Corner Weight

New guy here - I'm looking at doing the MS system as an educational project to play with. My car is a pretty much stock 91, but I figured having the MS in place and sorted out would be a good idea before I start adding things like a turbo kit. I've read most of the threads in this section and I think I have a good idea on what I need to do, but I just want to make sure I'm thinking straight so far.

I want to be able to completely remove the stock ECU and run everything off of the MS. I also want to be able to unplug the MS and re-install the stock ECU in case of emergency, or in case of a smog check.

I figure I need to:

Get MS1 v3.0 - w/ MSnS software.
Do the idle mod (either tip122 or the diyautotune kit) to control the idle
Get a throttle body with a TPS (not necessary, but I think it's a good idea)
I want to either use a PNP harness, or gut a stock ECU so the stock harness is unmodified, and the stock ECU can go in at any time.
Use the stock coolant sensor.
Use the stock IGN sytem to start with.
Control the fan, fuel pump, etc.

From what I see, this all looks doable, but am I missing something?

Also, what is a "CAS"? Crank Angle Sensor? Is the stock grank sensor and trigger compatible or do I need to do something different?

Thanks in advance,

John

Aussie Driver

The CAS is a cam angle sensor. It's at the back of the engine on the passenger side of the car. The signal from it can be read my the MS, all you have to do is complete the board mods so the inputs into the MS have the +5v pull up.

I wouldn't recommend that you use the stock temp sensors. Firstly you will need to change two of the resistors on your board to match the resistance of the temp sensors. Secondly, the air temp sensor is in the AFM and that is normally the first thing that we try and get rid of to reduce the restrictions in the intake.

Steve

Corner Weight

I was thinking I'd leave the AFM in place to start with, until I am sufficiently confident that the stock ECU wouldn't be going back in any time soon. Once it's fully sorted and relible, I figured I could always remove the AFM and add the GM IAT sensor later. I've looked at a lot of your posts and you were one of the main posters that gave me the motivation to tackle this. If I'm correct, you have a similar setup running everything with the stock ECU removed completely?

Aussie Driver

I still have the factory ECU in the car. I need to keep it in there for our local compliance laws (at least that's what I've been told) so I still have it connected and it's doing everything other than the fuel, spark and ignition (whatever that may be...).

I'm glad that my posts have been of some help to you
Steve

timk

Yeah Aussie Driver rocks!

I've got pretty much the same plans as you, Corner Weight. I'd like to use the factory CLT sensor but I'll be trying to track down the wiring connector the AFM uses so I can wire in a GM IAT sensor there. I'm also going to grab something like this extension harness so I can revert back to stock easily.

The extension harness will have the provisions to "borrow" the AFM wiring to use for the GM IAT, so to go back to stock I simply remove the extension harness and plug back the AFM and stock ECU. Guess I'm just paranoid!!!

Good luck with your setup, and keep us posted!

Corner Weight

Reliability paranoia was one reason why I wanted to be able to switch back (keep the stock ECU in the trunk? :-) ) - but I also thought I might have to put the stock ECU back in to pass California emissions testing (visual). It just seems strange to me to have the duties split between 2 ecu's, but that may be the best way to go.

What is left for the stock ECU to do after the MS takes over all of the engine controls?

Jefe

iTrader: (7)

AIC Solenoid, A/C, Cooling Fans, Fuel pump. Probably someother things as well, keep the stocker in parallel and you won't hae to worry about it.