Hello Everyone.. I need some help with PFS PMS
 

I have recently purchased a 1993 RX7 which came with PFS PMS and a 3 turn knob mounted in the glovebox, the old school version. Please share any information or tuning data if you're using the same tuning tool. My FD is seems to be all stock exception of the PF Front mount intercooler and PF full exhaust and a 3" downpipe. Thanx for looking into this thread. Your contribution will be greatly appreciated.

Purple box blues...
 

It's been a while since I've toyed with one of these, but I'll offer a few thoughts.

First off, history lesson: this was a product produced by EFI Systems (http://www.efisystems.com/) called the PMS or Powertrain Management System. Peter Farrell resold these devices with his own tuning maps pre-programmed for typical bolt-on mods, like yours. For lower outputs (<350 hp), this is an effective system. It lost popularity, I think, because of a stumble at or around 4500rpms that affected many of the stock RX-7's, but seemed to continue with the PMS. Other systems, like the Apex'i, generally removed this stumble and as such, most agreed the drivability with other ECU tuning packages (whether a piggy-back that retains the stock ECU like your PMS does, or something else, like Apex'i which outright replaced the stock ECU). Peter Farrell also experienced a few business challenges in the late 90's and as such, I think the marketing power behind this solution diminished.

Second: What kind of box did you receive? There is usually some writing on it. Some of the newer ones used a software tuning package calle d Interacq for Windows which was pretty powerful. Earlier versions required a handheld programmer with a digital display and a numeric keypad for entering data. Which do you have, or is the only thing you've got the 3-switch knob?

documentation - InterACQ for Windows manual
 

I found a copy of the manual in digital form. PM me for a copy, as it is a whopping 16MB zipped.

Hope that sharing doesn't violate some form of copyright -- just trying to help the guy out, and it's the product that's the value, not the manual, I hope.

Purple Box setup worksheets
 

I used these as templates for organizing my setup info. it might help you as well, as it should guide your navigation and understanding of how the various readouts of the keypad correlated with manifold air pressure and the like. To my knowledge, nobody else ever bothered to create such a worksheet, so enjoy!

tuning notes
 

If you have the keypad, I found some old notes that state:

- Aim for wide open throttle O2 reading of 0.86v (as the keypad reports -- not valid for widebands!)
- although the stock map sensor is only good for 2bar (14.7psi boost), with the PMS, you won't receive a check engine light if you run higher.

I ran a car with 16.0psi boost by making the last load setting a bit extra rich. The goal here is to allow the boost to creep past the max MAP sensor reading (14.7psi) and as it approaches 16.0psi, the extra air effectively leans out the flat fuel enrichment curve, since the ECU and PMS are unaware that the car is consuming more than 14.7psi. It's a bit dangerous, but quite quick and I ran a car this way for 30k miles without a problem (great engine provided by Tri-Point Engineering, back in the day) before we sold the car to make room for new toys.