New FAST 90MM TB sticks bad!
12-24-2005, 03:13 PM
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New FAST 90MM TB sticks bad! Ok, call me a dummy 
(or worse). I bought a FAST 90mm TB to go with the 90mm intake. I checked the TB out and it seemed ok. Put it on the car and the first time out it sticks at about 4000 rpm. I had to kill the engine, coast to a stop and restart. On the way back home it kept sticking at all different rpm’s.
I parked the Z and did some experimenting on the TB. I found that the blade will never stick while the engine is not running, but start it up and give it about 2% and let off and the blade will stick there. I noticed that there is no hole in the blade, which leads me to think that it’s the flow of air that causes the blade to stick and not something mechanical. The spring seems plenty strong, but it could use some help.
I wonder if drilling a small hole in the blade would solve the sticking problem. I bet the IAC closes up and when you let off the throttle there is just too much air flow over the top of the blade to let it snap back.
First I will try adding a spring return.
I don’t want to wait for another TB from fast, so if I cant fix it quick I will go NW for sure and sell the fast. Guess I took it in the shorts on this one. I should have followed my first thought and just got the NW.
Oh, and one of the IAC mounting holes wasn’t drilled and tapped deep enough.
Along with that I ended up siliconing and making a bracket for the MAP sensor as it was so loose I was afraid it would fall out of the hole.
Very poor quality.
(or worse). I bought a FAST 90mm TB to go with the 90mm intake. I checked the TB out and it seemed ok. Put it on the car and the first time out it sticks at about 4000 rpm. I had to kill the engine, coast to a stop and restart. On the way back home it kept sticking at all different rpm’s.I parked the Z and did some experimenting on the TB. I found that the blade will never stick while the engine is not running, but start it up and give it about 2% and let off and the blade will stick there. I noticed that there is no hole in the blade, which leads me to think that it’s the flow of air that causes the blade to stick and not something mechanical. The spring seems plenty strong, but it could use some help.
I wonder if drilling a small hole in the blade would solve the sticking problem. I bet the IAC closes up and when you let off the throttle there is just too much air flow over the top of the blade to let it snap back.
First I will try adding a spring return.
I don’t want to wait for another TB from fast, so if I cant fix it quick I will go NW for sure and sell the fast. Guess I took it in the shorts on this one. I should have followed my first thought and just got the NW.
Oh, and one of the IAC mounting holes wasn’t drilled and tapped deep enough.
Along with that I ended up siliconing and making a bracket for the MAP sensor as it was so loose I was afraid it would fall out of the hole.
Very poor quality.
12-24-2005, 03:50 PM
#2
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Shaft that juts into the TPS is also too short, causing faulty readings. One guy on this board "SUX2BU" lost his engine due to faulty readings and timing.
I too had a bad TB (early batch). Tried fixing it to no avail. Bought a TPIS 90mm TB and it worked wonderfully. My advice would be (as you've stated) to order a NW or TPIS, bolt it on, then send the POS FAST back to FAST for warranty work. Sell it when they send it back to you. This would cut any downtime.
One huge design flaw is the tiny spring FAST uses for such a large TB.
If you call them, they'll tell you to buy a carb spring and loop it on to the tube on top to help spring return. Tell them to take their carb spring idea and shove it up their a$$.
I too had a bad TB (early batch). Tried fixing it to no avail. Bought a TPIS 90mm TB and it worked wonderfully. My advice would be (as you've stated) to order a NW or TPIS, bolt it on, then send the POS FAST back to FAST for warranty work. Sell it when they send it back to you. This would cut any downtime.
One huge design flaw is the tiny spring FAST uses for such a large TB.
If you call them, they'll tell you to buy a carb spring and loop it on to the tube on top to help spring return. Tell them to take their carb spring idea and shove it up their a$$.
12-24-2005, 04:07 PM
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Also, set screw used to slip on the blade shaft, bearings must be peened, etc., etc., etc......
That TB is a total POS and FAST has not addressed the issues for 2 years now.
That TB is a total POS and FAST has not addressed the issues for 2 years now.
12-24-2005, 07:26 PM
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My buddy bought the 90-90 setup, he told me he had the same problem with the throttle hanging open. Seems like a great way to get in a wreck. He also ended up replacing that ho.
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12-24-2005, 11:13 PM
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Luckily I havent had any real problems with my FAST 90MM but did the "tricks" to hopefully prevent anything.
I wouldnt drill a whole into the blade.... wont solve the problem. What you can try is taking out the set screw from the back of the throttle cam, adjust the blade where it's completely closed or has only a slight crack (found this out to be easier tuning the idle after it is done but make sure its not out too far or the idle will be high from the start), and drilling a small indention on the rod for the set screw to embed in. This will prevent the screw from slipping and causing the RPM's to go wacko.
You can also take out the TPS and looking at the TB, make sure the bearing is countersunk into it a little bit (cant go much at all). If you are good there, take a small punch (or screwdriver) and ping around the edge of the TB in several places where it meets the bearing. This will prevent the bearing from backing out of its proper holding place and cause some issues.
I agree you shouldnt have to do anything to the TB to make it work but I just let it fall under the catagory of the little things you have to do to make some aftermarket stuff work.
I wouldnt drill a whole into the blade.... wont solve the problem. What you can try is taking out the set screw from the back of the throttle cam, adjust the blade where it's completely closed or has only a slight crack (found this out to be easier tuning the idle after it is done but make sure its not out too far or the idle will be high from the start), and drilling a small indention on the rod for the set screw to embed in. This will prevent the screw from slipping and causing the RPM's to go wacko.
You can also take out the TPS and looking at the TB, make sure the bearing is countersunk into it a little bit (cant go much at all). If you are good there, take a small punch (or screwdriver) and ping around the edge of the TB in several places where it meets the bearing. This will prevent the bearing from backing out of its proper holding place and cause some issues.
I agree you shouldnt have to do anything to the TB to make it work but I just let it fall under the catagory of the little things you have to do to make some aftermarket stuff work.
Last edited by LETHL_SS; 12-24-2005 at 11:18 PM.
12-25-2005, 07:09 PM
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i have the same problems and am very dissapointed.first i had to slot my throttle cable bracket because it was held open.had to grind a few threads off one of my screws for the tps.now even with a return spring it still sticks alittle.when i stop it usually idles down to around 1600 rpm and after5-10 seconds it goes down to 1000 where i have it set.one of the reasons i bought a 4th gen is i wanted a fast,low maintenance vehicle,this is starting to get old quick !!!
12-25-2005, 07:53 PM
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Yea, I'm kicking myself in the butt for getting that TB. When I got it I never expected that the air flow over the top of the blade was causing the problem. Damn spring is just too weak. I went to Ace Hardware and picked up spring #66 on their spring board. I am going to use one of the bolts on the water pump directly below the tab on the throttle cam to hold a washer with a hole drilled in it to hold the spring. At least that will kinda hide it all and actually look like it belongs there.
12-25-2005, 07:53 PM
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Originally Posted by slow trap
i have the same problems and am very dissapointed.first i had to slot my throttle cable bracket because it was held open.had to grind a few threads off one of my screws for the tps.now even with a return spring it still sticks alittle.when i stop it usually idles down to around 1600 rpm and after5-10 seconds it goes down to 1000 where i have it set.one of the reasons i bought a 4th gen is i wanted a fast,low maintenance vehicle,this is starting to get old quick !!!
12-26-2005, 11:20 AM
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Well Here is how I have temporally fixed the sticking problem. I don’t like this setup so I’m going to make a bracket for now.
http://www.circuitflex.com/FastSpring.jpg
I also noticed a lot of oil in the intake so here is my homemade catch can from Home depot.
http://www.circuitflex.com/CatchCan.jpg
http://www.circuitflex.com/FastSpring.jpg
I also noticed a lot of oil in the intake so here is my homemade catch can from Home depot.
http://www.circuitflex.com/CatchCan.jpg
12-26-2005, 03:27 PM
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Originally Posted by Jimmy P
I have been reading some of the TPIS TB's stick as well, but not nearly as bad or as often as the FAST.
