Slightly OT question, please help: what are some potential causes for too much NOx in

[Jason]

emissions? the car is a 1989 Cadillac Coupe Deville, w/the 4.9L V8 Thanks in advance.

[Robin-535im]

.

[Jason]

It must really haul

[Robin-535im]

It must really haul
Haul it does! It's noticeably faster than the mostly-stock 535 I had before, but strangely 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!

[Jeff N.]

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

[Bill R.]

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...







emissions? the car is a 1989 Cadillac Coupe Deville, w/the 4.9L V8 Thanks in advance.

[Robin-535im]

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
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?

[Jason]

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...

[Jeff N.]

Better discussed on the phone... :)



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?

[tdgard]

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.