The S5 Turbo MAP (pressure) sensor isn't supposed to have a check valve in the vacuum line, is it? Doesn't look like it in the FSM, but I could hardly get a clear picture on the internet.

My ECU isn't seeing a vacuum signal on the Palm, and it holds a boost signal after the BOV closes. There is a check valve installed on the vac line from when PO did the swap I believe, and neglected to take it off.

 

no there isn't supposed to be a check valve, it could be a line filter though if it is a clear valve which is fine.

there is supposed to be a metered orifice in the line though near the pressure sensor.

 

Ehh, this is definitely a check valve. Thanks for the info, brotha' Karack!

 

no problem, once you get it sorted out and get a map sensor reading see how smooth the signal is, if it is spikey and erratic then it is likely the map sensor line was replaced and the pill removed. you can make a new one with a small drill and some aluminum rod stock.

 

Fixed! And yes, it is relatively erratic (relative to the auto-meter gauge).

Kind of hard to do any MAP based tuning when the MAP sensor isn't sending a signal to the ECU

 

somewhat, keep in mind the stock setup only uses the map sensor for timing control so the losses are a bit less extreme. but for a decently accurate tune a smooth timing figure still helps to squeeze out that last 5 or so horsepower.

 

Will do. So basically just a short piece of aluminum bar stock with the OD of the ID of vac line... then I'll use the smallest drill bit I have to drill an orifice in it?

 

pretty much, enlarge the hole to the point that the signal is still responsive enough.

 

Advance sells one for 2 bucks! I'm back in bid'ness.

 

What's the part number/look up for the orifice from Advance?

 

I got mine at Advance here in Florida, its Dorman part 47311. Happy hunting.

 

Now I'm fighting an overheating issue... and I used to think I was the pro at overheating issues. Just replaced the thermostat with an Autozone one - it even had the damned jiggle pin in it, I'm going to see if Mazda has one locally, but I have little faith. I replaced the water pump a few weeks ago - I thought I saw a dried trail of coolant from the weep hole, this was before the overheating.

I've been scratching my head over whether or not there's a bubble in one of the lines somewhere, but I've pulled and pinched and no luck. Who knows...

 

If Mazda doesn't have a thermostat for for a FC, ask about one for a FD...they're the same thing.

 

And with regards to the jiggle pin I believe the thermostat needs to be inserted in a particular position/orientation.

 

yep... Jiggle pin towards the top. It was, and it still was getting too hot. My efan was running the whole time.... And this was at idle!

 

Mazda said they'll have it for me Wednesday!