junior419

Just a little back ground since I'm new to the site and new to the 3rd gen camaro. I have a mechanical back ground with new cars obd2 but not these.

I was supposed to be buyin my dream car with a 383 stroker with nos. Posi. And 700r4 with a shift kit. Well apparently I got stroked because it looks like a stock 305 with an Ebay nos kit, open diff. With some issues.

This is what dealing with the car will drive fine if I'm cruising around or going to work not hiccups or anything. The fans won't kick on until almost red lined over heating, so for now I kick on the a/c to work them manually. Also if I'm sitting at a light sometimes the idle will drop real low. I actually installed an idle air control valve which helped with it not wanting to stall but I had to turn the idle screw out some to help as well. So idles real high in park but is good while in drive l.

Now when I try to have some fun. Trying to wot the security light will actually flash each time the car will hesitate like 3 hiccups and it will go. Also the rpm guage will bounce with the hiccups too. Doesnt matter if I try to slap stick shift from 1 2 d it will still hiccup in 1st wot. I have noticed it does this more when it's cold. If I let it go past halfway on the temp guage. She is less likely to hiccup.

New disty
Msd coil
New plugs
New idl air control valve
Fluid levels are good.
Bypassed vats already still see security light flash.

1992 camaro 305 tbi

Ron U.S.M.C.

There is a very important procedure that needs to be done when installing a IACV. Also there is only one time that the stop screw will be adjusted properly.
The ECM relies on data from censors and the IACV and the position of the "I will call them butterfly valves "/Throttle,with many others
When those are not adjusted properly the hole system is off.




Its called setting the minimum idle speed. When you do this the IACV is properly set.
You start by setting the timing to stock when the car is at its normal operating temperature.


The rest requires a digital tachometer preferably on a timing gun.
When your done you can hunt down any other problems you have knowing you are working from a sound base.
This should be very high on the to do list.
Here's the complete procedure =

The car must be at operating temperature.
Setting the timing =
Start the car and idle until the car is at operating temp, disconnect the ESTwire, adjust timing, reconnect EST wire, shut off car ,


Setting minimum idle speed .=

• 1) Jump the A to B terminal under the dash with a paper clip
• 2) Turn the key on but do not start it
• 3) What 45 seconds (you should hear a slight ticking coming from the IACV valve) then unplug the IACV with the ignition still on.
  remove the jumper .
• 4) Start the car and unhook the EST wire.
• 5) Allow the engine to reach normal operating temperature.
• 6) Connect a tachometer. I used a digital timing gun with RPM feature.
  7) Adjust the minimum idle speed using the throttle stop screw.
  8) My Chilton’s says set it to 700rpm in park on an 89 TBI 5.0 auto.
  9) When done reconnect the EST wire and shut the car off .
• 10) Plug the IACV back in.
• Your done
• Some paperclips come with a very thin clear coating that is very hard to see. Scrape it off .

junior419

This is the iac on my 92 camaro. Screw into the throttle body. Next to the throttle position sensor. This doesnt look like its adjustable. Since it has a gasket on it. It looks like i need to screw it in flush. The tps however is adjustable but i havent replaced it yet. Is this procedure for the tps sensor?

Ron U.S.M.C.

Yes, the procedure affects the TPS. The throttle position censor will send the position of the butterfly's to the ECM. So when you set the minimum idle speed when adjusting the stop screw/butterfly's it allows the TPS to send the "proper" signal . Once you preform the procedure mentioned all three , the IACV, minimum idle speed/adjusting the butterfly's/throttle and TPS will all be set in there proper positions. The ECM "will" be very happy and you can move on to any other problems you might have.


That's not how the IACV works. You install the IACV like any other censor.
The ECM controls the tip/pintle's position .
It moves the tip in and out according to idle position.
When you use the paper clip to jump A & B terminals the clicking noise you hear is the ECM closing the pintle. That what is meant when saying "setting it".
It needs to do that by its self so don't move it .


So as you can see, how important the procedure is.
Its a pretty easy thing to do but in the beginning the information I had was a little "twisted".
I finally got it right on the third try.
I can do it in my sleep now .

junior419

Thank you for your help and input, I will go try this today.

Just 1 question. What is base timing for these vehicles I have searched, but found many answers ranging from 0 to 8 degrees advanced. I believe it to be 0 but again many different answers

Ron U.S.M.C.

Mines a "89" ,5.0,TBI, automatic and its "0"


Just be sure all the ports on the throttle body are caped or have sealed vacuum lines coming off of it.
A vacuum leak will through you off.


My running temperature is around 200* so you should be there or higher when making adjustments to the timing or setting the minimum idle speed.






An inexpensive temp. gun is handy.= http://www.harborfreight.com/non-con...ter-93983.html


Here's what the EST wire looks like in case you did not know =

junior419

I have a really nice timing light. Already, I also know about the est connector for setting time. I did not know about jumping terminals. Or what btc was.






Is this accurate for our diag box under the dash? Terminal a and b?

junior419

So I followed your instructions and I no longer see the security light when I wide open throttle. I'm guessing that the reason I was seeing this was because of the knock sensor. I checked where the timing mark was before adjusting it and it was sitting 12 degrees advanced. I big leap from 0.

It idles alot better and doesn't stall, however the oil pressure gauge is sitting almost in the red zone on the cluster now that the idle is lower. Is this a common issue? Was thinking about replace the oil pressure sensor first then the oil pump if that doesn't work.

Even though I don't see the security light anymore I still get 3 hiccups when I wide open throttle. Still confused about that one.

Ron U.S.M.C.

So now that that is done you can move on to other problems.
Oil pressure should not have much to do with it.
Minimum idle speed in park for mine is 700 rpm at operating temperature of 200*

junior419

Well its ok at operating temp but wants to stall when it's cold

Ron U.S.M.C.

I'm not sure where to go with that.
Cold to me means open loop.
Once the car reaches a certain temperature the ECM kicks in (closed loop)and takes control of Idle and starts taking information from the O2 censer.
I'm not sure about the others.
There are guys here that can help. I wish they would chime in.

junior419

I wish they would as well. I feel it might have somthing to do with a faulty temp sensor. I'm thinking that why the fans won't kick on until red zone on the temp gauge . Or it could be the fan switch.

Ron U.S.M.C.

The temperature gage on these cars is notorious for being off. Testing it against a Infored Laser temp. gun is highly recommended. Either buying the inexpensive one I listed or have a shop do it .It only takes them a second or two to do so they usually don't charge anything or very little. Just point it at the thermostat cover and then at the metal around the temperature sender next to the drivers side exhaust manifold/header and compare it to the gage.


Also the stock fan switch in the passenger side head does not even come on until 222* or so and cars with the second fan controlled by the ECM wont come on even higher then that .235* or so.
I installed an adjustable temperature controlled fan switch with a 180* thermostat. (as opposed to the stock 195*).Its set to come one at 180* and stays around that temperature.
(there's more to my cooling system then that but not necessary to bring up at this time.)


You really won't know until its tested.