susjam

Help!! I changed the valve covers and switched to an open element air cleaner on my 87 TA with carbed 305. Now it has what sounds like chattering at WOT especially when going uphill and when it switches into third. I had to unplug several things when I changed the covers. I've looked and it appears everything is hooked back up. Is there something in particular I could have left unplugged that would do this? Or could it be another problem?

1a12

sounds like your timing is off, not by far though.

86NiteRider

iTrader: (10)

I have the same setup in my 86 Camaro. I get pinging when I use regular gas. If I switch to 89 or 92 the pinging goes away. I also agree with the previous post. Check your timing. this also cause pinging on acceleration. It is one of these two I would bet. Keep the open air filter. You will notice the performance increase.

five7kid

iTrader: (14)

More than likely your EGR passages are plugged. Without that little bit of exhaust gas being introduced to cool the combustion temp, you get pinging (the timing advance curve assumes the EGR valve is working).

Changing to the open element also increased the air temp, which would exacerbate this situation. Before my mods and with an open element, I had to use mid-grade in order to run 6 degrees base timing without pinging. When I changed the intake to the one in my sig, which was new and therefore clean, I discovered these clogged EGR passages (this was done before the rest of the mods). I could then run 6 degrees and unleaded regular without pinging.

FWIW, with my current polished chamber heads and dual snorkel air cleaner, I'm running 10 degrees base timing on regular unleaded without any pinging.

susjam

someone told me that it could be that I unplugged the knock sensor.....does a carbed car have a knock sensor, and would this cause my problem?

five7kid

iTrader: (14)

It should have a knock sensor, and it should reduce pinging. Mine, however, did not catch it all when my EGR passages were plugged.

dimented24x7

iTrader: (2)

funny you should say it knocks at WOT. The egr is supposed to close at WOT if im not mistaken.