:THUMBSUP:
I have to try this one. The dealership says there is no problem but why does my car rev at 1800 rpm's when I start it? Hopefully somebody produces these for us guys without a dremel or tin snips. I have a lowes nearby though. Good job.

I have a friend who owns a machine shop. I'll make up a prototype and find out how much it will cost to mass produce out of steel rather than aluminum.

Does it stay at 1800rpm? Or does it fall down then rise back up to 1800?

Not exactly sure, but I think that's close to the starting speed.

The Mach1 starts at the speed. That is the speed that the starter turns the motor at to start the engine. Determined by Ford to be the lowest speed that the engine will remain idling/running under all starting conditions.

Now, having said that, staying at the speed for a long time, or rising to that speed when the engine has already warmed up and has been idling for a while isn't right. And could possibly indicate a problem.

Remember, the restricter plate mod, is for people who are tired of how long the RPM's take to drop down after letting off the gas, and whose cars take and excessive time to drop to a proper Idle upon startup.

Since this thread has moved back up the list let me add my .02c on the subject. I made my IAC restrictor plate and after a couple of minor size adjustments to the smaller hole in the plate the car now starts and idles perfectly. No more hanging RPMs between gears. The car drives beautifully and I swear it actually has a little bit more get up and go on the low end. My shifting is definitely smoother and the car brakes better than before.

Mach2Canuck, you're officially on my list of mods (see signature!). :THUMBSUP:

Glad you are happy with it.
I haven't checked, but is Mr. Hoag still available for questions? I wouldn't mind knowing what he thinks of the mod.

Yeah my car starts at 1800 ( sounds like I am racing my engine even though my foot is not on the gas) then stays there even after I put it in gear, the car does this for about the first two minutes of driving then drops down to normal idle speed at stops. The idle does drop rather slowly and at times it is a pain to shift. I brought it in to ford and they said there was nothing wrong with the car after connecting it to the computer so I took them at there word. I assume that this will fix or improve upon the problem though, I guess it's worth the try.

Great Mod!!
 

Awesome mod - works like a charm. Tough getting used to shifting 2-3 and 3-4 though!!!

Mach On! :THUMBSUP:

Yeah! It works GREAT!!!

:HOPPY:

:COOL:
This is the greatest free (almost) modification ever! It took me about an hour and a half in total and worked perfectly on the first try. I used a sheet of 22 gauge steel purchased at Pep Boys for a couple bucks.

A few observations on the process:
1. You don't need to remove the shaker. The IAC is accessible from the passenger side without removing anything else. Two 8mm bolts.
2. My car is a 5 speed and I made the smaller hole 9/32. The other hole is identical to the one in the gasket. No problem cycling the A/C compressor with that size.
3. Be sure to deburr the edges of the holes after drilling/grinding to ensure that no junk gets sucked into the engine!

I noticed no difference in the amount of "burble" on closed throttle deceleration. The surge felt when engaging the clutch at low throttle position is gone!

Thanks, Mach1Canuck, for posting this!


:machgod:

Here are some great installation pics from StangNet

http://forums.stangnet.com/showthread.php?t=470711

You're using the original gasket and now you've stacked a metal plate against the IAC... How does this seal? Shouldn't it require a 2nd gasket to seal properly?

If I decide to do this, I would purchase another gasket to assure no leaks.

Don't worry about the gasket, guys. It's just paper and is absolutely reusable. We're not trying to seal high pressure liquid, here. Just relatively low pressure air. See for yourself when you take it apart; it has very little deformation from the original install.

My point is, when you had just the IAC, you had metal face, gasket, metal face. Now, with the new part, you have metal face, metal face, gasket, metal face. How is it that the part seals?

Two gaskets=positive seal:MADNOEL:

I agree completely, it just appears that everyone is just using the one gasket in this thread and that didn't seem like a good idea to me... However, maybe it seals up just fine.... Personally, I'd just buy another gasket like you suggest.

I would agree. For COMPLETELY bulletproof install, use two gaskets.

I myself cut and made sure my plate was perfectly flat when I cut it.
Remember also that the aluminum plate (1/32") is also very maleable compared to what it is being sandwiched between and I'm sure it made a perfectly fine seal.

Want to check it? Get a friend that smokes, hold a lit cigarette near the seal while you rev up and let off the throttle. Does smoke get sucked in? If yes, then you have a leak, if not.. should be good to go.

Install pix from stangnet
 

Thanks
 

Mach1Canuck, thanks for a great fix,, these hanging rpms are annoying.

Believe it or not the 95-98 mustangs had the same problem and ford actually had this same fix and a part number. I think I read about that on stangnet back when I had my 02 gt, did the same thing. Obviously we have a different IAC and I doubt ford has bothered to fix this in the Mach's so it's great that someone figured it out for them. Good job :CHEERS:

Nice job on the mod Canuck! I'll keep it in mind...I like it!!

Another alternative guys, at least it helped me anyways. The IAC's that come originally with our Stangs suck and I can't figure out why. I got tired of it and so I went to local Ford dealer and bought a new IAC (was something like $40-$50)....removed the old one and put the new one on. Since then, no hanging rpms, rpms drop fairly quick, and it also fixed my engine stall problems. So, keep it in mind if you have/had similiar probs.

MyDream and I did this yesterday to our Machs and we both agree on the SOTP Dyno, that you can feel the difference big time. We both have the feeling our cars get up an go alot Sooner and faster. Hanging problem fixed. His had the 9/32 hole mine was a tad smaller. Cost was about .02 cents for electricity- we got the flashing for free. :D

Anyone else feel the SOTP difference?

SOTP Dyno is recording much better accelerator response.

I posted 3 responses on this thread, 2 on 06/05 and the last on 06/07. As I said on the last post, the difference is apparent at WOT highway speed but I am also feeling a difference at launch.

Of course, I also removed the MAF after getting a rich A/F after having after market mufflers installed. This seems to have cleared up this little problem.

The difference is incredible. I can now burn from a standing start. Not bad, considering I have an automatic. I even impressed my wife, the other night. I have had the car for about 9 months and it is faster now than ever. Of course, she reminded me that the cost of new tires will be deducted from any new mods I had in mind. :(

And, as you said, the cost was a whopping 2 Cents, give or take a penny or so. The steel was free and the mod took all of a half hour. Pretty good pay considering someone else spent between $40 and $50 for the same results. Lets see, if I am correct, that equals about $80 to $100 an hour. Not bad pay, if I do say so myself. :)

David <><

Can anyone make/send me one of these plates for a reasonable price??
 

Can anyone mail me one of these plates with the 9/32 hole for a reasonable price?? Thanks fellow Machers!!
PM me, if at all possible.
V/R...

Devery

Check this forum, Donathan is going to sell them for $20
the thread is titled " IAC Valve Restrictor Plate Production ".