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fuel system troubles
Chrysler Dodge, Plymouth, Jeep, Eagle, etc info/talk (rec.autos.makers.chrysler)
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#31
 
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Re: fuel system troubles -
02-25-2007
, 04:49 PM
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bllsht wrote: On Sat, 24 Feb 2007 21:32:37 -0600, Robert Reynolds <robbie (AT) kcnet (DOT) com wrote: bllsht wrote: It won't set a mixture code if the fuel pump just 'up and quits'. It also won't set a code if the pressure is only slightly high or low. With gas pouring out of the tail pipe, it will NOT set a code because it'll likely never achieve closed loop and can't know what the mixture is doing. It will, however, definitely set a code if the pressure is off far enough that the PCM can no longer correct the mixture. If it's misfiring, it 'should' set a misfire code. However, if the battery has been disconnected and the adaptive numerator has not been relearned since, misfire detection will be disabled. It would also be disabled if the engine is operating outside the normal paramaters that misfire detection occurs in. OK, this is interesting because the battery has been in and out a couple of times as I worked on basic tuneup items. If disconnecting the power would disrupt normal codes, I'm starting to think it may be something more obvious like an oxygen sensor. Stop right there. Now, before you start thinking again, go back and read what you quoted. Now, tell me where I said disconnecting power would disrupt normal codes. That's right, I didn't say that. I said MISFIRE DETECTION would be disabled if the PCM hasn't relearned the adaptive numerator since the battery was disconnected. OK. Resume thinking and take it to somebody that knows what he's doing. First of all, I'm trying to learn something here, rather than just taking my van to an "expert". I'll admit that I have a lot to learn in life, and I'm not scared of car maintenance. So you can take your arrogant attitude somewhere else. If you can help, that's great because that's why we're all here. |
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How does the computer know there is a misfire? Does it read the activity of the coils? I know my engine is misfiring because it has poor power and will not idle. I also know that the ignition system is not misfiring because I pulled the wires off the plugs and watched the sparks jump to the spark plugs. So I'm assuming there wouldn't be a misfire code anyway. |
because you see a spark doesn't mean the ignition system is working
properly.
The PCM looks for changes in crankshaft speed to determine if there is
a misfire.
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What would be helpful is to know what other conditions might cause excessively rich running without setting a code. I looked for vacuum leaks but didn't find any. Any other suggestions? |
#32
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That is correct. That's why I have a full factory service manual for each of my vehicles and who knows how many dollars worth of tools and diagnostic equipment. And if you're wondering if you have a fuel pressure problem on a 96-99 minivan, your best diagnostic tool is a fuel pressure gauge 'cause your vehicle's computer simply won't tell you. On Feb 25, 8:00?am, "maxpower" <damnnickn... (AT) yahoo (DOT) com> wrote: Just because you get a fault code for a particular part does not mean that part is bad. If you have a fault code for a map sensor/TPS sensor or anything else does not mean those parts are at fault. It simply points you into a direction of the problem. A fuel system rich or lean does not condemn the fuel pump but points you in the direction of the problem. NO THERE IS NOT a fault code that simply says fuel pump is bad. Just like there is no fault code that says 02 sensor, TPS MAP and so on are bad.... Glenn Beasley Chrysler Tech |
#33
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You need to learn to read, dipshit. |
#34
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Unfortunately, manuals and diagnostic equipment don't fix cars. In the wrong hands they're useless, Dipshit. |
#35
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Exactly. That's why I bought mine instead of taking my cars to you. In typical usenet fashion, you can't or won't refute someone else's facts so you resort to name-calling. I'd kill-file you if it weren't so entertaining. |
would be set. Go back and read it again. If you still can't grasp it,
tell me what you're having trouble understanding and I'll type it
slower for you.
Or just kill file me and quit your whining.
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Robert, if you're still there, check your fuel pressure with a good gauge. If it's good, then you've eliminated a potential cause. If it isn't, then you've found the culprit. On Feb 25, 3:55?pm, bllsht <nos... (AT) dot (DOT) net> wrote: Unfortunately, manuals and diagnostic equipment don't fix cars. In the wrong hands they're useless, Dipshit. |
#36
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1999 Plymouth Grand Voyager 3.3 flex fuel model... I've had some trouble with this van's fuel delivery. The engine doesn't idle. It can be kept running only at a higher throttle setting. Also, it makes clouds of unburned gasoline from the exhaust. I found that after running it for a while, the exhaust manifold is cold at cylinder #2 and finger burningly hot at #6. Also, with my wife keeping the engine running, when I pull the wire off of plug #6 the engine suffers, but pulling #2 or #4 has no effect. The wires will deliver big fat sparks to the engine block as well as the head of the spark plug, but obviously the spark is not doing anything in the engine. My assumption was that #2 and/or#4 injectors are delivering way too much fuel. So my next test was to pull these two injector wires. When I do that, the engine will idle (poorly of course because of the dead cylinders). I assumed at first that the problem was in #2, then I thought it might be in 2 and 4, but then I tried leaving #2 in place and pulling #4, and it improved the situation enough to allow the engine to idle. Further testing showed that all 6 injectors had the proper clicking sound with a stethoscope. Checking the system with a scan tool shows no codes. Questions for inquiring minds that want to know: Would excessive fuel pressure set a fault code in the computer? If not, I'll get a fuel pressure gauge and test it. Otherwise, I could assume that one or possible two injectors are stuck open even though they are getting the proper signal indicated by clicking noises. Assuming that I have one or two bad injectors, can they be cleaned and fixed, or do they have to be replaced? The reason I ask is because they cost $75 each, they have to be ordered, and they won't arrive until Monday. If the ones I have can be rehabilitated I'll give it a try. One other thing, can anybody think of anything else that would cause this problem besides a drooling fuel injector? Before I started scrutinizing the injectors I had thought that it might be a vacuum leak, but I can't find a leak anywhere. |
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