MSefi.com read only forum (Jan.15,2018)

Hello all,

I am very new to MS and to tuning in general. I am preparing to install a MS setup into my 1990 Toyota Celica ST (4afe motor) with the intention of boosting it 5-6psi after I get the MS up and running on the stock setup. I purchased all of the parts from a Celica owner in Tennessee who has already constructed a wiring harness for my engine. However, there are a few loose ends to tie up before I can dive in.

I understand that MS requires a potentiometer type TPS. Supposedly (I haven't confirmed this myself) the TPS that is on the car from factory is more of a switch than a potentiometer and will not work well with the MS. I know that later model GM sensors are supposed to work pretty well on the MS but has anybody heard of a more specific setup that might work well? I'm going to go shopping at Advance Auto soon for a suitable sensor but thought I would also check and see if anyone else has already found a solution.

I can post pictures of the current TPS setup if that will help. Worst case, I'll pick a decent GM TPS and engineer a mounting system of some sort to make it work.

Thanks in advance for the help.

Looks like it's a Bosch type switch TPS. You can use the MAP for enrichment, or a lot of '90s era BMWs have a TPS that can often fit in place of this - I am not sure which ones would work in your particular case however.

It should actually be a Denso TPS, so it'll be either a 3 wire or 4 wire TPS in that car. The 3 wire version is a normal TPS > ground, +5Vref, Signal. The 4 wire version is exactly the same, but the extra wire is an on/off idle switch to indicate when the throttle is closed. That's the one you most likely have, and if so, you just ignore the 4 wire, it's not needed for MS