Hard Throttle/Gas Pedal with Centrifugal Blower---Vacuum

**only90s** · 05-13-2010, 07:32 PM

Here is my Issue and Resolution.

If someone has a better idea I would love to hear it.

Issue: When cruising around the throttle/gas pedal is hard to push down, but when the car is off it is easy and moves freely. I have learned over the years that the 75mm Throttle Body is being sucked closed by the vacuum while at cruising speed. The Meth I inject makes it worse because that leaves dry windshield washer residue behind which aggravates the issue.

Resolution: Every 10-15 times I take the Fox out, I have to pop the hood and spray WD-40 just before the Throttle Body and open and close the throttle body several times. This makes the gas pedal smooth as silk for 4-5 rides and as the Meth dries it out it gets progressively worse. I have heard that a 70mm Throttle Body may not have the same issue.

Anyone else experience this?

==============================

6/6/10 Resolved

So decided to tackle this issue once and for all since it has been irritating me. I removed the blower intlet tube and studied/watched the throttle body in action for a few minutes. Discovered the throttle blade was catching at the bottom on the inside of the throttle body.

So I removed the throttle blade-took it to the grinding wheel for a few seconds. Removed less than 1/100th of an inch. Hit the entire blade edge with some 220 sand paper. Re-installed the blade and now a nice and smooth Throttle Body.

**Mustang5L5** · 05-13-2010, 08:45 PM

Does the tb have the little hole in the blade?

**only90s** · 05-14-2010, 08:02 AM

Originally Posted by Mustang5L5

Does the tb have the little hole in the blade?

I dont remember. Why do you ask???

**SmokinStang** · 05-14-2010, 09:50 PM

I thought I've heard alot of issues....but this one is a first to me. Has the "Fox Doctor" been stumped.....yet another first.

**only90s** · 05-15-2010, 07:30 AM

The Fox Dr prescribed WD-40 and it temprarily solves the problem and is not really a huge deal, but if someone knows of a better solution I am all ears...

**Mustang5L5** · 05-15-2010, 10:06 AM

Originally Posted by only90s

I dont remember. Why do you ask???

Well it helps with the vacuum issue. The hole is usually there though. A couple brands don't have them though, what brand you running?

However it sounds like your issue may be related to the methanol.

**only90s** · 05-17-2010, 05:17 PM

Originally Posted by Mustang5L5

Well it helps with the vacuum issue. The hole is usually there though. A couple brands don't have them though, what brand you running?

However it sounds like your issue may be related to the methanol.

I have an older BBK/Edelbrock 75mm TB....I will have to remove my intake pipe and look at it.

Where should the hole be? If there is no hole, should I drill a hole?

Any suggestions are welcome Sir...

**The92Foxbody** · 05-17-2010, 06:50 PM

Really odd scenario. My cousin has ran a 75mm throttle body with cobra intake manifold for 2 years and has never had this problem.

**only90s** · 06-06-2010, 07:38 AM

6/6/10 Resolved

So decided to tackle this issue once and for all since it has been irritating me. I removed the blower intlet tube and studied/watched the throttle body in action for a few minutes. Discovered the throttle blade was catching at the bottom on the inside of the throttle body.

So I removed the throttle blade-took it to the grinding wheel for a few seconds. Removed less than 1/100th of an inch. Hit the entire blade edge with some 220 sand paper. Re-installed the blade with some locktite on the screws-dont want one of those falling into the intake.

Now a nice and smooth Throttle Body and a much less irritated owner/opearator!

**only90s** · 06-14-2010, 03:23 PM

I can report after 3 additional runs that the throttle is still nice and smooth and my fix appears to have corrected the problem.

I just gave it a nice thrashing and sprayed quite a bit of meth in there....

and still feeling good.