Tachometer is not working.

#1

The tachometer on my car is not working. The previous owner (Mark) said it worked intermittently and then just stopped working completely so he installed a shift-light, but I would like to regain the std tach as well.

I tried replacing the cluster, but that didn’t work. I verified that all of the fuses are good and I’m wondering what else I should look into to? Maybe the batteries in the cluster are shot?

If it’s a lost cause I’d like to install an external tach. Any suggestions on what you guys are running?

#2

Is the car an “e to i” swap car? If so, there’s usually a little black wire over by the DME that gets neglected. When it wiggles loose the tach will go intermittant, and then when it gets a bit looser the tach goes the way of the dodo bird. Resecure little black wire, tach comes back.

#3

If you are going to replace with an aftermarket tach then I would replace your entire cluster with aftermarket gauges and make a panel to house them in where the stock cluster would go. Thats what we did with my car. I run a Autometer 5" tach, oil pressure gauge, oil temp gauge, and a water temp gauge. I don’t use my shift light as a shift light. I have it mounted on the dash and it is wired to be a low oil pressure warning light. Hopefully I will never see it come on. :laugh:

#4

That’s a great idea. I already have autometer oil pressure/temp and water guages. So that makes perfect sense. Do you remember what model tach you went with?

Do you have a picture of your cluster handy?

#5

I’d love to see a picture of that dash as well!

#6

No the car is at another location about 45 min. from where I lice and I drive to and from on the weekends to work on it. The other half is really getting tired of me being gone. :angry: I should be able to get one this weekend and I can post it. I also have another mounting plate where the radio would go that houses all my toggle switches for my fan and what not. I will get a pic of it as well.

#7

poke poke :smiley:

#8

To bring this back up…it looks like I’m going to go in this direction also.

Pics please! :slight_smile:

#9

no fuel gauge? do you always run full? always run empty? drain the fuel tank between sessions and fill to the desired amount?

#10

laz wrote:

Err, subject is tach and custom instrument panel. :slight_smile:

#11

rrroadster wrote:

[quote]Err, subject is tach and custom instrument panel. :)[/quote]I was talking about theironman9154’s dash. He said he replaced the cluster, but didn’t list a fuel gauge :slight_smile:

#12

Whelp - getting the stock tach working is still on my list of things to get done over the ‘winter.’ I just got a gauge cluster from Al and he confirmed it was a working unit. I swapped it out today and still no tach function. I’ll verify the black wire that was mentioned before, but are there any other things I should look for?

#13

I hope you figure this out. My Dad has the same problem and I haven’t had time to troubleshoot…

#14

i know this is basic, but have you checked fuses rob?

#15

kishg wrote:

I have.

#16

FWIW, I believe the tach signal comes out of the ECU through a three-prong connector (C101?). If memory serves the wire colors are black, green, & blue (I’m not sure about that but I think the tach signal was the black or blue/black wire). But you might want to check that connector.
–Fred

#17

Fred42 wrote:

[quote]FWIW, I believe the tach signal comes out of the ECU through a three-prong connector (C101?). If memory serves the wire colors are black, green, & blue (I’m not sure about that but I think the tach signal was the black or blue/black wire). But you might want to check that connector.
–Fred[/quote]

Fred,

That’s a good point. The tack signal must be in the C101 as it’s the only interface between the engine harness and the car electrical system except for the battery power. There are slight pinout differences between the early and late C101 connectors. The pinout diffences could explain the problem. Rob, has your tachometer ever worked with this engine harness?

#18

I recall the previous owner saying that the tach was intermittent and just stopped working. It never worked for me. He installed a shift light which gets the signal from the ecu connection. The shift light also tells the rpm and it has always been working.

#19

Fred42 wrote:

[quote]FWIW, I believe the tach signal comes out of the ECU through a three-prong connector (C101?). If memory serves the wire colors are black, green, & blue (I’m not sure about that but I think the tach signal was the black or blue/black wire). But you might want to check that connector.
–Fred[/quote]
The routing of the tach signal is a function of the production date of the car. Early cars (up to 8/87) take the tach (and econometer) signals off a three pin connector pigtailed off the engine harness near the DME connector. Later cars route the signal through C101 (the round connector next to the fuse box). So it matters that the engine harness and car have to match up.

#20

[scratching my head]

Does this diagram state which wire(s) are for the tachometer?

This image shows the gauge cluster connectors.