The tach on my 84 project car stopped working and I'm having a hard time fixing it. I checked all the connections in the engine bay, so I thought it must be in the dash, but I pulled the cluster and didn't see anything loose, so I cleaned the connections and still nothing..... is it time for an aftermarket tach?

 

check your trailing ignition

 

I checked the connections, I will have to a a full test later when it cools down.

 

Thats all you have to do is see if the trailing plugs are firing.

 

mine some times works but sometimes doesnt so i am just getting an aftermarket

 

FYI - buying an aftermarket tach won't fix your root problem which is that your trailing ignitor has blown out, and you're not running trailing ignition anymore.

Has your power and fuel mileage dropped off lately? (You DO check fuel mileage as a means of diagnosing problems with your '7, right...?)

Easy alternate check is to move your tach lead from the trailing coil to the leading coil on the same pole and see if your tach starts working again. Here's a picture for the 'hard of reading';


Note location of the single blue spade connector on the black wire that triggers the ECU and tach signal - here, it's mounted in the correct location to be triggered by the trailing coil firing.

 

Well the problem I have is that I have no normal wires left on this project car. When the previous owner did the 13b swap they rewired a lot of it. When the problem started I didn't have the car, I had loaned it to a friend for a week. After digging through the wires I found a fairly long red wire loose in the engine bay, but I don't know if it's related or not. I have serveral wires and hardlines left over from the swap, but they were never terminated so I don't know which are left overs and which are something that just came loose.

If I emailed you some pics do you think you could take a look?

 

I was gonna say it couldn't be trailing ignition or he would have no fuel either, but if the whole thing is rewired, maybe he has a different than stock juice line to the fuel pump so even with no trailing ignition he is getting juice to the fuel pump.

So casper, did you see if you have trailing ignition?

 

mine works every once in a while when it feels like it so it must be a loose wire. so i just wanna go aftermarket anyways

 

ok so from these picks the black wire controls the tach and fuel. Some idiot moved it to the leading on mine. That would explain why after moving to msd on leading why I get no fuel. So the leading ignitor has the green and yellow - side and black yellow on pos. trailing needs black and yellow on + side and black and yellow green on neg side. Is this correct?

 

woah... uh the black is the trailing and the blue is the leading (connector covers)??? and where the hell did you find that tach wire.... i have no such thing.

 

i took my trailing off at the distributor and no change in performance... that suckers blown.

also i think you have it backwards budmanracing, i could be wrong though, because my car runs like crap.

 

I dunno about wrong. I rewired everything added a jacobs and some msd coils and I am running like a champ. I think I have pics of my rewire on another post if so I will add them here. I did this last year and have had no issues at all.