I am very new to the car thing. I took my car to a mechanic and he couldnt find anything wrong. I have bad experiance with mechanics, they are always rigging stuff and screwing things up! So I would rather just ticker with stuff myself if possible. (plus its pretty cool! )
Anyway, here is the details on my problem:
In the morning I crank my car. It revs to about 2k rpm then drops and almost dies. It does this over and over until it dies. I crank it again. Sounds better this time but then goes to erratic idling. If I do not let the engine warm, it stalls and sometimes can not make it up the hill of my driveway. If i let it warm up it drives like crap but it works. Eventually, after it is really warmed up (15 min of driving 50 mph) the only problem I have is that it feels like it has a slight problem shifting gears. (Automatic 4 speed).
Thanks to some help from my guys friends I learned how to check the trouble codes. I got a 32 and 44. 32 is baro sensor and 44 is lean exhaust.
From other threads, it looks as if it is a vaccum leak. One guy said he replaced a gasket and others replaced hoses. Also people cleaned the IAC valve.
The first thing i was going to do was clean the IAC valve but my Haynes manual talks about relieving fuel pressure but i have not seen that mentioned in this forum.
Some threads make it seem as easy as just pulling the IAC valve out with a wrench...but then again my haynes manual starts talking about distance, pintles and conical valves.

I guess my question is, could someone give me step by step DETAILED instructions on how to clean the IAC valve( i own carb cleaner if that helps), best hoses/places to check for a vaccum leak, and possibly how to replace the gasket. If it is easier/safer just to replace the IAc valve then I am all for that too. I dont want to screw anything up!
Also any tools i may need besides a wrench and some screw drivers.
The more stupid details, the better.
Thanks!
BTW- i have already identified the IAC valve and I know how to take the airfilter and stuff off to get to the throttle body. Thats about the extent of my experiance.

 

Sounds like your on the right track. It definitely sounds like a vacuum leak or IAC valve problem.
Actually, for the fuel injected cars, code 32 is for the EGR valve system.

But, first, the easiest way to check for a vacuum leak at the intake manifold or at the base of the TBI unit is really easy. Just spray carb cleaner slowly around the base of the TBI unit (where the TBI unit and intake bolt together), and where the intake bolts to the cylinder heads, and listen for an immediate drop in idle speed (if you can get the car to run smooth). If you hear that sound, than where you just sprayed is where there is a vacuum leak. If your unfamiliar with how that sounds, spray some carb cleaner down the throttle body with the engine running, and listen to what it does. Notice how it idles down and bogs for a second, before returning to normal? That's how it will sound. If a vacuum leak is big enough, you will be able to hear it, usually as a loud hissing sound. Trace the sound until you find it.

As for the vacuum lines, it really just consists of finding them and checking them for any cracks, damage, and checking that they are all connected. Trace each vacuum line and make sure that they are all connected, and are in the proper place. There should be a vacuum diagram sticker on the hood that shows where all the lines should be.

Most of the vacuum lines on these cars are hard, prebent lines. If you have to replace any of them, you have the option of either buying hard vacuum line and routing and bending them just like the stock lines, or you can just buy the generic round rubber vacuum hose they sell at any auto parts store. Either kind of vacuum line will work. If your unsure of what size vacuum hose you need, just take the old one with you.



As far as the IAC valve goes, it's really not that hard at all. Here's my attempt at a step-by-step.

1. Take off the stock air cleaner assembly. It should be 1 wingnut, 1 vacuum hose, 1 electrical connector (on the bottom of the air cleaner, for the IAT sensor), and 3 screws (1 on washer fluid reservior, 2 in front of the air inlet).
2. Use a large wrench or an adjustable wrench to remove the IAC valve from the passenger side of the TBI unit.

The IAC valve is the large gold device in this picture:


The rest of the directions I'm going to quote a post from dimented24X7, he has some very detailed instructions on this:
The only thing I can think of to add to this is while you have the IAC out, clean out the IAC passages in the TBI unit, too. They get clogged up with gunk over time. Just spray some carb cleaner down the passages and scrub the gunk off until it's clean again.

And, one more thing, there is an O-shaped gasket that goes in between the IAC valve and the TBI unit. Don't forget to reinstall the old one, if it's still in good shape (not torn or about to fall apart). You can get a new one at an auto parts store if needed.


I know this is a lot to read, but none of this is hard to do. Just takes a little time and patience. Good luck, and let us know how it turns out.

 

Hm..i am glad you said that as I am confused over that. My Haynes manual says that 32 is the Baro Sensor but many threads mention the EGR valve. ALSO, someone bipassed my EGR valve and said that if it was the problem then bypassing should fix it..and it did not. Does that mean I can surely exclude the EGR valve as the problem?

Ok..i have seen that thread that you quoted..but I am confused about the part where it tells you to remove the IAC valve....then it tells you to to reconnect the connector and do the thing with the aldl and then it says it will eject the pintle then to remove the IAC and its components?? I thought the IAC was already removed? Or am i getting the valve and the IAC confused?? Can you explain those steps more?? Why cant i just remove the IAC valve be done with it? Why all that jumpering ?
Thanks for the reply! I am so excited about actually doing this!!

 

No. Actually, it's the complete opposite. To put it simply, when the EGR valve is just simply bypassed, the car's computer won't realize what's been done, and will set a code because it's detecting that something is wrong in the EGR system.

Think of this way, the car's computer is constantly monitoring and testing sensors, valves, and systems while your driving. If it "asks" a certain sensor or system to "do" something, it expects a certain response, and if it doesn't happen, it detects that something is wrong, and warns the driver by setting the Check Engine light. Make sense?

Yep, I can explain it some more. I can understand the confusion. The main thing to remember is that the IAC valve isn't just one single part. The IAC valve is already removed from the TBI unit, but the smaller parts need to be removed from it and cleaned, as well.

OK, once you have unscrewed and removed the IAC valve, you will notice that there is a spring and cone-shaped pintle on the end. Here's a picture to show what it looks like:

When you reconnect the electrical connector and jump the 2 ALDL pins, those are the 2 pieces that will fly out, the spring and the pintle. And those are what you clean.

You remove those pieces just so that every individual piece of the IAC valve gets clean. Just simply spraying carb cleaner on it won't clean everything, and you could still have problems. Remember, that gunk gets everywhere.

 

Update:
Wow! that was soo easy..except for unscrewing the IAC. I do not own a rachet...or.....anything beyond a screwdriver really but I got a cheap parts kit and it had some slip joint pliers so i used those. Took some effort..but the engine was still hot ( i couldnt wait to do it!). Did everything the instructions said....way to easy!. The IAC valve didnt look bad at all..which sucks...cause now I dont think that is the problem. Anyway, the gasket cracked and I just happen to have a Throttle Body Gasket Kit for TPI that some idiot at autozone gave me. (before i knew that I had TBI and just have not taken it back yet) so I guess i will break into that and take the IAC gasket.
Cleaned the parts with Carb cleaner, put it back together...now waiting till morning to see how it runs.

If this doesnt work any ideas for what is next (btw i did the carb cleaner around the hoses thing and didnt seem to find a leak)? I am thinking about changing the fuel filter but I dont own ramps. I guess i could take it somewhere and pay them to put in the new one but how boring is that? Wait...what am i saying? I dont even know where the fuel filter is!

 

If that doesn't help at all, first thing I would try is resetting the computer. Easiest way to do that is to just disconnect the negative terminal of the battery for about 30 seconds. Reconnect the negative terminal, and then drive the car around and see if it's any better or worse (it will run kinda bad at first, since the computer has lost it's "memory"). After that, pull the codes again and see what it gives you. Those 2 codes you got before might be old ones, not current ones.


Also, I should have asked this at the beginning, but how long has it been since the car has had a good tune-up (spark plugs, spark plug wires, distributor cap and rotor, O2 sensor, fuel filter, PCV valve, etc.)?

 

Had a tune up about 2 years ago.
Checked the spark plugs and they looked okay. Had signs of running lean but didnt look bad.

I replaced the IAC and the "idle" part of my problem is fixed.
Now I sorta have a "new" problem..in an old kinda way. If that makes since. The car still drives rough and wants to die when I put a load on it (turn on ac, put in reverse, go up a hill) if it has not warmed up. Most problems are at low speeds. Also, if i press the gas the reaction is WAY delayed. So....this weekend..I am going to replace the fuel fiter!! yay!

Thanks for all the help! If anyone has anything they want to say about fuel filters feel free. I have seen many threads on it and believe I am prepared.

 

Don't have much to say, except for watch out for when the gasoline starts pouring out of the lines once the fuel filter's loose. I haven't replaced a fuel filter yet without getting fuel all down my arms, and it burns after a while.

Although, I have heard that golf tees make great brake and fuel line plugs.

 

Hi, folks, would someone be gracious enough to post instructions on locating and cleaning the IAC on a 305 TPI engine (85 IROC)?

I'm also a newbie, and would appreciate the assistance.


Thanks,
Rick

 

Im pretty sure the tpis use a similar, or same IAC. the location should be in the front of the upper intake plenum in the throttle body. There may be a thread or threads on the TPI board that pertain to this.

 

dimented24X7 is right, there's a pretty good write-up on cleaning the IAC in the stickies on the top of the TPI board. Check out the last post in this thread:
https://www.thirdgen.org/techbb2/sho...hreadid=151240

The IAC valve on the TPIs is located on the throttle body, just under the throttle blades. If you take off the plastic air ducts that run from the air filter to the throttle body, you should be able to see it sticking out of the bottom of the throttle body on the passenger side with a 4-wire connector plugged into it. It looks identical to the TBI IAC valves.

 

I replaced my IAC sensor about 2 months ago... I recleaned my TBI on my 3.1L, and then IAC sensor had carbon deposits on it. Do I use a toothbrush or something to remove the carbon because I do not want to buy another IAC sensor...

 

A toothbrush will work fine. Just spray some carb cleaner on it, and if that doesn't remove most of the deposits, go at it with the toothbrush. Just don't go crazy with the carb cleaner, a short burst is usually all thats needed.

 

Thanks for the detailed description; I feel like I've won half the battle just having found it. After reading the document however, are the ALDL steps and adjustment of the Torx screw really necessary?

The cleaning part seems pretty straightforward up until that point, but the rest sounds pretty intimidating.


Rick

 

I guess you really don't have to adjust the idle screw, as long as you disconnect the battery for a minute or 2 and then drive the car for a while to allow the ECM and to "relearn" everything. But, honestly, it really won't take that much more time or effort to adjust it.


But, since your already right there at the throttle body and IAC valve, why not?

 

Where can I get the IAC coolant gasket?
Auto part store, junk yard, I broke mine yesterday.

 

Not really. On tbi cars it helps to have the air go through the bores instead of the IAC since the air is what shears and atomizes the fuel at idle. With tpi, it doesnt matter. The computer will jsut adjust the IAC as necessary to get the desired output so it doesnt matter as much how far the IAC is open. Either way the ecm still has control.

 

I thought you could buy them separately, but I can't find them online. But, they do sell throttle body gasket kits that come with the gasket you need. It includes all the gaskets for the throttle body, including the top plate, coolant cover, IAC valve, etc. Any local auto parts store should have it in stock. Here's an example:




$8 at Advance, GP-Sorensen part number 963008:
http://www.partsamerica.com/ProductD...pe=535&ptset=A

$5 at Autozone, same part number as above:
http://www.autozone.com/servlet/UiBr...%7ENONE%7C%7EW


Prices might be a little different, it just depends on where you live.

 

Ill try autozone because kragen is special order

 

I did find the gasket kit at auto zone... but now everytime I come to a complete stop, my idle wants to die out but bounces right back. I think i might have screwed up the IAC sensor, since i didnt use carb cleaner to clean it... I used fluidlighter instead.. Does this mean I screwer up the IAC sensor and if i get a new one, do i just install it or do I have to do something special to get it to work?