IAT sensor insulation - go or no?
 

Hi guys,

as I still have some problems with heatsoak on the IAT sensor, especially when the car is sitting for some minutes after a ride/and at warm weather.
(My AFRs tend to go down to 9.8 - which is the lowest the Zeitronix can display.)
When I drive it is gone after some 100meters.

On the other hand if the car runs at idle with climbing IAT temps this isn't happening.

What I thought, when I lately was at a homedepot-like store - they get this foam-insulation for housing installation pipes - If I wrap them around the pipe after my intercooler, where my IAT sensor sits, would this be clever or not?

On one hand it would keep the pipe from heat soaking so fast - on the other hand it also cools down slower (but as the cooling comes from the inside through the intercooler, it should still cool down fast.)

Am I missing something? Anyone tried this before?

Thanks for your advice!

tap your intercooler outlet to receive your IAT sensor. your heatsoak issues will go away, probably.

It won't - the IAT sensor sits immediatly after the intercooler.

aluminum foil zip tied around the sensor worked for me...reflected the head coming off the engine and rad

It looks like it isn't a problem with heat soak.

I had a chat with Ken at msextra and he told me it could be a vapor lock at the fuel pressure regulator. (The fuel in the fuel rail gets to hot and partly vapors and so the fpr see's no real map) - which could be, because my map signal line is tee'd into the fpr line and get's some strange readings, when this happens. (~95-100kpa at idle which sohould be 26-29)

Greets

Yeah, if you are getting 95-100kpa at idle, something is wrong with either your map sensor or more likely the vacuum line feeding the map sensor. Check that and see if your rich condition doesnt go away. A heatsoaked iat sensor will make you go way lean not way rich because the ecu thinks it is getting less air than it really is.

Solution found!
 

Hi,

I just wanted to let everybody now that I have found the solution to my hot start MAP/AFR problem.

It turns out that the European NB (99-00 maybe/surely the later also) have a valve inline the fuel pressure regulator line, which on hotstarts keeps the FPR from seeing vacuum for 150 sec - and so it kept my MAP line at the MS also from seeing vacuum and the MS dumped in a lot of fuel even at idle.

So beware European MX-5 drivers - do not use the line to the FPR for your MAP source! (Or at least use the line before the valve)

Now I just have to retune my MAT correction table.

Greets

Sven