well it apears my cluster is playing up. out of the blue my tacho did not respod at all 0 rpm, but my speedo was fine. it then started to magicly work again. does anyone know where the rev/rpm device which sends the signal to the tacho in the engine? (carby tn)? i wouldnt mind having a look at it or its connections.

well it apears my cluster is playing up. out of the blue my tacho did not respod at all 0 rpm, but my speedo was fine. it then started to magicly work again. does anyone know where the rev/rpm device which sends the signal to the tacho in the engine? (carby tn)? i wouldnt mind having a look at it or its connections.
It's the shielded brown/grey (depends on model. TM it's Brown, TP Grey) wire that controls the tacho. That'll be the usual suspect.

i cant find either of those wire colours on the instrument loom.

im not sure either IF its

1) the tacho itself in the cluster which has lost it

2) the sender unit in the engine (where is it located?)

3) intermediate wire fault b/w sender to cluster



now, i have reason to belive it may be the tacho itself (if i get the right wire colour i can see if any voltage is being sent to the tacho to see if its not the sender). my tacho has played up before but nohting serious, say when the cars warmed up at idle in gear, idling about 750rpm the needle violently jumps to 1000rpm and drops to 750rpm (the cars still idling smoothly - the tacho is wacky). but thats pretty rare - i think its gone altogehter now :(

anyone ?

The thick wire on one of the bigger plugs (think it's the rightermost one of the two)

It's nearly always the wire. However, if it is the cluster, I can lend you my old analogue one, if you need it.

hook up a tune up tacho to the dizzy see what that does.
How many k's has the car done?
I had same problem with my tm, eventually fixed it, if the problem is the tach itself its dead easy to rebuild.
I have some other ideas, but certainly check all connections are clean and tight first.

playin around with it more in the last 40min i relised its instrument cluster related. took it apart and saw the little circuit board which controlls the tacho, took it out and re-soldered EVERY joint on the back of it to get rid of those dry solder joints.

the thing which drives the tacho needle checked all the wires going to it and they are soldered securly and nothing is damaged.

gonna put it all back and go for a drive......

edit - oh its done 132,000kms. engine rebuilt at ~105,000kms :)

well it seems to be working now..... but for how long thats the question. now my speedo is a bit sus. i think it may be out of wack, i drive the car slowly (usualy it will show somethin on the speedo, then when i floor it it quickly jumps from 20 to 40 etc argh. need something to align my speedo.

I've got a spare analogue (TP Auto) if you ever need it.

no probs. it all seems to be working fine now. i guess it was just dry solder joints on the little controller which sends signals to the tacho needle which i touched up with fresh solder.

fantasic........ the tacho is stuffed again and it seems to be related to the heat. in the morning or when its relivly cool the tacho functions FINE. but when the cars been in the sun for a good period on a hot day (like today in melb) it stops functioning. drive home park car in shade let cool, start engine again and tacho works. it seems to be related to heat. if the cluster was faulty it wouldnt work at all (or work incorrectly). it seems like something in the engine is stuffing up. i have no clue whats going on here.

Man thats weird...Are you the one who removed the under bonnet heat material? That could be something to do with it...

yeh i have removed the sound detening it actualy helps with heat transfer. ive poped it back on and same thing. i cant fault the cluster (wouldnt mind another one to test for a few days) , im thinking its somthing to do with the signal from the engine now........ im GUESSING the signal would be obtained from the dizzy some way?

I think the tacho either comes from the coil or the dizzy, check your shop manual.

according to haynes white white wire to the coil, black to ground

pete

reading the wiring diagram, the tacho (whether it's a digital or analog cluster) counts pulses from the ignition coil. the wire is white but has a thick grey sheilding (could be brown - in my carby TM it's grey)

in this diagram (i can scan it all for you if you would like to see), there is a black (white trace) and a plain white wire joined to the ignition coil. The plain white is the other end to the wire.

Yeah, i thought so.

Any luck with it subby?

tacho feed comes from the negative coil

yeh ill look at it closely tommorow. it maybe the coil (works fine) but other components of it may be failing then again it is 18yrs old now.

well couldnt wait........ i checked the spade connectors to the coil and yup you guessed it they were LOOSE and wobbly as anything (veryyyyy easily slid off). that would explain why the tacho would work on/off as it pleased (the heat may have been a co-incidence). i rember takin a corner hard and then the tacho "sprung" to life.

tightend the spade connectors the the coil and it seems all good (tested it for 30min or so now). should be all good

your the man :cool:

He sure is TC, which must mean you arent lol :badgrin:

ill give him the benifit of the doubt :badgrin: