Probably trivial, but if you had a problem like mine below, to check your RPM gauge is reading correctly just disconnect MAF and step on the gas, watch the RPMs they should be 2400-2600. If you like to read the whole story keep reading.
1990 240SX Hatch with a 98 KA24DE (soon to be +T). Stock internals, SR20 370cc, FPR, Walboro 255, AEM F/IC using MAP reading.
I replaced the gauge cluster to have the original black background ones (the owner before me removed the black and put the blueish white crappy ones from ebay) and came to the problem of having to remove the needles to replace the faceplate of each gauge. I did try my best at measuring and putting them back together but I soon found out the RPM could be reading wrong. I dialed it in while the plastic cover was out and I was driving around. The counter weights on the needles seem to move around pretty easily. I struggled looking for a way to correctly measure RPMs and be sure it was okey since I do not have OBD2 port and our timing light pistol was stolen
So I came to the idea of connecting another RPM gauge or have my multimeter check the frequency on the injectors and what else not. Suddenly I moved to Michigan to work for Chrysler so I left my 240 at home.I am heading back home after 6 months to work on my 240 (goin turbo oh yeah) and had a realization this morning. Just disconnect MAF, RPMs should read 2500ish. if there is an offset I will be able to read it and dial it correctly.
