Tach signal made easy
 

A couple of weeks ago I installed an AEM Boost/AFR gauge that has data logging capability. It obviously already has the boost pressure and air fuel ratio information but what was missing was the engine RPM (tach signal). I contacted AEM and they sent me a link to MSD and a inductive sensor that they sell. Being inductive, it does not require you tapping into your cars wiring, it simply mounts to the 12V wire that either fires an injector or coil pack. It detects the signal using an inductive pickup and the re-creates the signal at the proper 12 volt level. Just what I needed.

Mine is on the way!

https://www.msdperformance.com/produ...ers/parts/8918

Rep points welcome!

I was having fits finding a good RPM signal for an Innovate MTX Boost/Shift gauge. This MSD GMR Pickup works perfectly. Hooked over the white/grey wire on any ignition coil. I used the one by the oil fill (cyl. #2). Set the MTX gauge to 1 cylinder/.5 pulse. All the ignition coils have a white wire with grey bands -> This is the one to put the MSD GMR on. All coils also have a black wire. The third wire varies on each coil. #1-yellow #2-green #3-blue #4-grey #5-violet #6-sky blue. The cylinder #'s from the front of engine back are 1-3-5 passenger side & 2-4-6 driver side. Hope this helps others.

rpm to failsafe wire aem
 

@wymoteeZ
anyone know if the aem let you set the mode like the MTX? I do not see it as an option. I may have missed it on the configuration page.

Tell me what AEM gauge you're talking about. I looked at their boost controller it doesn't have an RPM input. Give me the model number and I'll pull the manual and see if I can help. If you hook the MSD GMR to a single injector wire it thinks the motor is a 1 cylinder. You could also hook it to the main 12 volt feed to the injector harness and then select 6 cylinder. Your gauge might call it a multiplier? 1,4,6,8 ... basically how many spark signals will be occurring during one engine rotation.

@wymoteeZ
AEI30-4900
Failsafe boost +afr gauge
So the green wire/failsafe does not do anything unless I have some kind of aftermarket standalone? I thought it would at least have a warning or limit rpm.
Where did you hook your power to? I am told that it needs its own circuit for accuracy of information and reliability for any AFR gauge-something like a relay that could switch on/off with the key in "on" position.

Below was what I was told,
The green failsafe output wire just grounds internally when a failsafe condition occurs. It does not send any CANbus messages, but if your ECU has an analog or digital input that is pulled up to 5 or 12 volts, you can connect this wire to that circuit IF you can program the ECU to see the voltage drop as a failsafe to command less ignition timing advance, more fuel, limit throttle, etc.

As far as 12 volt power. Pull the passenger side trim panel in front of the door. You can tap into a good power source there. I think it's a big yellow wire. that's also a good power source for a fuel pump relay if you're upgrading your fuel pump.

do you mean the fuse box by the battery, new to wiring here...
wymoteeZ. I was told I don't need a relay for something so small...albeit innovate blog said otherwise for their afr gauge.
Wiring Tips, Tricks, and Best Practices To Make Your Gauge Install A Breeze - Innovate Blog

Passenger side. You're probably routing your oxy sensor cables through that side anyway, where the wiring harness comes through the boot. I'll try to attach a photo. No relay for your gauge is needed. Could not attach a photo without 'hosting' it somewhere?? email me at wymoteez@gmail.com my name is Wyatt.