I would post this is the SAFC section but that place is like a desert.

So, is there a reason why my SAFC doesn't show the correct RPM and Throttle?

It shows about 300rpm less than it actually is and it says I'm at 100% throttle when I'm actually at around +/-25%...

Thanks

 

Did you recalibrate the throttle position on the SAFC? Don't know about the problem with the tach if it is wired correctly.

 

Recalibrate?! huh?

How do I do that? I dont have the instructions and APEXi's site doesn't have it anymore...Only the wiring diagram. And yes, its wired correctly. I checked and rechecked.

 

actually mine is like that to and to be honest I would agree with what the safc says and expect the damn gauge to be wrong. Mine is not 300rpm off but it is 150-200 off.. and I think it is right because somtimes my idle is choppy and the tach reads 700-800 and the afc reads 550-650 and I know it should run smoother at 800rpm..

Dave

 

Likewise.

My safc actually gets worse. It's dead on from 0-3000 but anything after that slowly becomes off by a wider margin.

My throttle position is about dead on though.

Also, even though that place is a desert, one of the reasons it is as such is probably because of posts like this not making it into the right section. There are a couple of us who check it daily and give input on anybody in need.

 

The stock Tach is not very accurate. Some are but some are not. the SAFC is right. go by what your SAFC says and only use your stock tach as reference. Hooking up any tach will show a slightly different rpm then what the stock tach says.

My stock tach gets very bad. At idle (800rpm) my stock tach will say 1200rpm, 1000, 1500, and sometimes it will be right. I can even see the stock tach jump sometimes another 1500rpm when im near 4000rpm it will climb steady till then but will accelerate to about 5500 in a split second and then travel with the rpms of the engine.

The tach has NOTHING to do with your throttle sensor. Your TPS does not tell the SAFC what RPM you are at.

There is a way you can recalibrate your stock tach but I don't know how. Search on Google and im sure you will find it. "calibrate rx7 tach" or something like that.

If you have a series 4, then this is why. Series 4 engines have the narrow range sensor which only measures up top 25% throttle. After that, the TPS is full extended and the SAFC reads 100%. you need to have the throttle points in the safc at LO - 98% and HI - 99% for this reason.

Series 5 engine have both narrow and full range throttle sensor so you can hook the SAFC to the full range instead. If you really wanted to, you could install a S5 TB onto your S4 intake manifold and use the full range after some rewiring for your SAFC. Also transfer the OMP control linkage from the S4 TB to the S5 TB. That How to is listed in the link in my Sig called " My list of how tos"

 

How do I hook it up to the pressure sensor instead??

 

mine is about 300 off from the tach as well. the throttle is right on though. I would definitely trust the AFC over the guage. Guage = 20 years old.
S-AFC = much newer and tied into the ECU

 

mine is off too but only when driving. The idle chills between 700 and 750 on both tach and SAFC but once it's driving it's off by about 300RPMS also. I always assumed the SAFC was more correct.