MAP sensor fitment on FAST intake manifold
09-20-2014, 07:27 PM
#1
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MAP sensor fitment on FAST intake manifold Was just poking around under the hood and noticed some mung back around the MAP sensor on my FAST 90 intake manifold. I cleaned it up and popped the sensor out, and at some point someone had put RTV on it - I'm guessing that was one of the two guys who has tuned the car, and it presumably was done to help it seal better. I cleaned the RTV off, since it didn't seem to be helping. The orange seal on the MAP seems fine, but I'm wondering if others have any issues with the MAP getting a good seal on the FAST intake. I'm pretty sure that MAP sensor is original, so it could be that the orange seal is just hardened up a bit with age and not working as well.
You can see what the MAP sensor looks like . The nub that sticks down into the manifold is maybe 1/2" long, but on the FAST intake the plastic where the MAP sensor plugs into the manifold is less than 1/4" thick. I don't remember how the stock manifold was, but on the FAST that means the orange seal isn't really doing its job the way it's intended to. Instead of each of the ribs providing a seal, so you get 4 or 5 layers, probably only 1 or 2 ribs are making contact on the FAST.
I'm not sure it's worth spending $40 or whatever for a new MAP sensor (with a hopefully better orange seal), or if the design of the FAST intake means I'm better off just slathering some fresh RTV on there to seal it up better. Any thoughts?
You can see what the MAP sensor looks like . The nub that sticks down into the manifold is maybe 1/2" long, but on the FAST intake the plastic where the MAP sensor plugs into the manifold is less than 1/4" thick. I don't remember how the stock manifold was, but on the FAST that means the orange seal isn't really doing its job the way it's intended to. Instead of each of the ribs providing a seal, so you get 4 or 5 layers, probably only 1 or 2 ribs are making contact on the FAST.
I'm not sure it's worth spending $40 or whatever for a new MAP sensor (with a hopefully better orange seal), or if the design of the FAST intake means I'm better off just slathering some fresh RTV on there to seal it up better. Any thoughts?
09-20-2014, 08:49 PM
#2
I noticed the same thing on my fast 92 (used when I bought it) - except with me, someone had even drilled out the map input hole on the intake so it was a bit too big to even seal around the 1-2 orange "ribs" on the map. It's a bit jerry-rigged, but I found a washer that the map fit tightly into, super glued the bottom side of the washer to the intake and then used RTV on the top side to form a bit better of a seal around the map sensor. vacuum readings are good and, when I wiggle the map, there's no stumble or variation in idle, so i consider it fixed
btw, i did buy a new MAP sensor as part of the "fix" but it really didn't make a difference in the MAP's ability to seal - it was more about the hole into the intake
btw, i did buy a new MAP sensor as part of the "fix" but it really didn't make a difference in the MAP's ability to seal - it was more about the hole into the intake
09-20-2014, 09:07 PM
#4
Remove the intake manifold, it only takes an hour.
Tap with NPT, go to Home Depot and get a brass fitting in that size. I *think* I did mine in 3/8" or 1/2", just run whatever is the closest. The intake taps super easy, use some grease on the tap and no shavings will get inside. Run a simple piece of tubing to the MAP sensor and mount it where it fits best.
Tap with NPT, go to Home Depot and get a brass fitting in that size. I *think* I did mine in 3/8" or 1/2", just run whatever is the closest. The intake taps super easy, use some grease on the tap and no shavings will get inside. Run a simple piece of tubing to the MAP sensor and mount it where it fits best.
