92 SC400, 218K on it. Run like a champ. New plugs, new oil, new filter for test....
1. failed HC ppm on 15 mph roller test: 73 passing-129 measured! But it passed on the 25 mph roller 56 passing-50 measured.
2. Failed 25 mph NOx ppm 487 passing, 531 measured BUT passed on 15 mph 530 passing 407 measured. WTH? Running crap 87 Cali regular (son drives it and was not putting premium in it) and I think the timing for 87 octane is not optimal for the recommended premium fuel so that may be the NOx issue.
Cant explain the HC, maybe dirty injectors? I running a tank of Premium plus a bottle of octane boost and some injector cleaner in it now to retest this weekend. I think one of the cats is damaged as it was run about 3 miles on a dead coil so they took alot of unburned fuel into them and something sounds loose inside the exhaust. Maybe the matrix is breaking apart but I dont know which of the 3 convertors is toast? New CARB spec convertors are only $1400 a piece through Lexus or $450/pc on Ebay so I hope its not those!
EGR tube is clear, ran a fish tape all the way to the manifold and the intake passage is clear. EGR is functional and clean, tested stepper motor on bench and EGR temp sensor works. Did I miss anything? Club Lexus didn't like my "thinking outside the box" (ie $45 FED cats with OE Cali heat shields tacked back on to pass smog) so Im looking for some open minded DIY theories here.
Just point me in the right direction please. OBD1 sucks. Cant really tell what's going on and I cant adjust timing on this. I installed 4 new O2 sensors since failing.
1. failed HC ppm on 15 mph roller test: 73 passing-129 measured! But it passed on the 25 mph roller 56 passing-50 measured.
2. Failed 25 mph NOx ppm 487 passing, 531 measured BUT passed on 15 mph 530 passing 407 measured. WTH? Running crap 87 Cali regular (son drives it and was not putting premium in it) and I think the timing for 87 octane is not optimal for the recommended premium fuel so that may be the NOx issue.
Cant explain the HC, maybe dirty injectors? I running a tank of Premium plus a bottle of octane boost and some injector cleaner in it now to retest this weekend. I think one of the cats is damaged as it was run about 3 miles on a dead coil so they took alot of unburned fuel into them and something sounds loose inside the exhaust. Maybe the matrix is breaking apart but I dont know which of the 3 convertors is toast? New CARB spec convertors are only $1400 a piece through Lexus or $450/pc on Ebay so I hope its not those!
EGR tube is clear, ran a fish tape all the way to the manifold and the intake passage is clear. EGR is functional and clean, tested stepper motor on bench and EGR temp sensor works. Did I miss anything? Club Lexus didn't like my "thinking outside the box" (ie $45 FED cats with OE Cali heat shields tacked back on to pass smog) so Im looking for some open minded DIY theories here.
Just point me in the right direction please. OBD1 sucks. Cant really tell what's going on and I cant adjust timing on this. I installed 4 new O2 sensors since failing.
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