iamchevyman5

Hi, this is my first post here!
I recently acquired a 1998 Pontiac Trans am 5.7l V8 with 80,000 on it. It sat a lot during Michigan winters. Less than a week after I bought it, it began throwing a PO507 code (IAC malfunction, high idle). I sought advice from places like autozone, advanced, and oreillys. They all gave me the wrong advice and each time they did, it cost me money. I've cleaned the TB, MAF, TPS, IAC, and EGR. I finally took it to a local dealership, which also cost me money only to be told the wrong thing. They said it was a possible intake manifold gasket leak. WRONG, d@mmit.
I took off the manifold (it's still off), only to find all gaskets intact. HOWEVER, behind the manifold, the PCV hose has some weird stuff going on. There are two or three hoses that are directly behind where manifold was that I'm confused about. Please follow this link to the video I made of it so you can see what I mean.

http://www.youtube.com/watch?v=XqYjnukB4FA


After watching the video, can you tell me where these hoses go and what I'm supposed to do with them? Could the fact that they were disconnected be a cause of that PO507 code and high/rough idle?
I don't have a car until I figure this out, so PLEASE hurry! I've been trying to find the answer online, but there is no such resource.
Thanks,
Dan

LS6427

iTrader: (2)

Welcome dude. Your assistant looks pissed and probably wants you to sell that damn thing...right?

Just kiddin.

Look at the rear of your intake, the little one attaches to it. Its the A/C vacuum line. The other one looks like it should go together with that elbow you showed and join those two PCV lines.
With that A/C line not attached you will get a higher idle and the associated P0507.

And be very careful not to break the Oil Pressure Sending sensor when putting the intake back on, pretty easy to snap it off. Lift the intake up and over it inbetween the rear of the intake and the brake booster hose. Then drop it down into place.

I guess you learned a lesson about getting advice from auto parts stores.....so I won't rag on you. Just come here from now on with anything going on with the car.



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iamchevyman5

Ha, Chrissy is always pissed at me. I probably will be selling the trans am shortly though, can't afford it and I'm going away to college next semester to an area in the snow belt. Thanks for telling me where the ac line went, I checked and found what you were speaking of on the manifold. How sure are you that those two other lines connect to each other though? I mean it seems logical that they would, but I want to make sure. Where's this oil pressure sending sensor you were talking about? Maybe I'll try to search for an image for it.
Thanks for your help and the welcome to LS1Tech!
Dan

LS6427

iTrader: (2)

The OPSU is the black tube that sticks up at the rear of the engine, it has an electrical plug attached to it. Its about the size of a roll of quarters and sticks up about 3 inches. With the intake in place, it sits right there at the rear of it.

That thing looks very tough and strong, but you will break it off by sneezing on it. It doesn;'t just break off totally, it stress cracks and will still actually sit there in place. But it won't work anymore and you will have zero oil pressure.

You need to lift the intake up and over that thing, placing the intake so that the OPSU sits inbetween the intake and the brake booster hose. Just as your putting the intake back on, guard that thing with your hand.

And yes, that elbow looks like it joins those two other hoses....those are your PCV lines.

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iamchevyman5

Okay thanks for the help. Here's the progress I've made so far. The intake manifold is back in position, but still needs to be bolted down, EVAP canister needs to be replaced (I broke off part of it), and the fuel injector electrical connections need to be reconnected. I know how/where to get the EVAP canister, but does anyone have a parts number for the fuel injector connector retaining clips? They fling everywhere and now I only have like 3 of 8. I may have identified the original problem after putting stuff back together. Like I said, I just got this car so God knows what the last owner did to it. The PCV hose was there on the driver side, but it was only a makeshift part. I replaced this, and later found that there was nothing connecting to the passenger side like there should have been. That elbow shown in the video is all there was, but it's not meant for that and didn't connect. So, I reconnected the AC line you told me about and bought a few feet of PCV hose and fixed that problem.
Anyway, please let me know the PN of those clips if you have it, or let me know where I can get them!
Thanks,
Dan

sporttster

iTrader: (1)

Hate to ask how long it took you to get that off. I've got a 99 T/A that has a vacuum leak in the front of the intake manifold and have been told it'll cost $400 to replace the gasket. Am soo tempted to do it myself but am not a 'gear head'. Haven't seriously worked on a car since high school....26 years ago.

iamchevyman5

hey, sorry for the late reply, I didn't think anyone was actually reading my post.
I would rate the job as moderate. It's time-intensive, but if you take it a step at a time and think like an engineer like I try to, you'll be fine. Junkman2008 did a TERRIFIC breakdown of the job. Here's his post intake manifold removal breakdown

I did all that work involved in removing the manifold, and still haven't solved my problem. I'm going to make another video and show the car from the inside, from start-up to shut-down, focusing on how it idles so high while in gear, and the idle tremor.

Also, for anyone who's reading this, I also recently realized that my AC isn't working correctly. It blows warm and air will only blow on the driver's feet, nowhere else. Could a bad AC pulley cause this problem & be associated with my high idle?

Anyway, come back and look at my video which I will post today or tomorrow depending on popular (or unpopular) demand.

Anyway, a little there from your question sporttser, but to answer that question I'd say do it. Don't pay $400 for some shop to do it, but plan on doing it over a weekend at least unless you work efficiently and make a whole day of it.

linegtdt52

iTrader: (12)

no dude that vacuum line must have came loose because acuates the blend door when you switch your selected area to open the door to blow air in the selected zone. recheck the vacuum line. I can do the intake manifold removal and reinstallation in just over an hour. needless to say Ive done this a bunch. good luck.

sjsingle1

iTrader: (1)

the stock PVC hose system sucks big green donkey dicks.....its 10yrs or older now......EVERYONE should get a new hose 100$ + at the dealer......or install a LS6 valley cover....werd