asking this for a friend.... he has a 90 accord with a 94 jdm h22 swap which has been in there for awhile. we are having problems with the speed sensor not working. it works about 10% of the time mostly reading randomly on the speedometer. it usually reads 0 while driving when this happens vtec doesnt work and sometimes a cel for speed sensor pops up. we tried swapping in 2 different speed sensors with the same result. i then uses a multimeter and made sure the sensor had power and ground at its harness and it seams to be putting out voltage so i think the sensor is good however i may have just been getting into that 10% timeframe where it works. we tried swapping in another know working ecu just for fun with no help.
suggestions welcome on what else to look at next we are going to try running a new wire from the sensors signal wire to the ecu pin b10 i think just to see if the wire is shorting out somewhere, other than that we are stuck.

 

the only other thing it could be is your cluster. i have that same problem, my speedometer says 0, and every once in awhile it jumps up to about 60 or 40, then back down to 0. if you already tryed the VSS, then the only other thing i can think of is your cluster, gatta change it, then you should be fine

 

wouldnt vtec still work if it was just the cluster? because the vss sends signal to the ecu then to the cluster i think? ive been reading sometimes the harness goes bad so we may try changin out that plug
thanks

 

had the same problem in my 94 coupe i did a gsr swap and the speedo was jumping around at random times i replaced the vss and it still did it but with a brand new vss and correct signal and voltage. my vtec still works fine but my speedo still jumps so today i'm going to put in my sir cluster and see what happens will get back to you.