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2001 shuttering to start, won't move in drive.

Discussion in 'Generation 1 Prius Discussion' started by C Clay, Jul 18, 2014.

  1. C Clay

    C Clay Member

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    Just a recap, in last 60 days:
    - replace hybrid battery
    -throttle position sensor
    -maf sensor (eBay version)
    -cleaned the throttle body
    -found 12v battery within specs on this forum.
    -replaced spark plugs
    -inspected Ignitors. And just now switch1 and 2 and and 3 and 4.


    I cleared codes after switching Ignitors.... Drove for 3 miles including up a hill. Check engine light came in going up that hill, began to flash.... Then went off. It is still off. My scangauge 2 shows pending code p0301.

    This car drives like a car that is not firing on cylinder or two in my opinion. If you give it more gas, it will start to vibrate in engine. Easy on the gas, you really don't feel then hesitation or vibration in the engine.

    Only other thing I notice now is some sort of mild clanging in the rear....maybe in the muffler or in front if spare tire compartment. (Is that where the fuel tank and pump is). In just reminding myself- I don't know what the fuel pressure is. That's a major clue right?
     
  2. ChapmanF

    ChapmanF Senior Member

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    The fuel pressure is one useful thing to know, but measuring it is kind of a PITA. My lazy approach is to put my elimination list in order with the things easier to test first. I'm not sure I'd connect the mild clanging and the fuel pump necessarily - too many things that could be. With the P0172, suggesting rich running, I wouldn't suspect there's a fuel starvation problem ... I'd wonder more about how clean the MAF is, or bad spray pattern/flow imbalance of the injectors.

    Have you done a poor man's spark test? (Also, if you wiped the igniters with solvent to inspect them, I'd suggest going back with a very water-soaked towel to rinse them well and dry them - compatibility of various plastics with various solvents can be iffy. If you haven't but you were about to, I bet you'd get them plenty clean with plain water or just a dab of mild detergent - mine don't really collect anything but dust, up there on top of the engine.) How about that fuel trim reading?

    -Chap
     
  3. C Clay

    C Clay Member

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  4. ChapmanF

    ChapmanF Senior Member

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    C Clay likes this.
  5. C Clay

    C Clay Member

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    Thanks Chap. Here you go!
    ImageUploadedByTapatalk1405986922.620300.jpg
     
  6. C Clay

    C Clay Member

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    Check engine light had been off. Drove 2 miles and engine light flashed then went back to solid on. These are the current values. I now have only code p0301.
    ImageUploadedByTapatalk1405987982.001682.jpg
     
  7. ChapmanF

    ChapmanF Senior Member

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    Eh, very close to nominal, nowhere near the ±20 limits ... no smoking gun there. Hmm.

    When you've cleared codes recently, have you just used the clear function on the scangauge, or interrupted the 12V power? I wonder if there might have been a different trim value that could have gotten reset recently in all the activity.

    Anyway, I guess that reading hasn't narrowed the solution set very much - sorry about nagging you for it. We still kind of have ignition or fuel delivery as lead suspects (compression being another possibility we haven't tested). The spark plugs don't look as bad to me as they do to Patrick (I think maybe it boils down to: I agree they show signs that bad combustion has been happening, but they don't look to me like the cause of it - they look like they would make sparks). Eric has seen bad ignitors cause these symptoms, and astrolink saw bad injectors cause them, so both of those possibilities are still in the lineup.

    If you can strip up a few inches of bare copper wire, the poor man's spark test is pretty quick to do. If you see visibly lousy (or no) spark from any plug/igniter combo, then you're onto something. If they all seem to make good strong sparks, they might not be totally off the hook (conditions are different inside the cylinder than in free air) but they might slide down the prime suspect list a little, and maybe injectors would float nearer the top.

    Hmm, I have a vague memory that by searching the forums you might find somebody's trick of coiling a thin wire around the igniter stem, reassembling things with the wire sticking out, and using it to confirm spark under real operating conditions. Wish I remembered more details.

    Possibly next you would want to try swapping in some known good igniters or known good injectors, whichever you felt like trying first; I would not be surprised if one or the other solved the problem. I do have one set of injectors reconditioned by Rich Jensen that go with his flow test results posted here. (He does supply new O rings and seals when reconditioning, and even pre-lubes the O rings.) I don't have any igniters.

    -Chap
     
  8. C Clay

    C Clay Member

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    The values did get up to 27-29 during that 2 mile drive. Not sure if that matters.
     
  9. C Clay

    C Clay Member

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    I haven't reset codes since I got put in the LF1 xgauge
     
  10. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Is the passenger side, carpet soaked?

    Bob Wilson
     
  11. C Clay

    C Clay Member

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    No
     
  12. ChapmanF

    ChapmanF Senior Member

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    Well, for comparison, I just now went and cold-started my 2001 and took it for a nice four-mile jaunt around town. The LF1 did vary slightly during the drive, but never once went outside of -5 to +5.

    If you saw 27 to 29, I think you saw a witness breaking down on the stand, pointing out in the courtroom at your fuel system and screaming hysterically. (Comments from others? Would numbers that high be equally consistent with a spark problem? Does unburned fuel in exhaust drive up the fuel trim too?)

    Now, to strictly avoid jumping to conclusions, that could be various things in the fuel system, not necessarily the injectors. A really dedicated measure-twice-cut-oncer would probably measure the fuel pressure next. Pragmatically, though, you'll find with the amount of work it takes just to unbury the fuel line connector that needs to be disconnected just to connect a pressure gauge, you could pretty much already have swapped all 4 injectors, and with not-perfect-but-fairly-decent odds have already solved the problem.

    -Chap
     
  13. C Clay

    C Clay Member

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    Is this a safe method to rule out that it is not the ignition coils?
     
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  14. ChapmanF

    ChapmanF Senior Member

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    I don't get to watch youtube at the office. What is it saying to do?

    -Chap
     
  15. C Clay

    C Clay Member

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    He is (in a lexus by the way), pulling up the ignition coils while the engine is running. Seeing what coil pulled makes no difference, he then determines if it doesn't make a difference-- that is the bad one.
     
  16. C Clay

    C Clay Member

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    I'm not a mechanic, and Its interesting how one diagnoses these things. But can I give a recap as to where we are now?

    In 36 hours- the only code I'm getting is P0301. I haven't cleared them either. I have driven it now 20 miles. Next affordable step- replace ignition coil before we chase down the fuel system pressure??
     
  17. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

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    That should be a way to do it with no problem however, the system is telling you which one is bad. Unplugging it won't rule out the injectors or any other thing that hasn't been ruled out to this point.
     
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  18. ChapmanF

    ChapmanF Senior Member

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    The misfire codes seem to move around a bit. If I remember right, you first had cylinders 1 and 2 indicated, then in a later post 1 and 4 (remind me, this thread's getting too long to scroll back and look! had you just moved any actual component from 2 to 4, or had you just taken some things out, put them back where they were, and that was enough to move the reported codes around?), and at the moment it's indicating 1 only. Also if I remember right, the first set of codes included P0300 to indicate multiple-cylinder misfires, or where the cylinder numbers are inconsistent.

    Hard failures of components directly associated with specific cylinders would be expected to give you more consistent codes for the same cylinders. I am leaning more toward conditions that are degraded or marginal more across the board, so that which cylinders show misfiring at a given time will depend on various unpredictable conditions.

    For most of this thread there were not very many smoking-gun clues collected, just a bunch of general indications of misfiring. Plus, you know which parts you have recently replaced - it's not impossible they could be bad, but that slides them farther down on the suspicion list.

    Last night, you finally did get one instrument reading outside the normal range by four to six times - something like getting a 300 MPH speeding ticket in a 55 zone. (I didn't notice until just now that you had a picture showing 19 LF1 - I must have been already typing my surprised response at seeing only 3 in your first picture). So we know that at times your ECM is calling for far longer injection pulses than it thinks it should have to, for the amount of fuel it wants.

    The ECM could be wrong, or it could be right. Wrong could be if the MAF is telling it way less air is going in than what's really going in, or the oxygen sensor is saying there's way more oxygen remaining in the exhaust than there really is. Or the ECM is right, it's getting accurate MAF and oxygen readings, and there is really less fuel coming out of a normal injection pulse than there should be.

    What to do next is an interesting choice, because more tests and data gathering are possible, and also some likely-suspect parts replacements are possible (even if you haven't strictly gathered all the data yet), and the choices all have costs (data gathering as well as part swapping) in both dollars and your effort, to try to estimate and weigh. And I'm sure you eventually want to be done fixing your car so you can just drive it, and for that to be soon so you don't have to add the catalytic converter onto the shopping list.

    Possible part swaps...

    Igniters - if you suspected one in particular you could buy just one, I'm sure you've priced them, are they around $60 or $70 online, each? Under $300 for four. Effort - easy.

    Injectors - reconditioned OEM should be about $85 for a set (this I know 'cause I have a set); effort - more than igniters, but not much more.

    Oxygen sensor - I haven't checked recent pricing, and never done one on a Prius so I can't speak to the effort.

    Possible further testing...

    Fuel pressure - tools required: fuel pressure gauge (injection style, range to 50 or 60 PSI or so), release tool for fuel pipe fitting, adapter to mate gauge to fitting. What the shop manual suggests (pp. SF-6, SF-7) for making the adapter is to buy a spare fuel pipe at the parts window and take it apart for the fittings, then use various hoses, barbs, and hose clamps. Effort - obtain and assemble the needed equipment, do enough disassembly in the engine compartment to gain access to the needed fitting - when I was doing my injectors I figured that effort had gotten me most of the way to being able to reach the fitting for a pressure test. So this is kind of a job - if you wanted the test and didn't have everything needed, it wouldn't be crazy to have a shop do it instead of DIY. Of course that cost has to be weighed.

    There are probably tests in the shop manual for how to confirm if a MAF or oxygen sensor is bad, but I'm not familiar with them.

    Of course every part swap has two possible outcomes, it allows you to rule out that part (good), or it solves your problem (better), and the probability it will do one or the other you can weigh along with the cost ... and for each choice to continue with testing before getting parts, there's the cost of the test weighed with the likelihood that it will or won't change what you're already thinking about what parts to ultimately buy.

    Isn't diagnosis fun? :)

    -Chap
     
  19. C Clay

    C Clay Member

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    I'm getting lost and cant figure out how to quote your text from above, but here's what I know today. I drove this car.. .this car that wouldn't start on Friday morning.... about 40 miles today.
    -The symptoms of misfiring went away as far as I can tell
    -I did clear codes before I started my journey, and my code today is P0171
    -My fuel economy is about 45 mpg
    -the LF1 value is about 13 when I start the car and it hovers up to 33-39.

    I was about to buy one ignition coil this morning from Amazon prime but I didnt notice the rough driving anymore. If I threw the scanguage away and pretend I never got here- I would think my car runs like it did before it stopped running on me.

    FYI- I did put some HEET in the car after reading this:
    Prius misfire problem - Toyota Nation Forum : Toyota Car and Truck Forums

    I don't know what to do next, I really don't. I've already replaced the MAF sensor, suppose I could replace it again. I could change the O2 sensor and go ahead and buy an ignition coil. Anything with the fuel system is over my head.

    Why don't I just drive a few days and come back with a new thread :)
     
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  20. C Clay

    C Clay Member

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    Thanks. What stumps me is the LF readings of 14-33.

    I'll get ignition coils, that's easy. Could that fix problem ?