[JustJeff]

Originally Posted by RETed

Orange one?
I have a brief description here:
http://fc3spro.com/TECH/PROBLEMS/EM/solenoids.htm

It's basically for emissions and starting, although IMO it contributes more toward a flooding headache upon hot-start cranking.
Basically what it does is vent the FPR to atmosphere on cranking (hot only?).
This causes the FPR / fuel rails to run at a slightly elevated pressure ~40psi.
(Otherwise, cold-start cranking pressure is around 36 - 38psi.)
Mazda claims this is to combat vapor lock on hot-start.
It causes more fuel to be injected into the engine upon cranking on hot-start.

I will tend to pull all of that emissions crap on most of my customer's cars.
I've personally done it to my FC, and I've never had a problem cranking - hot or cold - as long as the engine has good compression.


-Ted

Thanks again Ted

I've got the UIM back on, but next time I take it off I'll look into removing. What I may do is remove the rats nest, but get some brake hose and bend it for the vacuum and fuel lines that I am using.

Overall I believe I have my vacuum issues worked out. One of the problems I found was that I couldn't find an accurate S5 TII diagram for removal of solenoids. I found plenty of S4 stuff and I even found one claiming to be S5 but it was using the S4 diagram. The most notable difference between the two is the nipple/port on the back of the UIM for the splitter to the OMP/MOP injectors. On S4 it's on the bottom, on S5 it's in the middle. IIRC the S4 also has 4 nipples on the back and the S5 has 3.

I made the mistake of thinking all the nipples on the intakes showed the same pressure/vacuum. This whole time I thought I had the wiring on my electronic boost gauge incorrect because it pegged to zero. It never moved at all. Well I do have my MBC set to go straight to the wastegate. Last night I put another splitter on the nipple under the BAC...WAAA LAAA mechanical boost gauge showed vacuum. Plugged in the electronic boost gauge..WAAA LAAA it's been wired correctly this whole time!!

Still need to work out the warning gauge for oil pressure, but I've got a good idea what I did wrong with that.