Ok, I have been having problems with my car stuttering and stumbling at idle when at a light or whenever stopped and almost wants to stall. I have a 1991 with a TBI 350. I have done a full tune-up including wires, coil, cap and rotor, thermostat and today just put plugs in..in which were a b. I have also put a new AIC valve a little while ago. Tonight I am going to order a pcv valve, some new vacum hoses and caps and whatnot. I am also going to get a EGR block off instead of a new EGR. Then one I have on there a couple years back was new and was stuck the next time I went to get emissions. I have no emissions now and want to just block it off.....and here in lies the question.

The EGR has vacum coming from the TBI into a little solenoid or relay and then from there goes to the egr. The same relay I guess also goes to the other side of the TB as well as to another emissons related, I am guessing, little ball located over the underside of the front driver fender. What exactly does that ball do, and can that be delated too? Sorry to get off the subject, but that relay, when you delete those, do you leave that relay plugged in to the electrical connecter and just cap it off, or do you pull the relay and let that connecter sit there unhooked? What will it do if you plug or disconnect it?

If anyone had any answers or input, please fill me in and let me know what else you would think a problem of the stutering could be. I have done searches but havent really found a person with a fixed answer on the problem.

Thanks.

 

I am also going to order some plug boot heat shields or whatever to put on the wires where they are near the headers. They sometimes tend to touch and could be arching or something.

 

The "black ball" is a vacuum storage device. It stores the vacuum pressure so when the engine is decelerating or other conditions where it is not producing adequate vacuum, there is always an ample amount. Just disconnecting the egr solenoid is not really a good idea. Pulling the electrical plug will cause your check engine light to come on. Leaving it plugged in with no vacuum lines going to the egr valve (you removed it) will cause the computer to alter the fuel/air/timing characteristics because it thinks the egr is hooked up. This can be bad for your engine. f you are not going to run egr, you really need to have your eprom (the computer brain of your car) reprogramed to delete the egr function entirely.

 

"Vaccum" and "pressure" are opposites. You can't store "vacuum pressure" together. Vacuum is simply the absence of matter (in this case, air). It would be more accurate to refer to the condition as "partial vacuum", since there is still some air in the engine (and storage ball).

BTW, low vacuum conditions (less pressure reduction) are produced under power; deceleration is a high vacuum (more pressure reduction) condition.

Nothing, is your SES light coming on? If so, have you checked for stored codes? A leaking EGR valve can cause the symptoms you are describing.

 

Yes, well, technically there is no such thing as a true vacuum in an automobile. Pressure is nothing more than a relative measurement usually compared to 1 atmospheric unit (approximately 15 pounds per square inch). If a suction (lower pressure than atmospheric, (known as vacuum in the automotive arena)) is applied to a flexible membrane, then atmospheric pressure will push the membrane toward the lower pressure side. Just as drinking through a straw, one does not suck the liquid up through the straw but creates a low pressure area and atmospheric pressure pushes the liquid through the straw. As far as storing this low pressure, I have to disagree with you on that point. Open any new can of coffee, baby food, etc...and you hear that sucking sound? Thats low pressure being stored in the can being replaced with higher atmospheric pressure.
As an engine increases rpm the demand for air increases. This demand for air creates a low pressure situation in the intake system (also know as vacuum pressure). This causes air to be pushed into the intake system by the higher outside atmospheric pressure. The low pressure in the intake system is the "vacuum" we use to operate many devices on the automobile. As the engine rpm decreases, the demand for more air decreases and the intake system moves closser to equalizing with atmospheric pressure, lossing it's "vacuum". This is where the little round ball comes in to play. It is that fresh can of coffee storing this previously created low pressure.

 

You need to put a vacuum gauge in your car, attached to a manifold source, and drive around a little. See if your description holds up.

 

+1

you are not taking into effect where the vacuum ports are located.

 

Oops! My Bad. Those darn throttle plates closing get me every time!