1990 convertible. L98. So the tack is way, way off, and pins at just about idle. I heard about a "regulator" that needs to be replaced. Looks too easy to do. Two wires, white and brown, and it has a ground strap / screw around what looks like a metal capacitor with a metal strap to hold it somewhere. It looks to me the (white wire) comes off of the rotor and disappears down the firewall into the darkness, and I have not found the other wire and have no clue as to just where the original regulator is. Heck, at this point, I'm open to just cutting wires and finding a spot to screw the new one in. Leave it where it is, where ever that is. But if I knew where to start looking for the brown wire I might trace it to the location and take that out for the new one.

I can't find the original location of the Tachometer location and or where one of the wires (brown) is connected.

anyone?

thanks

 

The tach filter (you called this regulator) very likely isn't your issue. Where does the tach park with 'KEY ON / ENGINE OFF' The fix for the tach variance is internal to the circuitry in the cluster circuit board. There's different procedures.

The tach filter is generally bolted to the back-side of the left cylinder head and I believe the wire is white both sides of the capacitor/filter

See 8A-20-5 in the FSM. Follow the white wire at the distributor and you should easily find the tach filter unless it's been modified by someone.

 

thank you in advance!
the tach works and runs up and down but it's way off. If idling it's around something like 3K. Rev it, jumps and hits the top of its swing then drops like it got unplugged. then after letting off the gas it wakes up again and hits the top end and will go to zero if you turn it off.

I'll take another look this weekend!!

Appreciate any info on this matter. The filter actually might be what the parts book had it at - my bad.

 

The problem you have is quite common for the 90 to 96 tach go to batee.com he has some video's on it, batee is the best place to go to get the tach fixed. I have a video on the subject on my YouTube channel.

 

I had this issue years ago on my 90. The P.O cut the tach wire and ran a new one and abandoned the original line. I'm guessing they were having the same issue and thought bypassing the filter would fix the issue. The gauge was still off and through different gears and acceleration would make it further inaccurate. the gauge cluster uses ohm resistance and from what I had read was the ohms lose resistance and that's what causes the gauge to become inaccurate. ( sorry if the lingo is off and its not as technical, did the repair about 8 years ago. ). Either way, I found more info on this forum like others have said and took the task on myself. Online or on this forum possibly you can find a schematic of the cluster to know where to add additional resistors. I believe it was 4k resistance added, but please research it and don't just take that value as gold. As another member mentioned. Batee does have knowledge and offers a restoration service on it.

As for what I remember. Remove the cluster, pull the back plastic plate off the back of the cluster where a it is held in place by screws that are 7mm head or possibly smaller, remove all the bulbs in the back of the cluster. Carefully pull the plastic cover off and solder the correct value resister to the correct location on the circuit board. Found all the info on the forum and some internet research. Hope this helps.

on a side note I would consider replacing the bulbs since you have them all out. Might not be necessary but it would be a little aggravating if you pull the cluster and then have to pull it again.

 

You guys are great support! thank you for everything. I"m a little afraid to pull the dash out. but I can also tell it was taken out at some point in its lifetime. It has some shiny wood screws that clearly are not original. If I get brave enough, maybe I might tackle that. Send off to that guy for a total repair! Grandpa-pa would have wanted me to do that.

On a totally different note: Acting brave. I have taken the steering wheel out to see if I can repair the turn signal. That was more challenging than I wanted. The compression spring was a surprise. Found a cast metal half-moon that cradles the turn signal stick, just from age, it cracked off. You can't really replace that as it's the metal column for the steering wheel. Can't imagine finding another one of those. So I attached a finger loop of 14 gauge wire to the white cog that the stick moves. I pull the wire and in turn, it rotates the cog and it slides the contacts and works again! Win!

thanks again guys

 

Whoa - the step-by-step video is awesome!!! Didn't know it was out there.!! Great work Mr. batee.com You will be seeing my dash board at some point here!