Erratic Idle, Backfiring (Page 1/6)
Addition1291 AUG 10, 01:38 PM
Hey guys.

So my V6 is having some strange issues and I may have found the culprit but I want to double check.

First of all, the engine is cammed and bored. When you are trying to get it to start moving from stop, you have to give it a tiny amount of gas, otherwise the revs drop like a brick and you get a lot of backfiring. It also has a very erratic idle and has died on me in the past. I can't tell you what rpms it fluctuates between because the tach is all off (probably because its cammed and bored). Once I'm in second gear or so, the car runs just fine.

Also, when I was looking around today I found this line and a matching hole in the back of the engine. I figured that might be the source of the problem but I don't know for sure. After tons of googling I still have no idea what this line does or what its called. My theory is that its a vacuum line, which would explain a whole lot.

Picture of the line next to the hole:


It is located behind the intake, around the blue circle. You can't really see it in this image but its here for reference.


Is there some sort of plug or sensor that I'm missing that goes in there, or should I just shove the line back in?

Thanks
AsaBergman AUG 10, 03:24 PM
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[This message has been edited by AsaBergman (edited 08-14-2019).]

fierosound AUG 10, 04:10 PM

quote
Originally posted by Addition1291:

It is located behind the intake, around the blue circle. You can't really see it in this image but its here for reference.



Shove the line back in. It's the "fresh air" for the PCV system.
The PCV on the trunk side valve cover is the vacuum side to draw out the vapours.

It appears the Recall was not done on your car.
http://www.fiero.nl/forum/Forum9/HTML/000032.html

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Addition1291 AUG 11, 02:32 PM
I threw the line back in. It didn't really make much of a difference but I sure feel a lot better lol.

I might also add that the car runs very rich and has some power issues getting moving. I'm thinking its the o2 sensor.
tshark AUG 11, 03:07 PM
The other end of that line should go to the intake tube.

The vacuum leak is likely somewhere else, such as the EGR system, or the cruise system.
Addition1291 AUG 11, 03:50 PM
I cannot believe I didn't see this earlier. I must be blind.

There's no EGR tube at all.


Where does the other end go?
Gall757 AUG 11, 07:44 PM
There is a hole on the under side of the intake manifold. Very possible your previous owner blocked it off.
Addition1291 AUG 17, 11:45 AM
Update:

I put in Rodney's EGR tube. The previous owner had indeed blocked off the EGR. I'm still having issues but it idles a little better. Last night when I was driving it, it died on me as I was coming to a stop. It was pretty hard to get it started again. It would start, and then immediately die if I didn't give it gas.

I think my next steps are to check out the EGR itself and make sure that there isn't another vacuum issue somewhere else in the car.

If anyone else has any ideas, I'm all ears.
Addition1291 AUG 23, 12:50 PM
So! I believe I may have found a solution and the source of my missing vacuum!

I was digging around old forum posts trying to find out what my problem might be when I encountered buddycraig's CODE 32 write up: http://www.fiero.nl/forum/Forum2/HTML/045528.html

It lead me to finding out that when the previous owner installed the "cold" air intake, he disconnected this vacuum line.


Now my question is: Would it be kosher to run a vacuum line from there to this existing hole in the "cold" air intake? Nothing was there before, so it would make sense to me.


I just wanted to double check with you all before I accidentally do something stupid since this is still new to me.

Thanks for any replies!
Gall757 AUG 23, 02:19 PM
Go for it. It's not really a vacuum line, but a clean air supply for the EGR solenoid. It may be disconnected at the firewall or at the solenoid.