astrozombie1138

So.....I was driving my car this morning and my tach decided to freak out on me. It would not go any higher than 2500 and then it started jumoing around all over the place. The car seems to be running fine and I don't know what the problem is. Also, it seems like I am losing boost in 3rd and 4th gar when I get near redline. Is this a normal problem or is it something that I ned to look into further.

astrozombie1138

bump....please help

No-Pistons-TT

could be alot of things i would just suck it up and take it to a dealer. before that check your factory service manual. if you dont mind reading through it. if you dont have one iluvmyrx7.com has them online. good luck lets us know how it went.

as for your boost problem sounds like your hitting fuel cut caused by over boosting. what mods do u have on your car? also are you seeing a loss of boost on your boost gauge or does it just feel like your loosing power.

pyro_racer_0016

i have the same problem but mine won't go over 1500 car runs fine but occasionally i will start the car and it will work correctly for a min or two. sometimes however it will begin to work again and will for sometimes up to ten min or throughout a short trip it will either stop working when i shut of the car and restart it or while i am driving i have heard of solders on the back of the tack cracking and not sending the signal correctly or of ecu to tach wiring harness problems

astrozombie1138

thanks guys....just trying to figure this out. Also, when I get toward red line in 3rd and 4th it maybe my gauge ios telling me wrong and i could actually be near redline

AgentSpeed

Take it to a dealer, are you crazy?!?!?!?!?! That's a bad idea unless they are well known to be knowledgeable.

Do a search on "tach" and a bunch of information will pop up. Mine only works when it wants too now. That's my project over the month...

petros_rx7

Dear astrozombie1138
The things is not so bad.
I have the same problem and I fix it.
First of all you must have basic knowledge about electronics soldering , desoldering and some tools soldering iron with thin tip 30-40watt ,desolder pump , solder wick and flux if you can find it.
Now you have to remove the instrument panel is easy it have only 2 screws left and right under the wheel.Unscrew it and pull soft the instrument panel (if you have gauges at the left you must first take out ).
When the instrument panel come out you have to disconnect the connectors but first take a marker and mark connector and cluster so when you have to connect it again you know the corect direction.
After you have in your hands the complete instrument panel you have to unscrew it and take off the tachometer it is easy only screw and some clips you find.
Here is some pictures

http://i24.photobucket.com/albums/c1...MAGE_00025.jpg

Now you have to seperate the tach pcb board from the plastic.To do that you have first take out the needle take a screw driver and put it between needle and black card with numbers and push very soft the screw driver downward.After that in corners you find little plastick covers turn the tachometer to look the pcb board and take a thin screwdriver and push the center of this plastic to take it off.
Know the card with tachometer number can easily take off and you can see 2 screw unscrew it and you have the pcb to your hand.Mark again the direction of pcb before you pull out so you can know the direction when you assemble again.

http://i24.photobucket.com/albums/c1...MAGE_00027.jpg

Finaly the pcb board have 2 big capacitors one electrolytic 1μf /50 v and one mkt 1500pf/50v ( before change this capacitors check it by your self because maybe yours tachometer have other values) you have to desolder this capacitors and replace it with new one.
After replace capacitors resolder all the pcb board and specialy the IC to be sure that there is no brake solder on it .
Assebly the tachometer and with your hand turn the tachometer complete left (unclockwise) before you install needle, if you sure that tachometer is complete left then attach needle normaly must be in possition 0.
After that is to replace some capacitors on speedometer but you dont have to disassemble that.
Replace all the capacitors 1, 2,2 47, 1000 μf and one more mkt 15000pf/50v (located under 100km/h -140km/h the uper side of speedometer as you look it.)
Final step is to check and clean very well with electronic spray ( I suggest blue philips without oil )the flex connector on the speedometer and on cluster too if it necessary use very very thin number sandpaper to take off the dirtiness.
Also I suggest you to clean all the contact on the cluster with the same way specialy this on speedometer and tachometer (the contact is the screws clean and scerws )
After all that you aer ready to assemble the instrument panel and install it into your car.

http://i24.photobucket.com/albums/c1...MAGE_00029.jpg

Good luck
If you not sure what you are doing go to electronic specialist.

Take off the negative pole of the battery and put it only when you sure that everything is ok and connectors is in correct possition dont forget to mark it before disconnect it.

Also service manual be helpful

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/94-fsms-available-download-449950/

Sorry for bad English

technomentor

iTrader: (18)

There is a DIY write-up on this also. Similar instructions to what petros_rx7 posted. I chose not to go that route since I amnot an electronics person and soldering very small components is not what I am good at. I just swapped in a tach from another guage cluster and everything works okay...except that I used a tach with cruise control in my R-1 and forgot to cover the light hole.

Richard

astrozombie1138

thanks guys....looks like it is going to be a bigger job than i thought.

illusion38

iTrader: (1)

I am just about to begin this process. I have a jumpy tachometer as well as a mis-reading speedometer. Since occasionally both read accurately is it fair to assume I do not need to replace the capacitors and just re-do the connections. I would like to avoid re-soldering EVERY joint, is there a specific couple that are prime indicators of misreading speedo and jumpy tach? Any advice would be great.