Joseph, it should only be open during part-throttle, I.e. cruise. It can actually help w/ MPG's since the EGR gas is exhaust, it displaces some volume of incoming air/fuel charge. EGR lowers peak combustion temp's to reduce NOX formation. We see various mods/ideas/hacks for EGR, but I'd leave it alone. On other hand, have you tried disabling it? I think the sensor on top is a position sensor to tell computer of EGR's functioning. This EGR is vacuum-actuated...won't be a vac. leak unless the actuator diaphragm fails. Test yours w/ a hand vac. pump to see.
I'd LOVE to have a Civic VX to play with! How's the MPG's?
Gadgetman Reno, NV
I haven't tried to disconnect the EGR yet, but the reason why I want to is because I have reason to think that it's thwarting the groove. I think that because of the following:
4-Wheel Bill and I have the same car; he has the California version I have the 49 state version; his EGR opens at 3000 rpm mine opens at 1500 rpm. When he grooved his he got mediate, amazing results when I grooved mine regardless the size of the groove, regardless how many different angles, or the space from the plate of the throttle body it all made no difference the car had absolutely or nearly zero response. It was as if I didn't do anything to the car, no rpm change no mpg change. I did notice a slight power increase where I could shift gears slightly sooner.
And oh yes, this is the greatest non hybrid gas efficient vehicle ever made! Before the groove my best 3000 + miles before I change the oil I average 57.17 mpg! N.B. these 3,000 + miles were mostly highway. My best fill up was 60.43 mpg! However, from what Bill has told me the 49th state version typically gets better MPG if you drive it slower, so for mine 49 state version I have to drive around 51 to 53 mph in order to get these numbers.
These Honda Civic VXs are extremely long lasting cars. My car for example has 342 thousand miles on it and still gets these type of numbers even after getting the engine rebuilt after 300,000 miles.
OK Joseph. More Q/A... With that many miles, rebuilt engine, how old are the cat's, and other parts? O2's are these original, aftermarket, or? I'll guess you and 4WD Bill have closely compared notes, example you know differences in the EGR's operating threshold. You could temporarily disable EGR and test results. Have you pulled the EGR itself to see if it's clogged w/ carbon or sticking open? Tested it w/ a hand vac. pump? Do the Calif. and Fed. spec Civic's use the same part# EGR? If same part#, is the intake man. same, or differences in the EGr passages? If everything is the same parts-wise, then the diff. is in how or when the ECU turns on the vacuum actuation to the EGR.?? Does the EGR vacuum circuit go thru a water temp TVS switch? Might this TVS have a different temp setpoint? Or does the EGR vacuum circuit go thru a computer-controlled solonoid switch? If all the EGR system's parts are same, then diff. is in the computer itself?
Or try a restriction in vacuum to the EGR, a hose connector w/ a smaller ID hole in it spliced into the vac. hose, as a test. Parts stores and junkyards a source for dinky parts like this. You would just have to try these ideas, and see what happens. How fussy the ECU might be, since if EGR doesn't open as much or as soon as stock, it's got that EGR position feedback sensor on top of it. If the EGR IS the real problem,and no problem with the EGR itself then it could involve delaying/reducing it's operation. Might need to research the EGR sensor on top, what it's output signal is, find which wire is output signal wire, how to modify it. From looking at the Rock Auto pic, EGR is opened by the vac. signal, and the output sensor on top is prob. a voltage-dividing potentiometer that has varied output back to ECU as feedback. It has 3 wires that's a clue right there. I don't know if disabling/tweaking the EGR would cause ECU to go into limp/default mode w/ accompanying bad MPG.
Other sensors, MAF, or MAP, ignition, temp, or whatever, any issues or info on those? Seems kinda counter-intuitive that a Calif. spec Honda would do better than a Federal spec one?? I'm not intimately familiar w/ Honda's, I did work on an '84 CRX a lot years ago, I admire Honda's in general.
Those are impressive MPG's on both Civic's you guys own despite Bill's ride doing better.
What about some other g-Man "tricks", tire press, MPG Remedy, Ozone dist. cap, fuel heating, synth. oil/lube's, anything to increase power or decrease losses? PCV re-route, Idle air re-route/restriction...? I can't recall all about what you and Bill have previously posted here. Whatever the issue is, there IS a reason/reasons for the results, I for one would like to see more in-depth info re: both of these Honda's. Honda's are enormously popular. Everyone here can benefit if we re-visit the Honda "bag"! Pics, we need more pics, AND info!
Do please tell more about these Pocket Rockets! (Tracy pants like a dog waiting for his treat...)
Gadgetman Reno, NV
To make a long story short I had a lot on my plate like so many others so I'm finally back. Sorry that it took a month to get back. I took off the EGR valve and here are the pics. It would seem to me that it's clogged shut not open, so I'm going to clean carbon out, cut a new gasket put it back on and see what happens. Any suggestions from here?
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