SPOautos

I ran a search for tach in this section since mine is acting up. I noticed that there are alot of us out there with tach problems.

DOES ANYONE KNOW HOW TO FIX THIS WITHOUT SPENDING A TON OF $$$$$$$$?????

Is there a connection somewhere thats easy to check??? I hit a bump and it started going crazy, after about 15 miles is just died and now sits there at 0.

Also, the rpm display on my power FC still works fine.

Thanks,
STEPHEN

G 's 3rd gen

I have the same F$cking problem!! My tach is eratic unless I am at WOT! PLEASE someone help us fix! Do we have to go into the instrument panel or is it accesible inside the engine bay?!

SPOautos

surely SOMEONE has fixed this problem and knows what the deal is!!!! I'm not going to take my dash apart for nothing, I'd like to know for sure whats up before ripping into stuff.

G's 3rd Gen......How do you like living in Daytona? I go there every year for bike week the 1st week in March. The locals probably hate bike week....hehe

I have fun though!!!

Later,

Greys 10th

>BUMP<

7at11

I am working on the problem now; mine may be related to my ignition wires, since when I press them on very tightly (MSD 8.5mm) the problems temporarily ceases. This is because the two wires coming from the center section of the ignition were too short for comfort; MSD is sending me longer ones now. Check your wires and hope for a miracle, I don't wanna replace my tach either!

maz_boy

i have this problem too. i am in australia.

maz

7at11

Every time I jam the ignition wires back onto the posts, the problem ceases...then always returns. I think I may try Jacobs wires, but our problem is still one in need of HELP! I bet I'll pay a grand to get my tach replaced or even have the problem looked at by a "professional."

dgarvich

I was quoted $470 for a gauge cluster from my local Mazda dealership. I didn't check their fee for installation.

Taking the dash apart really isn't *that* hard. Replacing the stock gauge cluster with another OEM gauge cluster wouldn't be too hard of a job if you're mechanically inclined. You can take a look at my site under the current tech project to see what I'm doing to fix my eratic tach. Should have it done this weekend! I can't wait!

potatobbq

i posted this in the tech support section but it looks like people are having a discussion here so... help!!!! is there a special tool or method to remove gauge needles? i was trying to recalibrate my tachometer because the previous owner installed white face gauges and messed up the calibration but when i pulled it off, the black plastic piece of the needle broke... i tried gluing it back together and when i put it back on it seems like the glue added just a slight amount of extra weight to the needle that the tach is even more inaccurate. i'm going to try to get an extra needle but does anyone have any suggestions on calibrating the tach? i know my car idles around 800 rpm according to an external reading but when ever i take off the needle and try to put it back at 800 rpm, it seems like there is a little bit of "play" on the tach and the reading will drop a few hundred rpm where i place the needle. for example, to get the needle to actually "settle" at 800 rpm, i have to initially place the needle at the 1300 rpm position and then once on the tach, the needle will drop to 800 rpm. i don't know if it's just the slight added weight by the glue or if my tach is really broken or what. any help would be GREATLY appreciated! i need to get my car running again...

mpetersrx7

Stephen,
I remeber someone on the bug list talking about this problem. I believe the solution was bad soldier joints. Ahh found it in the archive.

Quote from big list:
"You need to remove the tach unit and resolder the connections on it. I am
going to do a
how-to in the very near future. I have looked at several "bad" tachs and
they all had
multiple cracked solder joints. Resoldering all of the joints (there aren't
too many) corrected
the problem."

You can search the archive for solder and find it.

When is the IC group buy? Any pics of the ducts?

-Mark

mpetersrx7

Here is more info:

"Subject: Re: (rx7) RX-7 [3] Inaccurate Tach Problem


The solder joints on the surface mount components were all fine on the
units that I have seen. If you take a look at the circular solder joints (on
the
non surface mount components) with a magnifying lens, you should see a
circular crack that runs between the component leg and the outer perimeter
of the solder pad. Those cracks cause intermittent connections and varying
resistances between the components."

7at11

Thanks a bunch for the know-how. My dealer quoted new tach $570.....

SPOautos

I found out that my problem wasnt anything like that. There is a wire harness that runs across the front of the car, if you bend over like your trying to see up into the bumper you'll see it running along the top right there.

Well, mine had a short in it. Somehow I cut into the plastic of one wire just a little and the bare metal of the wire was hitting the car body causeing a short. The wire was the one that runs the tach. I wraped a little elec tape around it and wala....its fixed.

BTW - the gouge through the plastic was so small I could barely see it. I have a Pettit intake that I'd been taking in and out alot and I think i cut it with the heat shield peice.

Later,

7at11

What color is that wire?

SPOautos

seems like it was a white and red wire facing the engine but its been a few weeks or so my memory has been thru alot since then......I'll look when I get home tonight and see if I can tell

Later,

7at11

Thanks for the help, I want this problem fixed so badly.

SPOautos

I'll have to pull that intake heat shield out to see it and I havent had time, I've been real busy with work and stuff. I'll try and do it this weekend.

Later,

7at11

Hey, you don't have to do all that, I can probably find it in a wiring diargram online elsewhere. If you're working on it anyways that's cool, but you don't have to on my account.

G 's 3rd gen

Most people take to the bike crowd really well. Its fun to see so many different types of people. Everyone is having such a good time and we get to see some crazy **** at cabbage patch every year! I only wish wish there were more rotorheads around. Its tough only knowing one other person in town with an rx7. Maybe will see ya in 2002!

G 's 3rd gen

Thanks for all the tach info guys. I am going to start weeding out the problem to my crazy needle!!

7at11

mpetersrx7~ I cannot find that thread on this forum, do you have a link?

Everyone~ I've set this weekend aside to fix the problem, if you know of any pics or details of gauge replacement, fill me in, I hate interior work cause I usually brake stuff becuase I don't know how the little clips and clinks and pop fits all work. I know I can get manual pics off of www.iluvmyrx7.com but looking for more detail.

Thanks kiddies, happy rotoring.....

7at11

My gauges are apart in my living room, can someone tell me exactly what to resolder?? AHH! Help!

7at11

well, I found the cracks, now I just have to figure out how to get the needle off so I can get to them...I'll post the whole procedure when I'm done if i get it.

G 's 3rd gen

Thanks!Let us know!!!

7at11

Well, I can detail the entire process now.... to get to the dash, take of the steering wheel column cover (two screws, then gently squeeze/pull apart) then several screws to loosen the gauge cluster part of the dash (see RX7 manual at iluvmyrx7.com for diagrams). Three very tight push clips hold this part of the dash around the top. I used a screwdriver to pry apart the two sections of the dash to an extent and pulled and wiggled to get it off, it was quite difficult. Be very careful to watch the rest of the dash when you're pulling, as I pulled too hard and have a some misaligned pieces now (rampant cursing.....). There are about six to eight wiring harnesses to unclip, I had someone in the passenger seat reach over while someone outside the car looking in the windshield guided them, because the wires are very short and don't allow much visual inspection. Unclip all those by squeezing the tabs) and twist to loosen the light for the cigarrette lighter and it will pop out. Then remove that section of dashboard from the car. Several screws hold the cluster into the dash, remove these and press in the clips from one side to the other to separate the two halves. This can be difficult, as the clips want to pop back in as soon as you go on to the next one. You can use pennies inserted between the halves to keep them apart, and more than two hands helps as well. Then unscrew the tachometer from the plastic base. Apparently the solder joints that were cracked on my tach (as described in other posts) are the round ones on the very back of the tach... they are hard to find the first time, and are between the white plastic electric part of the tach and the face...look between these two pieces to find them. Mine were indeed cracked, exactly as described elsewhere. You must remove the needle to get the face off. Be careful with this, it is easy to break. The flourescent part of the needle is what is attached to the motor, not the black. I held the needle portion with thumb and forefinger on both sides of the black and used leverage against the gauge face to pull it off... seemingly no other method/amount of tugging worked (you must be firm, but pull it straight up!). It is tight.

With the needle off you can separate the face from the motor and get to the joints. I resoldered all of them, even though only a couple were cracked (use a magnifying glass to see better).

Now, with all that said, beware that this DID NOT fix my tach problem, even though my solder joints were definately cracked. I am going to take everything apart again this weekend and try again. The posts underneath the joints could also be cracked apparently, and I will inspect those as well. My problem has also seemingly been ignition wire related, so it may be a combination of things. Oh, and I didn't get the needle recalibrated correctly either with the method I used.... so if anyone has a sure-fire method fill me in. I have confidence this is at least part of my problem, if anyone has any questions PM me I'd be glad to at least offer more of what was involved.