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Original posts are below, after addressing the following items, NOx readings dropped like a stone. New #'s are as follows:
25/25 test -
1763 1st measured/1163 allowed/333 2nd measured; a drop of 1430 ppm
50/15 test -
1914 1st measured/1273 allowed/483 2nd measured; a drop of 1431 ppm
Astounding. I attribute the radical drop to the advice from Timothy Lee concerning the Chrysler Ignition issue. I do not think the other small items I addressed would have such a spectacular result. Anyway, here is what I did;
Retarded initial timing to 8 degrees BTDC (actually where it was for the initial test)
Plugged leak (very small) in intake hose (new one is on order)
Seafoamed intake/head
Filled tank w/about 10 gals of 93 octane gas ($2.10 her in Atl. w/discount, thanx W)
Patched leak in exhaust pipe between cat and rear muffler
Followed Tim's advice
Thought I would let everyone in on the results.
Bob K
'94 945T
'88 240DL
'84 242Ti
'89 560SL
'88 300TE
'68 GT500KR
ORIGINAL POSTS
I have since found a small leak in the intake hose between the AMS and TB. Thought that might throw things off a bit as well. I've taken the suggestions made previously and will attempt to pass again tomorrow. I'll let you know if I pass.
'88 240DL
Failed GA emissions
High on NOx in both 25/25 and 50/15 tests by about 600-700 ppm
(this is about 50% above acceptable #'s are as follows)
Reading/Allowed Reading/Allowed
1763/1163 1914/1273
Other tests (HC & CO) were OK
I tested for vacuum leaks and there are none.
The timing was retarded about 4 degrees from where it should have been so I reset it to 12 BTDC per spec.
Car has recently gotten new ignition components including O2 sensor, plugs, wires, cap/rotor.
Exhaust downpipe is tight, no discernable leaks.
I Seafoamed it.
I plan on adding some octane booster since the tank was just filled.
My question is, could the retarded ignition timing be the primary cause of the high NOx readings I am getting or is the reading too far off fot it to be just that? If so, have I missed anything besides checking the CAT?
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