Hey everyone, just signed up on this forum so i'm pretty new. I'm still in the process of leaning alot of things. If this post is in the wrong section please send me the right way or post some links that could potentially answer my question.

So the GF has a 93 Civic DX that myself and a buddy did a OBD1 b18b1 swap in. It runs good, drives fine, just a few things i'm unsure about. First off, since its a DX it didn't come with a stock tach so I installed one before we did the swap(old motor was a d15b7 5speed) and the tach was accurate and working fine. After the swap it still worked, but it doesn't seem to be reading accurate anymore. when the motor is at idle it reads about(1000-750ish), but when the needle moves it doesn't go past 3k-35k at the most. It's always been wired to the blue signal wire at the shock tower. the old ecu was p06, and when we did the swap we put in a p75 5 speed ecu.

I guess the my dumb question is that I can't really think of anything that would make the tach not read correct other then a different ecu maybe? I was told to wire it directly to the distributor, so where would it be wired to if I were to go that route? would it be a blue wire also on the distributor? any help would be awsome. thanks

 

Could be a bad igniter unit, a short/open in the blue wire, a bad cluster, or a bad tach.

 

The tach is brand new, it is a cheap one but it worked perfect with the old motor so that's kinda what is throwing me off.

 

Read the rest of what I wrote.

 

I have indeed read it. im just stating that the tach is brand new so i would think that its not the tach but it very well may be one of the other things you segguested.

 

Brand new doesn't mean it isn't defective.

 

why not just use a factory lx,ex, si cluster that has a tach in it? its plug and play, and you can put your speedometer into it to keep your mileage accurate.

 

I've thought about doing a cluster swap, but is it worth it? Also I understand that its A cheap rpm tach but I'm just trying to Figure out why its so off after the swap when it wasnt before. I would think that since its aftermarket tach is wired into the the blue wire which I was told is the wire for a stock tach that it would be off even if I wired it to a new cluster such as and si cluster or something.

 

I was told to wire the tach directly to the distributor for a correct RPM reading but was unsure of which wire to connect to? I assume that it would be the wire with the circled connector in the picture with the dizzy? The other picture with the the circle is where I originally had it wired to and read the wrong rpm(stock tach wire). I just wanna make sure the picture withe the red connector that is circled is the correct wire before i go and connect wire and have something get screwed up or ruin something.

 

Hi there i have a 2002 honda civic DX i have the same problem cant fine the signal wire and where in the engine bay. People say its behind the battery. Please help. Thank you.