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I just bought Hot Rod Harry's Billetflow throttle body and plenum and having some problems getting it to idle correctly ( It worked great on Harry's 03 ). I've followed Doug's instruction, although I don't know if it's the most current set. I've set the TPS to .980 and reset the computer etc. In all occasions it wants to hang momentarily at 1400 to 1500 rpm and gradually falls to around 900, never lower. I tried Doug's instruction that tells you to pull the IAC, plugged in and tape off the IAC's holes in the plenum. Then set the idle stop to 700 to 750 rpm. Even with the idle screw backed all the way out I can't get the idle lower than 900 rpms. I even fiddled with the TPS while adjusting the idle stop and still can't get a 700 to 750 rpm.. I'm at my wit's end..

Here's the instructions I followed:


) install TB and plenum
2) rotate the TPS CW(opposite throttle movement) then snug the screws
3) plug IAC in (DO NOT SCREW IT ON, LEAVE IT OFF)
4) duct tape over the IAC holes on the plenum
5) have someone start the car(DO NOT TOUCH THE GAS PEDLE) if it won't start, turn the butter fly stop screw in a bit, try to start again(repeat till running)
6) adjust the stop screw till you get the idle to 700-750RPM
7) let the car idle for 5-10 min's
8) turn car off
9) remove duct tape, install IAC
10) turn key to "on position" (do not start car)
11) set TPS to about .98V, tighten the TPS
12) start car(DO NOT TOUCH THE GAS !!!!!!!!)
13) just let the car idle, let the computer "LEARN" for 10min's
14) turn car off
15) done



I disconnect the negative side of the battery before I start working on it...when the stock one is off..put the new on on and put the IAC on and the TPS on of course too...everything connected....connect battery. Turn the key on(dont start the car) for 15 seconds...then turn it off.....do that again...then off and then again and off. The will reset your IAC(no one knows this...I dont say it online..but thats one thing that needs to be done) Then when you start it....you should be fine..I say should cause some times things dont go as planned. Then you will turn your key on(not the car) and check you TPS reading to see if its near .98 (even if its .96, thats fine) The gray wire with white stripe from the TPS is for the black ground probe from a digital volt meter and the gray wire with the red stripe is for the red probe . You can use a pin to stick in each wire and then touch them with the probes. I just tore a small piece of the outer wire coating off of each wire and test with probes that way..then just put some electrical tape around the wires till next time.

After further fiddling...

The curious part is that under no circumstances would the idle go under 900 rpm, even with the IAC plugged in and off the plenum which had tape over the holes. If I manually pushed hard on the TB throttle linkage to close it would drop down to 700-750 rpm. Once I touched the gas it would "stick" back at 900. It's as if there's something that's contacting the butterfly/shaft not letting it close completely. I also thought I might have a gasket leak but I could hear no leak "hiss" I also sprayed starting fluid all around the perimeter of the gaskets and got absolutely no change in rpm..


Learned input????
 

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The Ubiquitous Jimmy V.
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My Accufab Idles at about 850 when cold after i drive it a while the Idle settles to about 700..
 

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There is a newer/updated procedure than the one you are using available from Doug at BilletFlow.
Bear in mind there are five elements that have to work together to cause the idle to function properly (TPS, IAC, Vacum, Butterfly setting, computer). If one of these is a bit out of adjustment, the whole setup is off. Adjust one and the computer has to be reset.
But, get these elements functioning together properly, and the BilletFlow will make you very happy!

jmiller
 

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Undy .. Mine does the exact same thing as yours and I haven't found a cure yet. I had to lower my TPS voltage to .92 to get it to idle at 950. Sometimes it will idle at 1500 rpm for 10-20 seconds after coming to a stop and gradually settles down to 950.
 

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Do you guys have the updated TB from Doug? Once he re-machined mine the thing runs like STOCK. It was so bad before I had a check engine light. After installing the TB and not resetting the computer I drove it and after about 5 days even the computer recognized that everything was A OK and turned off the Check Engine Light.
 

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Undy, I haven't found a way to bring the idle down yet, BUT I think that I might have found a way to stop the VERY ANNOYING "1500 to 1200 to 950" slow rpm fall when you come to a stop. Here's what I did today. Since nothing I have tried has resulted in an idle lower than 900-950 rpm, I figured I might as well concentrate on the other problem. I don't really care if it idles at 1000 rpm, I just didn't want the damn thing to take 7 or 8 seconds to CREEP down from 1500 rpm after I come to a stop. So I put 2 layers of duct tape over the IAC air holes in the intake plenum & reinstalled the connected IAC over the tape. That cured the SLOW idle down problem and, since the car is idleing so high anyway, I haven't had any stalls from the rpm dropping TOO low after you blip the throttle. Even with the AC on, I still had an idle of about 850 rpm. However, with the AC on, the idle would drop to about 500 before stabilizing at 850 after a throttle blip.

I will find out how this "fix" effects cold start in the morning since the temp is in the lower 40s overnight. Even if I have to sit a couple of minutes for warmup I will be happier than having a 1500 rpm idle at stop signs.

Like you said above, I also have run the car with the IAC completely removed from the intake, TPS set EXACTLY right, computer resets done precisely as instructed, & still couldn't get the idle below 900 rpm. I even had a strong auxilary return spring hooked up.
If you look closely at the area where the throttle stop screw contacts the flange, you will see that the engine vacuum actually pulls the throttle blade open when the engine is started. That's why you can force the linkage closed with your fingers & get a lower idle reading. I don't know what the cure will be for the high idle, but I think that the above "fix" will unlock my jaw muscles somewhat during my daily commutes. I'll keep you posted on how this works after I get more seat time accumulated.
 

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Larry, is your TB re-machined by Doug? I do not think Chris Johnson did anything in my chip at all for the idle.. the idle hung before and after he burned my chip (w/ the new TB), it was not until Doug remachined it that it went completely to STOCK!


BTW, I was told by a Ford tech (take w/ a grain of salt) that the EEC strategy WILL hold the idle higher after a high speed run in order to keep the airflow up and preserve the Cats.. in other words to help cool them off. So SOME higher idle for short periods is normal according to that tech but the stuff you are describing clearly is not.
 

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Hi Jerry,
Yes, I have the remachined TB from Doug. I purchased mine from him after he had started working on the high idle problem. I have talked to him a couple of times since then and he sent me his latest installation instructions. I followed them EXACTLY but still have the high idle.
I have even gone as far as to seal the length of the throttle blade, where it passes through the shaft, with silicone just to insure that no air was passing through that area. I have NO vacuum leaks and I have tried a different IAC controller just in case mine was defective.
The most important fact is that the idle is high even with the IAC completely removed from the plenum(electric still plugged in). That totally eliminates the IAC as the cause of the problem.
 

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Cold start with IAC disabled

Well this morning the temps were in the mid 40s, so I got a pretty good test of how the engine would handle the initial startup without the IAC to boost cold idle rpm(see above "fix"). Here's how it went. I had the AC turned on before starting because I figured that this would be the "worst case scenario ". The car started same as always but the idle was noticeably lower for the first 15 seconds(about 650-700 rpm). I revved the engine slightly & the idle would fall to 500 or slightly less before stabilizing at 750-775 rpm. I then turned the AC off & the idle went up to 850 and stayed there. A couple of small throttle blips saw the idle fall to 650 before stabilizing at 850. The time lapse from startup to this point was about 2 minutes. The temp gauge had not started to move yet. I then took off to get my morning coffee from the local Bigfoot. The car ran as it always did while moving & the rpm drop below "normal" idle speed started to go away as soon as the engine began to warm up. Slightly before the engine reached normal operating temp on the gauge, the idle was back to its steady 900-950 point. I turned the AC on & had the 850-875 idle that has become "normal" for me with no drastic rpm plunges to 500 or less as I stopped.
So, here's my conclusion. I can either put up with a few minutes of inconsistant morning idle OR suffer the aggravation of the slow fall from 1500 rpm at EACH stop all the rest of the day. Guess which one I will choose:rolleyes:
 

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Actually, what I really want to do is to have the ECU accept an rpm of at least 1000 before it turns on the SES light. Right now, anything over about 800 will turn the light on after a couple of days. Then next I want to find one of the carb dashpots from days gone by, you know the ones that had a electric solenoid to kick the stop point up a little when the AC clutch engaged. I'm sure I can fabricate a nice bracket to mount the dashpot so that it will "cushion" the throttle bellcrank slightly AND compensate for AC operation. Of course, the above will only apply if Doug at Billetflow doesn't cure the high idle problem with a TB modification.
 

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Jerry said:
Have you gone back to stock recently just to verify it still is the BF TB and Plenum?
The BilletFlow has been on & off at least 3 times. Each time that I reinstall the oem TB, the problem isn't there. I'm absolutely positive that the high idle issue is directly related to the BF TB.

I talked to Doug again today & he requested that I send the TB back to him. He will inspect it & fix the problem or replace the TB. Now that's what I call great customer service. :) Doug, you da man.

Stocker on = no high idle
 
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