Why does the Engine fire but dies?.

The tach readout is controlled by software in the Instrument cluster (IC) based on the values sent from the VCM/PCM. The readout on your scanner should show the correct rpm values (120 to 240 is wrong). Therefore, if the engine is running normally, the computer is probably not sending the correct values to the IC, but the crank sensor is OK.

Likely the crank position sensor. That would operate the brain and the tach. You got a "check engine" light? If so, get the codes read, that will confirm or give you something else to look at.

Bad ignition module often will not set a code for itself. Hard to diagnose due to being so random. Also just possible tach feed wire is shorting somewhere, coming and going.

No Start Diagnostic Basics EricTheCarGuy Does it have spark ? fuel pressure ? Maybe your best bet would be to take it to a qualified repair shop .

Start by checking all your fuses. If not, take your time and look for any bad plugs or connections in the wiring harness. Oil or debris might be making a contact you don't need. TAKE YOUR TIME DOING THIS! Also notice Cam and Crank sensor are two different ones.

check your plug wires and or coil packs. my wife's car had hesitation problems and dying and when It died the tach always pegged out until you cycled your ignition switch and or attempted a restart.

Tach spring is breaking, you can get a seperate tach gauge in place of what you got. or how about this take dash out and get another tach gauge they are removable

Chances are its not the Tach. Look over the wiring to the tach. Its it brittle about to crust off? Is it shorted to ground? Now that would pin it. Check its connections off the coil. Engine side of this item is usually where you'll find the problem. This is nothing new with a vette definately not serious. Remember the tach responds to electrical signal it gets. Before you do the surgery on the gauge itself make sure nothing is shorting this out.

Well the only real fix for that is to replace IPC. The new one should come programmed and ready to go

Do the following:1)key in the ON position:remove the 7.5 gauge fuse.Tach needle should read "0:". 2)put it back,go on the engine and unplug the green plug on the igniter -the big one,with 5 or 6 wires on it.The needle on tach reading should be zero.If not you have a short circuit on the black wire between that plug and the plug on the conbination meter.3) If the reading is zero with the plug disconnected,the black wire for the tach is short-circuited inside the igniter. I have one available.email [email protected]