When using an AEM Failsafe what is the best way to wire in the failsafe to save the engine?
Thanks,
AEM Failsafe?
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The only way is to have it shut down the ignition really. The ecu can’t receive exterior signals to trigger a limp mode or whatnot.
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When using an AEM Failsafe what is the best way to wire in the failsafe to save the engine?
Thanks,
Unless you have an electronic boost controller, the AEM failsafe gauge by itself can not cut boost. There is a combo Innovate gauge that monitors boost pressure and air/fuel and is also an electronic boost controller that can cut your boost back to spring pressure if air/fuel or pressure goes above limits you set.
The AEM failsafe though can be wired to a relay to cut ignition like @iNewton mentioned as an option. There is a common 12 volt supply to each coil you can run through a relay, that the AEM failsafe could open if you go above the limits. You could also wire the relay into the fuel injector common power and/or cut fuel also. Do not wire it into the fuel pump to cut fuel though, since that will slowly decrease fuel pressure and cause a lean condition before cutting all fuel.
Hope that helps,
Dave -
The only way is to have it shut down the ignition really. The ecu can’t receive exterior signals to trigger a limp mode or whatnot.
It would appear the ECU's inability to accept external signals is also a problem with the Innovate Motorsports SCG-1. As @Dave@DDMWorks posted above, it's a combined AFR/Boost gauge and can be setup so that out-of-range AFR or Boost readings can operate a solenoid to reduce boost to whatever your basic spring setting is. I would think that if a 3 lbs+/- spring were used to set a base boost level and the solenoid was then used to control boost above that level with boost dropping back to 3 psi if a problem is detected would be a good thing, but, unfortunately, I have NOT read or seen any postings where anyone claims to have gotten the SCG-1 to work smoothly with our ECU.
I have the SCG-1 and have it monitoring AFR and Boost and am finally getting around to connecting it to the ignition system so I can track AFR & Boost vs RPM. I also use the PL-1 Data Logger from Innovate to record the AFR & Boost levels, but w/o being able to match both to engine RPM, the info doesn't really tell you enough about how the system is working.
If the Solenoid Boost control system isn't going to be used, Innovate recommends using their cheaper PSB-1 AFR/Boost combo gauge.
I would certainly like to know if anyone has figured out how to get the SCG-1 to work properly with the Slingshot's ECU. -
Is there a way to intercept the rev limiter built into the stock ECU and have the failsafe in effect fool the ecu into applying a rev limiter until the failsafe perceives "normal" conditions?
As I was typing the above... it occurred to me that maybe the traction control limiter could be intercepted instead of the rev limiter. The traction control takes away engine power... does it limit power by basically kicking in the rev limiter? If so could that be used?
I think you could possibly interrupt a wheel speed sensor and accomplish what you are thinking, but that might mess with stability control, etc. Cutting the 12volt supply to the ignition would be easier and not mess with another system in the Slingshot.
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Engine RPM is taken by the ecu by a halo effect sensor probing the crank shaft position. The only way you could fool the ecu into ignition cut would be to make it think engine is in the redline by generating a fake pulse to the ecu that would mimic sensor signal at 7000rpm.
There are so many reasons that would be a bad idea and would probably not work very well that we’ll just say that we forget about it...
Cutting power to the ignition would be the best way imo.
Or chuck the ecu and swap to a Elite 1500 and be done with it.
Is there a way to intercept the rev limiter built into the stock ECU and have the failsafe in effect fool the ecu into applying a rev limiter until the failsafe perceives "normal" conditions?
As I was typing the above... it occurred to me that maybe the traction control limiter could be intercepted instead of the rev limiter. The traction control takes away engine power... does it limit power by basically kicking in the rev limiter? If so could that be used?
