Tricking you rEGR.....

[MooseMotorsport]

Ok, having removed my EGR from my Neon almost 5 years ago and then changing my PCM from the AF/x back to stock my CEL has been on for it.

Installing a resistor to in the harness only shuts the CEL of part of the time.

So, I reinstalled the transducer and "looped" the EGR side to teh exhaust side and the code went away. BUT, I feel that the CEL will still come back since there isn't technically "pressure" on the bottom of the transducer to keep the diaphragm closed.

Is there anyway to get pressure to the bottom of the diaphragm WITHOUT reinstalling the EGR?

I was thinking about making another exhaust side "block-off" plate with a hole drilled into the center of it and then running a hose to the bottom of the diaphragm and just capping the EGR side of the transducer off.

Would this work? In theory from doing backflow preventors on domestic sprinkler systems it should work as is but I noticed there technically isn't any pressure on the bottom of the diaphragm to keep it closed, maybe when it goes into "test" mode and draws vacuum from the intake manifold with the lines from teh EGR valve and the Exhaust "looped" it puts pressure on the bottom of the diaphragm; but I don't know if its enough to keep the CEL off permanently.

[jrbisig]

why not just hook the egr back up? Sounds like a lot of work to keep the light off.

[MooseMotorsport]

Because the EGR is kind of a waste.

And its not that much work to trick the PCM to think that the EGR is still there. The problem is keeping the code off.

Just having the transducer looped it stays off 90% of the time. Its just every now and again it'll come on briefly.

[daytonajesse]

EGR is only active at light part throttle any way, it lowers your combustion temps which is good and betters your gas milage which is also good. Plus you computer is calibrated to adjust for the egr. Just hook it back up, your car will thank you.

[charger R/T]

Quote:

Originally Posted by daytonajesse EGR is only active at light part throttle any way, it lowers your combustion temps which is good and betters your gas milage which is also good. Plus you computer is calibrated to adjust for the egr. Just hook it back up, your car will thank you.

+1

[Stevien1]

+2

Your Neon (if it's 96 or newer) monitors EGR by watching for a rise in MAP when it's commanded on- so dicking around with the transducer won't keep the CEL off for good. If the PCM isn't calibrated to ignore EGR (like the Af/x), then hook it up.

-Chuck James

[Boogieman142]

well,it doesn't better your gas mileage, it hurts it cause exhaust gas does not support combustion.

[daytonajesse]

It uses less gas so...

[Stevien1]

Quote:

well,it doesn't better your gas mileage, it hurts it cause exhaust gas does not support combustion.

Think about this....

You are correct in saying exhaust gas doesn't really combust. When EGR is active, the content of the intake charge is now lets say 75% air and 25% EGR (FOR EXAMPLE). So that means we need 25% LESS fuel for proper combustion since the EGR has taken up that much "space" in the intake charge. Less fuel- better MPG, less unspent hydrocarbons- better emissions.

-Chuck James

[MooseMotorsport]

Actually, I've had the EGR off for almost 6 years. most of those years I ran with an AF/x Race. I just recently switched to an OEM DOHC ATX PCM (I've got a SOHC ATX) and when I did so I tripped the CEL for the EGR. I mainly switched abck because in April I'll be installing my turbo and new engine and youa ren't supposed to run an AF/x with a turbo.

I've never failed an inspection because my NOx emissions were up due to not having an EGR so I'm not too worried about it. That and the car has run very well without the EGR. Also, most newer cars being manufactured now are being built without EGRs all of the 2nd Generation Neons after 2000 do not have EGR valves. So, that must say a lot towards their overall usefulness.

At any rate, I've spent the past few days actually researching how the EGR and the Transducer work together and even went so far as to disassemble a transducer to figure out how it worked.

And the conclusion I cam up with is, that when the transducer is activated it opens the EGR enough to allow exhaust back into the intake charge at the same time it forces the diaphragm to close cutting off exhaust to the transducer. IF exhaust gasses get past the diaphragm it will see an exhaust leak and therefore set off the EGR CEL.

So, I've eliminated the diaphragm completely. In its place I put RTV. So, when it goes into test mode it doesn't see an exhaust leak and doesn't set off the CEL.

Now, of course this is only an experiment to see if my theory is correct. If it works than yay for me. And yay for the dozens of other people who have removed thie EGR vavles. If it does, oh well, I didn't lose anything other than a spare transducer I had lying around and some RTV.

[jrbisig]

Egr affect can happen a couple different ways. The basic way is a valve like you have. The other way is using valve overlap. The third way, which is similar to #2 is variable valve timing. Your seeing more of #2 & 3 in the newer vehicles due to better computer management. Not having a valve means less wiring, less things to go wrong. Egr is a good thing, esp. now. Back in 1980, sure ditch it. Not a dependle setup back then(in my opinion

[MooseMotorsport]

The function and the design of the EGR hasn't changed all that much over time.

Its not so dependable now either. I actually pulled the transducer completely apart and found that the diaphragm was rotted. Then did some research and found out that the rotting of the transducer diaphragm is probably one of the most common EGR failures and its what causes the majority of the CELs.

I removed the diaphragm completely and sealed it with RTV. Haven't had a problem with the CEL for about a week now because its not seeing a leak (not that the EGR is installed anyway) but it was still seeing a leak because air was getting by the diaphragm.