EGR and charcoal canister...

[rosadod]

How do you test the EGR and where is it located? What is the charcoal canister and how do I test it? I got my TT emissions chip and cat... going to get tested tomorrow.

[gofstbuick]

EGR valve is located on the drivers side of the middle of the engine (just behind the throttle body). The EGR solenoid is a rectangle box near the rear drivers side above the intake manifold. The ecm controls the vacuum signal to the EGR valve. To test, the engine needs to be at operating temp. While idling, place finger under the EGR vavle and lift the diaphram. Engine should run rough , stumble or die. This lets you know the passages are clear. With engine idling, remove the vacuum line on the EGR valve and install a vacuum pump on the EGR valve and pump, engine should run rough, stumble or die. Connect a vacuum gauge to the vacuum line to the EGR valve and rev engine, and you should see a vacuum signal, if not, remove the cover and filter from the EGR solenoid and place finger over filter port, you should see a vacuum signal.

Regarding Charcoal cannister, just make sure the filter under the cannister is clean. The cannister is a round container located next to the air cleaner box.

[rosadod]

Do I have to have a vacuum pump/gauge to test the EGR system. Is there another way? Didn't want to have to buy a gauge I'd probably only use once. I will lift the diaphram under the EGR vavle and see what happens.

[rosadod]

I lifted the diaphram under the EGR vavle and the engine started to stumble. So, this means the passages are clear. I don't have a vacuum gauge/pump to do the rest of the testing... is there a way to make sure the EGR system is working right without having a vacuum gauge/pump?

[gofstbuick]

On the back of the EGR solenoid is a cover. Remove the cover and you will see a small filter. Remove the filter and with the engine running, place your finger over the port that covers the filter. This will direct manifold vacuum to the EGR valve and the engine will stumble. there wil be your vacuum source.

[salvageV6]

Easiest way to test for vacuum is to put a high impedance, IE digital voltmeter onto the brown wire out of the EVRV system on the connector, with it still attached of course, and read the voltage black lead of the meter to a good ground on the car.

Should be a positive voltage at idle and go to 0 volts when the vacuum switch operates indicating good vacuum.

This is what the ECM uses to make sure it's working otherwise a code will be thrown.

Or else you can idle the engine with your finger on the hose and rev it up a bit and the emissions chip should command enough EGR to get some good vaccum going, enough to feel perhaps.

A vacuum gauge however is a very useful tool for any type car for diagnostics.