I have a 01 integra with type r swap obd1 anyone ever had this issue around 5500 tach drops to 0 until I come out of vtec

 

cylinder position sensor

 

2000, 2001 integras have this issue sometimes and it originates from the use of a coversion harness. And the fact that those years create the tach signal in the ecu.

Good news is that this is an easy fix. There is a blue wire coming out of the distributor that does not have a corresponding wire on the engine harness. You have to tap into or find a spare harness with the correct pin, and run it to the tach wire in the corner of the engine bay. There is a empty plug taped up in the harness right next to the clutch master cylinder area. If you connect these two blue wires together the tach will work properly.

 

This is correct to tap into the rpm signal but it seems OP's issue is he has the tach signal but it cuts out to 0 when he engages vtec. This could be anything from a weak signal to a ICM in the distributor going bad. Generally the tach will start to go erratic and jump around and or stop working intermediatly as a sighn of the ICM going out.

OP what engine harness are you using?

 

I went through this in the past, and again recently on my own car. It was 5500-5700 the tach cut out, every time. This was on my new motor with xenocron obd1 harness and a S300 P72 ecu. I swore up and down it was the distributor, swapped the igniter and then the whole thing with another mint oem, to no avail.

Running a wire is something you can do basically for free. I suggest that gets done first.