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Major Contributor
Slightly OT question, please help: what are some potential causes for too much NOx in
emissions? the car is a 1989 Cadillac Coupe Deville, w/the 4.9L V8 Thanks in advance.
Grand Master
My jeep failed NOx b/c of a bad EGR valve. (NT)
.
Robin
72 Chevy K10
01 E39 M5
Major Contributor
Thanks, how has the new car been treating you?
It must really haul
Grand Master
Haul it does! It's noticeably faster than the mostly-stock 535 I had before, but strOriginally Posted by Jason
y it seems to have a different profile for the torque curve. More in the mid range, and less in the upper range. I seem to remember more pull at the higher RPM's with the old setup, and the new car has a lot more pull in the 2500 - 5000 range.
The only problem so far is that this car is much flashier than my old one. This one's black with e39-style M parallels, the old one was silver with basketweaves. I notice people are more rude now than before, not letting me in the lane, challenging me more, etc. I did like the sleeper aspect of the old one, but then, I can pass people better in this one. And holy crud is that car sticky in corners. 17" Kuhmo Ecsta's and Dinan sways kick butt over the 15" Yokos and stock sways!
Last edited by Robin-535im; 05-18-2004 at 03:47 PM.
Robin
72 Chevy K10
01 E39 M5
Grand Master
Robin - I think the BEE engine has a different cam in it vs. the stock motor. Derek and I were trying to compare cam profiles (not very successfully) at one point to understand the differences.
The cam change is the most likely reason for the difference in the powerband. The non-stock cam in my car has certainly affected mine..
Jeff
Bellevue WA
90 535iM - not much stock remains. 3.7 liters, ported head, cammed, 3.73 diffy, M5 brakes, MAFed, yadda yadda yadda
86 Porsche 951 - Track Toy
Super Moderator
89 deville I thought was a 4.5... at any rate it has a
egr solenoid and the computer controls the opening of the egr valve... Frequently its not a bad egr valve on these but the passage that the egr opens is completely full of carbon and doesn't work... You have to remove the
egr and remove any carbon buildup in the manifold where its bolted in...
BG makes a special tool to clean these up but in your case you'll probably have to physically clean out the carbon buildup first...
Grand Master
Yes indeed. I've been meaning to ask you about that... Would changing the advance of the sprocket move the power band up or down? Not that I want to go to all that trouble, but I am curious.
Did you notice that before / after the adjustable sprocket?
Robin
72 Chevy K10
01 E39 M5
Major Contributor
Thanks Bill, you're right, its a 4.5
Grand Master
oh...that's a loong story.
Better discussed on the phone...
Bellevue WA
90 535iM - not much stock remains. 3.7 liters, ported head, cammed, 3.73 diffy, M5 brakes, MAFed, yadda yadda yadda
86 Porsche 951 - Track Toy
Big, Big Time Poster
Second--or third--or whatever the EGR
You should be able to feel the EGR valve doing it's thing. Warm the car up & reach under it--rev up to about 2-3K--valve should open. If not, it's one of two problems. Lack of vacuum or lack of pressure. The pipe from the exhaust should have pressure to the EGR. The line from the MAF (or thereabouts) should have vacuum. That one is probably routed through a switch or two. Normaly engine speed (over 2K) and temp. Check them all--but as stated above, it's most likely a blocked tube from the exhaust.
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