Ok, our cars have a nice little RF filter that keeps the radio from picking up interference from the waves coming off the distributor!! Well, when you hook up an MSD 6-AL and you mash the gas, the TACH jumps back and forth and it's because of this RF filter thing!! Now there's a tach adapter that you can buy for $25 that you're supposed to use to fix this problem that the MSD box causes but I don't want to waste my money when I can just remove this filter thing!! I don't have a radio in my car anyway!!

I need to know WHERE this RF filter thing is at!! I have a feeling its up in the dash somewhere, maybe behind the gauge cluster but I dunno what the thing really even looks like! Can anyone help me PLEASE!!

 

If your car has the tach filter, it will be located on the fire wall, behind the distributor. It's about 1" long & cylindrical, with a wire coming out of each end. If you have a 6AL, you should be driving the tach (white wire going from the coil into the harness) from the tach output from the MSD, which is a spade terminal on the side of the box.

Tim

 

This is my friends car I'm talking about!! He said that he tried driving the tach from the tach output on the MSD and it didn't work! There's some reason why he doesn't have it hooked up to the box!!



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1986 Trans AM
305 TPI
Well over 200,000+ miles (speedo/odometer non-funtional! Odometer reads 142,000)
4 Wheel Discs
9 bolt Borg Warner Rear (2.77's....oh joy) :P
Completely Stock
Soon to upgrade to a 355 TPI, Stock TPI ported, 24#/hr SVO injectors, Hedman Shorty Headers, Dart Iron Eagle heads (AFR's in my dreams), XE262 Cam ground on a 114 LSA, Moroso Blue Max Plug Wires, external MSD Blaster II Coil and an MSD 6-AL Box!!
Current project: Keeping my 305 running until I get my income tax returns!

 

im the one with the problem ...when i floor it the tach drops to 0 and the car keep reving you just cant tell how much! i have the wire running to the msd box not the coil when i hook it up to the coil itself it doesnt work at all. when its on the msd box it works perfect...untill i floor it!! the thingy isnt behind the dis. there is acutallly one in the hei dis. but its for the pickup coil. and now with the msd box is deleted! there was this "quick disconnect on the tach wire itself and i removed it and it still is doing it so that wasnt it!! does anyone here have apic of where and what the damn thing is and looks like?? anyone else been through this?

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89 firebird formula

356 10.5:1compression
comp cams xe262 cam
performer rpm intake
#1405 edlebrock 600
sportsman 2 heads 64cc 2.02/1.60 valves 200cc intake runner
msd 6al
h.e.i. proform 50,000 volt vac. advance ditributor
700r-4 with 3.08 first gear and 3.23 posi 7 5/8 rear end.
b trans shift kit(will kill shifts...suck dong!!)
shorty heddman hedders with custom 3" pipe y-pipe back(no damn cat!) with 40 series flowmaster!


future mods: 406 roller REALLY REALLY REALLY RADICAL!!!!!

 

Just get the tach adapter. It says right in the MSD, Holley, Crane, whatever manual that if your tach doesn't work right or drops back to zero to get the tach adapter.