So Im on the freeway just cruising and my car RPMS at 4000 while going about 75pmh Im afraid that that to high to just be cruising on the freeway....?is it?thanks!

 

No it is far from normal. What gear were you in? You tachometer might be off

 

well I wired an aftermarket tach and i have it in 5th gear

 

I dont need to tach to tell me that my engine is running that high in the rpm range on the road. Does the aftermarket tach you installed have dip switches to set for different sized cylinder engines? is 4,6,8? maybe its set up wrong? You need to give us more info to work with here.

 

Yes it does have that on the back of the tach but I do beleive its set up right if not I will chek again just to make sure, but what should be the normal range it shoudl be operating at on th efreeway going at that speed?

 

no one can answer that unless we know what trans you are running and what rear gear you have. We also need tire size and speed. Off the top of my head Id say you should be running between 1800 and 2200 rpm depending on the rear gear being used. you could have 2.73, 3.08, 3.23, 3.73, 4.10

 

I beleive I have a 3.23 gear ratio, and im running stock manual transmission on a 84 z28

 

what tach are you running and does the stock one work?

 

I am running a Sunpro tach and the stock one does not work it reads way to wrong, just never got to fix it so decided to wire a new one instead.

 

does the sunpro tach allow you to set it up for a 4 6 or 8 cylinder engine? if so then you have to make sure you have it set up right. where is the tach getting its signal from?

 

well i just looked at the back of the tach and all it says is 6,6,6 that doesnt really help so i turned on the car fliked the switch and the idle went from about 1500 and dropped to about 500.....and im sure i wired it correctly its wired o the distributor

 

the tach signal wire (green) should be connected to the negative side of the coil.

 

correct it is

 

all i can say is that you need to make sure you have the correct tach for a V8 now. Sunpro has a lot of different tacks on the market

 

alright well ima double chek everything and thanks for the help.

 

Your tach has the number of the Beast!!!

 

yea man i would burn it. not worth the trouble lol.

sounds like you have a v6 tach though

 

Stop trolling the boards and posting useless info.

 

For an overdrive manual trans it's physically impossible for your engine to be going 4000 RPMs at any kind of reasonable speed in 5th gear unless you have some SERIOUS clutch slippage going on, and you'd know if that were the case. Or your speedometer is telling you half your actual speed.

The tach is bonkers. Or set wrong.

 

update: so this morning i actually took a closer look at the tach and yes on the back it does say 4,6,8...i guess i saw 6,6,6 since it was night time when i took a look @ it...but aparatly it was on 4, and now that I put it on 8 the tach wont go past 3000 rpms when i can clearly hear the engine rev up....is that normal or somthing going on?