Northstar Engines and System Technical Discussion Discussion, Failed emissions test in Cadillac Engine Technical Discussion; My 97 SLS takes about 5 seconds to turn over and it also failed the emissions test for inspection here ...
My 97 SLS takes about 5 seconds to turn over and it also failed the emissions test for inspection here in NY.....I had the fuel rail replaced per the recall about 5-6 months ago....if that matters. Any ideas???
Did the inspector tell you why it failed the test? They will usually try to talk you into the repair. NYS will print a 10 day sticker if your vehicle fails the new test. You may spend up to 600$ on the repair to try to get the vehicle to pass the test. If the vehicle still fails the test after the 600$ point they will issue a sticker anyways. Then you will have to go through the whole process next year and the next... and so on and so on until the vehicle passes.
Is the Service Engine Soon light on, or has it been on in the past? Have you checked for diagnostic codes? I would check the codes, post them here, then clear them, drive it a week or two, and check/post them again.
If it takes 5 seconds to start, it could be a leaking fuel pressure regulator. That would dump extra gas in the intake, which would throw off tailpipe emissions testing, but I would think it would set a code too. I could be totally off base. Maybe you just need plugs and wires. Common after the fuel rail replacement. AC-Delco 41-950 plugs and AC-Delco 748J wire set for your car. You can get them at www.rockauto.com for a decent price, and look at this link to get another 5% off that:
Service engine soon light had been coming off and on often.....took it to the mechanic and he said there were so many diff codes he didn't know where to start so he cleared them all out.....this was about 8 weeks ago. He said to bring it back when it came on again. Since then the service light came on and went off twice right after that but I couldn't get it back to him before it went off again. Since then it hasn't come on again. I had just taken it in to have him check my directionals (seperate issue--just turned out to be a relay) and he noticed inspection was due and it failed emission test. Any ideas on either the fuel pressure reg or plug/wire set should run $$$ approx. would be appreciated. Going to drop it off with the mechanic again tonite. Thx-Joe
You can check the codes yourself with the onboard system by simultaneously pressing the OFF and WARMER buttons on the climate control panel.... No need for a mechanic.
Once the SES light comes on the code is stored even if the light goes out. It will stay there for quite awhile so the codes can be checked anytime.
Get the codes and report them here to see what is going on. It is nonsense to just throw up your hands and reset them all....looking thru the codes would possibley give a clue as to what is going on.
The fuel pressure regulator would be my first suspect. With the engine idling, simply pull the vacuum line off the FPR and watch the vacuum nipple on the FPR for several minutes for any sign of fuel seeping out. Simple and easy to do and it takes only 5 minutes....your mechanic should know this...if he doesn't find another mechanic.
What constituent does the car fail emissions for..??? Knowing whether it is HC, CO or NOx would be a major clue as to what is going on. Otherwise, "failing emissions" is a shot in the dark.
It failed due to HC...codes that my mechanic said are in storage are an O2 sensor code,P0300 code, and nock sensor code. I'm not sure if it's one of the previosly stated codes but also said there was a code for engine misfire--I forget the specific cylinders. He said he spoke to his GM guy who said that he has seen a history of wire problems???? My guess is that this problem stems from the recall fix for the fuel rail. This all started about a month after I had that done.
I think you're right about the wires. Many users here have reported misfires after they had the fuel rail recall done. Replace the wires and you should be good to go. If you're somewhere near 100k miles, you might as well do the plugs while you're at it. (Had to do mine at 80k) See my post above for other details.
I'm not so sure about the knock sensor code. I suppose a knock sensor could go bad, but that doesn't seem likely. More likely in my mind would be that somebody didn't reconnect something correctly or the PCM was replaced and the knock sensor module wasn't replaced. I dunno. bbob?
The O2 sensor code is probably right. Check the wiring for the O2 sensor indicated by the code and if that looks fine, just replace the O2 sensor. The O2 sensor code is why you're failing the emissions test if they're doing a tailpipe emissions test and not a computer test. Get that O2 sensor fixed and you should be good to go for the test, but you should still fix everything else nonetheless.
Now I'm not so inclined to think fuel pressure regulator, but you can check it very easily by removing the vacuum line while it's running. If you see fuel leaking from the FPR, replace it. If not, hook up the vacuum again and forget about it.
Find out what the codes are and post them here so we can be sure about things. Not the description of the codes, which is what your mechanic gave you. We need the actual codes. P0300 is the misfire code, but what exactly are the knock sensor and O2 sensor codes? We need all of them. Do the OFF and WARMER thing that bbob mentioned above and let us know. bbob is the man when it comes to Northstars.
In NYS 96 and newer vehicles get the computer test and if your in the NYC area I believe they get the tailpipe sniffer also. the O2 sensor code will cause it to fail emissions test. You cannot simply reset the codes and have it retested. The computer at the inspection station will not get a pass\fail value for the O2 sensor and the car will fail again. Even if you replace the O2 sensor in the parking lot and they hook it back to the inspection stations computer the car's computer will still have to relearn the value. It usually takes my car 25-30 min for the SES light to come back on. Give yourself some driving time after you fix the O2 sensor to avoid wasting your time at the inspection station.
My mechanic is going to replace the plugs and wires to start---see what that does. (Car just turned 70k miles) He has the car so I can't get the exact codes. I brought up replacing the O2 sensor and he said the car has 4 of them and they are over $100 ea (??) so he didn't want to go down that road just yet---I'll keep you posted---Thanks everyone for the help. Joe
That sounds like the right course of action, as long as he's using the right parts, but you'll probably never know for sure without looking at them yourself. I doubt the O2 sensor code is going to go away after the plugs and wires are replaced. If I was you, I would count on replacing at least one O2 sensors. A new OEM oxygen sensor costs about $65-$75, so he's going to charge you markup on that plus labor. Plan on $150-$200 for that job.
You still have the knock sensor code after all is said and done and that hasn't been addressed yet. If the emissions testing involves checking for SES light operation, it will probably still fail with that code, but that all depends on exactly what they check with the computer emissions test. If it still cranks a long time after the plugs and wires, the fuel pressure regulator (FPR) is the next suspect.
You're on the right track I think. See how it turns out when the plugs and wires are done.
OK--my mechanic replaced wires and plugs and it passed emissions, but said it is still hard starting---replaced fuel filter, and did an oil change(needed it anyway)---still hard starting. He said the fuel pump reg was fine. I owed him for replacing the directional relay---$450 total---picking it up later. Comments/suggestions???
So it cranks for about 5 seconds before starting, right? Once it does start, how does it idle? Nice and smooth at about 650-700 RPMs? Does it ever jump up a bit or idle higher or lower than that? Are there any driveability problems? Does it run well otherwise?
When you get it back, check the codes yourself and let us know what they are.