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Old 10-16-2011, 08:40 PM   #1
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Stupid idle

after putting in a cai the next day the idle shot up to about 1500 every chance it gets even when just sitting there or when i have the clutch in i have just recently done alot of idle work including a new iac and such but why would it suddenly be doing this? i have also tried to play with the idle screw but it hasnt done really anything. help thanks
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Old 10-16-2011, 08:46 PM   #2
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What kinda CAI? everything I sealed up tight? What year car
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Old 10-16-2011, 08:48 PM   #3
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Re: Stupid idle

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Originally Posted by NateNasty View Post
after putting in a cai the next day the idle shot up to about 1500 every chance it gets even when just sitting there or when i have the clutch in i have just recently done alot of idle work including a new iac and such but why would it suddenly be doing this? i have also tried to play with the idle screw but it hasnt done really anything. help thanks

Since it happened after you installed the CAI, try "clocking" (rotating) the MAF in a few different positions and see if that helps.

Sometimes aftermarket CAI's have strange effects on the airflow in comparison to the stock units and rotating the MAF will help cure the problem.
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Old 10-16-2011, 08:49 PM   #4
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It's an 86 so it doesn't have that sensor on the intake and I pretty much rigged up my own cai. I am pretty sure everything is I'm gonna check it again!
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Old 10-16-2011, 08:58 PM   #5
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Filter is in the fender, or underhood?

---------- Post added at 09:58 PM ---------- Previous post was at 09:51 PM ----------

The way you troubleshoot it is put the stock intake system back on and see if the problem continues. If it does the CAI is nit the issue.
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Old 10-16-2011, 09:00 PM   #6
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Re: Stupid idle

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Originally Posted by NateNasty View Post
It's an 86 so it doesn't have that sensor on the intake and I pretty much rigged up my own cai. I am pretty sure everything is I'm gonna check it again!
Oops! I missed that.
See below in bold print.


From Car Craft:
Speed Density systems accept input from sensors that measure engine speed (in rpm) and load (manifold vacuum in kPa), then the computer calculates airflow requirements by referring to a much larger (in comparison to an N Alpha system) preprogrammed lookup table, a map of thousands of values that equates to the engine’s volumetric efficiency (VE) under varying conditions of throttle position and engine speed. Engine rpm is provided via a tach signal, while vacuum is transmitted via an intake manifold-mounted Manifold Air Pressure (MAP) sensor. Since air density changes with air temperature, an intake manifold-mounted sensor is also used.

Production-based Speed Density computers also utilize an oxygen (O2) sensor mounted in the exhaust tract. The computer looks at the air/fuel ratio from the O2 sensor and corrects the fuel delivery for any errors. This helps compensate for wear and tear and production variables. Other sensors on a typical Speed Density system usually include an idle-air control motor to help regulate idle speed, a throttle-position sensor that transmits the percentage of throttle opening, a coolant-temperature sensor, and a knock sensor as a final fail-safe that hears detonation so the computer can ****** timing as needed.

All ’86-’87 and ’88 non-California Ford 5.0L-HO engines used Speed Density metering.
Because a Speed Density system still has no sensors that directly measure engine airflow, all the fuel mapping points must be preprogrammed, so any significant change to the engine that alters its VE requires reprogramming the computer.


Read more: Electronic Fuel Injection Mass Flow vs. Speed Density- Car Craft Magazine
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Old 10-16-2011, 09:20 PM   #7
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It goes in the fender an yeah I'll try that

---------- Post added at 09:20 PM ---------- Previous post was at 09:15 PM ----------

Quote:
Originally Posted by Trojan Horse

Oops! I missed that.
See below in bold print.

From Car Craft:
Speed Density systems accept input from sensors that measure engine speed (in rpm) and load (manifold vacuum in kPa), then the computer calculates airflow requirements by referring to a much larger (in comparison to an N Alpha system) preprogrammed lookup table, a map of thousands of values that equates to the engine’s volumetric efficiency (VE) under varying conditions of throttle position and engine speed. Engine rpm is provided via a tach signal, while vacuum is transmitted via an intake manifold-mounted Manifold Air Pressure (MAP) sensor. Since air density changes with air temperature, an intake manifold-mounted sensor is also used.

Production-based Speed Density computers also utilize an oxygen (O2) sensor mounted in the exhaust tract. The computer looks at the air/fuel ratio from the O2 sensor and corrects the fuel delivery for any errors. This helps compensate for wear and tear and production variables. Other sensors on a typical Speed Density system usually include an idle-air control motor to help regulate idle speed, a throttle-position sensor that transmits the percentage of throttle opening, a coolant-temperature sensor, and a knock sensor as a final fail-safe that hears detonation so the computer can ****** timing as needed.

All ’86-’87 and ’88 non-California Ford 5.0L-HO engines used Speed Density metering.
Because a Speed Density system still has no sensors that directly measure engine airflow, all the fuel mapping points must be preprogrammed, so any significant change to the engine that alters its VE requires reprogramming the computer.

Read more: Electronic Fuel Injection Mass Flow vs. Speed Density- Car Craft Magazine
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Old 10-16-2011, 09:21 PM   #8
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Quote:
Originally Posted by Trojan Horse

Oops! I missed that.
See below in bold print.

From Car Craft:
Speed Density systems accept input from sensors that measure engine speed (in rpm) and load (manifold vacuum in kPa), then the computer calculates airflow requirements by referring to a much larger (in comparison to an N Alpha system) preprogrammed lookup table, a map of thousands of values that equates to the engine’s volumetric efficiency (VE) under varying conditions of throttle position and engine speed. Engine rpm is provided via a tach signal, while vacuum is transmitted via an intake manifold-mounted Manifold Air Pressure (MAP) sensor. Since air density changes with air temperature, an intake manifold-mounted sensor is also used.

Production-based Speed Density computers also utilize an oxygen (O2) sensor mounted in the exhaust tract. The computer looks at the air/fuel ratio from the O2 sensor and corrects the fuel delivery for any errors. This helps compensate for wear and tear and production variables. Other sensors on a typical Speed Density system usually include an idle-air control motor to help regulate idle speed, a throttle-position sensor that transmits the percentage of throttle opening, a coolant-temperature sensor, and a knock sensor as a final fail-safe that hears detonation so the computer can ****** timing as needed.

All ’86-’87 and ’88 non-California Ford 5.0L-HO engines used Speed Density metering.
Because a Speed Density system still has no sensors that directly measure engine airflow, all the fuel mapping points must be preprogrammed, so any significant change to the engine that alters its VE requires reprogramming the computer.

Read more: Electronic Fuel Injection Mass Flow vs. Speed Density- Car Craft Magazine
Thanks guys, I think you guys solved a small issue for me( i also have a bbk cai w/speed density).The idle on my stang is a little loopy when warmed up. Almost like it has a cam. But it comes and goes roughly every couple minutes. I'll definitely know when I put the maf sensor in the next couple weeks.
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Old 10-16-2011, 09:21 PM   #9
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So I might have to change my computer to get a cold air?
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Old 10-16-2011, 09:28 PM   #10
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Quote:
Originally Posted by NateNasty
So I might have to change my computer to get a cold air?
Im a bewbee but what I've been told , just add the sensor with adapter.
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Old 10-16-2011, 09:29 PM   #11
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Re: Stupid idle

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So I might have to change my computer to get a cold air?
You may have to get it tuned via a chip for that to work.
Your best bet is to change it over to MAF. It is a lot more forgiving when modding the engine.

Quote:
Originally Posted by Jpstang View Post
Thanks guys, I think you guys solved a small issue for me( i also have a bbk cai w/speed density).The idle on my stang is a little loopy when warmed up. Almost like it has a cam. But it comes and goes roughly every couple minutes. I'll definitely know when I put the maf sensor in the next couple weeks.
Glad we could help. Let us know how your conversion turns out.
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Old 10-16-2011, 09:31 PM   #12
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Quote:
Originally Posted by NateNasty
So I might have to change my computer to get a cold air?
Just save for a MAF conversion, which will be needed for any other mods. MAF conv uses a diff ECU. Will be much better in the long run.
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Old 10-16-2011, 09:31 PM   #13
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Yes convert, it's not as bad as you think to install, and I believe Trojan has a link for it too.
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Old 10-16-2011, 09:36 PM   #14
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Re: Stupid idle

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Yes convert, it's not as bad as you think to install, and I believe Trojan has a link for it too.
Yes, we do have a link in this thread - Useful Mustang Info
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Old 10-16-2011, 09:39 PM   #15
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Quote:
Originally Posted by Trojan Horse
You may have to get it tuned via a chip for that to work.
Your best bet is to change it over to MAF. It is a lot more forgiving when modding the engine.

Glad we could help. Let us know how your conversion turns out.
I heard you have a link for install of maf . I'm a newbee and don't want to butcher it. I want to make you guys proud lol.
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Old 10-16-2011, 10:15 PM   #16
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Alright sounds like a god mode I'll hoop on that tomorrow thanks y'all!
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Old 10-16-2011, 10:19 PM   #17
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Re: Stupid idle

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I heard you have a link for install of maf . I'm a newbee and don't want to butcher it. I want to make you guys proud lol.
See the post right above yours. ^^
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Old 10-16-2011, 10:23 PM   #18
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I also thought my car was maf because of the sensor on my throttle body I guess I'm restarted because f this lol
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Old 10-16-2011, 10:31 PM   #19
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The MAF will mount down at the air filter.
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Old 10-16-2011, 10:31 PM   #20
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And all that says it shouldn't do that with a cai...
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Old 10-16-2011, 10:33 PM   #21
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Re: Stupid idle

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I also thought my car was maf because of the sensor on my throttle body I guess I'm restarted because f this lol
Nope, you're just learning.
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Old 10-16-2011, 10:38 PM   #22
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Click image for larger version

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Should help you picture how it goes together.
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Old 10-17-2011, 01:56 AM   #23
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Re: Stupid idle

First thing thought of after reading post, has been mentioned but it is usually a loose fitting on the CAI tubes to throttle body, EGR tubing came loose, PCV/breather on either side valve cover came loose.
A vacuum leak somewhere should be the easy fix. Good luck.
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Old 10-17-2011, 08:12 AM   #24
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Some **** prolly came loose. I'll take off the cai and put the stock one on first like someone said see if it changes :0
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