VSS support?

pedward · Post by **pedward** » Thu Jun 08, 2006 9:41 pm

Hi all, I've been out of the MS game for a while. When I heard MegaScott had EEC-IV adaptor boards, I jumped! I finally built an MS for myself; the Mustang. I used a v2.2 board and put an MS-2 chip on it. I'm really looking forward to running target-AFR with my FJO WB on the stang.

There are a few things I really like about the stock Ford computer, and I want to duplicate them as much as possible, so here are a few questions:

First, has anyone got a VSS input working? I'd really like to do a digital input, but that takes a lot of CPU, so I'm thinking of doing a frequency to voltage converter coupled to the true zero crossing detector I used in my datalogger. However, if there is a timer free, I'll use that.

The VSS is key to a few important things I want to achieve:

Dashpot for decel.
Fuel cut above RPM and speed.
Cruise control (maybe, gotta research the Ford cruise control)
EGR control (might as well try to keep our planet a little greener and save gas)
Potentially traction control...

I also want to do air injection control for the smog stuff.

I've got the beta/first rev MS2, so I don't have CAN support, just the basics. I will be coding in Linux with GCC.

I need to fix an exhaust leak and change the clutch before I can MS the car, because the NB sensor will be on the right bank, with the WB on the left, and the leak is caused by an interference on the ball/socket joint. I'm shooting for having the car started and running in a couple of weeks. It should be quick because I've already spent several years tuning the timing tables for the EEC, so that will transfer over.

Thanks,
--Perry

MegaScott · Post by **MegaScott** » Thu Jun 08, 2006 10:55 pm

Perry,

Wecome back, We missed you!!

Thanks again for helping me with the BOM for the new Board, with your help I think it's working great!!

When you said "cruise control" did you mean remove the existing cruise control box and emulate it with the Megasquirt sending signals to the existing actuator? There's only a few models of the EEC-IV that actually control the Cruise control, the Taurus SHO is one, Certainly not your Mustang.

Cheers!!

pedward · Post by **pedward** » Fri Jun 09, 2006 7:04 am

I know the old SD cars has a cruise control module, but I assumed that when they went with the A9S, 8LD, and A9L computers they integrated that into the ECU. I remember reading that the cruise doesn't work on some cars when you "upgrade" the ECU, because they don't have off-board cruise. Oh well, it doesn't work on my car very well anyway, the hysteresis is screwy and the car does the accel-decel cycle because the throttle is too responsive for their strategy. I've only got it to work in 5th on the highway, in 4th the car feels like someone with seriously doubtful skills is driving.

--Perry

MegaScott · Post by **MegaScott** » Fri Jun 09, 2006 7:59 am

Does your car have the Vacuum servo? (I imagine in 89 it still would) I think 95 and newer? They went to a Mechanical servo that works much better, changes in MAP don't affect the servo loop, so it's much better control. Mechanical type servo, much better IMHO. Certainly worth experimenting with..