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What is this part called and what does it do

2K views 17 replies 9 participants last post by  dougsmith 
#1 ·



Does anyone know what this part is, what it does, or why a crack in it would cause unwanted acceleration. P.S. I unplugged it and removed the ac fuses and I believe it stopped the ac and the unwanted acceleration. Thank you
 
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#2 ·
That's just a crack in the HVAC housing. As it gets worse you'll be blowing air under the hood and your air flow from the vents will decrease.
It has nothing to do with acceleration.

Now if you're talking about the plug above the blower motor, I'm not sure what that is for.
 
#3 ·
I see at least 11 parts in this picture, maybe more depending on how much you break it down. Gonna have to be a tidbit more clear about which part you mean. I assume, like Ranger did, that you're talking about the HVAC housing. But you could mean any of the spark plug wires, the a/c line, whatever that connector is....
 
#4 ·
Ok i was asking about what you have identified as the HVAC housing.

There has to be some connection to overcharging the ac system to the accelerating because my symptoms have gone hand in hand. When the ac is off or that hvac housing has the power cord removed, i have no acceleration issues.

When the ac is on or the hvac is plugged in I have them.

You will have to forgive me. I am trying to figure out a problem that no one seems to know about and im skeptical to take it to a mechanic without any real information of my own.

Any help or any ideas of any kind would be appreciated. Thank you
 
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#9 ·
Honestly guys here us exactly whats going on, and I apologize i don't have better information.

I filled the ac system with refrigerant maybe two months ago, and the gauge on the can did not work,

It immediately started surging the idle. When I say surging, I mean lurching at stops, harder to slow the car, and about a 1 mph acceleration per second with my foot off the pedal.

Scary stuff.

I looked it up and asked around, no info. My girlfriend told me she had an old sunfire that did that and when she turned off the ac it stopped.

I turned off the ac, it stopped.

I told her grandpa and he suggested that since I could not afford the proper ac gauges, to just let out ac refrigerant from the low port with a screwdriver.

I did that, the ac blew fine and no idle issues for a month.

I thought it was fixed.

Now the idle issues are back even with the ac off as it started on my way home from work last night.

I can turn off the car, and turn the car back on and its like it resets something and the idle issue goes away.

Until next time...... when it mysteriously comes back. And im basically forced to park the car and turn it off on.

I appreciate the advice. I have my bar exam in 3 weeks, am broke, and my gf wants me to take it to the shop. But I cant just take it in there and say good luck and rack up a huge bill, but obviously shes worried about safety, as am i, and the it'll be ok line only goes so far.

So if anyone has any idea at all i do really appreciate it. Thanks
 
#12 ·
All you did by venting the refrigerant was waste money and introduce air and moisture into the system.

The IAC does adjust idle speed when the A/C is on, but the idle speed doesn't increase. It just compensates for the the increased load.

When was the last time the TB was cleaned?
 
#14 ·
The ONLY possible relationship between refrigeration and a surging engine is if the compressor was internally damaged and about to seize, thus putting such a load on the engine as to drag down the idle RPM and the IAC valve is compensating by increasing it, but that is a real stretch.
 
#15 ·
One MPH per second is significant, I would think. No?
Trace the accelerator cable... (the cable that pulls the throttle when you put your foot down on the gas pedal.)
Is it possible that the accelerator cable is getting pinched somewhere?... does the gas pedal feel "stiff" at all? Or is the throttle lever sticking?

I believe you when you say it started happening at the same time as the A/C work... but my gut tells me something else got touched/changed/damaged unintentionally in the process of doing the A/C work. Or... the A/C being on is simply revealing a problem that is masked otherwise.

I would expect the idling of the engine to be heavier when the A/C is on. That would be normal for most any car. The engine has to work harder to crank the A/C, in addition to everything else.
But a noticeable increase in speed without your foot on the pedal-- that must be something else. Could something in the area of the clutch not be disengaging all the way... and the heaver idling (A/C on) just happens to get it to the point where it is noticeable?
 
#18 ·
Just in case anyone is still interested, unplugging the power to the hvac has stopped the unwanted acceleration. Its been i believe close to a month now with no problems. So no i dont know, and i realize there should not be a relationship, but, thats what happened. Thanks
 
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