recently picked up a 92 dx hatch, guy did a mini swap...

put a d16z6 in it, ex cluster, and a p28 ecu.... when he had it the tach worked fine, i got it, undid the battery for something and now the tach is messed up. it SAYS vtec is hitting at 4 and rev limiter at like 5700 but it is really just 1500 rpms off cause i can tell it is pulling to 7200 and vtec is hitting at 5500.

anyone know why this is? i know for a fact its pulling to 7200 but the tach says its only going to 5700.....

 

also, i tried switching the clusters, same thing on both clusters.

 

bump

 

I too would like to know, my buddy's car does the same thing.

 

I had this happen to me when I haven't turned on my car for 6 months (had to change battery cause the old battery died). I think my idle was below 500rpms cause thats what the needle read. Well I just kept driving the car and noticed that my vtec was kicking at the wrong rpm aswell. I took about a week for the rpms to recalibrate and now the tach is back to normal. My car is a stock 93 Civic Si. So I think the computer has to recalibrate for a bit get the tach right, or someone can chime in if there is another process of doing this.