Tach signal question - PeachParts Mercedes-Benz Forum

Fatmerc89 · #1 02-09-2022, 06:50 AM

I’m soon starting an EFI and turbo conversion in my 89 300se. I’ll be using a haltech ecu soo will be wanting to remove any of the old harness that controls the engine. Which wire from the ignition module provides tach signal to the fuel pump, instrument cluster and Klima relay? I want the tach and a/c to still be functional. Has anyone got the wiring diagram for the engine harness?

Frank Reiner · #2 02-09-2022, 10:33 AM

Fm:
The TD pin on the ignition controller (EZL) is the source of the engine speed signal.
If you retain the EZL to operate the ignition system it can be provided with a trigger signal from the new ECU, or from the existing flywheel trigger.

Fatmerc89 · #3 02-09-2022, 04:38 PM

Quote:

Originally Posted by Frank Reiner

Fm:
The TD pin on the ignition controller (EZL) is the source of the engine speed signal.
If you retain the EZL to operate the ignition system it can be provided with a trigger signal from the new ECU, or from the existing flywheel trigger.

Haltech will be handling fuel and ignition soo EZL will be removed. Soo if I connect the tach output on the haltech to the wire that connects to the TD pin all should work ?