Expert: Ted Ritter - 6/10/2009

Question
QUESTION: Hi Ted,

I am trouble-shooting a drive-ability problem by with my car. To see if the EGR valve is the culprit, I have removed and plugged the vacuum line from the EGR valve.

So far after driving the car like this for a day (18 miles), I have not had the driveablity issues but this is only one day of removing the EGR from contributing to symptoms. I need to leave the EGR valve plugged for more than one day to test out my theory.

How long can I leave the vacuum line removed from the EGR and plugged?

What does disabling the EGR valve do to the engine besides not feed exhaust gasses into the engine?

Thanks Ted!

Sincerely,

Mike

ANSWER: You can leave it unplugged for as long as you need to verify the problem, if the valve is disabled the NOX emissions will be higher and the engine may run a little warmer than normal, other than that there are no performance issues.

---------- FOLLOW-UP ----------

QUESTION: Hi Ted,

I have been running my Camry for months now with the EGR valve plugged by putting a screw in the vac line that goes to the top of the EGR valve. The car idles well all the time now. Occasionally I get a Code 71 with the vac hose off the EGR.

When I reconnect the vac hose to the EGR, the car idles normally sitting in my driveway idling before the engine warms up. Once the car warms up and I am after driving anywhere from 35 to 55 mph and then try to decelerate for a slow moving car or a stop sign, the idle becomes rough.

When the car sits for a period of time so the engine cools down, the idle is fine again until the motor warms up. Then when I try to decelerate from normal driving speeds the idle is rough. I need to keep s foot on brake and give car gas when slowing down.

Once I disconnect the EGR vac line again, the idle is smooth all the time.

I am guessing that the pinot valve in the EGR is not stuck open but may be sticking when it is trying to close? Am I on the right track here? If so, how does one clean the insides of the EGR valve after removing it from the vehicle?

My car is a 1995 Camry LE 4 cylinder with 158K miles.

Thanks Ted!


ANSWER: If the valve is sticking it should be replaced. It sounds like this is what's going on.

---------- FOLLOW-UP ----------

QUESTION: Hi Ted,

I only plan on keeping the car for maybe 2 or 3 more years. I don't really want to spend several hundred dollars on a new EGR valve for that short time span.

Could you share the best way to clean it to try to rehab the EGR valve please?

To remove the big nut on the bottom of the EGR valve that connects the hot gasses to the valve, will I be able to just spray the nut and threads with WD40 r will I need a bit of heat?

Thanks!

Answer
The big nut should come off ok but I would recommend spraying it with some type of rust penetrant and letting it sit for a while, after the valve is off clean the ports including the backpressure pipe with stiff wire and some carbon removing spray, open the valve by applying vacuum to the port on top and check the movement of the diaphragm, try lubricateing the pindle shaft with WD 40, while applying and releasing vacuum, make sure the shaft is not bent, if the egr valve fully closed there should be NO passage of air through it by blowing through the threaded port, this may work, I don't know, I've never tried cleaning one, we just replaced them. One other option for you may be to try to locate another valve at a used autoparts place or a salvage yard.