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Fiero Wont Start and/or Idle by mitchjl22
Started on: 07-03-2013 01:12 PM
Replies: 5 (710 views)
Last post by: phonedawgz on 07-03-2013 10:57 PM
mitchjl22
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Report this Post07-03-2013 01:12 PM Click Here to See the Profile for mitchjl22Click Here to Email mitchjl22Send a Private Message to mitchjl22Edit/Delete MessageReply w/QuoteDirect Link to This Post


What's Causing this? Which fusible link is this? Is it possible to tell? I have the cradle out right now so I can't really run the car.




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mitchjl22
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Report this Post07-03-2013 01:15 PM Click Here to See the Profile for mitchjl22Click Here to Email mitchjl22Send a Private Message to mitchjl22Edit/Delete MessageReply w/QuoteDirect Link to This Post

mitchjl22

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Member since Sep 2011
Oh and its an 87' GT 5 speed with EGR blocked off and no Custom prom is that helps for anything.
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phonedawgz
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Report this Post07-03-2013 03:25 PM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
Unplug your IAC connector. Unscrew the IAC body a few turn. See if it starts and idles then. If not remove the IAC and see if it starts and idles fast. It should.

The IAC controls the idle speed. It seems to me that your IAC isn't working for whatever reason. They rarely fail. The IAC has a pintle that it inserts into the IAC passage. The farther the pintle is inserted into the IAC passage, the less air and thus a slower idle.

Your video looks like it has a new IAC motor on it. That doesn't mean it is working however. You could have a bad ECM or bad wiring. Before replacing anything let's find out if your IAC passage is clear and working.

If you get to where you fully remove the IAC, there is a vacuum line to the lower intake manifold. You should be able to stick your finger into the hole the IAC was in and control the idle by pressing your finger against the hole (right hand side of the IAC hole) to slow the idle and remove your finger to increase the idle.

So if the engine will idle (fast like 2000 rpm) with the IAC motor removed then you know the IAC passage out is good. If that 'fixes' your won't start problem then the next thing is to look at why the IAC motor isn't moving.

If however the engine still will start with your foot on the gas, but still won't run with your foot off of the gas, and there is no sucking of vacuum in that hole to the right, then you need to figure out why your IAC to lower intake manifold passage is blocked.

Tube that connects the throttle body IAC output passage to the lower intake manifold


The input passage to the IAC valve, and the IAC valve itself. Note - the capped screw marked 'idle screw" is not an idle screw and do not uncap it and adjust it.

[This message has been edited by phonedawgz (edited 07-03-2013).]

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mitchjl22
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Report this Post07-03-2013 09:39 PM Click Here to See the Profile for mitchjl22Click Here to Email mitchjl22Send a Private Message to mitchjl22Edit/Delete MessageReply w/QuoteDirect Link to This Post
I replaced the IAC motor again just after the video was taken. (Under warranty) Also, while the upper plenum was off, i used Carb/Tb cleaner and sprayed a lot into the hole inside the tb and i removed the IAC valve annd sprayed and cleaned in there with q tips to try and clean it out. There was a LOT of black greasy oily gunk in the hole, but i figured i had cleaned it all the way after the 5th q tip came out without any gunk. Could i run something through the iac output like a trumpet cleaner or something that could snake through and clean?

Also, in the car's current state, it runs very very rich at idle. It smells like my dads old 66 mustang. (But it has a new cat) which i thought controlled how much unburned fuel exited the exhaust. The tips are very black, And the watery condensation the car's exhaust blows out when its cold , is black and leaves lots of carbon on the concrete garsge floor.
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Shonyman32
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Report this Post07-03-2013 10:02 PM Click Here to See the Profile for Shonyman32Send a Private Message to Shonyman32Edit/Delete MessageReply w/QuoteDirect Link to This Post
Do you have access to a scan tool?
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phonedawgz
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Report this Post07-03-2013 10:57 PM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
Runs very rich. - Pull the vacuum that runs from the upper plenum to the MAP and fuel pressure regulator. Inspect the vacuum line for fuel. If you have fuel there your fuel pressure regulator is leaking fuel. If no fuel then as a test try running a vacuum line directly from the upper plenum to the MAP sensor directly. If that makes it run much better, then you have a vacuum leak in the line that runs from the MAP to the upper plenum to the Fuel Pressure Regulator. If however it still runs poorly, reconnect the vacuum lines and electrically unplug the MAP sensor. If having the MAP sensor unplugged makes the engine run like normal then you have a bad MAP sensor.
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