Need help

[gtst_skyline]

Ok so i have a couple of questions and i hope someone can help me. i have a 91 r32 gtst with the rb20det. First thing first my tach doesnt want to work. it sits at zero and then randomly jumps around then all the way to 9000 then back to zero. but sometimes it will randomly work and give me acurate rpm. the weather temp time etc dont affect it. any help??? second thing is my BOV is recirc but i want it to blow off to the atmo cause it sounds cool. but when i cap of my recirc tube the car runs super rich and randomly stalls out sometimes but when i leave it open it still does the same thing. any help, comments, previous experience anything???? thanks guys

[derbeck]

Well our cars work off of a maf system so a bov doesnt work so well because when the bov dumps the car has no idea the air has left the system causing it to stall and act weird so you can change to a map system that will understand the air is gone in short form. as for the tach it sounds like the clip in the back of the speedo has came loose and might just need clipped the rest of the way in it is possible that the wrong guage cluster is in the car. ie yellow and blue/green back

[Nismo_line]

my tach did the same thing. sometime work and what not. i tried to resolder the connections and nothing so i had to swap in a new cluster. as for the bov, if you want a atmospheric bov then you will get that stall every now and then. not much you can do about it

[gtst_skyline]

But doesmt our car come with a stock bov? and when its set up to recirc it runs great and i have no problems. as for the tach it is the right one and i have already checked the connection so would it be something at my ecu or at my coil? where does it get the reading from ?

[craftz]

Tacho wire is yellow with orange tracer. You will have to pull the cluster and ecu. Isolate at both ends and check for good continuity. If good, go with Nismo_line.

[DarkCaporaL]

But doesmt our car come with a stock bov? and when its set up to recirc it runs great and i have no problems.

The recirc system is there for a reason.

The car runs off a Mass Air Flow (MAF) sensor, which calculates the amount of air in the system for proper air/fuel ratios. The stock bov outlet is recirced in the intake in order to keep the proper ratio. When you dump to atmosphere, you are letting all that extra air out without letting the computer know about it, which causes a rich mixture for a slight period of time, which will sometimes cause the car to stall. There's nothing you can do to prevent that unless you switch to a MAP system like previous stated above.