A lean condition is not just injector related, but could be a host
of other sensors and/or a combo of them.
O2 can be going bad. EPA mandates that 'major' emission components and
systems 'must' be good for 80,000 miles. So the OEMs 'have to' meet
that. Why 'some' after market components like O2s cost less than half
of what an OEM would...they are usually only good for around 20K miles.
Any gasket work on the engine? If they used a silicone based gasket
sealer, or RTV, it 'will' poison the O2's and cause them to report
false info to the computer.
Fuel pressure regulator could be going bad. Usually low, but it could
be cycling up and down to confuse the computer.
MAF or if you have a MAS sensor could be off
Even the plug/coil can cause the O2's to sense unburned,
so thinks rich, so leans it out.
-Ben Picture of my rig
1996 GMC SLT Suburban 3/4 ton K3500/7.4L/4:1/+150Kmiles orig owner...
1980 Chevy Silverado C10/long bed/"BUILT" 5.7L/3:73/1 ton helper springs/+329Kmiles, bought it from dad...
1998 Mazda B2500 (1/2 ton) pickup, 2nd owner...
Praise Dyno Brake equiped and all have "nose bleed" braking!
Previous trucks/offroaders: 40's Jeep restored in mid 60's / 69 DuneBuggy (approx +1K lb: VW pan/200hpCorvair: eng, cam, dual carb'w velocity stacks'n 18" runners, 4spd transaxle) made myself from ground up / 1970 Toyota FJ40 / 1973 K5 Blazer (2dr Tahoe, 1 ton axles front/rear, +255K miles when sold it)...
Sold the boat (looking for another): Trophy with twin 150's...
51 cylinders in household, what's yours?...
Ben's post underscores my point....there's a lot more to diagnostics than simply reading the code. The code only indicates the condition that the PCM observes, it doesn't tell you what's causing it. O2 sensors can be tested by comparing voltage/resistance to stated values, as can coil packs, etc. Determining continuity is not enough, input/output voltage must be within the correct range, sometimes only .2 or .3 volts for the PCM to process the output successfully.
If you are going the DIY route, you most definitely need the Helm factory service manuals that have the diagnostic trouble trees for every PCM code.
rlh6805 wrote: What exactly are the DTC's that the scan tool reported? The misfire should have been P0306 (cylinder 6 misfire), but what was the lean code?
Well, unfortunately, I could not see the specific codes - all I saw was the verbage/text on the scan tool display (very briefly, looking over the guy's shoulder at Advance Auto).
I saw where it said 'misfire cylinder #6' for one code, and 'lean condition detected' for the other. That was about it.
Note to self: Put an OBD scan tool on the Christmas or Birthday 'wish list'. Hehe.
Quote: If the PCM detects a cylinder misfiring, the fuel will be shut off at that cylinder. This can also cause a lean condition if it goes on long enough. When the O2's detect too much oxygen in the exhaust, the PCM tries to add fuel to get to the correct ratio (14.7:1). When an upper limit is reached (adding fuel), and the O2's still indicate too much oxygen, a lean code is set.
Ahh, makes sense. Thanks for the explanation, rlh. If this is true, then the lean condition DTC does NOT necessarily imply it is or is not a coil problem.
As BenK said, diagnosing these things based on the hints given to us by the PCM, can be fun.
Guess this afternoon when I put then new coil on, we'll have some answers to this.
willald wrote: Anyway, the fact that the computer gave a code for 'lean condition detected' as well, has me wondering if possibly the coil isn't the problem. Wouldn't a coil or plug issue cause the exact opposite, a rich condition? Lean condition has me kinda wondering if its more a fuel delivery problem for that cylinder, maybe a bad fuel injector?
Or, could it be that when the coil failed, the computer over-compensated for a rich mixture that resulted, and leaned out the mixture too much, causing the lean condition code to be generated?
I still think its the right decision to get the coil. Seems pretty good odds that its the problem, since those coils are so notorious for going. If the coil doesnt solve it, I'll then have a spare coil to keep handy, for when/if one of the coils does go in the future.
I believe if coil doesn't fix it, given the lean condition code generated...Next thing to look at would be the fuel injector for that cylinder, right?
Will
Not knowing exactly how the fuel injection systems are designed in the V-10, I cannot answer with 100% definity.
However, there are laws of nature that never change.
When the spark plug fails to ignite the fuel/air mix, the exhaust will have an excess of hydrocarbons in it. This will be registered by the O2 sensor as a "rich" condition. To compensate, the computer will reduce the injector dwell time (within it's design parameters). Dwell time is the amount in milliseconds that the injector is open. By looking at the injector bandwidth (dwell time), you should be able to tell if the computer is trying to lean out the fuel/air mixture.
Of course this will be above the level of Auto Zone diagnostics, and you will need a ford dealer, or one of the better independent shops.
One other thing I thought about the other day that might need consideration......Have you ever tried the off the counter fuel injector cleaners that you pour into your gas tank? I have had success using the stronger Valvoline, and STP fuel injector cleaners that you can buy at Wally's. I typically only use them when I have less than 1/4 tank of fuel just to keep it concentrated.
Not only could you have dirty injectors, but dirty injectors spray fuel droplets, instaed of a fine mist. These droplets collect on the back side of the intake valve, and cause carbon build up, which results into all sorts of issues. (a snowball effect, if you will) The least of these being restricted fuel/airflow, valve not seating properly, ticking, or knocking sound, the fuel becoming unsuspended in the airstream. Which also could produce a lean mixture.
It should also be noted that a lean mixture will cause a misfire in an otherwise perfectly operating ignition system.
Engineer9860 wrote: When the spark plug fails to ignite the fuel/air mix, the exhaust will have an excess of hydrocarbons in it. This will be registered by the O2 sensor as a "rich" condition.
The O2 sensors do not read hydrocarbons. They read oxygen, hence the name oxygen senors.
When a cylinder fails to ignite the mixture the hydrocarbons and oxygen go into the exhaust. The O2 sensors can't see hydrocarbons, but they do read the extra oxygen and interpret this as being a lean condition.
Mark
2002 Ford E350 van connected to a 1998 SunnyBrook 33 FKDS travel trailer by a Hensley Arrow hitch
Former Ford Automatic Transmission Engineer, 1988-2007
Excellent points, from both Engineer9860 and Mark Kovalsky. Thanks again for posting, this has made for some very interesting and informative reading, at least for me.
Well, sorry, still no news. After all this, not only does Autozone not have the coil, they have no tracking #, and no clue as to where/why such part has not been received. I finally said ENOUGH with their nonsense, yesterday afternnon went in there, got my $$ back from them, then went to Advance Auto and ordered exact same (Visteon) coil. They will have it today, so hopefully tonight we will put the new coil on.
Note to self for the future: Stay away from Autozone. Those folks don't know their tail ends from a hole in the ground, LOL. Advance Auto has a much, MUCH better system for getting parts, when you need something they don't stock in the store.
Anyway...Engineer9860, as to your specific questions, about fuel injector: Look back on this thread, you'll see that at first I thought it was a fuel injector. I meant to run some fuel injector cleaner through it, but that did not happen. I *did* run 'bout 80 miles worth of premium fuel in it, though. When that didn't help, I decided that given how notorious these engines are for coils going out...The coil was a good bet. Worst case, if coil isn't it...I'll have an extra coil to keep, for when one does go.
I guess its still possible that this is just a really dirty injector, and some cleaner will solve it. If the coil doesn't solve it, I may just run some cleaner through it like you said, see if that helps. Failing that...I'm not sure. I'll probably pull the plug on that cylinder and have a look at it, or possibly look at replacing the injector on that cylinder. That, or at that point I may just cry 'Uncle', and let the dealer have at it. Like Don (Burbman) said, if you keep throwing parts at something, eventually you'll pass what it'd cost to have a professional do the job. Here's hoping it doesnt come to that...
Will & Angela
2 wonderful children that love camping, Stephen & Allison
2003 Ford Excursion V10 4x4
2003 Thor Citation 33M, Hensley Arrow hitch, Brakesmart Brake Control
(wanna see? Here is a picture of it )
Fuel injectors are $71 each at Rock Auto. I would agree that the coil pack is a more likely culprit than the injector.
This is what sets the good dealers and shops apart from the mediocre ones....expertise in repair today is all about the diagnosis, less about the actual mechanical work. For the most part, changing the part is not that difficult, it's figuring out what's broken that's the hard part.
Engineer9860 wrote: When the spark plug fails to ignite the fuel/air mix, the exhaust will have an excess of hydrocarbons in it. This will be registered by the O2 sensor as a "rich" condition.
The O2 sensors do not read hydrocarbons. They read oxygen, hence the name oxygen senors.
When a cylinder fails to ignite the mixture the hydrocarbons and oxygen go into the exhaust. The O2 sensors can't see hydrocarbons, but they do read the extra oxygen and interpret this as being a lean condition.
Exactly right!!!. I was going to correct Engineer9860 last night, but you beat me to it!!!. Anyway, all modern On Board Diagnostics have very complex misfire detection algorithms. So much so, that they can even detect which cylinder is causing the trouble. When this happens, the PCM will cut out the single injector. This is so not to have unburnt fuel passing through the HOT catalytic converter (fire!!!). You were also dead on about the O2's reading more oxygen in the exhaust and therefor possibly setting a lean code on top of the misfire.
Another point to noodle is that these now very complex systems have
interdependencies and are now designed with whole system metrics.
Meaning the margins are orchestrated in concert much tighter than ever
before.
Meaning that one bad part/system can and will weaken to then take out
another component or system.
Foreign vehicles have slimmer design margins because of their whole
system orchestration and is 'one' aspect of how, why they ate
Detroit's lunch...but...with that slimmer margin comes less tolerance
for out of spec interdependencies. Detroit has learned this aspect
and am now seeing tighter or more intelligent design margins.
Meaning just changing parts might have you going in circles re-replacing
parts as the 'new' part has been stressed and now failing. A cascading
of aliments and failures.
Don't run in a lean condition long, as burnt valves just around the
corner if driven long and/or hard.
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