MarkV

Failed Again! 1977 Seville

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California has different standards for different vehicles and years. When I had my 1976 with carburetor and no catalytic converter it could pass if hydrocarbons (HC) were below 300 ppm, but it could be adjusted to give about 100 ppm or even below that so I would get it to pass easily even if at 120 ppm. My 1987 Japanese import with fuel injection and catalytic converter was I think 100 ppm or less to pass, and i failed and needed a new Cat which brought it below 100 ppm easily. And now my 2002 Toyota pickup has 58 ppm HC as allowable max and it passed last time with 19 ppm.

 

This Cadillac has max HC 129 ppm I see.

 

1528668376122851700066.jpg

Edited by mike6024 (see edit history)

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Just noticed it failed on excessive carbon monoxide, not HC. It is called "too rich" but is really incomplete combustion. See here. If fuel pressure checks out maybe time for something else ?

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High CO results from a mixture that is too rich. High HC is generally caused by a misfire of some kind, such as a lean misfire or an ignition problem (among other things).

Edited by Bloo (see edit history)
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Have the injectors been cleaned? It doesn't take much buildup on the pintle to hold them open enough to cause excess fuel to be dumped into the intake.

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Being an old boiler operator, I have seen elevated CO levels when the products of combustion "lick" a relatively cool spot. I wasn't kidding about blocking the radiator with a piece of cardboard on the way to the test. Get everything as hot as you can. You are close, just a nudge will do it.

 

When taking any kind of test, and knowing what the answer should be, doesn't sound like a big problem.

Bernie

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On 6/15/2018 at 5:17 PM, MarkV said:

Replaced the thermostat with the 195 and coolant sensor on the 77 seville. And it failed smog again for being too rich, so I am at a loss, I took it into another mechanics shop, he seems to be pretty confident he will find out what's up with it. 

 

I think now it is pointing to the MAP sensor circuit. The fact that it is located in the ECU, and there is a vacuum connection inside of it is suspect. Vacuum hose sitting inside an ECU in a car subject to 41 years of California heat makes me think.... I would suggest that you locate the vacuum hose that supplies the MAP information to the ECU and explore further. You are almost there,,,,,,,  

Edited by John348 (see edit history)
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1 hour ago, padgett said:

Try this or similar.

 

That tool is not designed for this type of application and heat generated from the exhaust might cause a problem for the tool. These are designed to be used in confined spaces such as manholes for personal life safety. It would have to be modified for the type of use you are suggesting

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35 minutes ago, John348 said:

These are designed to be used in confined spaces such as manholes for personal life safety.

 

Like one of these.

image.png.2213fffb1e7aa7bc8c21710f7a25e911.png

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29 minutes ago, John348 said:

 

That tool is not designed for this type of application and heat generated from the exhaust might cause a problem for the tool. These are designed to be used in confined spaces such as manholes for personal life safety. It would have to be modified for the type of use you are suggesting

 

You are correct about that meter being designed for testing air quality in confined spaces.  They are also designed to operate in an environment of little or no gas flow (velocity), so introducing the meter's sensor into the exhaust  pipe of a running engine might confuse it.  That's just my feel for the situation, based on little other information.  A call to the manufacturer of the meter should answer these questions.

 

The exhaust pipe temperature of a running (1400 rpm) 1977 Seville should be fairly low, but, again, I'm not sure what those values would be.  I'm guessing that the exhaust pipe temperature at 1400 rpm would be fairly low ... on the order of 200°F +/-.

 

Cheers,

Grog

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Have you checked the plastic air intake  'accordian' for cracks?  That could be affecting the air/fuel mixture.

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The air temp sensor should be verified just in case. It would richen things up if bad.

 

John348 is correct that this points to the map. I am almost sure at this point that the solution is going to revolve around the MAP somehow.

 

I did not originally understand how California's test works, and could not understand why there were two lines with about the same engine speed. First of all, apparently California does not test at idle in a case like this... at all.....  (they must have solved all those traffic jams. I should look into moving there). No, this is an "ASM" test (only), run on a dyno.

 

I should take a moment to explain that power enrichment on cars is not usually gradual. It is either on or off. There are exceptions, like 60s Chryslers with 3 stage fuel metering, but even those aren't really gradual in the transition to power mixture. On a carburetor with a typical style power valve, like a Holley for instance, the enrichment is either on or off. GM CCC shuts off the fuel control solenoid altogether at wide open throttle (full rich). Some cars have a "three dimensional fuel map". They really do, but it is just little changes to improve things under different conditions. For all practical purposes, the enrichment is either on or off. This applies to almost every car ever made that is new enough to have power enrichment. You could do it with a switch. In fact it has been done. If anyone doesn't believe this, hook a vacuum gauge to your car, tape it to the windshield, and go for a drive. the transition from cruise to acceleration is several inches of vacuum. You'll see.

 

Now back to the California test. MarkV's post shows that it is an ASM test. Whats that? Well according to this (page 12):

 

https://www.bar.ca.gov/pdf/Smog_Check_Manual_ENG_2013.pdf

 

           

"The ASM emission inspection includes two loaded mode sequences known as the 50/15 test and the 25/25 test"

 

So then, what the hell is a 50/15 test and 25/25 test? California didn't bother to say, but according to this (page 2):

 

https://www.saddleback.edu/uploads/atas/autotech/courses/bar-97-transition-class-student-workbook.pdf

 

"ASM testing equipment tests the vehicle at two constant speed and load levels

          (A). 50% load at 15mph (known as a 50/15 test)

          (B). 25% load at 25mph (known as a 25/25 test)

 

Now we are getting somewhere. I see what they are up to. When you take off from a stoplight, you probably give the accelerator a pretty good stab. When the car gets moving you probably let up and continue accelerating, but with less pedal until you get to your desired speed, then you back off on the pedal some more and cruise. The are trying to see if you are getting into the power enrichment mode during acceleration in normal driving (not hard acceleration).

 

Remember that mode is almost like a switch.

 

A perfect cruise mixture (IMHO) is stoichometric, or 14.7 to 1 air to fuel by weight. This corresponds to 0.3% CO (theoretical) or 0.7% CO (practical). Leaner cruise mixtures give greater fuel economy, until you get to the point of lean misfire. GM was apparently trying to do that in the late 70s on carbureted vehicles (it did not work out well). They very well could have calibrated this car leaner than 0.7. They wouldn't have calibrated it richer. These are numbers all for the engine itself. The tailpipe CO emissions (after the catalytic converter) would be lower.

 

Now lets have a look at MarkV's numbers again.

 

HC         47ppm    43ppm

CO         1.60%      2.00%

O2          0.00%     0.00%

CO2       14.1%     14.0%

NO(x?)  108ppm  97ppm

 

Now, what would I expect? On a healthy engine, BEFORE the catalytic converter, something like this:

 

HC         188ppm

CO          0.7%

O2          2.2%

CO2       13.6%

NO(x?)   400ppm?

 

So what do the numbers show us? They show us that the catalytic converter is working. HC is below 100ppm, and you generally don't get below 100 without a catalyst. Low 02 proves you really do have a sample of the exhaust. CO is 14, and you don't usually get that high without a catalyst either. You might get 13.8 if the mixture wasn't too rich, but it is too rich. 1.6% CO proves that it is too rich. NO(x) wasn't looked at much in my day, but MarkV's numbers are lower than what a healthy engine emits, so that also points to a working catalytic converter.

 

Since the catalytic converter is working, we can infer that it is reducing the CO also. From MarkV's numbers, I would guess the actual CO is 6% or higher. 6% is in the neighborhood of a perfect full throttle rich fuel mixture for maximum power. Some engines may like a little more, and many are calibrated more like 10-12%, sometimes causing a slight reduction in power.

 

Yes, that is all wild speculation, but I used to do this for a living and I'll bet it isn't far off.

 

Since this looks like a full throttle power mixture, there is a good chance that this car IS into it's power enrichment. How does the system decide when to do that? With the MAP sensor. How does the MAP sensor determine that? By measuring the Manifold pressure (vacuum). When vacuum gets low enough, the power enrichment comes in.

 

Why would the vacuum be low?

 

Cam timing could do it (probably not on this car, it has a new cam and cam chain)

 

Ignition timing could do it. (It needs to be checked, or re-checked, and set in the right way, whatever that is. Many cars of the late 70s and 80s have some "gotcha" in the timing procedure).

 

Vacuum leaks could sure do it. Either a leak in the map hose causing the MAP to measure a lower vacuum, or just general vacuum leaks everywhere, causing the vacuum to be low. Bad diaphragm in the purge valve? Bad diaphragm in the diverter valve? Hole in the brake booster diaphragm? Just leaky old 1977 vacuum hoses that don't fit on their nipples tight enough?

 

The MAP itself could be bad, but I would suspect dirty connections or vacuum leaks first

 

Remember that this car was backfiring through the throttle body due to the bad camshaft. That could have blown out a diaphragm somewhere.

 

Edited by Bloo (see edit history)
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Well sorta. GM computer cars of the 90s had a "lean cruise mode" of 15.7:1 and "Power Enhancement" (PE) may drop to 10-12:1 (why it is better to downshift for a hill than let it go into PE in top gear).

 

However since the Seville has no feedback (O2 sensor), it is just guessing and evidently needs tuning. Fuel line pressure is the easiest thing to change without impacting other things.

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2 hours ago, padgett said:

Well sorta. GM computer cars of the 90s had a "lean cruise mode" of 15.7:1 and "Power Enhancement" (PE) may drop to 10-12:1 (why it is better to downshift for a hill than let it go into PE in top gear).

 

However since the Seville has no feedback (O2 sensor), it is just guessing and evidently needs tuning. Fuel line pressure is the easiest thing to change without impacting other things.

 

If that is done then all he would be doing is compensating for a problem without finding the problem? Secondly it really is not a "GM" computer car as we know it, it is a Bendix unit and is similar to the K-Tronic that was used in European cars in the 70's.

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Ok so find someone who repairs/tunes Volkswagen Squarebacks.

 

ps was commenting on A/F mixtures in GM P4 systems not Bendix/Bosch K-Jetroninc.

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56 minutes ago, padgett said:

Ok so find someone who repairs/tunes Volkswagen Squarebacks.

 

There is guy near you in Deltona

 

56 minutes ago, padgett said:

 

ps was commenting on A/F mixtures in GM P4 systems

 

But that is not what is in his car so why confuse anyone, with your vast knowledge of a different system? 

 

56 minutes ago, padgett said:

 not Bendix/Bosch K-Jetroninc.

 

The system in his car is a Bendix system

Edited by John348 (see edit history)

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The only thing worse than being misquoted is not to be quoted at all.

 

ps Deltona is a fur piece from California.

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52 minutes ago, padgett said:

The only thing worse than being misquoted is not to be quoted at all

 

I will have to remember that, so not to make you feel worse I will always make sure to quote you when I ever I can but no misquoting here, that was all you and your words, just like above. 

 

52 minutes ago, padgett said:

ps Deltona is a fur piece from California.

 

Might be, not really into furs, but Deltona is up the road a piece from Orlando

Edited by John348 (see edit history)

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On ‎6‎/‎16‎/‎2018 at 5:37 PM, misterc9 said:

In New York we don't have the tailpipe sniffer. We do have to have the check engine light not on to pass inspection.  A vehicle with a check engine that won't stay off can get a waiver to get an inspection certificate. The vehicle owner after spending a certain amount of money on repairs can furnish receipts for emission/check engine light work to an inspection station. These receipts would need to be for work relevant to the problem and from a registered repair shop. The inspection station can then apply for and then get the waiver to issue an inspection certificate.  California must have something similar to this.

I don't know what gas is available in CA. I would think a non feedback car would run leaner on gasohol than no alcohol gasoline. I might even try adding a small amount of E85 to dilute the fuel. Nobody wants to put gasohol in their old car but. I don't know how far over the limit you are rich. Maybe the fuel difference wouldn't even help it.

 

ny only dos that on cars 1996 and newer

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12 hours ago, ted sweet said:

 

ny only dos that on cars 1996 and newer

 

That would make things a lot easier if this car stored codes. I don't know now but there was a time where only the lower 8 counties had a much more rigorous emission test, and I still step over the rollers in my friends shop used for the dyno test years ago. California being California, should go the way of NYS and not have the emission test on vehicles older then 1996, but it is all about money..... 

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How soon they forget. Before ODB there was ALDL (1981) and before that there was test equipment that could record much the same thing. Part of a dig here would turn up a Unisys, Distributer tester, exhaust gas sniffer, portable ignition scope, couple of break out boxes, fuel pressure testers (still use those), and a big Sun "do it all". Have never had a dyno though.

 

If needs must could open a shop for obsolete technology.

sunsleuth2.jpg

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2 hours ago, padgett said:

How soon they forget. Before ODB there was ALDL (1981)

 

Well, ALDL is Assembly Line Diagnostic Link, and GM at least uses ALDL to refer to the under-dash connector on both OBD I and OBD II systems.

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Well sorta. GM never called them OBD-I. The ALDL connecter was the access point to the early Computer Command Control (CCC) and later the faster P4 system.

 

Back in the bad old daze of early computer cars. there was little commonality. Every car/model/drivetrain had their own setting and had to use the right programming card (early) or the right cartridge with manual entry (I like the OTC 2000 with 93 Pathfinder cart).

 

Today I use a Moates adapter with C.A.T.S. and Tuner Pro RT software for GM ALDL and an Autel Diaglink for OBD-II & EOBD-II systems. Also have Torque Pro, Carly Pro for Mercedes, and Touchscan Pro Software & am working with an Arduino to scan data streams.

 

Instrumentation/reprogramming is another of my hobbies. Somewhere I have a NIB Prince Automotive Computer  circa 1978.

 

I'd like to play with the Seville system but is a bit too far away.

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2 hours ago, padgett said:

Well sorta. GM never called them OBD-I. The ALDL connecter was the access point to the early Computer Command Control (CCC) and later the faster P4 system.

 

Back in the bad old daze of early computer cars. there was little commonality. Every car/model/drivetrain had their own setting and had to use the right programming card (early) or the right cartridge with manual entry (I like the OTC 2000 with 93 Pathfinder cart).

 

Today I use a Moates adapter with C.A.T.S. and Tuner Pro RT software for GM ALDL and an Autel Diaglink for OBD-II & EOBD-II systems. Also have Torque Pro, Carly Pro for Mercedes, and Touchscan Pro Software & am working with an Arduino to scan data streams.

 

Instrumentation/reprogramming is another of my hobbies. Somewhere I have a NIB Prince Automotive Computer  circa 1978.

 

I'd like to play with the Seville system but is a bit too far away.

 

Mr P,  I do not want to be accused of misquoting you (again) but, please read what you posted and think about it and ask yourself what it has to do with the system in this car? and why do you insist on telling us how much you know about an unrelated system? The system in the Caddy is tested with a volt/ohm meter, if the Bendix test box is not available.

 

2 hours ago, padgett said:

 

I'd like to play with the Seville system but is a bit too far away.

 

Maybe that is a good thing....  

Edited by John348 (see edit history)
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