egr valve

[jptq45]

I am having check engine light problemsthe engine runs good, except the fuel consumption is a little highand I just replaced the air filter and cleaned the throttle body,and the battery posts, after that it cleared the check engine lightuntil it came on a couple of days later.

I Just had my q45 scanned at autozone, they said its EGR valve causing the excessive fuel consumption, before I decide to invest in a new EGR valve can I get some feedback from you guys, since this is my firstpost. I read your articles when I need information on the Q and it really helps.

Thanks98 q45 ODO 68K jpt

[911/Q45]

Check the vacuum lines that run to the EGR valve for leaks. Check the valve itself and the tubes that runs to it from the exhaust for clogging. With your mileage a simple cleaning with carb solvent may do the trick.

[rsiwicki]

I had my EGR unkowningly chopped off when I had custom headers built in my mad mind state search for more HP and it did cause higher fuel consumption. I went from about 19mpg to 15mpg which sucks....so I would have to say it is from the lack of EGR based on my experience.

[jptq45]

I'll clean it out and inspect the lines, Let you know in a few days depending on what hurricane jeanne does down here in floridaThanks

[Q451990]

You can check it for operation by touching the bottom of the valve while reving the engine. If it lifts up and flutters when you rev the engine, between about 1500 and 3000 RPM, then it's working. Then try pushing up on the valve while the engine is at idle. The idle should slow way down or even kill the engine. This is a test to see if you're still getting some flow through the valve and tube.

If the valve isn't functioning, be sure to check the control solenoid electrical connectons for corrosion. I always noticed a slight "clunk" from the differential after moderate acceleration when the valve wasn't working - not sure why, but I could recreate by unplugging the connector.Heath

[dcook]

just a comment.... I know about 10 people (myself included) who have taken their cars to Autozone for their diagnostic test...and it's ALWAYS the EGR valve....bet Autozone is making a killing selling those! dc

[Q45tech]

Common thing for those who abuse their cars by not cleaning EGR frequently [every 30-45k] after the first 60k. So important to cruise MPG and emission test. Just like not cleaning out the PCV system or throttle body or plenum.

[duck3986]

How do you properly clean an EGR valve. I have my plenum off right now so it should be easy for me to do properly.

[Q451990]

Just spray it out with brake parts (or throttle body) cleaner until you don't see any more carbon. Open and close the valve by pushing up on the bottom while cleaning. The BPT valve cleaning is pretty much the same - just spray brake parts cleaner through it. The EGR port on the plenum seems to be the real sticking point. I've found mine blocked up to 70% before. Sometimes a dental pick or small bottle brush is helpful in these cleaing projects too.

Heath