My 91 recently failed. It has long tube headers with a brand new heated O2, otherwise it is stock and in good running order. Any ideas on what to check on based on the results?
Standard High Speed Standard Low Speed HC 143 160 F 147 147 P CO 1.60 0.49 P 1.24 0.48 P CO2 13.7 13,8 O2 1.1 1.0 NOx 905 1378 F 990 2034 F Dilution >6 14.2 >6 14.3
check/replace plugs, wires check egr. If that don't get it a new cat will most likely push it into the go zone. :) Oh, also do the headers/pipes leak at all before the cat? Fix that too for sure. Does it even have a cat? Those long tube headers are legal? just curious. What truck and engine is it?
91 C1500, 5.7L the headers are legal, plugs and wires have less than 10K miles on them and are in good shape. Has true duals with two cats, but they have been pushed a ways back from the motor because of the headers, this is why I put a heated O2 on it (headers and exhaust were like this when I bought it).
======= =======
Check the EGR valve ..............
and.... make sure that engine is HOT.....during the testing.
~:~ marsh ~takes a sip of his mushroom tea....... mmmmm.....good stuff~ ~:~
What operating tempature is the engine runing?
Whitelightning
Good point, it needs to have a 190 t-stat to run correctly. The last couple of times I've gone to the parts place for a t-stat they always ask if I want a low temp one.....I wish those that know nothing about cars would just shut up and sell the right parts.
"your car is overheating? you must need a 160 t-stat, that 190 is way too hot!" LOL (AutoZone type places)
Might be easier to get a mailing address two counties over and not worry about smog tests ;-)
Could be. I will see how hard it is to get a low mileage waiver. I only drove it 1500 miles this year, less than 1000 last year. Had the EGR replaced, so if it fails again, I am applying for the waiver.
How old is the gas in the tank?
Whitelightning
Maybe he's blending in some McDonalds deep-fry oil. :-)
not old enough to matter
Ok,
I replaced the EGR valve and had the inspector put the probe in the passenger side of the dual exhaust, the cat on that side is closest to the motor (and by my reasoning will heat up better and hopefully work better). It passed easy.
I agree, however since it was this way when I bought it, your comments don't help.
Have something to add? Share your thoughts — no account required.
Ask the community — no account required