SAFC RPM signal help.

[folashade96]

Hello. I'm in the process of installing a piggy back ecu on a 1994 LS400. All connections are good except for the RPM signal. I've tried connecting it to a fairly large yellow wire on the end wiring loom (NE+ I believe) and it reads rpm fine when set to 2 cyl mode but stops reading correctly after 1200 rpm. I tried connecting it to a black ecu wire which I believe was either G1/G2+ and those wires are reading about 8000-9000 rpm. Does anyone know which wire is the proper one to get rpm signal from on a US 1994 LS400?

 

[gloverman]

Give an IGF signal a try. This should be very similar to the RPM signal which should also work but it located in the body plugs.

 

[stevieg]

One of the two stock ignitors connectors has 5 wires instead of 4, this 5th wire drives the stock tach and will probably work for you

 

[folashade96]

Thanks mates. I might try one of the IGF wires. I'm not to sure about the ignitors since the SAFC won't reach that far.

 

[extractors]

IGF wires that run into the ecu.

Apexi lists your car and correct pin outs, did you check the manual ?

 

[stevieg]

Trace the wire back to where it goes into the cluster and tap into that side

 

[folashade96]

I did check the manual. The only issue witht he manual is that when I was installing it, the pins weren't in the right place as the diagram shows. I got it figured out eventually except for rpm. I'll try the IGF wire as soon as I get off of work.

 

[extractors]

I'm pretty sure I have the full ecu pinouts of your car at home. By the time I get it you will possibly already have fixed it though.

 

[folashade96]

Correct you are. Thank you everyone! SAFC is reading RPM perfectly now. I was probably color blind in the moment because I swore I saw atleast 2 or 3 different yellow-black / yellow-green wires on the ecu plug. Now to get the Wideband installed and have the beast tuned.

 

[extractors]

Excellent, I have installed several SAFC over the years, they are a great unit when tuned correctly.