Adrianls4

I recently upgrade my ecu to on my 1995 Lexus SC300 2jZGTE with a megaSquirt. I bought it with a custom harness that came off a 1989 supra. Everything works fine except my RPM. I tried to have the wire that goes to my tach connected to the megasquirt but no luck. I have also tried two different clusters to see if that was the problem but no luck. If anyone has run in to this problem and can help I would appreciate it.

Thanks,

Adrian

LexIS007

iTrader: (1)

Don't you need a signal converter from the ECU to the cluster (i.e., Dakota Digital box, etc...)?

RudysSC

LexIS007 has it right - you need to convert the old signal to the digital form that MS3 will accept. I believe a Dakota Digital will work, but contact MS directly and they'll help you!

zazzn

Mk3 supras use a mechanical gear to spin the dash which then generates a signal. Newer cars like the SC use a sensor in the trans which sends this info digitally to the dash through a sensor.

You need get the speed sensor from the body connector on the SC300 (don't know which since I know mk3 supras) and wire it to the megasquirt.

Does the harness still have the M1 connector attached?

Looks like this

If so you need to find the wire that would connect to the speed sensor (if you removed your stock harness you probably removed this sensor wire) and connect it to the ECU.

Normally the speed sensors are in the transmission. So look for a transmission connector that is not hooked up there is usually 2. ABS and the Speed Sensor.