After pulling out my hair trying to find out why my car is running a rough idle and rich, I discovered that the EGR connecting tube was extremely hot about three to four minutes from a dead cold start-up.

I replaced the EGR valve with a new one several weeks ago. It could be defective.

Question:

When the car is first started and running in open loop , the EGR is unoperable especially at idle. Am I correct on this assumption? Also, could this condition cause the motor to run rich, I would think that it would lean out the air/fuel mixture , or am I wrong?

 

Shouldn't affect AFR at all.. if you think about it, even if there's a substantial amount of exhaust gas leaking past the EGR valve, that exhaust gas is displacing air.. i.e. volume X of exhaust gas would result in volume X of air not passing the mass airflow sensor, thus the mass airflow sensor will still only read the actual amount of fresh air in the system...

If you were running in limp mode without the MAF, however, it would throw the tables off since the tables would expect more fresh air than actually available

 

Well my assumptions were correct. After writing out my last post I decided just for the hell of it to block off the EGR connecting tube that attaches to the upper plenum. I made a blocking plate out of 14 gauge steel traced from an old gasket.

The car finally runs great.

After all the expense of replacing every sensor, rebuilding the distributor, new plugs and wires, having my injectors cleaned, installing all new manifold gaskets, new EGR valve, new pressure regulator, cleaning all three parts of the intake manifold system, cleaning the rockers and sub-components,all it took was a lousy piece of sheet metal to straighten out an idle that would have shaken my tooth fillings out eventually.

I never would have thought that a new EGR valve would have been defective. If I didn't burn my hand on that connector tube when I started it this morning , I probably would never have checked to see if that new EGR valve was bad.


Now all I have left is to figure out how to adjust the throttle valve cable. I tried to adjust it by The Haynes manual , but it still doesn't shift when it should. Actually it shifts like it is delayed as far as rpm's goes. Does anyone out there have some advice on this procedure?

 

To adjust the TV cable see transfixleo's post here:

https://www.thirdgen.org/techbb2/sho...+back+AND+hard

RBob.