CA Smog Emissions Fail

[bytes311]

Another tip, while looking for sparks in the dark around a running motor, keep BOTH hands in your pockets. A ticking noise around the distributor means either you did not seat the cap or rotor properly or you did not seat all of the spark plug wires completely into the cap. Or you may have damaged a spark plug wire near the distributor and it is sparking. That ticking noise will result in a cylinder misfire and that will fail you in an emissions test.

Thank you for that information, David. Hopefully it's just the case of a loose plug wire.

[bytes311]

I just got back from the smog shop. The results came back pretty much the same as before, with HC measuring at 5. This was after replacing the plug wires, the cap, and the rotor and adjusting duty cycle within spec. I even removed the cat and let sit in laundry detergent overnight. It was clean before and after. The O2 sensor wasn't fouled either.

I left the car at the shop so they can perform their own diagnosis. Basically they said there's too much oxygen getting in. I'm guessing vac leak somewhere.

[DMCVegas]

I even removed the cat and let sit in laundry detergent overnight.

Where did you get THAT idea from? How could that possibly help with cleaning up your exhaust when your HC levels are far too low?

Your NO_x levels are high because the mixture is running too lean. If it was normal and the CO/HC was too high, THEN you could start looking at the Catalytic Converter. But ONLY after you checked the ignition system and balanced the fuel mixture. This absolutely does NOT apply in your case!

Listen, I'm not trying to be a jerk here. But what I'm seeing happening with your car is you're shotgunning repairs left and right, trying to find something to "fix" with the hope that one single item is the cure to all of your problems, and you're pissing away allot of cash in the process. Not to mention you're going to get really mad at the car and have a very bad experience. I, and others here, are trying to help you.

There are ways to test for a vacuum leak. The first of which is of course a visual inspection of all your hoses, vacuum lines, and gaskets. You need to go through those items and replace any bad parts. IF you need to, you can even take a can of starting fluid, and quickly spritz certain suspect areas around the engine. BEING VERY CONSERVATIVE WITH THE FLUID, AND DOING THIS SLOWLY TO GIVE IT TIME TO EVAPORATE BETWEEN SPRAYS! If you've got a leak, the RPMs will jump without you touching the throttle after spraying that particular area, and you'll know where you've got that leak at.

Once you get the vacuum leaks sorted out, THEN you need to move on to Ignition Timing. Gap your spark plugs correctly and set the timing as per the Workshop Manual.

After that is done, THEN you have to set the Fuel Mixture. This is done by measuring the exhaust gasses BEFORE the catalytic converter. The preferred method would be an Infrared Exhaust Gas Analyzer as per the Workshop Manual which any garage should have, but you can also tune using an A/F Meter and a proper Oxygen Sensor that will tell you when you're at 14.7. All of which is done sampling exhaust gas BEFORE the Catalytic Converter!

If you've still got problems with emissions levels, which at this point should only be high HCs if you've got a problem with a bad injector or spark plug accompanied by a poorly running engine, you can then go through each cylinder and start a separate set of diagnostic procedures then. Which are fundamentally the same as any other EFI System.

Once you've done all that and the engine is running fine, a properly functioning LAMBDA system will complete all fine-tuning on the fly, and the Catalytic Converter will clean up an stray exhaust problems. Because remember, it's there to merely help, NOT correct all the problems with a poorly running engine.

I hope your catalytic converter isn't damaged. Because if it is, even once you've gotten the engine sorted out and fixed, I foresee another almost $400 repair bill in your future for a replacement cat.

Please man, I learned car repair as a whole off my own DeLorean. Don't make the same mistakes that I did in the past. You can do this, and it's actually not that difficult. But it's only going to work if it is done the correct way which is to be methodical about it.

[bytes311]

Where did you get THAT idea from? How could that possibly help with cleaning up your exhaust when your HC levels are far too low?

From this forum. There are numerous threads where owners tried this method as a kind of last ditch effort short of buying a new Cat. I do see your point about my HC levels being so low that it doesn't even matter. I figured that since I already had the Cat out of the car to inspect, that it wouldn't hurt to clean any possible carbon residue inside.

Listen, I'm not trying to be a jerk here. But what I'm seeing happening with your car is you're shotgunning repairs left and right, trying to find something to "fix" with the hope that one single item is the cure to all of your problems, and you're pissing away allot of cash in the process. Not to mention you're going to get really mad at the car and have a very bad experience. I, and others here, are trying to help you.

No worries, and I most certainly appreciate the time you take to write out your responses in such detail.

There are ways to test for a vacuum leak. The first of which is of course a visual inspection of all your hoses, vacuum lines, and gaskets. You need to go through those items and replace any bad parts. IF you need to, you can even take a can of starting fluid, and quickly spritz certain suspect areas around the engine. BEING VERY CONSERVATIVE WITH THE FLUID, AND DOING THIS SLOWLY TO GIVE IT TIME TO EVAPORATE BETWEEN SPRAYS! If you've got a leak, the RPMs will jump without you touching the throttle after spraying that particular area, and you'll know where you've got that leak at.

I have checked every vacuum hose that I can access short of the ones down in the valley. I've even sprayed carb cleaner around suspected areas and did not find any leaks or sudden spikes in RPM. I have positive vacuum at the vacuum advance when I give it throttle, and none at idle.

Once you get the vacuum leaks sorted out, THEN you need to move on to Ignition Timing. Gap your spark plugs correctly and set the timing as per the Workshop Manual.

After that is done, THEN you have to set the Fuel Mixture. This is done by measuring the exhaust gasses BEFORE the catalytic converter. The preferred method would be an Infrared Exhaust Gas Analyzer as per the Workshop Manual which any garage should have, but you can also tune using an A/F Meter and a proper Oxygen Sensor that will tell you when you're at 14.7. All of which is done sampling exhaust gas BEFORE the Catalytic Converter!

Other than re-gaping the spark plugs (which were new and properly gaped last year), the A/F meter and Gas Analyzing stuff goes beyond what I can do in my own garage. This is only the second time in my two years of ownership that my car has been to the shop. I'm sure with their tools they will be able to narrow it down quick. I would rather pay them to properly diagnose the issue at this point.

Please man, I learned car repair as a whole off my own DeLorean. Don't make the same mistakes that I did in the past. You can do this, and it's actually not that difficult. But it's only going to work if it is done the correct way which is to be methodical about it.

No, I hear you! The last two years of ownership has been quite a learning experience, and I love it. And everyone here has been extremely helpful.

[David T]

Don't beat yourself up. You tried. California is the hardest State as far as emissions testing goes. It may require checking and adjusting the valves or replacing an injector. Any little thing can fail you and usually there are several little things! Everything must be "just right".

[DMCVegas]

From this forum. There are numerous threads where owners tried this method as a kind of last ditch effort short of buying a new Cat. I do see your point about my HC levels being so low that it doesn't even matter. I figured that since I already had the Cat out of the car to inspect, that it wouldn't hurt to clean any possible carbon residue inside.

I get it man, believe me I do. I tried all sorts of snake oil crap that did more damage to my car than good. Prime example was the idea of running a bottle of denatured alcohol through the system. Didn't fix a damn thing, car still had to have an injector replaced, AND I wound up with a destroyed O-Ring in my Primary Pressure Regulator which caused hot start problems. Big-ass Barrel-O-Fun that was, I tell ya. Wasted money, and further damage down the road. I just hate to see others go through such problems.

Sometimes there is no easy way to get out of doing what we have to. But ironically enough, it's sometimes easier to just do things properly the first time.

Other than re-gaping the spark plugs (which were new and properly gaped last year), the A/F meter and Gas Analyzing stuff goes beyond what I can do in my own garage. This is only the second time in my two years of ownership that my car has been to the shop. I'm sure with their tools they will be able to narrow it down quick. I would rather pay them to properly diagnose the issue at this point.

That's fair enough, I understand that.

But... What if there actually WAS a way for you to do all that yourself?

Ignition timing isn't that difficult at all. I have faith that you can easily do that no problem. There are plenty of YouTube videos and whatnot what will show you how. But what about the Air/Fuel mixture? There are ways as described by others to go ahead and use a dwell meter to also set your mixture.

Now I might also be jumping the gun here, and Dave or anyone else please correct me if I'm wrong, but you should be able to simply also use one of these devices as well:

http://www.jegs.com/p/Innovate-Motor...74546/10002/-1



You don't even have to permanently mount it in the car. Just screw it into the O2 port on your car, and connect it to the rest of the device. Put the LAMBDA into open loop, and tune it. Pop the plug on the CO mixture screw, adjust it slightly, plug it back up, give it a few seconds to settle down since you just created a tiny vacuum leak when you removed the plug. Observe the reading and adjust as nessisarry. Keep on doing that until you're at 14.7 and then just shut it all off to cool down the engine and then swap sensors and button everything back up.

These meters are used all the time to set the AFR on carbureted engines, so there is no reason we shouldn't be able to do the same here.

No, I hear you! The last two years of ownership has been quite a learning experience, and I love it. And everyone here has been extremely helpful.

It sounds like a very positive experience, and I'm glad to hear that. In truth, the DeLorean is actually a very simple car to work on. It just looks intimidating is all.

[bytes311]

You definitely piqued my interest in getting one of those AFR gauges. Would this one work in our cars? https://www.amazon.com/Innovate-Moto...dp/B001QFH2S6/

[Bitsyncmaster]

You definitely piqued my interest in getting one of those AFR gauges. Would this one work in our cars? https://www.amazon.com/Innovate-Moto...dp/B001QFH2S6/

Yes that would work but removing and installing the wideband sensor just to adjust your AFR may or may not be a lot of work.

You can permanently leave it installed and drive the stock lambda ECU with it.

Another option is a tailpipe mount for the wideband but if you have a CAT that affects accuracy.

[DMCVegas]

Yes that would work but removing and installing the wideband sensor just to adjust your AFR may or may not be a lot of work.

You can permanently leave it installed and drive the stock lambda ECU with it.

Another option is a tailpipe mount for the wideband but if you have a CAT that affects accuracy.

Question about that permanent installation: if you're directly dividing the signal from the O2 between the LAMBDA and the sensor, is there not a risk of power loss from that division which could deliver a false signal to both? Carbureted cars with these gauges don't share the signal with anything else other than the gauge, and EFI systems either install a dedicated sensor, and other systems simply query the computer via OBD-II to report back what the findings are.

Overall, using this method it would honestly be *less* work than what the existing procedure in the manual recommends. In that one you've got two separate brass plugs to pull to install probes onto each cylinder bank, instead of the single O2 sensor. And you still have to initiate cool-down periods before and after testing to remove those plugs, and then reinstall them. On top of that, you'd either need a single exhaust gas analyzer with dual inputs, or two separate ones on each cylinder bank.

Yes, there would be an advantage to quickly isolate a vacuum leak to a particular cylinder bank. However, given the nature of the points of failure on the PRV with the shared O-Rings and Gaskets and their prices, you'd probably just replace ALL of the seals anyway rather than just a single side, or even a single cylinder. So measuring at the exhaust confluence becomes more advantageous with the significantly lower amount of work needed for the measurement process. In reality, only the exhaust manifold gaskets are kept separate, and you can audibly hear when you've got a leak there.

We could cut this work down even MORE with an adaptor harness for the newer O2 sensor, but I'm not sure if this is a 3 or 4 wire sensor in the kit.

[Bitsyncmaster]

A wideband sensor does not directly produce a voltage related to AFR like a narrow band sensor. It has 6 wires (or more) and electronics drive the sensor to get signals from it.

So the Innovate system has that electronics which the wideband sensor plugs into. Then that electronics can produce the signal that simulates the narrow band voltage and you drive that signal into the lambda ECU. The advantage is you can set the AFR you want so the simulated signal produces what the narrow band would have produced at 14.7 AFR.

The display uses a second output out of that electronics to show you the AFR.

So you are not modifying anything connecting your stock lambda ECU to the system.