Well i just got my new 355 in and running, it has prolly 200 miles on it. First problem when im going through the gears it seems that the tach and speedo cant keep up. Anything over 4k the tach jumps everywhere. Also I have a charging problem. I have a new alternator from gm maby 5k miles on it and a new optima red top battery but when im goin down the road the charge of the car drops. Also when i cut the car off and go to restart you can tell the battery is weak its drags for a few secs and slitly gets faster with each turn. Also when i first fired it up i got a code 16 everything else on my scanner turns out good. Any sugestions?

 

Check all of your grounds. There should be one from the battery to the block, one from the computer to the block(by the dipstick), and one from the head on the drivers side to the frame rail. Maybe not the answer but easy to check.

 

Thanks, anyone else?

 

Ignition problem. Sounds like opti, could be the coil or icm also, I guess.

- The coil or icm is screwing up the spark before it makes it to the plugs, OR

- The ecm is not receiving the correct signal from the opti- broken, mangled, disconnected wires, opti malfunction, etc.- Keep in mind your opti is still working, though- I disconnected the opti harness just to test one day, couldn't get the car to start after multiple attempts. When the connector was hanging halfway out of the opti was when I was having this problem.

I'd still like to figure out which wire it was that causes this- Is it high res or low res signal that would cause that?

 

Well i cant see the it being the opti being bad even tho i kno there bad to go. The car is running strong when it has good voltage. The tach is the weirdest thing i have ever seen. I have never seen a tach bounce back and forth like it does. Plus the security light comes on when the tach starts jumping. Is the car to fast for the tach? I raced a buddy of mine and we was running prolly 150 or so i was way into it in 6th and the speedo said like 130??? i dunno i love to hate hotrods haha.