I have a '92 Camaro Z28 with the stock tach and Haltech DFI. I've noticed that the factory tach is faster at idle by ~150 rpm, and by 5600, its buried (over 7000 rpm). The rpm numbers are what the DFI shows I'm running. When I hit the rev limiter at 5600 rpm, the engine sounds like 5600 rpm, not over 7000. Any suggestions.

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1992 Camaro Z28; Engine:383 w/Edelbrock RPM ported heads. Lunati Solid Roller Cam 224/232 .502/.502, Fluidampr, 1.5 Roller rockers, 30 lb injectors. Haltech E6GM DFI, SLP 1 3/4" headers, 4" Mufflex, T56, 4.10. Super Ram.

Mo steel for Mo stremph!

 

The Haltech is probably correct.
To find out for sure get a third opinion. Hook up tachometer #3 and see what it reads.

To correct the factory tach you will have to take it out of the gauge-cluster circuits and wire it directly to your ignition with a good ground.
Most people just swap to an aftermarket tach because it's easier and is quicker reacting.

 

Every once in a while, the tach will jerk and jump all over the place. Do you thinks its the electronics in the cluster, or a bad signal?

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1992 Camaro Z28; Engine:383 w/Edelbrock RPM ported heads. Lunati Solid Roller Cam 224/232 .502/.502, Fluidampr, 1.5 Roller rockers, 30 lb injectors. Haltech E6GM DFI, SLP 1 3/4" headers, 4" Mufflex, T56, 4.10. Super Ram.

Double-Pump This! EFI Rules!

Definition:

NOPI: n. 1. import 2. Sticker worth 47 hp 3. import with 6" exhaust tip
antonym: smallblock