Hard Start Throws Misfire Code
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Hard Start Throws Misfire Code
Hello, I have a 2005 F250 with the 5.4. This truck has been one thing after another, as you can tell from my other posts. The problem this time is, if it cranks hard to start because it's cold(can be anywhere from as high as 32, but usually in the teens) it will start just fine, then several minutes later throw the check engine light. Put the scanner on, like clockwork, 4 codes, always cylinder 1 misfire pending, misfire on first 1,000 revolutions pending, cylinder 1 misfire confirmed, misfire on first 1,000 revolutions confirmed. Sometimes you can hear a slight lope in the idle when it does this. Clear the codes, runs perfectly fine. It will never do it after it's been started for the day. Some days you would think for sure it would throw it when it's frigid and the winds been blowing on it, it doesn't bother, other days you wouldn't think it would, and it does. Any ideas? Can the computer think that since it didn't start right up, it misfired? Has anybody else ever experienced this? Thanks
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Yes, absolutely dry. I checked to make sure it wasn't trying to hydraulic. The plugs and coils were replaced a thousand miles ago with brand new Motorcraft plugs and Motorcraft coils. I've had this issue since I bought the truck 2 years ago, it only happened once in a blue moon, but with the new plugs and coils it seems more prevelant. The motor runs strong,never misses, has no clatter, and since the change of plugs and coils the fuel economy has gone up 3.5-4 mpg. It's more of a pain to have to constantly carry the scanner with to clear codes.
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From: FL
You can swap coils (#1 coil with #2 ) to eliminate the possibility of a bad coil issue . Double check wirings /plugs (both #1 coil and #1 injector ) fully engaged ? . Is #1 coil booth new? no arcing ? , remove and double check #1 spark plug , is it OK ?
If these are all fine , then focus on #1 injector . Then you need to run some diagnostics on #1 injector ( noid light tells you if injector #1 is getting power to pulse . You also need pressure/leak test on injector #1 to see if it is mechanically working OK . This test may require professional equipment ).
Good luck,
If these are all fine , then focus on #1 injector . Then you need to run some diagnostics on #1 injector ( noid light tells you if injector #1 is getting power to pulse . You also need pressure/leak test on injector #1 to see if it is mechanically working OK . This test may require professional equipment ).
Good luck,
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The coils, boots, and plugs are all brand new, properly torqued, fully snapped down, and no arcing. I feel if the injector was a problem, it would show up every time, not just when it's cold, and any cylinder with a weak injector would show up. The truck can sit for a day and do this, or sit for a week and not do it. If you think about it, cylinder 1 is the first to fire, the first to get fuel and air, the first to read compression, therefore the first to read back to the computer, and the first to misfire. If it cranks longer than the computer has figured for the temp, the computer will retard/advance the timing, resulting in a richer mixture to start, or leaner if it is too rich. The same as if the cylinder misfires, the computer will advance the timing, or retard it, to compensate for any hiccup. I'm beginning to wonder if there is a flat spot in the starter or in the alternator, resulting in an extensive draw on cold startup, but not always repeating itself.also, it can throw the codes, shut the truck off and clear them, start it again when it's still just as cold, and it won't throw them again. I'm not ruling anything out, but just trying to think outside the box.
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Why would it being cold have any effect on the injector? If it leaked down, wouldn't it leak down no matter what temp, resulting in a misfire at any temp?
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From: FL
Diagnostic work for misfire(s) is always a very challenging work . You need to approach it by testing every component systematically and then ruling it out .
Good luck,
Good luck,
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Its more than likely a very small leak that the pcm can compensate for. What might be happening as as it sits that fuel leaks on top of that valve or into the cylinder if the valve in open. Now if this is the case when you crank it up there is way too much fuel in number 1 and it cant light it all causing it to miss. Like I said flooding itself out, but its not bad enough to foul the plug so it comes out of it.
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Once the weather gets above freezing, ill do some more testing, as my outside garage is currently at zero. I started it this afternoon when it was zero, it has sat at least 24 hours, it cranked hard, more like a weak battery due to the cold, and when it started, the belt squealed, like the alternator working hard. Here's the thing, no code, no lope in the idle, and the squealing stopped in 20 seconds.
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paulcalif
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Jul 18, 2010 10:09 PM