Decreasing EGR INCREASES 0-60 Time?!? - PeachParts Mercedes-Benz Forum

sailor15015 · #1 11-13-2005, 04:11 PM

Has any one else here noticed a decrease in performance after disconnecting their EGR valve? I removed the orangish vacum line and capped it but I left the blue one that attached to the turbo intact. Are they both used for the EGR opperation? I thought they might be because they're bundled together and look like they head in the same direction. Anyway, after capping of the vacum hose at the EGR, I noticed my 0-60 times went down from 17-18 to around 23-24. I'd been driving it like this for about a week then last night I hooked the EGR back up and my times went right back down to around 17.5. Has anyone else experienced this kind of situation? Right now its hooked back up. Thanks in advance.

boneheaddoctor · #2 11-13-2005, 04:23 PM

you must have inadvertantly did something else too....there is no way that alone can hurt power. On these W123 pre computer modles in any case.

#3 11-13-2005, 04:26 PM

Is it possible that whatever you used to cap the vacuum line is leaky? If you introduced a leak in the vacuum system it may affect other things. Just a thought.

sailor15015 · #4 11-13-2005, 05:54 PM

Quote:

Originally Posted by boneheaddoctor

you must have inadvertantly did something else too....there is no way that alone can hurt power. On these W123 pre computer modles in any case.

That is the only thing that I capped, using an actual vacum cap, and as soon as I removed the cap and hooked it back up, touching nothing else, the former times returned.

TheDon · #5 11-13-2005, 06:04 PM

ya know i just realized that the lil access pannel in the front passenger area is not their and i can see a lil knobby thing that has EGR on it.. i wonder if its correctly hooked up

#6 11-13-2005, 06:10 PM

Quote:

Originally Posted by sailor15015

That is the only thing that I capped, using an actual vacum cap, and as soon as I removed the cap and hooked it back up, touching nothing else, the former times returned.

I assume you capped the vacuum line, not the EGR itself. The vacuum line must be leak tight to ensure everything else gets appropriate vacuum.

sailor15015 · #7 11-13-2005, 07:25 PM

I did cap the line. It was very snug, in fact it was a bit of a bear to get off after being sucked on their really snugly after driving.

#8 11-13-2005, 07:27 PM

I'm at a loss, your air filter is not too clogged, is it?

sailor15015 · #9 11-13-2005, 07:48 PM

I had the whole air cleaner assembly out when I adjusted my valves a week or two ago. I replace the filter at my last oil change, about two months ago. That makes sense that it might be clogged but the power immediatly returned when I reconnected it. I also replaced my prefilter about three days ago. I haven't checked the condition of the tank screen but I will be as soon as the replacement o-ring for it arrives and I run down the rest of this tank, in a few days.

NateVentura · #10 11-14-2005, 03:07 PM

Seth,
Is your car a California model? Have you tested your EGR valve to see if it holds vacuum (i.e. doesn't leak)? I don't have the diagrams in front of me, but there are some additional vacuum circuits in the California '85 model, one of which bleeds boost under certain conditions (gotta love those performance enhancements...). There may be some kind of weird interaction going on there...

sailor15015 · #11 11-14-2005, 08:25 PM

I've seen under the hoods on CA model cars of the same year as mine on ebay and mine definately doesn't look liket that. I don't have a Mitty Vac but I'm going to be getting one soon because I'm right in the middle of rebuilding the rear brakes on my bimmer. As soon as I get one I'll probably go nuts and check every vacum fitting on the car.

Brian Carlton · #12 11-14-2005, 08:47 PM

Quote:

Originally Posted by sailor15015

I noticed my 0-60 times went down from 17-18 to around 23-24.

Just to make a further point regarding the impossible scenario that you have presented:

The EGR is shut off completely at wide open throttle. The cams on the valve cover only allow EGR when off idle and before the engine requires full power.

sailor15015 · #13 11-14-2005, 09:17 PM

Quote:

Originally Posted by Brian Carlton

Just to make a further point regarding the impossible scenario that you have presented

Are you saying I'm making this up? I said I did runs within minutes of each other, one with it plugged and one with it hooked up and it ran better with it hooked up. Its not an "impossible scenario" because that's what happened.

Brian Carlton · #14 11-14-2005, 09:19 PM

Quote:

Originally Posted by sailor15015

Are you saying I'm making this up? I said I did runs within minutes of each other, one with it plugged and one with it hooked up and it ran better with it hooked up. Its not an "impossible scenario" because that's what happened.

I'm telling you that there are other parameters affecting the outcome that you are not aware of. There is no EGR at maximum power.

sailor15015 · #15 11-14-2005, 09:26 PM

Then please tell me what they are. I'm sorry if I'm coming off sounding offensive its just what I've observed. I'd just like to know what's going on under there.