Hi,
I have 86 Iroc which have a crate 350/ 290 deluxe engine installed. I decided to reconnect the evap emission control system as I was getting significant odor one I park the car in my garage. I used all the OWM part to installed from cannister, control valve, tank pressure valve, etc. I had to use 1 4way splitter to allow connection of all hoses to manifold vacuum., as the Holley 670 carb does not have as many outlets as the Rochester carb.

My concern is the idling of the car is poor. When start from cold, the rpm around 500. Before it would idle at cold start about 1500. It seems like is running well otherwise. But it takes a very long time to get to the point where it is idling at around 800-1000. Also, if I turn on the air conditioner, it shut off on a red light occasionally.

Any advice or suggestion are appreciated.

 

It sounds like you created a vacuum leak.
If you pinch off the vacuum line you connected to your Holley carb,
does the idle return to normal?
Pictures and the emissions hose diagram you followed would help.

 

Yes it does return to normal. Se picture attached.

 

OK, so how did you connect yours?
If you connected manifold vacuum to where it is not supposed to be, then there is your vacuum leak.
Does your Holley carb have a bowl vent connection?
How did you connect #3 in your picture, the CCV - Canister Control Valve?

 

 

 

Like this?

 

Yes

 

Pinch off each line while the engine is idling.
The one that restores your idle is the culprit.

 

Ok will do, and will let you know. Appreciate your help!!

 

The most change I got, was when pinched “man vac” on number 3 in your picture above. It dropped rpm. I changed all the hoses today; it seems that now rpm are constantly around 800. I do get big drop (about to 500) when I turn on the a/c.

 

That's good.
What happens when you pinch off each line on the charcoal canister?
Turning the AC on will load the engine some and drop the rpms.

 

Hum...didn’t pay attention to the canister. I can check tomorrow. What should I expect? I have noticed however, that the gasoline odor is gone since I installed the system.

 

Unless your CCV valve itself has a leak, the only line you have left is going in and out of the charcoal canister, then in and out of the tank pressure control valve (#10) and then to the fuel tank.
You could have a leak in the lines under the car - either dried out rubber hose sections in that line or rotted metal lines.
If all checks good, there should not be enough air flowing in that that the engine should see a huge vacuum leak. Notice the restriction in the line at the fuel tank (#8).
Pinch the line off at each section to see where it makes a difference to the idle.
Then inspect that section for leaks.

 

Something I failed to mention, my tank pressure control valve (#10) does not have #3 connected, on the picture attached. can it be open? The previous diagrams does not illustrate where it should go.

I have seen in other engine designs that can be connected to the PCV hose, to the manifold vac, to the line itself that come ro

rm the fuel tank to the canister, etc.

 

#3 on that valve needs to be connected to manifold vacuum. The connection is usually a plastic TEE in the PCV valve line.
The writing above that picture describes the valve's function and whether it's open or closed with vacuum applied.

Please post a pic of that entire page.

I would have to say that your TPCV (#10) is normally OPEN and starting the engine (applies vacuum to the #3 port) CLOSES that valve.
With no manifold vacuum line connected to it, the valve always stays OPEN and that is the reason for your "vacuum leak".

Add that vacuum line to #3 on your TPCV, and as long as the valve is good, when you start your engine vacuum will close that valve and solve your vacuum leak!

 

 

 

One of these is usually in the PCV valve line and the 3rd port goes to your TPCV #3 connection.
But you can run a line from your TEE (you call it a splitter) to TPCV #3. Same difference - both are manifold VAC.

The description of your TPCV works opposite of what I thought.
Even so, test your valves as the text describes, because if they check bad, then that could cause your vacuum leak.

 

Ok I will connect to the PCV. I Did check the TPCV a while back nd is working properly. So I think you hit the nail on the head with the open #3. I will do tomorrow and let you know how it works. Thanks again for all your help!

 

So, I connected TPCV #3 manifold vacuum. The idling improved. It runs about 800 rpm. Again, I pinched all hoses, the only that reduces the idling/rpm is any hose that leads into #2 “man vacuum” in the CCV. I will follow and check this weekend the hose that goes from the tank to the canister. Anything I should look for? I guess cracks, restriction seen on the picture??

 

It sounds like your good to go now.

 

 

You are welcome.