Car question

[infinite monkey]

I guess I'm overly sensitive on tw's behalf.

Sorry, and carry on.

[tw]

Originally Posted by BigV

I am really not being shitty to him, I'd love to solve this rough idling problem glatt's car has. I don't know everything there is about cars, and I love to learn new stuff. But unless tw has some magic trick he's still hiding, I don't see how his explanations achieve the desired result.

That is the point. You do not understand the relevance. Do not understand how that information results in solutions.

Solve problems in two steps. First collect facts. Much later solve the problem. Some of that stuff posted fix a problem without first determining what is wrong is called shotgunning. Could even exponentially complicate his problem. Those was some of the most random and irrelevant wild speculation I have read in a long time. Any mechanic that did that would have been quickly unemployed. You should have been mocked for those consecutive and irrelevant recommendations. But then making all those mistakes is how we eventually learn. I just ignored them suspecting that glatt also would probably be doing same.

Embarrassing was a claim that two cylinders fire simultaneously. And a few other bogus claims. Each cylinder fires separately. You should have known that since it was taught even in primary school science. No reason to mention that until now that you decided to entertain your ego. I was not going to say anything then. But now you need to learn some humility. Big time.

We have a list of suspects from the shop manual. And a few others not on that list. Facts such as diagnostic codes, information collected by a portable computer from the dealer, and gasoline mileage all provide relevant information. Facts to significantly reduce a list of suspects to but a few. Even the fact that roughness did not correspond to an engine code was useful information.

Also important are conditions that cause or co-exist when roughness does and does not exist. Whereas tire pressure likely is not relevant, it is still a change that should known. Never short the help of a change only because you consider it random or irrelevant.

Use the oxygen sensor as an example. Some assumed an oxygen sensor could cause rough idle. Why? An oxygen sensor is mostly about operation at high speed; not at idle. An oxygen sensor (in most designs) has no influence on how idle works. Why then did someone suspect an oxygen sensor? An example of implementing a solution long before a defect was even defined.

Gasoline mileage goes a long way to exonerating many suspects. But not everyone would understand that for a same reason why some might automatically suspect an oxygen sensor.

Another example was recommended. Full to the floorboard acceleration repeated after each engine restart. So that diagnostic codes might report some other defects. It should have been done especially when one has no idea what that will discover. What was to you random was actually targeting specific suspects.

You have no idea why gasoline mileage numbers were important. Numbers more useful had those numbers been taken when the car was running better. Numbers that would have even said more if taken for a tank of Liberty and another tank of Shell.

Moving on. Another explained what high octane gas is. It is not cleaner or better. High octane does not burn out crud. It is only different. Some brands include additives that make other differences.

For example, Mobil once contained high detergent additives. Therefore gas was cleaner? No deposits? Nope. High detergent levels in Mobil caused increased carbon deposits on valve stems.

Same applies to high octane. High octane can increase engine wear and failure on some parts. The word high does not mean better (except at the end of the day in a room with a towel covering that hole underneath the door).

[glatt]

I push in the trip odometer every time I fill the tank, and it's usually around 280 miles if I've been driving around town and 310 miles or so if I've been on the highway for the entire tank. I haven't noticed a huge change in those numbers. How big would the change in mpg have to be to be significant? I haven't noticed a change, so I figure the mileage hasn't changed by more than 5%, if it has changed at all. I think it has stayed the same.

[tw]

Originally Posted by glatt

How big would the change in mpg have to be to be significant? I haven't noticed a change, so I figure the mileage hasn't changed by more than 5%, if it has changed at all. I think it has stayed the same.

The difference between crap Liberty gas and Shell gas would (for example) result in maybe an 8% difference without any noticeable change in idle smoothness. If your numbers are as reported, then Liberty gas should have caused a noticeable mileage difference. The fact that you saw no difference is troubling.

In another event, a tank of Mobil destroyed my fuel injectors. I knew something was wrong due to a slight roughness in idle. But the resulting mileage change was from 32 MPG to about 27 MPG in that tank. And 24 MPG in the next tank. (Honda replaced those injectors for free). In that case, diagnostics never reported a problem.

In another case, a problem with an EGR valve kept causing a check engine light. No mileage change. Symptoms that helped me trace the problem to a hard and not easily diagnosed problem. (BTW, EGR valve is not connected to the idle system; so did not affect idle. And that failure was unique so as to not affect gas mileage.)

Examples of different failures that do and do not result in mileage changes. And that isolated the problem quickly to a shorter list of suspects.

Assuming that 5% coincided with road conditions (heavy traffic, summer open road driving, etc), then is we can assume you have a problem traceable to the idle system and that does not affect the other 'normal operation' system.

BTW, remember Cloud's problem. That was also traceable to the idle system and that would not cause mileage changes. That mechanic had one clear advantage. The Civic's diagnostic system pointed exactly to the defect - which that mechanic refused to address. An example of why some people just refuse to learn good diagnostic procedure.

Now, with Shell, what is happening? What are the latest symptoms?

[glatt]

Well, the roughness seems to be not so bad the last week or so, but I'm not sure. The roof used to buzz from the vibration and that's not happening recently, but there is still some roughness in the idle after it warms up. You can feel it in the steering wheel and the cds in the door pocket rattle. It still goes away when you give it some gas.

I have old records of the mileage from when this car was new and I was better at tracking that stuff, and I can compare that to the mileage the next time I fill the tank, but keep in mind that gas didn't have ethanol in it back then, so it would be comparing apples to oranges.

Is it worth it to buy a bottle of fuel injector cleaner and dumping that in the tank? Would that harm anything other than a few wasted dollars?

Also keep in mind that we don't drive much. I take the subway to work, so it might be a couple weeks before we fill the tank again.

[tw]

Originally Posted by glatt

The roof used to buzz from the vibration and that's not happening recently, but there is still some roughness in the idle after it warms up. You can feel it in the steering wheel and the cds in the door pocket rattle. It still goes away when you give it some gas. ...
Is it worth it to buy a bottle of fuel injector cleaner and dumping that in the tank? Would that harm anything other than a few wasted dollars?

Is that a new symptom? Roughness was when warm; not when cold? Or is roughness same when engine is warm or cold at 1000 or 1200 RPM - the cold idle speed?

I would avoid even trying to fix anything. First establish some trends. You still have some Liberty gas in there. And you really do not have MPG numbers. Only mileage for some approximate gallons of gas.

Stated earlier: first get facts. Dumping that miracle fluid in only adds another variable; can create confusion. One step at a time. You describe something that is not serious. You can live with it for a few months until the problem makes itself obvious.

Or you can take a nuclear option. Spend more. Take it to the dealer. My preference is to learn from an anomaly that is minor - will not leave you stuck. Not just learn how a car works. But how to better diagnose any problem. A memorable moment in life is that "Aha-Ha" moment. When that solution is sudden, obvious, and appears to materialize from nowhere.

I would avoid that additive until current trends stabilize - ie enough tanks to accurately identify gas mileage or to see roughness stabilize – become predictable. Currently roughness is different at different engine temperatures? Or just at different idle RPMs?

[BigV]

Originally Posted by tw

That is the point. You do not understand the relevance. Do not understand how that information results in solutions.

right, RIGHT. Exactly. Now, at last, you understand my question. Of what possible relevance is gas mileage measurement fixing a rough idle?

Originally Posted by tw

Solve problems in two steps. First collect facts. Much later solve the problem.

You have some facts. You don't have all the facts. You'll never have all the facts until the problem's solved.

Originally Posted by tw

Some of that stuff posted fix a problem without first determining what is wrong is called shotgunning. Could even exponentially complicate his problem. Those was some of the most random and irrelevant wild speculation I have read in a long time.

No, it's not called shotgunning. It's called an iterative process, a process of elimination.

Originally Posted by tw

Any mechanic that did that would have been quickly unemployed. You should have been mocked for those consecutive and irrelevant recommendations.

Well, he's not taking it to a mechanic, he's asking us, asking me. I think a mechanic that did the things I suggested would be employed far longer than a mechanic that did the things you suggested. Just curious, what part of my recommendations do you consider irrelevant?

Originally Posted by tw

But then making all those mistakes is how we eventually learn. I just ignored them suspecting that glatt also would probably be doing same.

Embarrassing was a claim that two cylinders fire simultaneously.

Cite. An even firing sequence is pretty common, anything else is unusual for an inline four.

Originally Posted by tw

And a few other bogus claims.

Cite.

Originally Posted by tw

Each cylinder fires separately.

Cite.

Originally Posted by tw

You should have known that since it was taught even in primary school science. No reason to mention that until now that you decided to entertain your ego. I was not going to say anything then. But now you need to learn some humility. Big time.

Buddy, I've been sayin that from the beginning. If you have something to teach me, bring it on. To this point you have not been forthcoming. I've asked you and asked you for your explanations, only to be be met with silence and bloviation in equal measure. You have some mechanical explanations for what's happening here, I'm interested in learning them, humbly. I'm still waiting...

Originally Posted by tw

We have a list of suspects from the shop manual. And a few others not on that list. Facts such as diagnostic codes, information collected by a portable computer from the dealer, and gasoline mileage all provide relevant information. Facts to significantly reduce a list of suspects to but a few. Even the fact that roughness did not correspond to an engine code was useful information.

Sure. We have some facts, ok, I agree. Now what do you suggest to do with the facts you have?

Originally Posted by tw

Also important are conditions that cause or co-exist when roughness does and does not exist. Whereas tire pressure likely is not relevant, it is still a change that should known. Never short the help of a change only because you consider it random or irrelevant.

I short the help of a change (???) when it a distracting obfuscation. Like gas mileage. You do know that the gas mileage of his car when idling is zero, right?

Originally Posted by tw

Use the oxygen sensor as an example. Some assumed an oxygen sensor could cause rough idle. Why? An oxygen sensor is mostly about operation at high speed; not at idle. An oxygen sensor (in most designs) has no influence on how idle works. Why then did someone suspect an oxygen sensor? An example of implementing a solution long before a defect was even defined.

Gasoline mileage goes a long way to exonerating many suspects.

Really?? For a rough idle? HOW? How? That is my question, how does knowing the mileage fix the rough idle? It doesn't man. You might have posed a better question by asking how the mileage has changed. But even then you would have gotten a small range of answers, same, better, worse, LOTS better, LOTS worse, all over the place, stuff like that. But even knowing which of those answers was the "fact" leaves you with no suggestion as to what to *DO*.

Originally Posted by tw

But not everyone would understand that for a same reason why some might automatically suspect an oxygen sensor.

Another example was recommended. Full to the floorboard acceleration repeated after each engine restart. So that diagnostic codes might report some other defects. It should have been done especially when one has no idea what that will discover. What was to you random was actually targeting specific suspects.

You have no idea why gasoline mileage numbers were important.

If you do, please tell me.

Originally Posted by tw

Numbers more useful had those numbers been taken when the car was running better. Numbers that would have even said more if taken for a tank of Liberty and another tank of Shell.

Moving on. Another explained what high octane gas is. It is not cleaner or better. High octane does not burn out crud. It is only different. Some brands include additives that make other differences.

For example, Mobil once contained high detergent additives. Therefore gas was cleaner? No deposits? Nope. High detergent levels in Mobil caused increased carbon deposits on valve stems.

Same applies to high octane. High octane can increase engine wear and failure on some parts. The word high does not mean better (except at the end of the day in a room with a towel covering that hole underneath the door).

So, based on what facts we all know, what do you think could be the reason for the rough idle and what do you suggest to resolve that symptom?

[tw]

Originally Posted by BigV

No, it's not called shotgunning. It's called an iterative process, a process of elimination.

What was posted was classic shotgunning. As I said before, a major reason for fixing things is to learn. Eventually you may learn that those long posts were classic examples of shotgunning. You were even trying to fix things that were not relevant to his symptoms. Trying to fix things base upon "it might be this so do that". That is shotgunning.

Some of your suggestions would fix things not even relevant to the symptoms. Understandable because even some basic concepts, essential to auto repair, were unknown. A firing order for a four cylinder engine is typically 1, 3, 2, 4. Two cylinders do not fire simultaneously. That would cause imbalances. Explains many suggested actions that were irrelevant. Shotgunning often happens when underlying concepts are not first learned. Again, cylinders do not fire simultaneously.

what do you think could be the reason for the rough idle and what do you suggest to resolve that symptom?

Exactly the point. Once never cures symptoms. Symptoms are part of the process of identifying a defect. Fix defects; not symptoms. First identify the problem. Fixing comes much later. Shotgunning is suspecting and then fixing things when one has not a clue.

In an example, you asked how gas mileage fixes rough idle. Again, fixig comes later. Gas mileage is the process of first identifying the defect. Using gas mileage to fix roughness is an example of 'shotgunning'.

Based upon facts, a defect is not yet identified. A long list of suspects exist. Many might be eliminated with better knowledge, labor, or equipment. Ie. remove a suspect to test it on the bench. But that would take time, more posts, and sometimes creates new problems. Instead, use better knowledge, for example, to know an O2 sensor is an unlikely suspect (based upon symptoms provided).

No rush. The car still works. Plenty of time to identify the problem.

Facts provided a reduced suspect list - posted earlier. Still too many. Listed was how to obtain more facts since even mileage numbers could reduce that list. Mileage numbers are still too subjective.

However if you know more, then define what will identify or exonerate each suspect. The list is there. If you know more, then detail how to identify the defect from that suspect list.

Other relevant questions were asked such as behavior at various RPMs and temperatures, changes after Liberty gas has been fully displaced by regular Shell, operation so that engine diagnostics can see some problems, and using an onboard computer to monitor engine parameters when roughness does and does not happen.

In thinking back, I don't remember. Another of many still unanswered questions. Were spark plugs and wires changed a few thousand miles before this roughness started?

[Pete Zicato]

Originally Posted by BigV

So, based on what facts we all know, what do you think could be the reason for the rough idle and what do you suggest to resolve that symptom?

Trying to get a straight answer from TW is like trying to nail jelly to a tree, innit?

[Lamplighter]

Someone drove the car until the gas was very low, and/or
the gas cap was not put on tightly so the check engine light came on.

Full tank of fresh gas + tight cap + running engine 30+ minutes => light goes out = problem solved.
.

[BigV]

I'm tired of arguing with you tw.

I misspoke about two cylinders firing at the same time. What I was trying to communicate is that two cylinders are UP and two cylinders are DOWN at the same time. One of the UP cylinders is on the compression/power stroke and the other UP cylinder is on the exhaust/intake stroke. My point is still valid and that is if there's something that causes one of the cylinders to misfire, that will cause the engine to be unbalanced. This in turn is felt as a vibration, a roughness.

As for the rest... we just disagree on a couple of things. What you call shotgunning, I call eliminating possible problems. What you call gathering information, I call sitting on your thumbs. What you call no rush, I call no clue. That's fine. You seem to want more and more information until you know what to do, and then you want to spend one bullet only to kill the problem. That is definitely one way to fix problems. It's not the only way, and in my opinion it is not a very effective way. But it's your way and that's cool.

The rest of your crap, whatever dude.

[tw]

Originally Posted by BigV

I'm tired of arguing with you tw.

Why are your arguing? Did you always argue with your algebra teacher when concepts were too hard?

What you call eliminating problems is classic shotgunning. No way around reality. Since you never learned good diagnostic procedure means it must be wrong?

Many never learn this stuff. Assume it is too complex; therefore must be wrong. Get angry and become argumentative rather than learn. No argument exist. Just facts. Fatigue is you fighting to avoid learning. Only you can choose to learn or remain argumentative. Well proven reality, for some reason, distresses you. As if learning this stuff would somehow hurt you.

OK, so how an engine works was completely contrary to what you accidentally posted. Fine. And still irrelevant to the topic - rough idle.

glatt has options (and outstanding questions) to find an actual defect. Or to whittle that list down to but a few suspects. Apparently you want him to keep replacing parts as a mechanic did to Cloud - four times and how many $hundreds? A new mechanic who did not shotgun meant Cloud's defect was eliminated the first time. He followed the evidence. A concept also defined in Japan as “work smarter; not harder”.

Good diagnostic procedure finds a defect before wildly replacing good parts on speculation. Follow the evidence. They even made TV shows based on the concept.

[classicman]

Cloud's defect was eliminated the first time.

Actually the fifth. The first mechanic had already tried four things.

A concept also defined in Japan as “work smarter; not harder”.

Um, isn't that actually the min-max rule?

jus sayin.

[tw]

Originally Posted by classicman

Actually the fifth. The first mechanic had already tried four things.

A second mechanic was forced to testify before the grand jury?

[classicman]

no, that was the gas station attendant that noticed the wipers malfunctioning.