Automotive (EGR) Questions

[rp2813]

The "check engine" warning lit up on my 2003 Subaru Baja recently.  I didn't notice any change in the way the car ran or how the engine behaved, but took it to the shop this past Friday.  The mechanic called to advise that an air/fuel ratio sensor had failed, gave me a quote and I authorized the work.

 

Later that afternoon I was informed the car was ready, that the EGR valve had been replaced, and that the fault had been corrected so the "check engine" warning was no longer displaying.  I picked up the car and noticed immediately that the balky clutch which has been an annoyance ever since I bought the car a few years ago (with 121K miles on it) was now operating like brand new.  Smooth as silk.  Per Subaru forums I had visited in the past, I assumed that this sub-optimal condition was just how Subaru sticks functioned.  I think it had slowly become worse over time, as I was getting more and more annoyed with it -- to the point of considering dumping it and finding a turbo model with automatic transmission.  Needless to say, I'm thrilled that shifting through the gears is now a pleasant and satisfying experience, just like on other Japanese makes with manual transmissions that I've driven in the past.

 

So how did the EGR valve correct this situation?  I thought EGR stood for "exhaust gas recirculation."  How this translates to air/fuel ratio, I don't know exactly although I can see how there would be a connection, but that's beside the point since I'm so happy with how the car behaves now.  Has this new component caused the engine to behave differently under a load such as when the clutch engages?  Might I also notice better MPG now? 

 

Also, why did it take the "check engine" warning so long to light up, since it seems that this has been an issue the whole time I've had the car (I've put 10K miles on it)?  I don't know if the mechanic could have answered these questions when I picked up the car, but he wasn't present at the time.

 

Any experts care to chime in here?  I've worked on my own cars in the past, but when it comes to this sort of thing, I leave it to the pros.

 

[ea56]

Ralph

Perhaps your clutch operates with vacuum assistance and the replacement of the EGR valve restored the vacuum to the correct setting? I’m no expert but that would be my uneducated guess.  Chevrolets from about 1939 thru 42 had vacuum assisted gearshifts that operated with little pressure when they were working properly, but you could still shift even if the vacuum assist wasn’t functioning properly, just with more effort.  Same thing with power assisted brakes, if the vacuum assist fails, you can still stop the car, but with more effort.

 

Eddie

 

[rp2813]

Very possible Eddie.  I know it has a wet clutch, but that can't be related to the EGR I'm pretty sure.  The rubber tubing associated with the wet clutch had a leak and was replaced about a year ago.  Combined with the new EGR valve, I don't think performance can be any better at this point.

 

[qsd-dan]

Generally when EGR's fail the poppet (or actuators if digitally controlled, sometimes with multiple orifices) that actuates them gets carboned up and the valve doesn't completely seat and hangs open. This usually causes a choppy idle but modern fuel injection can sometimes compensate for minor leaks. The orifices themselves can plug up in the valve, intake manifold, or exhaust manifold. Sometimes the EGR valve can be cleaned depending on the design and access.

In the old days with vacuum operated valves (especially ones that lacked computer monitoring), I'd pull the EGR valve off and stick a stopper or cork in the orifice of the intake manifold. If the idle smoothed out, problem was found.

 

[mattl]

It also may be that resetting the computer had an impact.  On my GM cars after replacing a component the computer is reset and the engine "learns" how I drive all over again.  Does not take long.

 

[goatfarmer]

Maybe they adjusted it, as a courtesy.

 

[yogitunes]

stranger things have happened....and who is to say why....

I say, better that it operating like it should, rather than cause issues....

take the blessing as it is, and dont question it...

I also wonder where the EGR valve is located on your vehicle....I can't help but wonder if they had to remove or move a part(s) out of the way to replace it....and the new position has corrected your issue...

putting a starter on the HEMI, according to the manual, required us to remove the motor mounts and lift the engine 5 inches for clearance....but we had to remove and loosen a lot more than just the mounts...

I know when we put a new clutch in my AMC Eagle, the clutch wouldn't work when we first started it.....but let it sit overnight, the next morning, it worked like it should...all we could figure out is when new fluids were put in, it stirred up a bunch of air, and had to settle out of the oil...

 

[rp2813]

Thanks for the replies.  Good points raised by all. 

 

Yeah Martin, I'd like to understand how this happened, but I'm not looking a gift horse in the mouth for sure.

 

 

 

[ea56]

Ralph,

Why not just give the service dept. a call and explain how your clutch is working better after the recent EGR replacement and ask them if this a fringe benefit of the recent work.  They can probably tell what you’d like to know.  Couldn’t hurt and may answer your questions for free.

 

Eddie

 

[rp2813]

Eddie, I may do that later this week.  I'm in the middle of a project with a deadline right now.