to believe that its a connection problem. Either rpm signal, ground or 12v power supply.

So in any case I removed the meter panel to inspect it. Found that all the copper connections were oxidized after owning the car for 16yrs. So I decided to clean all the contacts. The only way to properly clean the contacts is to use very fine sandpaper. 1500 grit is just perfect. Tear a small bit and start sanding the contacts GENTLY! The copper tracks are very thin, so be gentle and careful. As soon as you see a fresh copper layer stop.

Then you will notice that the places where the contact are indented by the male socket will not be sanded. So take a fine flat head screwdriver (the ones used for sunglases) and start GENTLY scraping the oxidation away. Once finished, just use zippo lighter fluid and a cotton bud to reclean the contacts an install.

You can see from the pics that the lower set of contact oxidized and not cleaned yet. Since the panel was out I decided to do all the contacts.

http://i1110.photobucket.com/albums/h444/jonlsl/Meter%20panel%20contacts/P7270490Small_zps2e420cd2.jpg?t=1374904970

 

[12savefuel]

Re:UPDATED 28 Jul 2013 Fixed - A32 Cefiro RPM intermittent problem

I have been testing the car and the rpm problem came back. I noticed that it would fluctuate and jerk just at start up which normally doesn't happen and when it does work properly you can see that the needle is as smooth and as progressive as it normally would. Since I also made a direct connection for the meter's earth and signal wire, its for sure not a signal or earth problem. Not a 12v problem also as the same 12v is used by the other meters.

So I removed the rpm meter and had a close look at it. I didn't find any cold solder joints that I could see but since I removed it might as well re solder all the joint.

But I did find a 16V 1000uf electrolytic capacitor on the 12V input used as the main filter capacitor. I thought this might be the problem unfiltered 12v which can caused fluctuations from a failing or failed capacitor. Since the cap is in parallel with the circuit (as used as a filter cap) the meter would still work if it was failed or removed.

So I replaced it with a 35V 1000uf unit. That is the max voltage rating cap you can go as any bigger it wouldn't fit in the space as its a tight squeeze. Nor would it help to go bigger.

So I put it all back and so far so good and the rpm needle looks nice a smooth now.

For them to put a 16V cap in a 12V circuit its very wise, when the actual running voltage is actuall 13.5-14.0V usually 13.5-13.7V. That doesn't leave you much room for reliability. Or the cap could have just lost its dielectric properties through age. But in any case 16V cap is too close for comfort. All the other smaller 1uf caps were rated at 50V so that was ok.

I went though all this trouble because I could find our local CKD A32 meter panel. All the potong kereta that I went to only had A32 Jap as expected and the meter look absolutely horrible and so old fashion. The maxima US also used a white face which I didn't really like. So I tried my best to fix it.

Fingers crossed, so far so good.

 

[12savefuel]

Re: UPDATED 28 Jul 2013 Fixed - A32 Cefiro RPM intermittent problem

Yes confirm the problem fixed and the bad capacitor was the cause. Running well now.