questions on IAC cleaning and !egr (couldnt think of better title)

[thebulgd]

A few weeks ago I cleaned the IAC, cut down the EGR pipe in the intake manifold, replaced the PCV vavle, and did the throttle body bypass. The results of this are;
1) 2.5 mpg gain
2)smoother idle
3) better oil presure

better oil pressure? before doing said mods the oil pressure would be between 25-30 at idle, needle would often fluctuate, and just below 40 while driving, no fluctuation. Afterwards my oil pressure at idle is 37 or so and above 40 while driving.

Question is; which one of these things would affect my oil pressure like that? Just looking for some understanding.

[thebulgd]

anyone?

any idea's?

[GradeZ28]

When you cleaned the IAC, did you also clean on top of the TB where the PCV system connects to?
I bet it has something to do with the PCV valve

[Phantompooper]

PCV Valve is the only one of those associated with oil. I'd guess that was it.

[01Z]

Please allow me to impose on this thread to ask a few questions for myself.

I did a throttle body coolant bypass on my 95 LT1; is there any differences in doing this on my newly obtained 01 LS1?

As for cleaning the Idle Air Control module; is this difficult or risky? I'm looking for any precautions as I'd like to do some pm on my camaros and I think I need to do it on my son's car. It's not throwing any codes but his car sure idles erratically when first started.

As for 'cut down the egr'; is this term a procedure as in 'remove and block off' or is there some other modification for this that benefits performance and will still allow my car to pass emission testing?

Thanks

[Phantompooper]

01Z, dig it www.installuniversity.com the EGR mod involves removing the system and cutting a pipe that sits right behind your throttlebody, allowing more air into your intake with less restriction. The IAC just involves spraying carb cleaner into it to clean out the gunk in there. There are really no differences in doing the coolant bypass in the LS1, same concept, pretty much the same procedure.

[TripleZ's]

Would bet that you cleaned or broke loose some junk on the PCV system. When you are able to pull more vaccume on the crankcase it will cut down on the windage, less windage gives you better oil control...and so on.

01Z your car should not hav the EGR pipe. that was on the 98-99 cars.

[Phantompooper]

That's true, I didn't even catch that Triple Z, good point.

P.S. The 2000 cars had them too.

[1BADLS1]

so what is the EGR do.....? when u remove it does it let mor eair flow through?

[GradeZ28]

Originally Posted by 1BADLS1

so what is the EGR do.....? when u remove it does it let mor eair flow through?

When the A/F is too lean, instead of adding more fuel (which would waste it), the pcm allows the exhaust gases to enter into the intake which lessens the oxygen density, thus allowing a less-lean burn. Egr not only helps make the engine run cooler, but it also helps prevent detonation from it being too lean. Removing it will not do you much good unless you have your car tuned for your weather and altitude.

[1BADLS1]

so if my car is bascially stock i shouldnt take it off i have a 99 Z

[thebulgd]

Thanks for the answers everyone.


as for cleaning the IAC it's a really easy thing to do. two torx screws and some carb cleaner, becareful to push the pintle in before reinstalling so you don't damage it. that and I had bought a new gasket for it in case I needed it, I didn't so I just got a refund on it. Don't forget to clean inside the throttle body where the IAC sits, was pretty dirty in there on my car.