Northstar Engines and System Technical Discussion Discussion, 97 deville trouble code help me in Cadillac Engine Discussion; my 97 deville keep s throwing a P420 code. I reset it and it goes about 1200 miles or so ...
my 97 deville keep s throwing a P420 code. I reset it and it goes about 1200 miles or so then come back. I give it WOT and I get alot of black smoke everytime I hammer on the car. It also feels a bit heavy but that my be because the A/C is on always lately. My Question is How do i know if it is the Catalytic conv. or 1 of the 2 O2 sensors mounted in fron and back of the cat.??? Help me out here because im not inot replacing expensive parts that won't fix the problem.
If one of the sensors is bad, you will get a code for the sensor. If there is no sensor code, I would go with the bad catalytic converter theory. If it's running a little sluggish, the thing is probably getting plugged up and needs replacement.
I had the black smoke always during fast acceleration with my 96 caprice LT1 and someone told me the Cat's were plugging up causing more carbon deposits to build up. Then when running ride open it blows out or something like that.. Does this sound possible? I do get a cloud of black smoke if I open the N* up on the highway...
Closest to the firewall. Use these for spark plug wire installation: it's important.
For all the code definitions use the link in the "How to Pull codes" sticky with "obd2" in the URL - that will open a page with the Master Index. Use the blue links to get lists of all P,B,C, and U codes. Bookmark the link.
"clouds of black smoke" is a fuel/air mixture problem (which will set a cat efficiency code) so do a thorough throttlebody cleaning, air filter checks, fuel pressure regulator checks, MAF and MAP connector checks, ..........eliminate small maintenance problems before spending money ($$$$) on a practically non-existent OEM cat.
Read the Cadillac Technical Archive ^^^ article "Occasional full throttle operation is good for your engine" and go out on a quiet road and do a few. Also, do this: When clear, put the stick in 2 and begin a slow roll - all clear ?? Punch it - stick your foot through the firewall and leave it there - the car will accelerate to redline and shift to 2. Just before 2-redline, flip your foot off the gas. Let the engine pull the car down to about 20 mph. All clear ??? Slow to 5 mph and do it again. What you're doing is loading the engine to the max, heating up the combustion chambers and piston tops and shedding carbon, while the forced coastdown unloads the pistons and rings, causing the rings to rotate in their grooves, shedding more carbon. (If you miss the 2-redline foot off the gas, not to worry - the transmission will simply shift to 3. It will not let you break anything.)(The stick in 2 merely says "This is my preferred gear". Exceed safe limits and the transmission will shift.)
Automobile(s): '97 DeVille present, '99 DeVille past
Re: 97 deville trouble code help me
Yep, p0420 means catalytic converter is performing below efficiency. The vast majority of the time it is due to a bad/removed/clogged catalyic converter however I have also seen exhaust leaks between engine and cat or a bad rear o2 sensor throw the code. Most of the time a bad sensor will set another code too but not always.