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Idles high

2K views 24 replies 7 participants last post by  jimfulco 
#1 ·
i put a jegs "Max Box" upper sheet metal intake plenum, for shortys headers, BBK cold air induction system, and BBK high performance H-pipes with out converters, everything else is stock. The car idles high, even with the throttle screw screwed out all the way. What did i miss. How can i idle the car down? It idles at 1 1/2 thousand rpms, in park, and a little over 1 thousand rpms in gear. Do i need a chip or different program. that will idle it down? :confused: :confused:
 
#5 ·
all this was also happening before we changed all this so its not a new problem was just hoping changing this stuff may help it some. one guy above said

Be sure that you secondary throttle blades are closing all the way.
Can you explain this to me?? me and my dad are use to older cars with carburetors on them so the whole injection and crap is kind of confusing :).
So if u guys could explain these questions u have for me a little better it would be awesome!!, and would changing the throttle body help any?? do you guys know what the stock 1991 5.0's throttle body size is??.
 
#9 ·
Toddclary said:
i put a jegs "Max Box" upper sheet metal intake plenum, for shortys headers, BBK cold air induction system, and BBK high performance H-pipes with out converters, everything else is stock. The car idles high, even with the throttle screw screwed out all the way. What did i miss. How can i idle the car down? It idles at 1 1/2 thousand rpms, in park, and a little over 1 thousand rpms in gear. Do i need a chip or different program. that will idle it down? :confused: :confused:
What is it or what was it?

Bogie
 
#15 ·
Help :)

http://forums.musclemustangfastford...scussion/idles-high-wont-come-down/index.html

in here they are talkin about a Throttle position sensor.. what is that and or where is it?? could this be my problem??

"Did you you reset the ecm when you replaced the IAC motor?"
this was also a question asked.. I got the manual to work on my car, but it doesnt say much about this stuff because thats a "take it to a specialist" kinda work.. SO here comes the newb questions.. How can you reset the ECM and or where is it located.. as well as the IAC motor.?

If we change to a 65 throttle body do we have to change the injectors as well as the mass air flow sensor? if we need to what is recomended.. How easy or hard are all these changes?? :confused:
are the injectors as simple as unplug and plug in??
 
#20 ·
What is your manifold vacuum at idle? Do you hear any hissing sounds? Your question on the TPS(throttle position sensor) what is it where is it, it is located on the throttle body on the opposite side of the throttle cables.

To help determine whether or not it has a vacuum leak use a propane torch(unlit) with a hose attached and spray the propane all around the intake area. When it starts to idle the engine down with the added propane enrichment you will find where your leak is located. Also shoot some of the propane through the air filter intake, this will tell you if it is just running too lean.
 
#21 ·
idles high

The throttle body is easy to change,just four bolts.The throttle position sensor is on the throttle body itself.It has a couple of screws holding it in place and a couple of wires.If you have a stock cam,I would go no larger than 24lb injectors and maybe a 77mm mass air sensor.These things you can do yourself if you have tools and a guide.The ecm is the computer that controls the engine it is located on the passenger side kick panel.
 
#25 ·
Ever figure it out? If not, look for a big vacuum leak. My 5.0 T-bird decided it wanted to idle at 45-50mph with no power brakes any more. Turned out the cheezy little plastic vacuum manifold on the firewall inboard of the brake booster had a nipple broken off, causing a ~3/8" leak in the brake vacuum system. I fixed mine with a brass tee.
 
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