Car question

[Griff]

^tw's sock puppet

[glatt]

Yeah. I need to ponder this.

[tw]

Originally Posted by glatt

Yeah. I need to ponder this.

Demonstrated was why shotgunning does so poorly at eliminating problems. So what has changed? As Gravedigr suggests, collect facts. List every part that was touched (not just moved- touched) when you replaced a filter. What has been touched recently? Not when the intermittent occurred. But even a week previously.

The number of possibilities is literally approaching 1000. No exaggeration. Good diagnostic procedure means reducing that suspect list to more like 100. Which is why replacing the filter only on speculation was so unlikely to be the defect. Especially if blowing in the old filter did not expose a restriction. And since a restricted filter only causes problems on acceleration - not at idle.

Imagine a wire of 32 strands. All are broken. Move that cable and some remain in contact. Move the cable and too many are disconnected causing confusion to the computer or insufficient power to a solenoid. Replace a solenoid. That new one might work with two less strands connected. But the problem still exists. Just fails less often. Only symptoms cured.

Above demonstrates what you are dealing with. Previously listed were how to eliminate some more common suspects (ie EGR valve, vacuum advance and retard system, intermittent manifold leak or defective idle control valve, partially broken cable, dirty connector that gets cleaned by making and breaking and then fails months later because the reason for that corrosion was not identified and eliminated, etc).

Well, one symptom that eliminates some suspects is temperature. Apparently (does?) temperature is unrelated to good and bad operation. Has fuel been eliminated as a suspect - were consecutive tanks from the same station or brand? When the intermittent exists, what exactly do you do to make the problem repeatable or make it worse? Do lights change intensity? Do tires make more noise? Irrelevant is a belief that tires are irrelevant. Solving intermittents means collecting all facts irregardless of whehter you believe it is irrelevant. BTW, that is a repeated concept so accurately expressed in a TV show called House.

I routinely get called when others cannot solve strange problems. Many never learn that this is critically important. Collecting facts and symptoms is completely unrelated to identifying the problem. Which is also irrelevant to what comes later - eliminating the defect.

As I said without exaggeration. Your list of suspects is somewhere approaching 1000. Getting that number down means collecting facts as Gravedigr noted. And then identify a defect long before replacing any parts. Yes, even strange noise from tires in rare cases can be the kicker that identifies an intermittent engine problem.

[sexobon]

Originally Posted by tw

... Solving intermittents means collecting all facts irregardless of whehter you believe it is irrelevant. ...

[bold mine]

Eloquently said.

[glatt]

The weather was finally nice enough yesterday for me to work on the car. Except of course, Murphy's law said that I was booked solid for most of the day with other stuff. I only had about half an hour in the late afternoon to look at it.

But I found a problem.

I wanted to start by pulling the spark plugs and looking at them so see what shape they were in. Then I wanted to get a spark tester to check that there was a good spark at each plug.

The car is 12 years old, and I was concerned that the plugs might be hard to remove. I had read about some guy on the internet who tried to check his plugs, and one broke off during removal, leaving threads locked in place in the cylinder head. That would suck, and I wanted to avoid that. So I planned ahead by switching the cars in the driveway so I could use the other one all day running errands, and the Camry engine could get nice and cold. Cold metal shrinks. I also went to the parts store to get the proper sized spark plug socket and an extension, and I got an ignition tester. I squirted a little PB Blaster down into the spark plug tubes about 5 minutes before I tried to loosen the plugs.

So it was time. I pulled the wires off the first plug, put the socket on the extension, attached it to the ratchet, and fed it down into the tube and onto the plug. I tentatively started to push on the wrench, and the plug started unscrewing with almost no effort at all. It was about as hard as unscrewing a light bulb.

I pulled the plug out. It was wet from the penetrating oil I had sprayed in there. But it looked like this:


There's a little carbon build up, but I don't know how much is normal. Each plug looks like this.

The thing that took too long to jump out at me though, is that it's the WRONG spark plug. This car is supposed to have special plugs with two grounding electrodes. One on each side. This 5S-FE engine takes the NGK BKR6EKPB11 spark plug. It's a special metal with two prongs, not your standard single prong. Plus, these plugs were so easy to get out, I think the previous owner had changed the plugs not too long ago and put the wrong ones in.

So then I checked the spark with the tester. This is basically a fake spark plug that you stick into the end of a plug wire and ground against any convenient grounding point. I'm not sure how you're supposed to perform this test. With the engine running, or starting it up each time after making the connection. Anyway, I did it with the engine running, and even without completing any circuits with my body, I was getting zapped while trying to plug it in to the spark plug wire with the engine running. I put on an extra pair of rubber gloves over the nitrile gloves I was wearing, but was still getting a shock through those gloves. It was kind of comical. But anyway I saw consistent sparks in the tester at each wire and they looked equally strong to me. But what do I know? It's the first time I've seen sparks, and I'm not sure how they are supposed to look.

So now two questions:

1. I was running the engine for a while with various spark plugs disconnected. The engine obviously ran poorly during this time, but it was nothing like the way it behaves when it's about to stall. The weird thing though is that the check engine light never came on. You'd think the computer would be pissed off about no spark in various cylinders over a 5 minute time frame, but that light never came on, and no codes were reported. It that a problem?

2. Would the wrong spark plugs with only a single grounding electrode instead of the dual grounding electrodes cause the intermittent stalling problem? The manual said using the wrong plug would result in poor engine performance, but I figured it would be consistently poor, not intermittently poor. I didn't put the correct plugs in yet. Too late in the day to go out and track them down and I was losing light. But I'm definitely going to get the correct plugs and put them in.

[glatt]

Oh, and the voltage was maybe a little high?

12.75 at the battery with the engine off, and 14.75 with the engine on and alternator running. Later after the engine warmed up, it was 14.55 with the engine on and alternator running.

[fargon]

That plug looks good, it is burning properly. I would replace the wires and plugs just because, and drive that car until till the wheels fall off. I would check the cold start injector for function. Go to the library and get the Chiltons Manuel for that car it will tell you the proper diagnoses procedures for the fuel injection and other systems. Do not use Haynes books they don't tell you anything about trouble shooting.

[glatt]

Originally Posted by fargon

That plug looks good, it is burning properly.

Thanks. It's nice to have a second set of eyes looking at this.

[tw]

Spark plug tester really says little that is useful. Same could be learned by connecting to spark plugs mounted atop the engine. Crank the engine (someone else inside) while observing plug spark. Each spark will be strong and obvious.

Ceramic around the center prong should not have anything caked on it. Problem is if carbon has formed that would short the center prong to plug's metal - a path that would not create a spark. Carbon means the engine is eating oil.

More problematic would be a spark plug of the wrong heat range. You cannot test for that. Strange, but when I tried various heat ranges, it did result in poorer operation. In the days when normal was for an engine to leak oil, we would use a plug of one heat range higher. This burned off oil but also caused the engine to run poorer.

I have seen where another manufacturer's equivalent plug did cause some lesser performance. IOW I had trouble with an AC Delco equivalent. Ended up replacing the NKGs.

Since those days, we no longer replaced spark plugs. Electronic ignition and better machined engines eliminated spark plug replacement.

Since plugs are out, then just replace them with new ones. Plugs are cheap. Nothing can properly test a plug and what is important - its heat range.

Two electrodes or one makes little different. At one point, scam manufacturers were one hyping a superior design. In reality, the plug only creates a spark across one path - not matter how many other paths might exist. However using only various plugs recommended by the manufacturer has (in a rare case) proven important.

Be very careful about restoring plugs with proper torque. Over torquing is why plugs break off, strip threads, or seize in an aluminum block engine.

[lumberjim]

Why does my hemi have two plugs per cylinder?

[Clodfobble]

Is that what the kids are calling it these days?

[Undertoad]

[tw]

Originally Posted by lumberjim

Why does my hemi have two plugs per cylinder?

Part of making a 70 Hp/liter engine involved the swirling of fuel inside a cylinder. So that an ignited flame did not slam directly down on the piston. But instead swirled down. This even scoured and burned condensing fuel from cylinder sidewalls.

A best way to accomplish this used four valves per cylinder. Another technique was to trigger an ignition with multiple plugs. A technique also implemented in Wankels. Some designs would even stagger when plugs fired.

None of that is relevant to his spark plug inspection.

[lumberjim]

Oh, i looked that up after I asked it. What I found said it fires the second plug during the exhaust stroke to clean up its emissions.

[glatt]

That's interesting. I learned from the manual that this Camry has a wasted spark system, which means the park plug fires twice. Once to ignite the fuel, and once during exhaust with the piston at the bottom. It didn't specifically say this was for emissions, but that's a fringe benefit. This wasted spark ignition system does away with a distributor, which supposedly makes the engine more reliable. The computer controls it all based on input from the camshaft sensor and crankshaft sensor.

But anyway, progress last night. Things came to a head. The car started misfiring and the check engine light came on! Misfire in cylinder 4. The idle dropped down to around 500 like it had been doing. So what I think happened was that I made whatever the problem was even worse by pulling the plugs and reinstalling them. That makes me think it's a spark plug wire. I had ordered new plugs and wires yesterday, and will replace them this weekend, after we get back from a funeral (my aunt's) in NEPA. If the plugs and wires don't fix it, it's probably the 1,4 coil/igniter. I think it was gravdigr who said way back in the beginning that it was a coil. We shall see.