: Bad Smog result



nikoh
03-09-04, 02:26 PM
Hi
i was lately at the smog station. I passed it, but the 15miles test was just at the limit. What could that be? The catalytic converter? Could be a tune up fix that problem? By the way what could be not tuned right??? :hmm:

Thanks in advance

BeelzeBob
03-09-04, 02:47 PM
Hi
i was lately at the smog station. I passed it, but the 15miles test was just at the limit. What could that be? The catalytic converter? Could be a tune up fix that problem? By the way what could be not tuned right??? :hmm:

Thanks in advance

any clue as to engine, model year, car, etc...??

What constituent was high...???...HC, CO, NOx....????

Really need to know what is high to decide what to do or look at.

nikoh
03-09-04, 03:23 PM
Sorry, forgot all the stuff...
1996 Eldorado, 4.6L,
Vin 1G6EL12Y9TUXXXXXX

the test result is attached!!!

BeelzeBob
03-09-04, 04:07 PM
Sorry, forgot all the stuff...
1996 Eldorado, 4.6L,
Vin 1G6EL12Y9TUXXXXXX

the test result is attached!!!


So.....it looks like the HC are the only thing high.....check the fuel pressure regulator. Lots of previous posts on this. With the engine idling pull the vacuum line off the FPR (the small canister shaped device on the fuel rail that has the fuel return line leaving it and a vacuum line attached to it...) and watch the vacuum nipple on the FPR very closely for several minutes for any sign of fuel leakage......there should be none.

Your car is an OBD2 package so there is a catalyst efficiency monitoring sytem and an engine misfire detection onboard diagnostic test. Either would trip the SES if they saw a problem.... so...I would say that the engine is running OK and the cat is ok and has good efficiency...just the engine out HC are likely high. Most likely cause if there is no direct engine miss is the fuel pressure regulator leaking fuel past the vacuum diaphragm and into the intake via the vacuum hose or possibly an injector leaking/dripping. You could check this by unsnapping the fuel rail and lifting the rail up so that the injectors clear the intake manifold ports. Turn on the key to energize the fuel pump and watch the injectors for dripping .

Budabear
03-09-04, 04:50 PM
I experienced the same thing a few days ago. I just purchased the car and it wouldn't pass the inspection due to the HC & CO being to high. The car was running just fine but the mechanic told me I needed a tuneup. I had the car fully tuned up and it passed without a problem.

nikoh
03-09-04, 04:55 PM
ok, i will check that!
where have you made the tune up, at a 'gas' station around the corner, or at a cadillac dealer? I am asking that stupid, cause I am new to the USA and I am not sure where I can get 'good' service.
thanks !!

BeelzeBob
03-10-04, 11:27 AM
I experienced the same thing a few days ago. I just purchased the car and it wouldn't pass the inspection due to the HC & CO being to high. The car was running just fine but the mechanic told me I needed a tuneup. I had the car fully tuned up and it passed without a problem.


A "tuneup" might be applicable to a 94..... There was no onboard misfire detection on a 93-95 Northstar....so if there was a plug/wire problem or something of the sort it might help to have a generic "tuneup".

The 96 in question has the onboard misfire detection so you can be pretty sure that a tuneup is NOT the answer as all that can be "tuned up" is replacing the spark plugs and wires. If they were faulty there would be a miss and an engine misfire detect.

There is also a big difference in failing for just HC and failing for HC and CO.....


I would stick by my recommendations and avoid the generic tuneup as it doesn't directly address the problem.

Also, be cautious when a vehicle fails and the same shop "tunes it up" and then it passes.... They make their own work by failing the car, then tuning it up and then , mysteriously it passes. There is nothing to "tuneup" per se on a Northstar. If there is a dead miss a plug or wire could be replaced...but, other than plugs and wires, there is really nothing to do that... So, it would be a curiosity as to what was actually "tuned up" to make that 94 pass.... If anything, a 94 usually clogs the EGR passages in the phenolic spacer plates between the intake and the cylinder head causing the NOx to fail..!!! Interesting that the HC and CO would fail on the 94 and then a tunup fixed it.

Budabear
03-10-04, 12:16 PM
A "tuneup" might be applicable to a 94..... There was no onboard misfire detection on a 93-95 Northstar....so if there was a plug/wire problem or something of the sort it might help to have a generic "tuneup".

The 96 in question has the onboard misfire detection so you can be pretty sure that a tuneup is NOT the answer as all that can be "tuned up" is replacing the spark plugs and wires. If they were faulty there would be a miss and an engine misfire detect.

There is also a big difference in failing for just HC and failing for HC and CO.....


I would stick by my recommendations and avoid the generic tuneup as it doesn't directly address the problem.

Also, be cautious when a vehicle fails and the same shop "tunes it up" and then it passes.... They make their own work by failing the car, then tuning it up and then , mysteriously it passes. There is nothing to "tuneup" per se on a Northstar. If there is a dead miss a plug or wire could be replaced...but, other than plugs and wires, there is really nothing to do that... So, it would be a curiosity as to what was actually "tuned up" to make that 94 pass.... If anything, a 94 usually clogs the EGR passages in the phenolic spacer plates between the intake and the cylinder head causing the NOx to fail..!!! Interesting that the HC and CO would fail on the 94 and then a tunup fixed it.
Actually even though I am not a mechanic I am not a sucker. I took my car to one service ststion that I use to trust for the inspection. After trying the inspection several times and failing for the CO and HC he told me that he wasn't sure what the probably was this or it could be that. I saw where that was going and I took it to another mechanic that I do know and trust implicitly.

After seeing the results of the test he told me that it was definitely a tune up problem. He tuned it up using genuine ac delco parts which I might not have done myself, then reinspected the car and it passed. If it seems difficult to believe that this could have solved the problem, it did.

BTW The NOx had passed the inspection originally.

BeelzeBob
03-10-04, 05:17 PM
Actually even though I am not a mechanic I am not a sucker. I took my car to one service ststion that I use to trust for the inspection. After trying the inspection several times and failing for the CO and HC he told me that he wasn't sure what the probably was this or it could be that. I saw where that was going and I took it to another mechanic that I do know and trust implicitly.

After seeing the results of the test he told me that it was definitely a tune up problem. He tuned it up using genuine ac delco parts which I might not have done myself, then reinspected the car and it passed. If it seems difficult to believe that this could have solved the problem, it did.

BTW The NOx had passed the inspection originally.


I was just trying to make the point that a generic "tuneup" is not in any way gurantee'd to cure an emission problem (nor any other problem) and it falls under the heading of throwing parts at a problem without understanding it.

Also, to make the point that there is a significant difference with a 96 Northstar and a 94 Northstar when it comes to diagnosing what could be wrong. Plugs and wires (which is all I assume your mechanic changed) will only cure a misfire if it was occurring.....a 96 will turn on the SES if there is a misfire...so that shouldn't be a problem and shouldn't be affected by plugs and wires.

Really, to think about it, your story is just a variation of what I presented. You failed at one station. They failed to get your "tuneup business" but you took it to another shop. A "tuneup" seemed warranted based on the numbers so you got that....and of course it passed. You don't think that your "trusted" mechanic would fail or let you down do you??? He solved the problem and the car passed....easy enough to do. Who knows if it really failed originally anyway...????

I am just a natural cynic I guess but there are way too many stories of abuses like this out there. About 4 weeks ago on the Caddyinfo forum a drive took his car into the emission test station (N Jersey I think it was) and the tech immediately checked his car and it failed and suddenly had a bunch of "trouble codes" stored in it.... The car just came out of the dealer with no codes and not problems.... And since the individual knew how to check the codes himself with the onboard diagnsotics he knew there were no codes in the system when he drove in.....they were apparently trying to drum up some business....probably just a "tuneup" would fix it....LOL

Not saying or implying that you are a sucker.....but the fact is that you do not know for a fact that the car actually failed that emission test....what parts did the mechanic replace with the "tuneup"???and did it drive or perform any differently afterward?...and making it "pass" the second time is rediculously easy for the knowlegable tech...... You may not know what you don't know, here.

Budabear
03-10-04, 09:15 PM
When the car originally failed the machanic showed me on the computer and gave me the print out of the high CO and HC that failed the test. He then told me that it could be several things not mentioning a tune up.

I then went straight to someone I knew I could trust and he after looking at the failed inspection report told me it merely needed a tuneup. The replaced parts I remember were changed was the plugs, wires, and gas filter. At the time I had a K&N air filter in the car so there was no filter for him to replace.

I since then removed the K&N conical filter and put the original filter back which was new.

Unfortunately I also got the bad news that the crankcase is leaking oil, not badly but that is one expensive job I'll have to tackle. I'm not looking forward to that one.

BeelzeBob
03-10-04, 10:39 PM
When the car originally failed the machanic showed me on the computer and gave me the print out of the high CO and HC that failed the test. He then told me that it could be several things not mentioning a tune up.

I then went straight to someone I knew I could trust and he after looking at the failed inspection report told me it merely needed a tuneup. The replaced parts I remember were changed was the plugs, wires, and gas filter. At the time I had a K&N air filter in the car so there was no filter for him to replace.

I since then removed the K&N conical filter and put the original filter back which was new.

Unfortunately I also got the bad news that the crankcase is leaking oil, not badly but that is one expensive job I'll have to tackle. I'm not looking forward to that one.


Not to belabor this but the point is that a knowlegeable tech can show you whatever numbers he wants off the "computer". There are cases where the emission numbers shown are from another car....or the subsequent passing numbers are from another car. Data can be stored and printed anytime.


How did you get the news that your crankcase was leaking?? After someone went under the car and pointed out the oily engine?? Or was it dripping on the ground and you saw the drips?? The LCC oil leak on the Northstar is greatly overblown in most cases. There are enough cases where the owner is shown a "leaking crankcase" with all sorts of dire predictions. The fact is that a little seepage at the LCC joint on a 10 year old engine is not something to get worked up over and certainly not something to spend any sort of money or time repairing in my opinion. There is no chance that the oil seepage is going to get any worse and it certainly is not going to spew oil one day and leave you stranded. The LCC joint is not sealing pressurized oil....it is just splash oil inside the engine and any seepage is just that...seepage. Why on earth bother to pull the engine to "fix" that. There is really nothing to fix, particularily if the oil is not dripping onto the ground. Forget about it. Save the money towards your next Cadillac!!!

Many so-called lower crankcase leaks are really the result of seeping oil filter adapter seals or the oil cooler line connections or the cooler lines themselves. It really takes a thorough diagnosis to confirm where the leak is before even considering any repair. If the leak is hitting the ground with drips then I would suspect the oil filter adapter or cooler line connections...both of which are easily repaired with the engine in the car. Find a dealer that has the flourescent dye to put in the oil so that the leak can be viewed with a black light to determine the exact source. Or, thoroughly clean the lower end with solvent/brake clean and run the engine to fine the exact leak. Don't just assume that the LCC is leaking.

Budabear
03-11-04, 07:56 AM
Thanks, that is good advice. I wasn't to worried about it because I haven't noticed any oil on the ground yet. I was shown the oil while the car was up on the lift.